Soil Development and its Relation to 

the Ages*of Morphostratigraphic Units 

in Horry County, South Carolina

U.S. GEOLOGICAL SURVEY BULLETIN 1589-B

Prepared in Cooperation with the U.S. Department 

of Agriculture, Soil Conservation Service

Chapter B

Soil Development and its Relation to 

the Ages of Morphostratigraphic Units 

in Horry County, South Carolina

By H. W. Markewich, M. J. Pavich, M. J. Mausbach, 

B. N. Stuckey, R. G. Johnson, and Virginia Gonzalez

Prepared in Cooperation with the U.S. Department 

of Agriculture, Soil Conservation Service

Soil profiles developed in 200-ka and 2.5- to 3.0-Ma 

barrier and back-barrier deposits have been analyzed 

texturally, mineralogically, and chemically to identify 

processes active in weathering and pedogenic alteration 

of parent material

U.S. GEOLOGICAL SURVEY BULLETIN 1589

PEDOLOGIC STUDIES IN THE EASTERN UNITED STATES 

RELATIONS TO GEOLOGY
DEPARTMENT OF THE INTERIOR 

DONALD PAUL MODEL, Secretary

U.S. GEOLOGICAL SURVEY 

Dallas L. Peck, Director

UNITED STATES GOVERNMENT PRINTING OFFICE: 1986

For sale by the Books and Open-File Reports Section, U.S. Geological Survey, 

Federal Center, Box 25425, Denver, CO 80225

Library of Congress Cataloging-in-Publication Data

Soil development and its relation to the age of morphostratigraphic units in Horry County, South Carolina.

(Pedologic studies in the Eastern United States, relations to geology) (U.S. Geological Survey bulletin ; 1589-B) 

Bibliography: p. 25 

Supt.ofDocs.no.: I 19.3:1589-8

1. Soils South Carolina Horry County Age. 2. Soil formation South Carolina Horry County. 3. Geology South 

Carolina Horry County. 4. Geology, Stratigraphic Cenozoic. 

I. Markewich1, Helaine W. II. Series. III. Series: U.S. Geological Survey bulletin ; 1589-B.

QE75.B9 no. 1589-B 557.3 s 85-600230 

[S599.S58] [552'.5]
PREFACE

Some geologic investigations of Quaternary deposits, especially in the conterminous 

United States, have attempted to use relative degrees of weathering and soil formation to 

establish chronosequences of glacial and (or) fluvial landforms. Most studies have been 

in the glacial terrane of the midcontinent and the Western United States. Few such studies 

have been conducted in the Eastern United States, especially in the unglaciated Middle 

Atlantic and Southeastern States.

From 1979 to 1984, the U.S. Geological Survey and the U.S. Department of 

Agriculture's Soil Conservation Service conducted cooperative regional studies of the 

relations between soils and geology in the Middle Atlantic and Southeastern States. The 

primary goal of these studies was to determine if soil properties could be used to estimate 

ages of associated landforms. Deposits associated with marine and fluvial terraces for this 

study and for previous geologic investigations were sampled for age determinations by 

isotopic analyses; these ages were then related to biostratigraphy and regional rockstratigraphic correlations. Specific site investigations were conducted on Pliocene to 

Holocene marine and fluvial terraces in the Atlantic and eastern Gulf Coastal Plains and 

the Appalachian Plateau. Soils on granite, schist, and quartzite parent rocks of the Appalachian Piedmont were sampled to test the use of soil properties as indicators of soil age. 

Each chapter of this bulletin series examines the relation of soils to geology in a specific 

geographic area.

The cooperative study involved research scientists from both agencies and field 

personnel from State offices of the Soil Conservation Service. Responsibility for sample 

analysis was divided between the Department of Agriculture's National Soil Survey 

Laboratory in Lincoln, Nebr., and the U.S. Geological Survey in Reston, Va. This report 

was prepared by scientists from both agencies who participated in specific site investigations or in studies of pedogenic processes.

Preface III

CONTENTS

Preface HI 

Abstract 1 

Introduction 2

Purpose and scope 2

Previous work 2

Geographic setting 4

Geologic setting 4

Acknowledgments 5 

Methods 5 

Results 6

Barrier soils 6

Back-barrier soils 7

Carolina bay soils 10 

Discussion 10

Tectonic control on topography and drainage 11

Textural and stratigraphic control on drainage 12

Argillic versus spodic horizons 12 

Spodic horizons (humates) 12 

Argillic horizons 14

Carolina bay and barrier soils 15 

Back-barrier soils 20

Age estimates 22 

Conclusions 24

Pedogenesis 24

Age determinations 25 

References cited 25 

Tables 1-18 29

FIGURES

1, 2A. Maps showing:

1. Horry County, South Carolina 3

2A. Morphostratigraphic units of Horry County, South Carolina 4 

2B. Cross section through the morphostratigraphic units of Horry County, South

Carolina 5

3. Plot of texture on clay-free base for barrier soils 8 

4-7. X-ray diffraction patterns for:

4. Pedon 001 9

5. Pedon 002 10

6. Pedon 003 11

7. Pedon 004 12

8. Plot of texture on clay-free base for back-barrier soils 14 

9-15. X-ray diffraction patterns for:

9. Pedon 012 16

10. Pedon 013 16

11. Pedon 014 17

12. Pedon 015 17

13. Pedon 006 18

14. Pedon 007 18

15. Pedon 009 19 

16. Plot of texture on clay-free base for Carolina bay soils 20

Contents V
17. X-ray diffraction patterns for pedon 010 21 

18-20. Summary plots of:

18. Thickness of sola and argillic horizons versus age of solum for all 

pedons 21

19. Thicknesses of Bt, BC, CB, and C horizons having values of 

chroma greater than or equal to six versus age of solum for all 

pedons 22

20. Clay mass versus age of solum for all pedons 22

21. Plot showing ratio of sand texture versus argillic horizon thickness for all 

pedons 23

TABLES

1. Correlation of upper Tertiary formations with morphostratigraphic units on the 

southwestern limb of the Cape Fear Arch 30

2A. Correlation of pedon number with morphostratigraphic unit and topographic 

position 30

2B. Analytical methods and units of expression for analyses conducted at Soil Conservation Service National Soil Laboratory 31

3. Pedon S80SC-051-001:

A. Field description 32

B. Textural analysis 32

C. Physical and chemical analyses 33

D. Bulk chemistry 33

4. Pedon S80SC-051-002:

A. Field description 34

B. Textural analysis 34

C. Physical and chemical analyses 35

D. Bulk chemistry 35

5. Pedon S80SC-051-003:

A. Field description 36

B. Textural analysis 36

C. Physical and chemical analyses 37

D. Bulk chemistry 36

6. Pedon S80SC-051-004:

A. Field description 38

B . Textural analysis 38

C. Physical and chemical analyses 39

D. Bulk chemistry 39

7. Pedon S81SC-051-006:

A. Field description 40

B. Textural analysis 40

C. Physical and chemical analyses 41

D. Bulk chemistry 41

8. Pedon S81SC-051-007:

A. Field description 42

B. Textural analysis 42

C. Physical and chemical analyses 43

D. Bulk chemistry of the <63-|mm fraction 43

9. Pedon S81SC-051-008:

A. Field description 44

B . Textural analysis 44

C. Physical and chemical analyses 45

D. Bulk chemistry of the <63-|m,m fraction 45

VI Contents
10. Pedon S81SC-051-009:

A. Field description 46

B. Textural analysis 46

C. Physical and chemical analyses 47

D. Bulk chemistry 47

11. Pedon S81SC-051-010:

A. Field description 48

B. Textural analysis 48

C. Physical and chemical analyses 49

D. Bulk chemistry 49

12. Pedon S81SC-051-011:

A. Field description 50

B. Textural analysis 50

C. Physical and chemical analyses 51

D. Bulk chemistry of the <63-|m,m fraction 51

13. Pedon S81SC-051-012:

A. Field description 52

B. Textural analysis 52

C. Physical and chemical analyses 53

D. Bulk chemistry of the <63-|Jim fraction 53

14. Pedon S81SC-051-013:

A. Field description 54

B. Textural analysis 54

C. Physical and chemical analyses 55

D. Bulk chemistry of the <63-|jim fraction 55

15. Pedon S81SC-051-014:

A. Field description 56

B. Textural analysis 56

C. Physical and chemical analyses 57

D. Bulk chemistry of the <63-|m,m fraction 57

16. Pedon S81SC-051-015:

A. Field description 58

B. Textural analysis 58

C. Physical and chemical analyses 59

D. Bulk chemistry of the <63-jxm fraction 59

17. Clay mineral trends-peak height ratios: 14.2 A/7. 2 A + 4.85 A for pedons 001, 

002, 003, 004, 010, 012, and 014 60

18. Altitude, age, and estimated uplift rates for individual barrier systems in Horry 

County, South Carolina 61

Contents VII

PEDOLOGIC STUDIES IN THE EASTERN UNITED STATES: RELATIONS TO GEOLOGY

Soil Development and Its Relation to the 

Ages of Morphostratigraphic Units in 

Horry County, South Carolina

By H. W. Markewich, 1 M. J. Pavich,2 M. J. Mausbach, 3 B. N. Stuckey,4 R. G. Johnson,2 and 

Virginia Gonzalez2

Abstract

Soils of the lower Coastal Plain in Horry County, South 

Carolina, were sampled to determine whether their chemical, 

mineralogical, and morphological properties are related to soil 

age. These soils have developed on marine barrier and backbarrier deposits that paleontological data indicate are 200 ka 

(Conway and Jaluco barrier systems) and 2.5 to 3.0 Ma (Horry 

barrier system). These three barrier systems are the major morphostratigraphic units of barrier systems present on the southern limb of the Cape Fear Arch, which has affected deposition 

and deformation of Coastal Plain sediments at least since the 

Cretaceous. The late Cenozoic tectonic history of the arch is 

not known in detail, but previous studies have suggested regional uplift throughout the Neogene. The present topographic 

positions of barriers and back barriers are due to either eustatic 

changes in sea level, regional uplift, or a combination of the 

two.

Barrier deposits consist predominantly of well-sorted, 

fine-grained and very fine grained quartzose sand; interbeds of 

sandy clay and clay range from less than 1 to 5 m thick. Barriers 

of the Horry system have crest heights of 30 to 40 m, the 

Conway barrier reaches a maximum altitude of 17 m, and the 

Jaluco barriers have heights up to 12 m. The preserved topography is similar on all barriers. The Horry barrier system is 

somewhat more dissected and is more deeply incised than the 

Conway or the Jaluco barrier systems. Carolina bays are ubiquitous on the sandy surfaces of the barrier systems. Humates (or 

spodic horizons) are present within many of the barrier sands 

and are almost always associated with Carolina bays.

Field descriptions of Horry back-barrier soils indicate 

argil lie horizon thicknesses ranging from 60 to 90+ cm. Textural and microfabric data indicate that many of these soils 

have argillic horizons thicker than 150 cm. These soils are 

therefore considered to be Paleudults, whereas soils on the 

Conway and Jaluco back barriers are Hapludults. Well-drained 

barrier soils of the Horry, Conway, and Jaluco systems all clas-

'U.S. Geological Survey, Doraville, GA 30360.

2U.S. Geological Survey, Reston, VA 22092.

3U.S. Department of Agriculture, Soil Conservation Service, National Soil Survey Laboratory, Lincoln, NE 68508.

4U.S. Department of Agriculture, Soil Conservation Service, Columbia, SC 29201.

sify as Hapludults. Soils developed on the 200-ka Conway and 

Jaluco systems are similar both physically and chemically to 

those developed on the 2.5- to 3.0-Ma Horry barrier system. 

Data indicate that soils on the Horry barrier system have 

bisequal development; our samples were from the surface horizons only and do not represent the full profile.

Two sample sites were near or on the rims of Carolina 

bays on terraces of the Little Pee Dee River. The differences in 

dominant grain size and sorting of the parent material preclude 

a direct comparison of soils developed on barriers with those 

developed on Carolina bays. The characteristics of Carolina 

bay soils, however, appear to be more like those of the Conway 

and Jaluco barrier soils than the Horry barrier soils. By inference, then, soils associated with the Carolina bays are apparently nearer 200 ka than 2.5 to 3.0 Ma.

All the soils developed on the Horry, Conway, and Jaluco 

barrier systems and on Carolina bays have an accumulation of 

low-charge hydroxyinterlayer dioctahedral vermiculite in the 

upper parts of their profiles; kaolinite dominates the lower 

horizons and the parent material. Gibbsite and goethite as well 

as quartz are present in the clay-sized fractions. Halloysite is 

present in soils of each age that have significant Bt horizons. 

Although halloysite appears to be an indicator of in situ development of clay, its presence or absence seems to be associated 

more with drainage conditions than with the ages of sola.

Only a few pedogenic parameters were found to be useful for estimating soil and surface ages. The position of Bh or 

spodic horizons within the profile may indicate differences in 

profile ages, but not enough is known about the origin of 

spodic horizons to allow their use for age determination. The 

thicknesses of sola and argillic horizons and the mineralogies 

of the <2-(jim fractions all show trends with increasing age, but 

they also are related to drainage, as the soils containing high 

percentages of medium-grained to very coarse grained sand 

illustrate. The lack of thick argillic horizons in the barrier sands 

may be the combined result of excessive drainage, little inherited clay, and a small percentage of weatherable minerals. 

Microfabric analysis of back-barrier profiles proved to be the 

most reliable indicator of the depth and degree of sand, silt, 

and clay translocation and may prove reliable for estimating 

soil age.

Soils and Morphostratigraphy in Horry County, S.C. 1
INTRODUCTION 

Purpose and Scope

Soils and weathering profiles in Horry County, South 

Carolina, were studied as part of a regional investigation of 

the relations between geomorphic surfaces of late Cenozoic 

age and associated soils and weathering profiles in the 

Southeastern United States. The lower Coastal Plain of 

South Carolina (fig. 1) was selected as an initial study area 

because sufficient stratigraphic data are available to establish the ages of the marine-barrier and back-barrier deposits 

on which study sites were located. Soils were sampled from 

200-ka and 2.5- to 3.0-Ma barrier systems. Two study sites 

were on the rim area of Carolina bays developed on a terrace 

of the Little Pee Dee River. The ages of Carolina bays have 

not been determined, but evidence suggests that they may be 

between 60 and 120 ka (Markewich, 1985).

Soil horizon designations and descriptive terminology 

used in this report follow the Soil Survey Manual (Soil 

Survey Staff, 1981). Microfabric terminology follows 

Brewer (1976).

The goal of this project was to assess the usefulness 

of soil- and weathering-profile data (both physical and 

chemical) in establishing the ages of land surfaces in the 

Southeastern United States. Specific objectives in Horry 

County included comparing barrier and back-barrier deposits to gain a more complete understanding of processes 

involved in soil formation. Of particular interest was the 

study of pedogenic processes active in soil formation in very 

sandy siliceous parent material in humid-temperate to subtropical environments. The effects of poor internal drainage 

on pedogenic processes were also studied.

Physical and chemical analyses of the soil and weathering profiles are presented in tables 3 through 16. These 

data are compared with published data from Horry County 

and from sediments of similar age in southeastern Virginia 

to determine if such data can be used to estimate ages of 

constructional landforms in the Southeastern United States. 

We suggest that the texture of parent material and the position of the local water table determine the course of soil 

development, and we discuss the evidence for in situ development of clay from alteration of aluminosilicate minerals 

and from authigenesis within argillic horizons.

Previous Work

The late Cenozoic history of the Coastal Plain of 

North and South Carolina in the area of the Cape Fear Arch 

has been of interest to researchers since the late 1800's. Dall 

and Harris (1892) contributed to the stratigraphic framework 

of upper Miocene and Pliocene units in the Atlantic Coastal 

Plain. Most of the investigations in this region after 1940 

were concerned with bivalve biostratigraphy of the Pliocene 

and Pleistocene marine beds. Results of paleontological investigations have been presented by DuBar and Chaplin 

(1963), DuBar and Howard (1963), DuBar (1971), DuBar 

and others (1974a, b, 1980), Ward and others (1978), and 

Blackwelder and Ward (1979). Hazel (1971, 1977, 1983) 

and Cronin and Hazel (1980) determined ages and correlation of the Pliocene and lower Pleistocene of Virginia and 

North Carolina by using ostracode biostratigraphy. Cronin 

(1980) and Cronin and others (1984) summarized the correlation of Pleistocene marine deposits and sea levels of the 

Southeastern United States by using ostracode taxa and concurrent ranges and published planktic, paleomagnetic, and 

radiometric data. Oaks and DuBar (1974) tentatively correlated all post-Miocene units in the Atlantic Coastal Plain 

south of Virginia. Mixon and others (1982) evaluated the 

uranium series dating of mollusks and corals in the 

Chesapeake Bay region; their observations are applicable to 

other isotope ages from the Atlantic Coastal Plain.

MacNeil (1950) referred to Hint's (1940) excellent 

summary of the work by "McGee, Darton, Shattuck, Salisbury and Knapp, Wentworth, Campbell, and Cooke" on 

Pleistocene sediments of the Atlantic Coastal Plain. Cooke 

(1930,1931, 1936,1937, 1945; Cooke and MacNeil, 1952) 

can be credited with establishing the terrace concept of 

mapping the Pliocene and Pleistocene deposits of the Atlantic Coastal Plain. His model of seven terraces, each corresponding to a high stand of sea level, has dominated 

geologic investigations in this region for more than half a 

century. Cooke was opposed by many, but the most direct 

rebuttal came in 1940 from Flint, who claimed that there 

were only two or three recognizable marine scarps in the 

lower Coastal Plain and therefore only two or three terraces. 

Flint did not actually accept the concept of terraces, which 

he felt were not mappable with any degree of certainty by 

using concordant altitudes. Cooke thought that Hint's definition was too rigid, and he added a possible eighth terrace 

to his model (Cooke, 1945). Doering (1960) revised 

Cooke's model and brought some gulf coast terminology 

into the Atlantic Coastal Plain. Many of Doering's ideas, 

especially concerning age and correlation of the highest 

terraces, influence present work in the region.

Despite differences in the number and origin of terraces on the Atlantic Coastal Plain, each investigation considered terraces to correspond to high stands of sea level 

during interglacial periods. Explanations for the association 

of increased altitude with increased terrace age varied between successively lower sea-levels stands, continual uniform regional uplift of the southeastern Atlantic coast during 

the Pliocene and Pleistocene, or a combination of both. 

Doering (1960), Daniels and others (1966), Thorn (1967a, 

1970), Daniels and Gamble (1974, 1978), Harris and others 

(1979), and, more recently, Cronin (1981), Seller (1983), 

and Markewich (1985) all discussed the geomorphology and 

late Cenozoic tectonics of the Coastal Plain in the area of the 

Cape Fear Arch, but most of the areas of interest were in the 

middle and upper Coastal Plain of North Carolina. Only

2 Pedologic Studies in the Eastern United States
79°30' 78°30'

-=^5. T^~ Green Swamp

WILLIAMSBURG CO K2.-~. GEORGETOWN CO-- f;,,

ATLANTIC OCEAN

5 10 15 20 25 MILES 

I I I I

I I 

0 5 10 15 20 25 KILOMETERS

Figure 1. Horry County, South Carolina, study area.

Johnson and DuBar (1964) and Thorn (1967a, 1970) were on late Cenozoic tectonic activity are available for the area

interested in the geomorphology of Horry County and other in and around Horry County, but Winker and Howard

areas on the southern limb of the Cape Fear Arch. No data (1977) suggested that the Cape Fear Arch has been an active

Soils and Morphostratigraphy in Horry County, S.C. 3
10 KILOMETERS

Figure 2A. Morphostratigraphic units of Horry County, South 

Carolina (modified from DuBar, 1971, p. 6). Site locations are 

identified by the last three digits of their pedon numbers. Location of cross section on figure 28 is shown by line A-A'.

feature throughout the Pliocene and Pleistocene and that all 

but the youngest marine terraces are warped upward in the 

area of the arch.

Thorn (1967a, 1970) discussed the geomorphology of 

fluvial and marine features in Horry and Marion Counties, 

South Carolina, and of the ubiquitous Carolina bays. 

Thorn's (1967a) report is particularly relevant to this study. 

His data on the age and depth of weathering of the fluvial 

and marine units of Horry County, coupled with the stratigraphic control provided by DuBar and others (1980) and by 

the unpublished data of J. P. Owens, provided the geologic 

framework necessary to attempt an investigation into the 

variations in degree and type of weathering and soil development within this region.

Daniels and others (1971, 1978b) first suggested that 

marine and (or) fluvial surfaces in the North Carolina 

Coastal Plain have remained essentially unmodified since 

their formation. For many of the surfaces, the time intervals 

involved are 3 to 5 Ma. Many of the soils on these surfaces 

have developed without interruption over these time intervals. Gamble (1965) and Gamble and others (1970) investigated the origin of the sandy surficial horizons associated 

with many of the upper and middle Coastal Plain soils in 

North Carolina. These soils, which occur throughout the 

Coastal Plain of the Atlantic and Gulf Coast States, are 

developed on parent material estimated to be as young as 

middle Pliocene and have surface horizons 1 to 3 m thick.

Thorn (1967a) suggested that soil profiles developed in barrier sands as young as late Pleistocene in age can have 0.5- 

to 1.0-m-thick sandy surface horizons that contain 

micropodzolic or bisequal profiles.

Although there is a great deal of literature on the 

processes involved in podzolization and the formation of 

Ultisols, very little data are available on soil chemistry, soil 

physics, clay mineralogy, or soil genesis of the Ultisols in 

the Coastal Plain of South Carolina (Coleman and Jackson, 

1945; McCollum and McCaleb, 1954). Ingram and others 

(1959) discussed the clay mineral assemblage found in some 

of the Carolina bays. Bryant (1965) provided detailed descriptions and some analyses of soils associated with Carolina bays in Scotland County, North Carolina, about 80 km 

northwest of Horry County, South Carolina. Malcolm 

(1964) investigated the interactions between mobile soil organic matter, clay minerals, and sequioxides in several Carolina soils. Swanson and Palacas (1965) analyzed humate in 

the coastal sands of northwestern Florida, and Daniels and 

others (1976) studied humate within the zone of pedogenic 

modification in the Coastal Plain of North Carolina. Thorn 

(1967b) discussed the relations between humate and coastal 

geomorphology of northeastern South Carolina. He concluded that the elliptical features called Carolina bays that 

are ubiquitous on the land surface of Horry and Marion 

Counties, South Carolina, formed where humate had developed, but he did not present any data on age(s) or origin of 

humates or on the chemical processes involved in their 

formation.

Geographic Setting

Horry County (fig. 1) is the northeasternmost county 

in South Carolina and is bordered on the east by the Atlantic 

Ocean, on the north by North Carolina, and on the west and 

south by the Little Pee Dee and the Pee Dee Rivers. Thorn 

(1967a) has discussed in detail the agricultural and botanical 

history of the area, which was first settled in the early 

1700's and has been agriculturally active ever since. Horry 

County is in the Coastal Plain physiographic province of 

Fenneman (1938) and in the "lower Coastal Plain" physiographic subprovince as defined by Colquhoun (1969, p. 3), 

"a surface that is dominantly one of primary topography." 

Altitudes in the county range from sea level to about 33 m. 

Maximum relief is 15 m. Most of the constructional landforms are marine in origin and were formed when relative 

sea level was higher than it is at present. The majority of 

ancient barriers, spits, and back-barrier flats are parallel or 

subparallel to the present coast (fig. 2) and have been modified only slightly by erosion.

Geologic Setting

Horry County is located on the southwestern limb of 

the Cape Fear Arch (or the Carolina Arch as defined by Dall

4 Pedologic Studies in the Eastern United States
Pleasant Hill

(Daisy Strand)-

Nakina barrier

2.5

EXPLANATION

Wando Formation 

90 ka-recent

Socastee Formation 

200-500 ka

Canepatch Formation

Waccamaw Formation 

1.5 Ma

Bear Bluff Formation 

3-4 Ma

Figure 2B. Cross section through the morphostratigraphic units of Horry County, South Carolina.

and Harris (1892)). The surface deposits are early Pliocene 

in age or younger. Morphologically, the sediments comprise 

a series of barrier and back-barrier complexes or systems. 

The Horry barrier system (2.5-3.0 Ma) is the oldest morphostratigraphic feature that has recognizable constructional 

landforms. The Horry and Jaluco barrier-back-barrier system and the Conway back barrier are underlain by a 

coarsening-upward sequence of marine clay, silty clay, and 

sand (Thorn, 1967a, b). The surface layer of fine- to 

medium-grained sand in the barrier complexes is rarely 

more than 5 m thick and is usually less than 3 m thick. The 

barriers are composite and form a broad multiridge area 

several kilometers wide. Unlike the Horry and Jaluco barriers, the Conway barrier is composed entirely of sand and is 

only one ridge wide. Maximum width of the Conway barrier 

is about 2 km.

All post-middle Miocene strata in the South Carolina 

Coastal Plain consist of unconsolidated sand and beds of 

fossiliferous clay, marl, limestone, and lenses of partially 

indurated sandstone. Gravels are present as lenses and (or) 

thin beds throughout the section. Each formation ranges 

from 9 to 15 m thick, except for narrow channel fills in 

excess of 30 m thick. McCartan and others (1982) showed 

that, on the basis of biostratigraphy and (or) isotope or 

amino acid chronology, three or four major marine transgressions onto the mid-Atlantic Coastal Plain occurred during the Pleistocene. In Horry County, sediments are preserved from at least two of these transgressions and from 

one transgression considered to be Pliocene in age. Age 

determinations of the Pliocene and Pleistocene marine deposits are based largely on paleontological evidence, as the 

section entitled "Previous Work" notes.

Table 1 shows several interpretations of Pliocene and 

Pleistocene stratigraphy on the southwestern limb of the 

Cape Fear Arch. Included in this table is J. P. Owens' (oral 

communication, 1984) current interpretation, which is 

based on recent geologic mapping of the Florence I°x2° 

quadrangle. This work is still being revised as paleontologic, lithostratigraphic, and radiometric data are generated. 

Two differences between DuBar and others' (1980) interpretation and that of Owens are (1) Owens' association of 

the Horry barrier system with the Bear Bluff Formation 

(middle Pliocene) rather than with the Waccamaw Formation (lower Pleistocene) and (2) the fact that Owens considered the Jaluco barrier system to be the seaward extension 

of the Conway barrier system (as originally proposed by 

Thorn, 1967a).

Acknowledgments

We would like to express our appreciation to J. P. 

Owens, R. B. Mixon, and J. T. Hack of the U.S. Geological 

Survey and R. A. Daniels and Klaus Flach of the U.S. 

Department of Agriculture's Soil Conservation Service for 

their initiative in suggesting a cooperative project between 

the two agencies and for their encouragement throughout the 

study period. We also extend our thanks for the assistance 

of Soil Conservation Service field personnel in sampling the 

study profiles. Travis Dudley and Don Hallbick helped to 

select and describe the field sites.

METHODS

To compare soil and weathering profiles on the 

Pliocene and Pleistocene age barriers and back barriers, 12

Soils and Morphostratigraphy in Horry County, S.C. 5
profiles were sampled from the least-modified positions on 

the barrier crests and in the back-barrier flats. These barrier 

systems range in age from 200 ka to 3 Ma. The ages of two 

profiles from rims of Carolina bays have not been determined, but the bays are considered to be no older than 

200 ka (Markewich, 1985). Table 2A lists the profile numbers and their associated morphostratigraphic units. All soil 

pedons were described and sampled by the authors and local 

Soil Conservation Service (SCS) personnel. Pedon numbers 

are SCS standard notation, which gives the year, the state 

abbreviation, the county number, and the pedon number in 

the county (for example, S80SC-051-001). Pedons discussed in this report are referred to by the last three digits of 

their complete pedon numbers. (Note that there is no pedon 

005.) Horizon designations and descriptions follow the format used in the Soil Survey Manual (Soil Survey Staff, 

1981). Samples were sent to the SCS National Soil Survey 

Laboratory (NSSL) in Lincoln, Nebr., where they were 

split; one set was then sent to the U.S. Geological Survey 

(USGS) laboratories in Reston, Va., and the other was retained by NSSL. Analyses conducted at the NSSL 

(table 28} include textural analyses, cation exchange capacity, pH, and base saturation. The USGS laboratories performed X-ray diffraction on the <2-|xm fraction (glycolated, 350 °C, 500 °C; slurry mount on glass slide), bulk 

chemistry of the whole sample (and, in some cases, the 

<63-|xm fraction) by X-ray fluorescence, and oxalate extraction and atomic absorption of iron and aluminum. Diffraction patterns presented in this report represent untreated 

clay in an oriented mount.

X-ray fluorescence analyses of soil samples were performed on a Diano 8600 spectrometer5 after samples had 

been fused with lithium tetraborate. Major-element concentrations were then determined by comparing unknown intensities for each element with calibration curves prepared from 

USGS silicate rock standards (Flanagan, 1976), a method 

that usually results in relative errors of less than 5 percent. 

In the present study, many of the <63-|xm fractions were 

predominately quartz sand containing more than 90 percent 

SiO2 and thus exceeded the range of validity of the calibration curves. Samples high in SiO2 consequently were diluted 

by a factor of two with a low-silica standard, BHVO-1. 

This extra step decreased the relative precision of the determinations by 5 to 10 percent. Therefore, the chemical data 

presented for most of the horizons are semiquantitative at 

best. Despite high uncertainties, the analyses show trends of 

the major constituents from top to base of each pedon. 

Analytical data are presented in tables 3B-3D through 

16B-16D and are arranged roughly from oldest to youngest. 

Those data that are considered useful in establishing a relative and (or) absolute soil chronology are presented graphi5The use of brand names is for descriptive purposes only and does not 

imply endorsement by the U.S. Geological Survey.

cally later in this report (figs. 18-21). Data that characterize 

other soil properties such as water content or water retention 

are included in the tables but are not presented graphically 

or discussed in the text.

RESULTS 

Barrier Soils

Samples from profiles S80SC-051-001 and S80SC051-002 are from the Horry barrier, samples from profiles 

S80SC-051-003 and S80SC-051-004 are from the Conway barrier, and samples from profile S81SC-051-008 are 

from the Jaluco barrier. Where it was sampled, fine-grained 

sand constitutes approximately 60 to 80 percent of the surface sediments of the Horry barrier; total sand comprises 

about 80 to 95 percent (tables 3B, 4B). Fine- and mediumgrained sand are the dominant size fractions in the barrier 

sediments of the Conway barrier system (tables 5B, 6B). In 

the barrier sediments, these size fractions comprise 80 to 

90+ percent of the total sediment (60+ percent fine-grained 

sand, 25+ percent medium-grained sand) (tables 5B, 65). 

The Jaluco barrier sediments are about 90 percent sand. The 

fine-grained sand fraction comprises about 30 percent, the 

medium-grained sand about 45 percent, and the coarsegrained sand about 15 percent (table 9B).

Several of the barrier soils have humates or spodic 

horizons (pedons 003 and 008) (see tables 5A-5D, 9A9D). The spodic horizons all have more than 85 percent 

sand and less than 5 percent clay. Bulk chemistry of the 

spodic horizons is variable, and accurate values were difficult to obtain because of the organic matter and water content. Most totals sum to less than 90 percent (tables 5D, 

9D). In pedons 003 and 008, SiO2 values are anomalously 

low in all horizons except the Bh3 (see tables 5D, 9D). 

Anomalous values for SiO2 and A12O3 are most likely due to 

difficulties in preparing samples that are dominantly quartz 

sand. Fusion with lithium tetraborate may leave SiO2 in the 

crucibles. Results will therefore give anomalously low values for SiO2 . Future work on silica-rich pedons should result 

in more rigorous procedures for determining the elemental 

chemistry of these horizons.

To completely characterize pedons, both dry and 

moist bulk density values must be obtained for each sample 

collected. The bulk density data are not complete owing to 

the difficulties in obtaining clods in material composed of 

more than 95 percent uncemented quartz sand. For the samples measured, bulk density values of spodic horizons range 

between 1.6 and 1.7 g/cm3 (oven dry) (see tables 5C, 9C). 

This range is apparently more narrow than the ranges of 

other horizons within the same sola, but a greater data base 

is needed for accurate comparisons. The argillic horizons 

have bulk densities of 1.6 to 1.8 g/cm3 (oven dry); values for 

the A horizons are 1 to 1.6 g/cm3 (oven dry). Values for 

both the A and the argillic horizons are typical of Coastal

6 Pedologic Studies in the Eastern United States
Plain soils; it is also common for the surface and subsurface 

horizons in sandy Coastal Plain soils to have similar bulk 

density values.

Barrier soils contain only a few percent weatherable 

minerals, mostly potassium feldspar or muscovite in the 

light fraction. Although a few grains of hornblende and 

epidote are present, the heavy fraction is composed predominantly of minerals considered to be nonweatherable, particularly zircon and rutile. Quartz constitutes most of the sandand silt-sized fractions.

Soils developed on barriers of different ages appear to 

be similar, although both physical and chemical data suggest that soils developed on the Horry barriers may be 

bisequal and that the data presented represent only the upper 

parts of the profiles. Figure 3 shows horizon thicknesses and 

particle size distributions (clay-free base) of soil profiles for 

the five barrier soils that were sampled. Weight percent clay 

is superposed on the same plots. Solum thicknesses of soils 

developed on barriers range from 80 to 145 cm. Variation in 

weight percent clay in the B horizons is so great and nonsystematic that weight percent clay and (or) clay mass cannot 

be used as parameters for age determinations. For Horry 

barrier soils, these variations are from 12 to 16 percent (001) 

and 4 to 5 percent (002); for Conway barrier soils, 8.5 to 

12.5 percent (003) and 6 to 10.5 percent (004); and, for 

Jaluco barrier soil, 2 to 3.5 percent (008). Clay-mass data 

(grams of clay per square centimeter integrated through 

thickness of solum) show little relation to age in barrier 

soils: for Horry barrier soils, 5 (002) to 18 g/cm2 (001); for 

Conway barrier soils, 9 (003) to 12 g/cm2 (004); and, for 

Jaluco barrier soil, 3 g/cm2 (008). Values for cation exchange capacity divided by weight percent clay (CEC/clay) 

are the same (0.2-0.5) for both Horry and Conway barrier 

soils; the use of CEC data as an indicator of age is thus 

limited. (CEC data for the Jaluco barrier soil are anomalous 

and cannot be used for comparison (table 8C).)

Microfabric analysis (using Brewer's (1976) terminology) of the argillic and C horizons of the barrier soils 

shows that quartz dominates the skeleton grains in all the 

sola. In pedon 003 from the Conway barrier, the basic 

structure in the Bt2 (73-91 cm), the A'2 (91-105 cm), and 

the Bh21 (126-146 cm) horizons is granular. In the Bt2, 

clay films are both coating and bridging, and an opaque 

material is coating the clay. Skeleton grains in the A'2 

horizon are also coated with this opaque material. In the 

Bh21, horizon, grains are only partially coated. In pedon 

004, also from the Conway barrier, the basic structure of the 

Bt horizon (61-95 cm) is agglomeroplasmic, and the plasmic structure is skelsepic. Grains are coated with clay, and 

some have clay bridges. Clay is coated with an opaque 

substance. The C horizon (138-169 cm) in pedon 004 has 

3.6 percent clay, a granular basic structure, and some clay 

bridging between grains, all of which suggests that there has 

been translocation of clay into the C horizon.

Basic structure of the Btl horizon (74-98 cm) in 

pedon 001 from the Horry barrier system is agglomeroplasmic and has insepic plasmic structure. Basic structure of the 

C horizon (141-177 cm) is granular. The presence of some 

thin discontinuous clay bridges in the C horizon suggests 

that there has been translocation of clay at least to 177 cm, 

the maximum depth sampled. Basic structure of the Bt horizon (48-69 cm) from pedon 002, also from the Horry barrier 

system, is granular and has skelsepic plasmic structure. The 

C2 horizon (120-136 cm) of pedon 002 has only 0.8 percent 

clay and a granular basic structure. Skeleton grains of quartz 

are almost perfectly clean. The C3 horizon (136-173 cm) 

from pedon 002 has agglomeroplasmic basic structure and 

skelsepic plasmic structure. There is some clay bridging, 

which is obscured by opaque coats on clay. Almost all 

skeleton grains are coated. No microfabric data are available 

for pedon 008 from the Jaluco barrier.

Hydroxyinterlayer dioctahedral vermiculite (also referred to as HIV), kaolinite, and gibbsite are the predominant phases in the clay fractions of the barrier soil horizons 

as observed in other soils of the Eastern United States 

(figs. 4-7) (Douglas, 1977; Karathanasis and others, 1983). 

Halloysite is also present as a major component of the Bt 

horizons. Pedons 001 and 004 show that peak intensities of 

vermiculite and halloysite are inversely related and that halloysite is better developed in the lower parts of textural B 

horizons. Vermiculite is better developed in more permeable sandy A horizons. Quartz is present at various depths 

in the clay fraction and does not show a consistently stronger 

intensity in the uppermost A horizons. HIV (14.2 A) is 

present even in barrier soils containing less than 5 percent 

clay in the solum (fig. 5). Possible explanations for its 

presence are discussed later.

Back-Barrier Soils

Samples from pedons S81SC-051-006 and S81SC051-007 are from the Conway back barrier; samples from 

pedon S81SC-051-009 are from the Jaluco back barrier; 

and samples from pedons S81SC-051-012, S81SC-051- 

013, S81SC-051-014, and S81SC-051-015 are from the 

Horry back barrier. Very fine grained and fine-grained sand 

are the dominant size fractions in the back-barrier soils of 

the Horry barrier system (50 to 80 percent of total sediment) 

(tables 135, 14fi, 15fi, 16fi). In the Conway back-barrier 

sediments, the percentage of total sand varies from 4 to 70. 

Fine-grained sand is dominant, up to 47 percent; very fine 

grained sand and medium-grained sand range from 1.5 to 

15 percent (tables IB, 8B). The Jaluco back-barrier sediments show a fining-upward sequence from medium- to 

fine-grained sand (from 85 to 65 percent total sand) from the 

C horizon to the surface (table lOfi).

Back-barrier soils are significantly different from barrier soils in that they are dominantly silty clay loams. Figure 8 shows the clay-free texture of back-barrier soils. The

Soils and Morphostratigraphy in Horry County, S.C. 7
Ap 

E1 

E2

B21t

ISI

B22t9

B23t

25 50 

PERCENT FINER

75 100 25 50 

PERCENT FINER

75

Ap

E 

B2t

B3 

C1 

C2

2C3

o

100

0150

Ap 

A21 

A22 

B21t

B22t _,_

O

A2 3

N

O

Bh1 z

Bh21

Bh22

Bh3

25 50 75 

PERCENT FINER

100 25 50 

PERCENT FINER

75

Ap

A21 

A22 

B1

B2t 

O

33

B31 o 

B32

C

100

Figure 3. Weight percent clay and weight percents of silt and sand on a clay-free base for barrier pedons 001 (A), 002 (8), 003 

(C), 004 (D), and 008 (£). Horizontal lines show weight percent of clay (<2 (Jim) for each horizon. Vertical lines denote percent 

finer than 20, 50, 100, 250, 500, and 2,000 (xm on a clay-free base. Clay-free texture of each horizon is calculated by subtracting 

weight percent of clay; weight percents of coarser fractions are summed, and that sum is used as the denominator in recalculating 

the percentages of each silt and sand fraction.

weight percent of clay by horizon is also plotted. Solum 

thicknesses range from 135 to 200+ cm for the Horry backbarrier soils and from 104 to 170+ cm for the Conway 

back-barrier soils and are as much as 180 cm for the Jaluco 

back-barrier soil. Thicknesses of the argillic horizons as 

described in the field range from 46 to 90 cm for the Horry 

back-barrier soils and from 50 to 80 cm for the Conway 

back-barrier soils and are as much as 112 cm for the Jaluco 

back-barrier soil (tables 7A, 8A, 10A, 13A, 14A, 15A,

16A). CEC/clay percent values for the same soils are 0.2 to 

0.4 for the Horry, 0.2 to 0.5 for the Conway, and 0.2 to 0.3 

for the Jaluco (tables 7C,8C, 10C, 13C, 14C, 15C, 16C). 

Clay-mass data are 44 to 60 g/cm2 for the Horry, 68 to 

76 g/cm2 for the Conway, and 123 g/cm2 for the Jaluco. No 

age trends are evident in these data, except for thicknesses 

of argillic horizons.

If we assume that the clay curves shown in figure 8 

are representative of Horry back-barrier soils and ignore

8 Pedologic Studies in the Eastern United States
25 50 75 

PERCENT FINER

100

EXPLANATION

<2|j.m clay [&-&I 50-100 JJLITI very fine sand

2-20 |o.m fine silt [''.'./J 100-250 JJLITI fine sand

250-500 (Aim medium sand

- ;

[il||| 20-50 H.ITI coarse silt

>500 H.ITI coarse 

and very coarse sand

Figure 3. Continued.

field-designated horizons, then Horry back-barrier soils appear to have argillic horizons greater than 150 cm thick (for 

example, pedon 013 would have an argillic horizon 161 cm 

thick) (see table 145). Conway and Jaluco back-barrier soils 

have argillic horizons less than 120 cm thick. Thin-section 

analyses indicating that thick clay skins developed in the 

lower horizons of soils in Horry back-barrier sediments support the assertion that we have not sampled the entire argillic 

horizon of these pedons.

Microfabric study of pedon 006, developed in backbarrier sediments of the Conway barrier system, shows a 

vughy porphyroskelic basic structure and mosepic plasmic 

structure (terminology from Brewer (1976)) in the Bt horizons. The Cgl horizon shows an agglomeroplasmic basic 

structure and the same mosepic plasmic structure of the 

overlying Bt horizons. The Cg2 and Cg3 horizons have 

agglomeroplasmic basic and vosepic plasmic structures. 

The Bt horizon of the Jaluco back-barrier soil (pedon 009) 

shows the same vughy porphyroskelic and mosepic structures as the Bt horizons of the Conway barrier system. The 

BC horizon has agglomeroplasmic basic and vosepic plasmic structures, whereas the 2C has granular structure. The 

basic structure of the Bt and BC horizons in pedons 012, 

013, and 014 developed in Horry back-barrier sediments is 

agglomeroplasmic, and the plasmic structure is mosepic, 

except for the moskelsepic structure of the Bt2 horizon in 

pedon 013.

Microfabric studies show that quartz dominates the 

skeleton grains in all back-barrier and barrier profiles. Clay, 

clay-silt, silt, and sand flows are characteristic of C horizons 

in all back-barrier profiles. In Bt and Cl horizons of the 

back-barrier soils, the quartz grains appear to be pitted and 

in some cases highly fractured. Both the degree of fracturing 

and the number of pitted surfaces appear to decrease downward from the Bt to the Cl to the C2 and underlying horizons. The presence of a few labile minerals was noted. A 

few feldspar grains were observed in the Cg2 horizon (152- 

193 cm) of pedon 006, developed in Conway back-barrier 

sediments, and in the BCg horizon (134-180 cm) of pedon 

009, developed in Jaluco back-barrier sediments. Numerous 

hornblende grains were observed in the 2C horizon (196- 

243 cm) of pedon 013, developed in Horry back-barrier 

sediments.

The Btl and Bt2 horizons of back-barrier soils have 

nearly continuous clay skins in pores and (or) channels. 

Probably the most striking feature recognized from microfabric studies in the Bt3, BC, and C horizons of back-barrier 

soils is the thick, dark-red areas of oriented clay masses that

333

Figure 4. X-ray diffraction patterns for untreated samples from 

pedon 001. This profile shows upward increases in the peak 

intensities of vermiculite (HIV), gibbsite (G), and quartz (Q) and 

decreases in the peak intensities of kaolinite (K) and halloysite 

(H) above the Bt3. Illite (I) and goethite (Go) are also present. 

Peaks are measured in angstroms. Depths of horizons are in 

centimeters.

Soils and Morphostratigraphy in Horry County, S.C. 9
333

HIV K G H Q K Q

Figure 5. X-ray diffraction patterns of untreated samples from 

pedon 002. This profile shows upward increases in the peak 

intensities of vermiculite (HIV) and gibbsite (G). Kaolinite (K) 

and halloysite (H) intensities are strongest in the Bt horizon. 

Quartz (Q) peak intensity is strong in all but the BC horizon. 

Peaks are measured in angstroms. Depths of horizons are in 

centimeters.

appear to be disrupted clay-filled pores. These zones of 

oriented clay are highly contaminated with silt.

Clay mineralogy of the back-barrier sediments is 

dominantly kaolinite and gibbsite and lesser amounts of 

quartz, goethite, or other iron-oxide and mixed layer illite/ 

smectite (see figs. 9-15). Pedogenic HIV (14.2 A) increases 

toward the surface in all profiles except 007, which contains 

expandable illite/smectite to the surface. Data given in 

table 17 suggest that the peak height ratio of 14.2 A (HIV) 

to 7.2 A (kaolinite) +4.85 A (gibbsite) tends to increase 

toward the surface in all back-barrier soils. A plot of clay 

ratio versus KC1 extractable aluminum for pedons 012, 014, 

003, and 004 (see fig. 21) shows a decreasing amount of 

extractable aluminum and an increase in the clay ratio in the 

back-barrier profiles 012 and 014. This plot can be tentatively interpreted to mean that increased aluminum interlayering in HIV reduces the available extractable aluminum. 

This same trend is not seen in the barrier profiles (003 and 

004). (In agricultural areas, a decrease in extractable aluminum upward in the profile can also be related to liming.)

Carolina Bay Soils

Pedons S81SC-051-010 and S81SC-051-011 are 

developed on the rims of Carolina bays formed in the surface sediments of a terrace of the Little Pee Dee River. 

These soils appear to be less developed than any of the 

barrier or back-barrier soils, in agreement with their estimated age of less than 200 ka (see fig. 16 for plot of texture 

on clay-free basis). Parent material of the bay rim soils is 

dominantly medium- and coarse-grained sand-sized quartz 

(tables llfi, 125). For pedon 010, medium-grained sand 

comprises 40 to 50 percent, coarse-grained sand comprises 

21 to 36 percent, and fine-grained sand comprises 8 to 13 

percent of the sample by weight percent. In pedon Oil, 

medium-grained sand is 40 to 53 percent, coarse-grained 

sand is 14 to 19 percent, and fine-grained sand is 14 to 17 

percent of the sample. Pedon Oil has up to 21 percent silt 

in the solum below the A horizon. Pedon 010 has a maximum of 14.5 percent silt in the Bt horizon (63-96 cm) but 

less than 10 percent in the other horizons. One striking 

characteristic of pedon Oil is the high silt content (40 percent) in the first 18 cm below the land surface, a fourfold 

increase from the 10-percent silt in the subjacent El horizon 

(18-33 cm). The variation in silt content throughout the 

solum and parent material suggests that silt is an artifact of 

deposition and not the result of pedogenic processes. Possible explanations include the possibility that pedon Oil developed in a localized depression on a bay rim that has a 

"cap" of silt-sized loess and (or) colluvium. The origin of 

the silt in the Bt horizon of pedon 010 is also not easy to 

surmise, but the existence of such a fine-grained, 30-cmthick depositional layer may have facilitated the formation 

of an argillic horizon where it would not have developed 

otherwise.

We did not prepare thin sections of any samples from 

Carolina bay soils. X-ray diffraction patterns show that vermiculite, kaolinite, and gibbsite are all present in pedon 010 

(see fig. 17). Unlike the barrier soils (for example, pedon 

004) (fig. 7), pedon 010 shows vermiculite at a maximum 

in the Bt horizon, where quartz peak intensity is also at a 

maximum. Both HIV and quartz peak intensities decrease 

above and below the Bt horizon.

DISCUSSION

The soil and weathering profiles developed on the 

barriers and back barriers of Horry County are representative of the lower Coastal Plain of the southeastern coastal 

States and include Hapludults, Paleudults, Aquults, and 

Aquods (Soil Survey Staff, 1975). Hapludults and 

Paleudults (Red-Yellow Podzolics of the old classification 

system) are restricted to the better drained areas, usually at 

the dissected margin of a barrier, on a fluvial terrace several 

meters or more above local base level, or on the interfluves 

within the back-barrier part of the barrier-back-barrier system. The Horry back-barrier soils are within the Pale-Great 

Group of the Ultisol Order and have argillic horizons greater 

than 150 cm thick, whereas soils on the Conway and Jaluco 

back-barrier deposits are in the Hapl-Great Group and have 

argillic horizons less than 120 cm thick. As sampled, all 

well-drained barrier soils, regardless of age, classify as

10 Pedologic Studies in the Eastern United States
333

Figure 6. X-ray diffraction patterns of untreated samples from pedon 003. This profile shows an upward increase in the 

peak intensity of vermiculite (HIV) and upward decreases in the peak intensities of gibbsite (G) and halloysite (H). 

Kaolinite (K) peak intensity is greatest in the Bt1 horizon. Quartz (Q) is present throughout and does not show an upward 

increase in peak intensity. Peaks are measured in angstroms. Depths of horizons are in centimeters.

Hapludults. If the Horry barrier soils had been sampled to 

greater depths, the data probably would have shown them to 

have bisequal development and to be thick enough to be 

within the Pale-Great Group.

Aquults and Aquods have developed locally where 

water has ponded above a bed of sandy clay or clay. These 

soils are also characteristic of Carolina bays. Thorn (1970) 

thought that Carolina bays formed where sand cemented by 

disseminated organic matter had formed a relatively impervious substrata (humate or spodic horizon).

Jenny (1941) listed several factors in his formula for 

soil formation: climate, topography, parent material, biota, 

and time. Delcourt and Delcourt (1979) suggested that the 

vegetation assemblage of the coastal region of South and 

North Carolina alternated between boreal and temperate 

forest throughout the late Pleistocene. They found short 

periods of cooler, but not cold, climate. The factors of 

climate and vegetation are thus considered constant for the 

purposes of this study. We therefore focus our discussion on 

the remaining variables in Jenny's equation: parent material, 

topography (drainage), and time.

Tectonic Control on Topography and Drainage

One of the more puzzling aspects of the Pliocene and 

Pleistocene deposits in Horry County and in other parts of

the lower Coastal Plain is the remarkable preservation of 

primary topography associated with deposits that are paleontologically and (or) radiometrically dated as more than 

1 Ma. Even where they are deeply incised (12-15 m), 3.0- 

to 4.5-Ma shallow marine and estuarine deposits of the 

lower Coastal Plain are represented by relatively unmodified 

constructional landforms that reach altitudes of more than 

80 m (DuBar, 1971; Colquhoun, 1974; Markewich, 1985; 

J. P. Owens, oral communication, 1984). Cronin (1980, 

1981) suggested rates of uplift between 10 and 20 m/Ma 

during the Pliocene and Pleistocene for the middle and 

southeastern Atlantic Coastal Plain. Markewich and Seller 

(1983), Seller (1983), and Markewich (1985) suggested that 

differential uplift affected the Cape Fear Arch in the area of 

the Cape Fear River during the Pleistocene. Cinquemani and 

others (1982) suggested that Holocene transgression south 

of the Cape Fear Arch was characterized by frequent fluctuations in sea level. R. L. Weems (oral communication, 

1984; Weems and Lemon, 1984) has suggested that, during 

the Pliocene and Pleistocene, the South Carolina Coastal 

Plain experienced alternating periods of uplift and relative 

quiescence and an increase in the average rate of uplift from 

about 350 ka to the present. If the positions of the Horry, 

Pleasant Hill (Daisy Strand)-Nakina (see fig. 2; unit not 

sampled), Conway, and Jaluco barriers are plotted against 

age and if the maximum rates of uplift between periods of

Soils and Morphostratigraphy in Horry County, S.C. 11
333

HIV

C 

133-169

Figure 7. X-ray diffraction patterns of untreated samples from 

pedon 004. This profile shows upward Hecreases in peak intensities of halloysite (H) and kaolinite ^K). Peak intensities of 

vermiculite (HIV) and gibbsite (G) increase above and below 

the Bt horizon. Halloysite peak intensity is greatest in the Bt 

horizon. The peak intensity of quartz (Q) varies throughout the 

profile. Peaks are measured in angstroms. Depths of horizons 

are in centimeters.

deposition are plotted, then the hypothesis of periodic uplift 

throughout the Pliocene and Pleistocene is supported (table 

18). If this hypothesis is correct, then preservation of the 

morphologic forms of the Horry and younger barrier systems is due in part to periods of relatively slow rates of 

uplift, dissection, and erosion.

Vertical migration of water, a primary control on soiland weathering-profile development, is limited by the degree of dissection and incision of an area. This limitation is 

reflected in the profiles that characterize both the Pliocene 

and Pleistocene deposits. Well-drained and moderately well 

drained Hapludults and Paleudults are present only in areas 

of maximum relief, near the edges of barriers and fluvial 

terraces, where downward infiltration of water is relatively 

unimpeded. In less well drained localities, the type of pedogenic alteration and the specific weathering processes are 

not so easily identified, nor are the soils so easily classified. 

The edge effect and the problems in mapping and classification produced by that effect have been discussed by Daniels 

and Gamble (1967), who also presented examples of differences in soil development caused by local changes in parent 

material. Horry barrier system soil profiles exemplify the 

problems associated with such sites.

Textural and Stratigraphic Control on Drainage

The Horry and Jaluco barrier systems have subsurface 

lithologies of thin- to thick-bedded massive sandy clay and 

clay interbedded with thin- to thick-bedded sand and peat. 

In general, the sediments are poorly sorted. Surface sand of 

the Horry and Jaluco barrier systems is commonly less than 

3 m thick. Clay beds and discontinuous horizons cemented 

by disseminated organic matter underlie many of the local 

swamps, including numerous Carolina bays. In the Horry 

and Jaluco barriers, water moves rapidly through the surface 

sand but locally ponds on the underlying clay or cemented 

sand layers. The Conway barrier is sandier than either the 

Horry or the Jaluco barrier, and the Conway back barrier is 

less extensive than either the Horry of the Jaluco back barrier. Water appears to move to depth more easily in the 

Conway barrier than it does in the clay-rich Jaluco or Horry 

barrier.

Thorn (1967 a) reported that the Horry barrier sediments are weathered to depths exceeding 7 m, that the clay 

is locally weathered to a reddish color, that mottling is 

prominent, and that illuvial horizons in the Horry barrier 

sediments extend to depths of 2 to 3 m. In contrast, he 

showed that weathering in Conway barrier sediments and in 

sandier parts of the Jaluco barrier sediments extends to 5 m 

and that illuvial horizon depths range from 3 to 4 m. Our 

data show the depths of illuvial horizons in the Conway and 

Jaluco to be somewhat less than those reported by Thorn 

(1967a). Data from both studies indicate significant differences in weathering and pedogenic development between 

deposits that differ by an order of magnitude in age. Similar 

results were reported by Markewich and others (in press) for 

Pleistocene age sediments in the Coastal Plain of Virginia.

Surface drainage in the region parallels the barriers. 

Dissection and drainage density increase with altitude (gradient), which in Horry County is coincident with an older 

age of deposit. Both drainage density and depth of incision 

are most pronounced in the back-barrier part of the Horry 

barrier system (Thorn, 1967a).

Argillic versus Spodic Horizons

Spodic Horizons (Humates)

Two prominent soil-forming processes in the lower 

Coastal Plain soils of the Southeastern United States are 

accumulation of clay in argillic horizons and accumulation 

of organic acids in spodic horizons. In general, water movement plays an important part in podzolization in the middle 

and lower Coastal Plain (Daniels and others, 1978b). The 

argillic and spodic horizons are separated areally and in 

vertical profiles (Daniels and others, 1976). Argillic horizons tend to form in materials having textures finer than 

loamy sand. Spodic horizons form in sandy sediments 

where drainage is impeded. As Thorn (1967b, 1970) sug12 Pedologic Studies in the Eastern United States
gested, the spodic horizon can become a further impediment 

to drainage.

Pedons 003 and 008 have developed in sandy parent 

materials and are characterized by spodic horizons (or humates) (see tables 5B,9B). The importance of the texture of 

the parent material to the formation of humate-rich spodic 

horizons has been observed in the tropics. Leenheer (1980, 

p. 515) noted that, in the Amazon basin, "a spodic horizon, 

rich in humic material, is often found above a clay lens, or 

above clayey parent material which underlies alluvial 

sands." Leenheer also observed that the lack of clay in 

alluvial sand is important to the preservation of organic 

material. He contrasted spodic horizons with clayey 

latosolic soil horizons over which a thick near-surface organic layer does not form. He stated (Leenheer, 1980, 

p. 516) that

...the lack of this [litter] layer is indicative of 

more rapid decay processes than those which occur in shallow podzols. Presence of a brown A 

horizon 5-20 cm thick indicates sorption of soluble humic materials upon the yellow and red 

clays. Thus, because of more rapid decay and 

sorption, soluble humic substances do not occur in 

high concentrations in waters which drain latosols.

Thus, clays in the latosols play an important role in 

the sorption and decomposition of humic substances. If the 

soluble humic material is not decomposed near the surface, 

it can accumulate in a spodic horizon or pass into ground 

and surface water. Leenheer (1980) suggested that humic 

substances are relatively stable in the near-surface ground 

water of sandy podzols because of the lack of nutrients, 

light, and clay and because of the anaerobic conditions that 

inhibit oxidation. Near-surface aerobic conditions in a less 

sandy parent material result in more nutrients and light and 

greater degrees of sorption and oxidation.

The active movement of organic material from the 

surface to a spodic horizon at depth appears to be associated 

with pedons that contain less than 8 percent clay above the 

spodic horizon (Daniels and others, 1978a; DeConinck, 

1980), although it is not unusual for a spodic horizon to be 

present beneath argillic horizons that contain more than 

10 percent clay. One such profile is pedon 003, which has 

12.5 percent clay in the argillic horizon above the spodic 

horizon. It is not common, however, for a spodic horizon to 

be present beneath an argillic horizon having more than 15 

to 18 percent clay, such as Markewich and others (in press) 

reported in 200,000-yr-old marine sand on the Eastern 

Shore of Virginia.

In these anomalous cases, soluble organic material 

has either moved vertically through the profile and accumulated before formation of the argillic horizon or has moved 

laterally and been deposited by ground water beneath the

argillic horizon. In the latter case, lateral movement is always above a lower clay-rich horizon that has impeded 

downward drainage. This lower boundary is important in 

the formation of a spodic horizon, regardless of whether the 

mode of formation is from vertical or horizontal movement 

of water and humic substances. If there is no lower layer to 

impede downward migration of water, humic substances 

may migrate out of the system into the surface water, as the 

lack of a spodic horizon in pedon 002 shows, even though 

the Bt horizon of pedon 002 contains less than 8 percent 

clay. Detailed analysis of 14C activity and organic geochemistry might distinguish between vertically and horizontally 

transported organic matter.

Because bacteria may be important in converting 

lignin and other plant tissue to humus, a relatively low 

density bacterial population may be another factor facilitating the preservation of organic matter during transport. Bacterial population density appears to be limited by the surface 

area available on the substrata. This surface area would be 

minimum for a clean, well-sorted sand.

Low initial amounts of iron and aluminum and a parent material of well-sorted sand appear to provide ideal 

conditions for the accumulation and movement of organic 

chelators. Humic material in soil and sediments contains a 

high percentage of aromatic groups (Schnitzer, 1977; 

Hatcher and others, 1981), which may be most effective as 

chelators of aluminum and ferric iron owing to their high 

content of carboxyl groups and phenols (Wright and 

Schnitzer, 1963; DeConinck, 1980). Although soluble organic acids are continually leached from spodic horizons, 

the rate of leaching is probably limited by slow water movement at and below the water table. The precipitated organic 

acids are apparently immobile and chemically stable within 

the spodic horizon.

The clean barrier sand in which the spodic horizons 

form provides a parent material in which the chemical clayproducing pedogenic processes are limited. Unlike the 

argillic horizons observed on finer grained parent material, 

the spodic horizon is developed with relatively little mass 

change in the Bh horizon (Markewich and others, in press). 

There is no evidence for pedogenic loss of mass from the Bh 

horizon or for eolian input of clay or silt. Limited mass loss 

is important in preserving the original morphology of the 

older barriers over very long time periods (that is, greater 

than 106 yr). Transmission of humic material through the Bh 

horizon is the dominant pedogenic process acting on the 

landform and results in slight to no modification of the 

landform, in contrast to the pedogenic processes active in 

the formation of argillic horizons on less chemically stable 

parent material, such as the metavolcanic, metasedimentary, and plutonic rocks of the Appalachian Piedmont 

(Pavich, 1985). In the Piedmont, mass loss by dissolution 

combines with a relatively high rate of erosion to result in 

much less stable land surfaces.

Soils and Morphostratigraphy in Horry County, S.C. 13
25 50 75 

PERCENT FINER

25 50 75 

PERCENT FINER

100

50 

PERCENT FINER

25 50 75 

PERCENT FINER

Ap 

E

Bt1 

Bt2

o

33

BC1 o

BC2

100

Figure 8. Weight percent clay and weight percents of silt and sand on a clay-free base for back-barrier pedons 012 (/A), 01 3 (B), 

014 (C), 015 (D), 006 (E), 007 (F), and 009 (C). Horizontal lines show weight percent of clay (<2 JAITI) for each horizon. Vertical 

lines denote percent finer than 20, 50, 100, 250, 500, and 2,000 JAITI on a clay-free base. Clay-free texture of each horizon is 

calculated by subtracting weight percent of clay; weight percents of coaser fractions are summed, and that sum is used as the 

denominator in recalculating the percentages of each silt and sand fraction. Patterns are the same as those in figure 3.

Argillic Horizons microenvironments. Soil microenvironments, in general,

For the pedons analyzed in this study, the clay miner- are determined initially by local drainage conditions and

alogy of argillic horizons is discussed with respect to varia- textures of the parent material. Subsequent modifications of

tions of drainage conditions within horizons, or soil microenvironments are the result of changes in drainage

14 Pedologic Studies in the Eastern United States
Ap

50 

PERCENT FINER

25 50 75 

PERCENT FINER

100

EXPLANATION

50 

PERCENT FINER

<2(jim clay

2-20 (Jim fine silt 

20-50 (jinn coarse silt

O33

s

50-100 (Jim very fine sand

100-250 |jim fine sand 

250-500 |o,m medium sand

>500 jxm coarse 

and very coarse sand

BCG

Figure 8. Continued.

conditions and of physical and chemical alteration of the 

parent material by pedogenic processes. In the sandy barrier 

and Carolina bay soils, argillic horizons form as the result 

of eolian deposition of silt and clay, of textural differences 

due to primary stratification, or of accumulation of claysized grains at the upper surface of a zone cemented by 

colloidal silica and (or) organic acids.

Carolina Bay and Barrier Soils

Argillic horizons are present in most of the barrier and 

Carolina bay soils (pedons 001, 002, 003, 004, and 010). 

The parent material is quartz sand (85-98 percent by

weight) (tables 3B , 4B , 5B, 6B , 11B). This high percentage of sand and total SiO2 appears to inhibit formation of 

clay-rich horizons in barrier and Carolina bay soils. Lack of 

silt- and sand-sized aluminosilicates prohibits the formation 

of clay by alteration of original minerals. Colloidal suspensions and allophane are inhibited from forming because 

water can move freely downward through the solum and 

parent material, thereby reducing interaction time of soilwater solutions. The lack of allophane and colloid suspensions prohibits the formation of secondary products (clay 

minerals) through these pathways. Also, any eolian contribution of clay moves easily through the sand instead of 

experiencing the slow migration from the A horizon through

Soils and Morphostratigraphy in Horry County, S.C. 15
354

Figure 9. X-ray diffraction patterns of untreated samples from 

pedon 012. This profile shows upward increases in the peak 

intensities of vermiculite (HIV) and gibbsite (G). Kaolinite (K) 

peak intensity decreases above the Bt1 horizon. Halloysite (H) 

is present in the Bt1 horizon, and goethite (Go) is present in the 

Bt1 and BC horizons. Quartz (Q) peak intensities in the Ap and 

Bt1 horizons are weak. Peaks are measured in angstroms. 

Depths of horizons are in centimeters.

the E horizon into the underlying B horizon that is typical of 

most soils.

The result of these limitations on development of 

argillic horizons is that many stable surfaces mantled with 

parent material that is predominantly sand may be relatively 

old and may have undergone extensive weathering. The 

soils, however, lack argillic horizons thick enough to be 

classified as Paleudults on the basis of observations to 2 m. 

The sandy surface sediments of the barriers and bay rims 

may have extremely thick elluvial horizons in which 

micropodzols have developed. Thick illuvial horizons 

underlie many of these surface sands but at sufficient depth 

that either borrowpit exposures or drilling is necessary to 

prove their presence, particularly for any morphostratigraphic unit more than 1.0 m.y. old. The following paragraphs describe the argillic horizons from pedons that we 

sampled in barrier and Carolina bay sediments. The difficulty in classification is particularly evident from the descriptions of pedons 001 and 002 from the Horry barrier 

system and somewhat evident from the descriptions of pedons 003 and 004 from the Conway barrier.

354

Go K Q

Figure 10. X-ray diffraction patterns of untreated samples from 

pedon 013. This profile shows upward increases in the peak 

intensities of vermiculite (HIV) and gibbsite (G). Kaolinite (K) 

peak intensity is greatest in the Bt3 horizon. Quartz (Q) is 

present only in the Bt1 horizon. Peaks are measured in 

angstroms. Depths of horizons are in centimeters.

Carolina bay pedon 010. Pedon 010 is from the 

crest of the rim of a Carolina bay that has developed on a 

terrace of the Little Pee Dee River. The Bt horizon is 33 cm 

thick and has 6.4 percent clay (3.1 percent more than the 

underlying Bhl horizon and 5.2 percent more than the overlying Bw horizon) (table 11B). No clay skins are evident. 

The structure of the Bt horizon is single grain, as is the 

structure of the overlying Ap, E, and Bw horizons. The clay 

fraction of the Bt horizon is composed predominantly of 

vermiculite and quartz and minor amounts of kaolinite, 

gibbsite, and halloysite. In contrast, vermiculite and quartz 

are dominant above and below the halloysite-rich Bt horizon 

in barrier pedon 004. The small percentage of halloysite as 

a pedogenic phase in the Bt of pedon 010 could be explained 

by the absence of the labile minerals necessary to form 

halloysite and (or) the fact that vermiculite and clay-sized 

quartz are originally wind deposited and subsequently elluviated from the surface into subsurface horizons (fig. 17). 

The position of the Bt horizon is coincident with a silty

16 Pedologic Studies in the Eastern United States
G HQ Go K Q

Figure 11 . X-ray diffraction patterns of untreated samples from 

pedon 014. Vermiculite (HIV) peak intensity is greatest above 

and below the Bt horizons. Peak intensity of-halloysite (H) is 

greatest in the Bt1 horizon. Kaolinite (K) peak intensity is greatest in the BC2 horizon. Peak intensities of gibbsite (G) and 

quartz (Q) show slight increases upward in the profile. Goethite 

(Go) is present in the BC2 and C horizons. Peaks are measured 

in angstroms. Depths of horizons are in centimeters.

354 333

Figure 12. X-ray diffraction patterns of untreated samples from 

pedon 015. Vermiculite (HIV) peak intensity increases upward 

relative to kaolinite (K) and gibbsite (G) above the BC2 horizon. Maximum gibbsite peak intensity occurs in the Bt1 horizon, but it is also a major component of the Bt2 and BC1 

horizons. Goethite (Go) intensity increases downward below 

the Bt1 horizon. Quartz (Q) is present in the upper three horizons. Peaks are measured in angstroms. Depths of horizons are 

in centimeters.

horizon that could be the result of either original stratification and (or) eolian deposition. Both silt and clay could be 

accumulating above the relatively impervious spodic horizon.

Jaluco barrier profiles. Although the field description of pedon 008 from the Jaluco barrier system does not 

include an argillic horizon, particle size data indicate a 30- 

cm-thick horizon that has six to eight times more clay than 

either the overlying or the underlying horizons (table 95). 

This 30-cm-thick zone of clay maxima includes the Bh 

(31-41 cm) horizon and the Bw horizon (41-61 cm), which 

contain 3.4 and 2.4 percent clay, respectively. (The values 

of weight percent clay throughout the profile, however, are 

within laboratory precision for sandy soils having relatively 

high contents of organic matter.) The Bh horizon exhibits a 

subangular blocky structure, which is in contrast to the 

single-grain structure of the A and E horizons and the massive structure of the Bw and the underlying Bh horizons.

Despite the presence of 3.4 percent clay, no crystalline 

material was identified on X-ray diffraction patterns. Clay 

was either masked by the organic matter or not present.

Conway barrier profiles. On the Conway barrier, 

pedons 003 and 004 show similar thicknesses of Bt horizons 

(36 and 34 cm, respectively) and maximum clay percentages (12.5 and 10.5 percent, respectively) (tables 5B , 65). 

Pedon 003 has Bh horizons below the argillic horizon, 

whereas pedon 004 has BC and C horizons below the argillic 

horizon. They show only minor differences in original texture and mineralogy of parent material, and the surface slope 

at both sample sites is 0 to 1 percent. The resulting profiles 

are similar in physical and chemical parameters and in clay 

mineralogy (see tables 5A-5D, 6A-6D; figs. 6, 7).

The Bh horizons (105-190+ cm) in pedon 003 have 

ratios of fine-grained sand to medium-grained sand of 3:1 

and 4:1 in comparison to the 2:1 ratio in the BC horizons

Soils and Morphostratigraphy in Horry County, S.C. 17
354

G H Go K Q

Cg1 

104-152

Cg2 

152-193

Figure 13. X-ray diffraction patterns of untreated samples from 

pedon 006. Kaolinite (K) and vermiculite (HIV) are the predominant clay phases. Vermiculite increases in intensity upward 

from the Cg2 horizon to the Bt1 horizon but decreases relative 

to kaolinite in the Ap horizon. Gibbsite (G) is a minor phase 

and increases in intensity upward above the Btg horizon. 

Goethite (Go) is present throughout and reaches a maximum 

intensity in the Cg2 horizon. Peaks are measured in angstroms. 

Depths of horizons are in centimeters.

(95-138 cm) and the C horizon (138-169+ cm) of pedon 

004. In the Bt horizons (61-95 cm) of pedon 003, the ratio 

of fine-grained sand to medium-grained sand is 3:1; in the 

Bt horizon (61-95 cm) of pedon 004, the ratio is only 2:1. 

Pedon 003 shows no measurable fine-grained silt in the Bt2 

horizon or in the underlying Bh horizons. The Btl horizon 

shows a ratio of fine-grained silt to coarse-grained silt of 

1:3. Pedon 004 shows a ratio of fine-grained silt to coarsegrained silt of 2:1 throughout much of the solum. Similarly, 

pedon 003 has no measurable fine-grained clay in the profile, whereas pedon 004 has 0.8 to 4.0 percent fine-grained

3.33

Q

BCg2 

142-170

Figure 14. X-ray diffraction patterns of untreated samples from 

pedon 007. Kaolinite (K) is predominant throughout the profile. 

Vermiculite (HIV) and quartz (Q) show increasing peak intensities above the Bt1 horizons. Minor amounts of gibbsite (G), 

halloysite (H), and goethite (Go) are present in the Ap and Bt1 

horizons. Peaks are measured in angstroms. Depths of horizons 

are in centimeters.

clay distributed throughout the profile. The BC2 and C 

horizons of pedon 004 have no measurable coarse-grained 

silt (tables 5B, 65).

The clay phases present in the argillic horizons in 

pedons 003 and 004 are similar in that both have strong 

halloysite and HIV peaks, and kaolinite and clay-sized 

quartz are present in both pedons (figs. 6, 7). Thin sections 

show clay coats on all skeleton grains and some bridging 

between grains in the C horizon (138-169 cm) of pedon 

004, an indication that clay has been translocated below the 

BC2-C boundary at 138 cm. The top of the Bt horizon is at 

61 cm; therefore, if the clay distribution curves are accepted 

as criteria, the argillic horizon in pedon 004 is between 90 

and 150 cm thick.

Horry barrier profiles. Although the following 

paragraphs discuss pedons developed in Horry barrier 

sands, the data suggest that the horizons sampled are not 

completely representative of an Horry barrier soil or weathering profile. Thorn (1967a) indicated that the contact between the elluvial and illuvial horizons in Horry barrier soils 

was between 3 and 5 ft (1-2 m), that the illuvial horizons 

extended from 5 to 9 ft (2-3 m) deep, and that micropodzolic bisequa were not uncommon. One interpretation of the 

data presented herein supports Thorn's observations of deep 

weathering and elluvial-illuvial contacts in the Horry barrier

18 Pedologic Studies in the Eastern United States
354

K Q

BCg 

13<M80

Figure 15. X-ray diffraction patterns of untreated samples from 

pedon 009. Vermiculite (HIV) and kaolinite (K) are predominant throughout the profile. Vermiculite shows decreasing 

peak intensities relative to kaolinite above the Bt2 horizon. 

Gibbsite (G) shows an increase in peak intensity toward the 

surface. Quartz (Q) is present throughout and does not show an 

increase toward the surface. Lepidocrocite (L) is present in the 

Bt2 horizon, and goethite (Go) is present throughout the profile. Peaks are measured in angstroms. Depths of horizons are 

in centimeters.

sediments. If this interpretation is true, then our data could 

represent the upper part of a thick bisequal profile. The 

possibility of 3- to 8-m-thick bisequal soils on 106+-yr-old 

deposits should be considered in future work.

There is a strong contrast between pedons 001 and 

002 on the Horry barrier. The major difference between the 

two is in situ development of clay in the argillic horizon of 

pedon 001. Both gibbsite and halloysite are present in the Bt 

horizon of pedon 001 but not in the Bt horizon of pedon 002. 

The Btl and Bt3 horizons of pedon 001 show a strong 4.5-A 

reflection (fig. 4), interpreted to be a reflection from halloysite. This same peak was documented by Brindley and 

others (1963) and appears in the halloysite-rich horizons of 

weathering profiles from the Coastal Plain of the Middle 

Atlantic States investigated by Owens and others (1983).

Because of the peak intensity of halloysite in the Bt3 horizon 

relative to intensities higher in the profile, we interpret halloysite to be the result of in situ alteration of feldspar.

Owens and others (1983) did not find halloysite in the 

clay fraction of the Parsonsburg Sand, which they interpreted as eolian. D. R. Seller (oral communication, 1984) 

found halloysite at moderate depths (5-10 m) in weathered 

Coastal Plain sediments, but he did not find halloysite in 

clay fractions of eolian dunes adjacent to the Cape Fear 

River on the North Carolina Coastal Plain. Thus, the presence of halloysite in Horry County soils is taken as evidence 

for in situ clay formation (alteration of kaolinite) and not as 

an indicator of eolian activity. In the Horry and Con way 

barrier profiles, the intensity of the 4.5-A halloysite peak 

increases with increasing clay content in the Bt horizon 

rather than with the age of the solum. The low percentage 

of clay in pedon 002 and the lack of halloysite and gibbsite 

in pedon 002 (fig. 5) are apparently due to differences in 

argillic development in pedons 001 and 002.

The argillic horizon of pedon 002 was described in the 

field as 21 cm thick. This Bt horizon has 4.8 percent clay, 

only 0.4 percent greater than the overlying E horizon and 

2.8 percent greater than the underlying BC horizon. Quartz 

grains in the Bt horizon are coated with an opaque substance, probably iron, and have no bridging clay skins. Even 

if the E and BC horizons were considered to be part of the 

argillic horizon, the total thickness of that horizon would be 

only 60 cm, much less than the 100+-cm-thick argillic 

horizon of pedon 001 (tables 3B, 45).

Data indicate that local variations in the texture of 

parent material and (or) local drainage conditions (pedon 

001, 0 percent slope; pedon 002, 10 percent slope) are the 

dominant influences on pedogenic development and therefore on argillic horizon development. There is 13 to 15 times 

as much fine-grained sand as there is medium-grained sand 

in the solum and in the underlying parent material in pedon 

001. In comparison, the ratio of fine-grained sand to 

medium-grained sand is 3:1 in the solum and 7:1 in the 

parent material of pedon 002. There is more than 10 percent 

fine-grained clay in the Bt2 horizon of pedon 001 and less 

than 1.0 percent in the Bt horizon of pedon 002 (tables 3B , 

4B). Weaver (1975) suggested that fine-grained and very 

fine grained sand was the most reactive grain-size fraction 

coarser than 2 u,m. His data suggested that, in the humid 

tropics, silt was less significant as a source of dissolved 

silica than the fine-grained and very fine grained sand fractions were. Although the ratio of fine-grained silt to coarsegrained silt varies in the C horizons of the two pedons, the 

ratio in the argillic horizons is the same (1.4:1), an apparent 

corroboration of Weaver's (1975) findings. The 10-percent 

surface slope at the site of pedon 002 could be significant 

enough to enhance removal of dissolved silica and therefore 

impede development of pedogenic halloysite.

In all of the well-drained and moderately well drained 

soils of the southeastern Coastal Plain and Piedmont, the

Soils and Morphostratigraphy in Horry County, S.C. 19
50 

PERCENT FINER

25 50 75 

PERCENT FINER

EXPLANATION

<2|jim clay

2-20 jxm fine silt 

20-50 |a,m coarse silt

$$j£l 50-100 |jim very fine sand 

100-250 jxmfine sand 

250-500 (Jim medium sand

>500 jxm coarse 

and very coarse sand

increase in clay mass in the argillic horizons is associated 

with the increase in clay-sized quartz, which is a direct 

result of dissolution of the larger silt-sized and very fine 

grained sand-sized particles within the argillic horizon 

(Vita-Finzi and Smalley, 1970; Moss and Green, 1975; 

M. J. Pavich, H. W. Markewich, and E. J. Dwornik, 

manuscript in preparation, 1986). As Thorn (1967b), 

Adams and Thorn (1968), and Thorn and others (1972) 

noted, our data also show an increase of 14.2-A HIV toward 

the surface and a corresponding decrease in kaolinite. Perhaps when bases are recycled through the biota, silica and 

alumina are released by dissolution of the very fine grained 

sand- and silt-sized fraction in the solum, and kaolinite is 

transformed to the low-charge vermiculite. The frequency 

of wetting and drying cycles and the increase of solute 

activities due to drying may also favor the formation of 

vermiculite (Markewich and others, in press).

Back-Barrier Soils

The dominant clay minerals in back-barrier sola are 

kaolinite and HIV and lesser amounts of gibbsite and halloysite. In general, HIV peak intensities increase toward the 

surface. There is little development of halloysite in the backFigure 16. Weight percent clay and weight percents of silt and 

sand on a clay-free base for Carolina bay pedons 010 and 011. 

Horizontal lines show weight percent of clay (<2 |xm) for each 

horizon. Vertical lines denote percent finer than 20, 50, 100, 

250, 500, and 2,000 JAITI on a clay-free base. Clay-free texture 

of each horizon is calculated by subtracting weight percent of 

clay; weight percents of coarser fractions are summed, and that 

sum is used as the denominator in recalculating the percentages of each silt and sand fraction.

barrier soils except in pedons 014 (fig. 11) and 015 (fig. 12), 

where halloysite does appear in the Bt horizons. Goethite is 

also a significant component of the B and C horizons in the 

back-barrier profiles. In contrast to HIV peak intensity, 

goethite peak intensity generally increases downward beneath the upper Bt horizons. The goethite may be related to 

repeated oxidation-reduction cycles within the poorly 

drained lower horizons. In the Conway back-barrier pedons, 

there is very little evidence for mineral alteration, as the lack 

of halloysite development and the presence of feldspar in the 

B horizon indicate (pedons 007 and 009) (figs. 14, 15). 

Some potassium feldspar was identified petrographically in 

the very fine grained sand fraction of the BCgl horizon of 

pedon 007.

Argillic horizons developed in soils on back-barrier 

sediments of the Horry, Conway, and Jaluco barrier systems 

range in thickness from 20 to 110 cm. Field descriptions 

indicate no apparent correlation between the thicknesses of 

the argillic horizon as described in the field and the ages of 

soils or of the parent material. Particle size data, plotted on 

clay distribution curves (tables IB, 85, 105, 135, 145, 

15B , 165) (see fig. 8), and microfabric analysis suggest that 

argillic horizons are thicker than field observations indicate 

(>150 cm).

20 Pedologic Studies in the Eastern United States
333

20°

Figure 1 7. X-ray diffraction patterns of untreated samples from 

pedon 010. Vermiculite (HIV), kaolinite (K), gibbsite (G), and 

quartz (Q) are present throughout the profile. Peak intensities 

of vermiculite and quartz are greatest in the Bt horizon. Intensities of all peaks decrease toward the surface. Halloysite (H) is 

not present in the profile. Peaks are measured in angstroms. 

Depths of horizons are in centimeters.

The problem with the clay distribution curves (thick 

argillics) of Horry back-barrier soils is the difficulty in differentiating pedogenic clay from detrital clay. In most 

cases, the lower horizons containing more clay also show a 

sand distribution different than that of the overlying horizons (fig. 8). The presence of clay films in thin section can 

be misleading, because the finer sediments tend to stop the 

downward movement of clay and thus facilitate the formation of clay films. However, thin sections showed that the 

colors of thick clay skins in the lowermost horizons are 

commonly different than those of thick clay skins in the 

shallower Bt horizons, the suggestion being that they 

formed and were oxidized in the Bt horizon at a time before 

translocation.

Textural and microfabric analyses show that the minimum scatter of solum thickness is in the 200-ka backbarrier soils and that sola of the 2.5- to 3.0-Ma back-barrier 

soils are substantially thicker than the 200-ka sola, even 

though field descriptions suggest little to no correlation between age and thickness of argillic horizons or sola (see fig.

<" S V) t!

100

O 8

10 5 10 6 

AGE, IN YEARS

EXPLANATION 

A Barrier solum Back-barrier solum

A Barrier argillic 

horizon

O Back-barrier argillic 

horizon

Figure 18. Thicknesses of sola and argillic horizons for Jaluco, 

Conway, and Horry barrier and back-barrier sites.

18). Increasing argillic horizon thickness probably results 

from the translocation of clay and silt downward through the 

profile, which, in turn, explains the lesser value of clay 

mass for the Horry back-barrier pedons in comparison with 

the values for the Conway and Jaluco back-barrier pedons 

(see fig. 20).

Tables 135 and 155 show the apparent effect of 

downward translocation of clay in pedons 012 and 014 developed in Horry back-barrier sediments. It is probable that 

the horizons labeled as BC, CB, and C are, in fact, part of 

the argillic horizon and should be designated as Bt horizons. 

The solum thickness of the Horry back-barrier soils would 

then be much greater than the 3 to 6 m sampled and probably 

deeper than standard backhoe excavation can reach. Therefore, the soils developed on the back-barrier sediments of 

the 2.5- to 3.0-Ma Horry barrier system appear to be correctly placed in the Pale-Great Group and are characterized 

by certain parameters that are significantly different from 

those that characterize the 200-ka soils developed on the 

Conway and Jaluco back-barrier sediments.

The back-barrier soils of the Horry and Conway barrier systems show a 10-percent increase in fine-grained sand 

in the upper 20 to 47 cm of the sola. Although this surface 

layer is generally described in the field as an A and (or) E 

horizon, this sandy surface could be eolian in origin, or the 

sand could be residual from eolian activity that has removed 

the intervening fines. Daniels and others (1969) referred to 

windblown sands associated with Coastal Plain river valleys. This dunal material associated with the rivers and 

Carolina bays of the lower Coastal Plain are evidence 

enough to suggest that loose sand, silt, and clay at the 

surface have been subjected to eolian processes either conSoils and Morphostratigraphy in Horry County, S.C. 21
150

co 125 

££

O LU

b! 1 

O z 100

X LU

LL. U

O Z

50

I

EXPLANATION

A Barrier

 Back-barrier

10 5 106

AGE, IN YEARS

Figure 19. Thicknesses of Bt, BC, CB, and C horizons having 

chroma greater than six versus age of solum.

tinuously or at periodic intervals since deposition (tables 

IB, 85, 135, 145, 155, 165).

Age Estimates

One of the primary purposes of this study was to 

determine if soil parameters could help bracket the ages of 

constructional landforms and their associated sediments on 

the Coastal Plain of the Atlantic Coast States. Data from the 

Eastern Shore and the Rappahannock River terraces of 

southeastern Virginia (Markewich and others, in press) indicated that, for constructional landforms up to several hundred thousand years old, soil parameters such as chroma, 

thickness of sola, thickness of argillic horizons, clay mass, 

and (or) depth and degree of clay translocation could be used 

to estimate ages. The most apparent differences are between 

soils that vary in age by an order of magnitude. Data from 

Horry County, South Carolina, also indicate that there are 

significant differences between soils that are several hundred thousand years old versus soils that are more than 1 Ma 

(figs. 18, 19, 20, 21). These differences are similar to those 

seen in the Coastal Plain of Virginia and result from timeprogressive postdepositional modification of the parent material. Pye (1983) summarized the near-surface modification 

of Pleistocene and Holocene dune sands of Queensland, 

Australia, which included reduction in mean grain size, 

poorer sediment sorting, reduction in voids ratio, reduction 

in porosity and permeability, and increased interparticle 

cohesion.

Data from Horry County suggest that near-surface 

diagenetic processes in sandy siliceous Coastal Plain sediments of the middle and Southeastern United States produce

150

125

100

-J cc

CJ LU

75

50

25

I

EXPLANATION 

A Barrier 

 Back-barrier

105 106

AGE, IN YEARS

Figure 20. Clay mass versus age of solum for Horry, Conway, 

and Jaluco barrier and back-barrier profiles. Barrier sites show 

no increase of clay mass with age. Back-barrier sites show a 

decrease of clay mass with age.

characteristics similar to those described by Pye (1983). 

Figure 19 shows that older (more than 1.0 m.y.) backbarrier pedons exhibit a greater total thickness of horizons 

having chroma greater than or equal to six, probably because of deeper oxidation in the back-barrier sites through 

time. Data are not sufficient to show a trend in pedons on 

barrier sites. The increase in high chroma is only one of the 

criteria for identifying increasing solum thickness with increasing age in the back barriers (fig. 18). Textural data 

show no obvious trends in age for soils developed on the 

Conway and Jaluco barrier systems (figs. 8, 18, 20, 21). 

Figure 21 shows, however, that soils of different ages cluster when we plot the ratio of sand textures against thicknesses of argillic horizons. Although the data are too few to 

establish the usefulness of this plot, future studies in this 

region may provide the data necessary to evaluate its usefulness.

Although this study could not establish any particular 

association between clay mineralogy and age of deposit, 

D. R. Seller (oral communication, 1984) provided evidence 

that quartz, gibbsite, and vermiculite are clay-sized eolian 

components of both the Holocene dunes and sand sheets 

associated with the youngest Cape Fear River terraces and 

the >40-ka dunes and Carolina bay rims present on older 

fluvial and marine terraces in the lower Coastal Plain of 

North Carolina. HIV, gibbsite, and clay-sized quartz form 

in situ in the B horizons of Pleistocene and Pliocene soils in 

both Coastal Plain and Piedmont soils of South and North 

Carolina. These soils are therefore the most probable source 

for the eolian HIV and clay-sized quartz encountered in

22 Pedologic Studies in the Eastern United States
+ 20

C/3 

O

C/3

!i: 10

00

I I 

EXPLANATION

o Jaluco barrier

 Jaluco back-barrier

D Horry barrier

 Horry back-barrier

A Conway barrier

A Conway back-barrier

D

D 

I

20 40 60 80 100 120 

THICKNESS OF ARGILLIC HORIZONS, IN CENTIMETERS

140 160

Figure 21. Ratio of silt (S) plus very fine grained sand (VFS) plus fine-grained sand (FS) to medium-grained sand (MS) plus 

coarse-grained sand (CS) plus very coarse grained sand (VCS) versus the thicknesses of argillic horizons for Horry, Conway, and 

Jaluco barrier and back-barrier profiles.

many of the dunes. Athough these minerals may be able to 

form in situ in the soils associated with the Carolina bays on 

higher terraces of the Cape Fear River, the very young age 

(5,700-7,700 yr B.P.) (USGS Radiocarbon Laboratory, 

Reston, Va., sample numbers W-5141 and W-5157, cited 

by Seller (1983)) for the dunes on the lowest terrace of the 

lower Cape Fear River suggests that these minerals were 

formed elsewhere and blown into the sandy dunal material. 

X-ray diffraction patterns that show strong HIV and quartz 

peaks in the upper 20 cm of Horry County soils suggest a 

similar origin for the material above the Bt horizons in this 

region (figs. 4-7).

In Horry County, South Carolina, and in southeastern 

Virginia (Markewich and others, in press) where landforms 

are older than 500 ka and where there has been minimal 

dissection of the terrane, many of the sola have thicknesses 

in excess of 4 m; thus, sampling from core or from manmade exposures is required. Without core or large exposures, data such as those presented in this report from the 

Horry barrier system probably reflect only the near-surface 

aspects of profiles having bisequal development. Data also 

indicate that in all cases, but particularly in those where 

quartz sand and silt comprise more than 95 percent of the 

parent material, complete soil characterization is needed to 

identify those parameters related to microenvironments and 

those related to age of sola (time). Microenvironments include microdrainage differences, local differences in mineralogy, and bisequal pedogenic development.

The work of Thorn (1967a, b, 1970; Thorn and others, 

1972) in Horry County and the work of Seller (1983, in 

press) on the terraces of the Cape Fear River in North Carolina suggest that depth of weathering and depth of oxidation can be used to estimate the age(s) of the surface of 

constructional landforms. Thorn (1967a) showed progressive differences in depth of sola and degree of oxidation 

with increasing age of barriers. Adams and Thorn (1968) 

and Thorn and others (1977) showed a progressive increase 

in fine-grained material with increasing age of barrier. 

(Markewich and others (in press) showed a similar trend of 

increasing fine-grained material with increasing age for terrace sediments along the lower Rappahannock River in 

southeastern Virginia.)

Thorn (1967a) suggested that depth of oxidation 

varied from 1 m in the <30-ka terrace deposits (Thorn's 

Terrace I) to 1.5 to 2.5 m in the >36-ka Dune Sand II, 

Myrtle Beach Barrier, and Terrace II to about 5 m in the 

200- to 500-ka Jaluco and Conway barriers (considered to be 

200 ka in this report) to more than 7 m in the 2.0- to 3.5-Ma 

Horry barrier system. Similar observations on increasing 

depth of oxidation with increasing age have been made for 

100-ka to 4.5-Ma fluvial and marine deposits in the valleys 

of the Cape Fear and Little Pee Dee Rivers in North and 

South Carolina (J. P. Owens and D. R. Seller, oral communication, 1983; Seller, 1983, in press; H. W. Markewich, 

unpublished data, 1982-1984).

Depth of oxidation is probably the easiest usable 

value to obtain in the field for comparing thicknesses of

Soils and Morphostratigraphy in Horry County, S.C. 23
weathering profiles. Comparing depths of oxidation can 

provide a relative chronology for units in terranes where 

increasingly older deposits are encountered with increased 

altitude and degree of dissection. Since depth of oxidation 

is directly related to depth to the water table and degree of 

internal drainage, depth of oxidation should be measured 

only in areas of maximum relief and (or) drainage density 

such as margins of barriers and (or) terraces. In areas such 

as the lower Coastal Plain of South Carolina, which has 

been only slightly modified by dissection and in which the 

depths to which streams are incised vary greatly, the limited 

number of acceptable sample localities would restrict the 

size of the data set and thus affect the accuracy of estimates 

on surface ages. Other data that could be collected to determine the depth and degree of weathering include information on heavy and light minerals, mineral trends from depth 

toward the surface for the clay, silt, and very fine grained 

sand and fine-grained sand fractions (see Owens and others 

(1983) for an example of this type of analysis), and the 

degree of SiO2 dissolution determined by bulk chemical 

analyses (a reflection of the mineral trends).

CONCLUSIONS

Several factors have contributed greatly to the successful correlation of soils and surfaces of similar ages: (1) a 

climate that has been relatively uniform over much of the 

Pliocene and Pleistocene (allowing for catastrophic events 

producing features such as the Carolina bays); (2) similar 

topographic positions of marine deposits of a given age; 

(3) similar vegetation assemblages through the Pliocene and 

Pleistocene; and (4) similar composition and sorting of parent material. Similar degrees of dissection and drainage 

conditions in units of different ages work against such correlations, because the degree of dissection and the development of soil and weathering profiles are greatly dependent 

on local gradient. If there are no significant differences in 

gradient, it becomes difficult to determine the differences in 

soil and weathering profiles, even though they have developed on surfaces that differ greatly in age.

Conclusions drawn from pedogenic studies in Horry 

County, South Carolina, can be divided into two categories: 

(1) those related to pedogenesis and (2) those related to 

using soil characteristics for estimating the age of a constructional landform (surface age determined by age of 

solum).

One conclusion that belongs in neither category but is 

nevertheless an important logistical consideration concerns 

sampling needs for soil and weathering profiles developed 

in the humid temperate climate of the Atlantic Coastal Plain. 

If landforms older than 106 yr are to be sampled, one of the 

following must be used: (1) several 6-in core holes placed 

within a few inches of one another, (2) undisturbed shelby 

tube samples arrayed like the 6-in core, or (3) successively

deeper backhoe trenches. Depths that can be excavated by 

standard backhoe are not adequate because of the 3- to 8-m 

thicknesses of the sola. If the thicknesses of the sola and 

associated weathering profiles are considered, depths of 9 to 

15 m would not be uncommon. Several core or shelby tube 

holes would be needed to obtain the volume of sample 

needed for complete analyses of any horizon.

Pedogenesis

Physical alteration of the parent material appears to be 

greater than and not necessarily the result of chemical alteration in most of the barrier and back-barrier profiles. There 

is little evidence of pedogenic chemical alteration at sites 

that are either excessively well drained (pedon 002) or 

poorly drained (back-barrier pedons 012, 013, 014, and 

015).

The bulk of the evidence for physical alteration is 

found in back-barrier pedons. For several periods, clay 

movement resulted in cutans of different hue and chroma. 

Also, weatherable minerals present in back-barrier sediments are not found in the sola, whereas, in the barrier 

sands, no weatherable minerals were identified in the parent 

material or in the sola. Finally, significant reorientation of 

clay has taken place in the argillic horizons.

X-ray diffraction data indicate that the presence or 

absence of clay minerals is related more to microenvironments, drainage conditions, and texture than it is to the age 

of the solum or to minor differences in the original compositions of parent material. Examples include the associations 

between halloysite and weight percent clay and between 

goethite and mottles (suggestive of cyclic alteration of 

oxidation-reduction conditions in the zone of fluctuating 

water table).

Data suggest that halloysite is an indicator of pedogenic clay development and not of indigenous clay content 

or eolian contribution.

The increase in the peak height ratio of 14.2 A (HIV) 

to 7.2 A (kaolinite)+4.85 A (gibbsite) minerals toward the 

surface corresponds to a decrease in extractable aluminum 

toward the surface and suggests that HIV is incorporating 

aluminum into interlayer positions.

Pedologic development proceeded along two pathways. Soils developed in parent material characterized by 

low clay content and impeded drainage developed spodic 

horizons (or humate) at or slightly above the seasonal water 

table. Soils developed mostly in fine-grained or poorly 

sorted sediment accumulated more clay during weathering 

and have argillic horizons.

Humate development can occur by translocation of 

organic material downward through a sandy solum containing little clay or by lateral migration of soluble organic 

material in ground water above a confining layer.

24 Pedologic Studies in the Eastern United States
Humates contain variable amounts of iron and (or) 

aluminum and very little clay. Characterization of the organic content of humates and (or) isotope chemistry may 

help define the processes involved in the development of 

humates.

Locally, soil drainage conditions appear to be dominant over time in determining the development of argillic 

horizons. That is, the influence of topography is apparently 

greater than that of time in the development of the sola in 

certain parts of the landscape. This conclusion may prove 

incorrect if further investigations show substantially thicker 

profiles on the Horry barrier system or on any sandy 

siliceous marine sediments of equivalent age in the region.

Age Determinations

Data are insufficient to differentiate soils of the Jaluco 

and Conway barrier systems. This conclusion is in agreement with the mapping of Thorn (1967a) and J. P. Owens 

(oral communication, 1984), which placed the Conway and 

Jaluco barrier systems in the same map unit and considered 

them to be equivalent in age. Although our data suggest that 

there has been only a minimal degree of pedogenic alteration 

in the Jaluco and Conway barrier systems of Horry County, 

Seller (1983, in press) showed that up to 10 percent of the 

fine-grained sand fraction of terrace sediments in the lower 

Cape Fear River valley consists of feldspathic or other 

weatherable aluminosilicate minerals. J. P. Owens (oral 

communication, 1984) suggested a similar subsurface composition for the Horry barrier sediments. The lack of these 

labile components in near-surface sediments of the Jaluco, 

Conway, and Horry barrier systems suggests that leaching 

of weatherable minerals may be the first step in the pedogenic alteration of these deposits. If this hypothesis is true, 

then evidence of pedogenic development may not be recognizable for several thousand years after subaerial exposure. 

A logical next step in research would be quantitative analyses of weathering and pedogenic alteration with respect to 

mass loss from these 106+-yr-old landforms.

Differences in thicknesses of argillic horizons can be 

used to separate soils that differ in age by an order of 

magnitude. Back-barrier soils of the 200-ka Conway and 

Jaluco barrier systems have argillic horizons and sola that 

are thinner than back-barrier soils developed in the Horry 

barrier systems.

Thicknesses of the argillic horizons support placement of the Horry back-barrier soils in the Pale-Great Group 

and are consistent with the Pliocene age presently assigned 

to the underlying Bear Bluff Formation. Barrier soils of the 

Horry barrier system are not sufficiently well developed to 

classify as Paleudults.

For most areas of the lower Atlantic Coastal Plain, 

relief is great enough to allow simple comparisons of oxidation depths, percentages of labile minerals, and ratios of

heavy minerals to be used in determining the relative age of 

landforms. Caution is needed, because these factors more 

directly measure differences in relief and (or) dissection 

between the units rather than differences specifically related 

to weathering and (or) soil formation. If refinement of ages 

is necessary, complete pedogenic analyses are probably unavoidable, and sampling techniques are critical because of 

the depth of the sola.

The back-barrier part of a barrier system may be the 

source of the HIV and quartz eolian contribution to barrier 

sands. Such a system would result in depletion of backbarrier surface fines and preservation of barrier forms by 

accretion. More detailed mineralogical characterizations are 

necessary to support or dispute this hypothesis.

Three parameters that could be used to estimate ages 

of surfaces in other parts of the lower Coastal Plain in the 

Southeastern United States are as follows:

1. The thicknesses of the solum and of the argillic horizon, 

determined from textural and microfabric data, appear 

to be acceptable indicators of soil age when soils several hundred thousand years old are compared with 

those over a million years old, if the entire profile has 

been sampled. Profile thicknesses estimated from field 

descriptions do not appear to be reliable for soils developed in barrier and back-barrier units, or at least not 

where field descriptions are limited to within 3 m of the 

surface. (The ratios of fine-grained particles (clay plus 

fine-grained silt plus coarse-grained silt plus very fine 

grained sand) to coarse-grained particles plotted 

against the thicknesses of argillic horizons (fig. 21) 

cluster for individual morphostratigraphic units. This 

treatment of the data suggests a method of providing 

age estimates, but it must be tested on many more sites 

of known age before its usefulness can be determined.)

2. Clay, silt and clay, silt, and sand flows appear to indicate 

an age of at least 105 yr for sola developed in backbarrier sediments of the lower Coastal Plain. Several 

periods of translocation, indicated by the presence of 

both red-brown and brown cutans and by the layering 

of cutans around skeletal grains, are characteristic of 

sola developed in back-barrier sediments more than 106 

yr old. More work is needed before microfabric analyses can be used for estimating age, but the technique 

may prove useful.

3. As an adjunct to microfabric analysis, clay mass may be 

useful in differentiating units that differ in age by an 

order of magnitude. Back-barrier soils more than 106 yr 

old begin to lose clay mass in the upper part of the 

solum as clay is translocated downward.

REFERENCES CITED

Adams, R. D. and Thorn, B. G., 1968, Relationship between 

coastal landforms and size distribution of surficial sediments

Soils and Morphostratigraphy in Horry County, S.C. 25
Horry and Marion Counties, South Carolina: Southeastern 

Geology, v. 9, no. 1, p. 39-56.

Blackwelder, B. W., and Ward, L. W., 1979, Stratigraphic 

revision of the Pliocene deposits of North and South Carolina: 

South Carolina Division of Geology Geologic Notes, v. 23, 

no. 1, p. 33-49.

Brewer, R., 1976, Fabric and mineral analysis of soils: New York, 

Kreiger, 470 p.

Brindley, W., Santos, P. S., and Santos, H. S. 1963, 

Mineralogical studies of kaolinite-halloysite clays, pt. I, 

Identification problems: American Mineralogist, v. 48, 

p. 897-910.

Bryant, J. P., 1965, Soils of the Carolina bays and interbay areas 

in Scotland County, North Carolina: Raleigh, N.C., North 

Carolina State University, unpublished Ph.D. dissertation, 

256 p.

Cinquemani, L. J., Newman, W. S., Sperling, J. A., Marcus, 

L. F., and Pardi, R. R., 1982, Holocene sea level changes 

and vertical movements along the east coast of the United 

States: A preliminary report, in Colquhoun, D. J., ed., 

Holocene sea level fluctuations, magnitudes, and causes: 

International Geologic Correlation Programme Annual 

Meeting, 61st, Columbia, S.C., 1981, symposium volume, 

p. 13-33.

Coleman, N. T., and Jackson, M. L., 1945, Mineral composition 

of the clay fraction of several Coastal Plain soils of the 

southeastern United States: Soil Science Society of America 

Journal, v. 10, p. 381-391.

Colquhoun, D. J., 1969, Geomorphology of the lower Coastal 

Plain of South Carolina: Division of Geology, State Development Board of South Carolina Map Series, MS-15, 

36 p.

 1974, Cyclic surficial Stratigraphic units of the middle and 

lower coastal plains, central South Carolina, in Oaks, R. Q., 

Jr., and DuBar, J. R., eds., Post-Miocene stratigraphy of the 

central and southern Atlantic Coastal Plain: Logon, Utah, 

Utah State University Press, p. 179-190.

Cooke, C. W., 1930, Correlation of coastal terraces: Journal of 

Geology, v. 38, p. 577-589.

 1931, Seven coastal terraces in the southeastern states: 

Journal of the Washington Academy of Sciences, v. 21, 

p. 503-513.

 1936, Geology of the Coastal Plain of South Carolina: U.S. 

Geological Survey Bulletin 867, 189 p.

 1937, The Pleistocene Horry Clay and Pamlico Formation 

near Myrtle Beach, South Carolina: Journal of the 

Washington Academy of Sciences, v. 27, p. 1-5. 

-1945, Geology of Florida: Florida Geological Survey

Bulletin 29, 339 p.

Cooke, C. W., and MacNeil, F. S., 1952, Tertiary stratigraphy of 

South Carolina: U.S. Geological Survey Professional Paper 

243-B, p. B19-B29.

Crisp, E. L., 1971, Environmental significance of variations in the 

shell chemistry of Pleistocene mollusks along the Intracoastal 

Waterway, Horry County, South Carolina: Atlantic Coastal 

Plain Geological Association, Guidebook 12, p. 124-128.

Cronin, T. M., 1980, Biostratigraphic correlation of Pleistocene 

marine deposits and sea levels, Atlantic Coastal Plain of the 

southeastern United States: Quaternary Research, v. 13, 

p. 213-229.

 1981, Rates and possible causes of neotectonic vertical 

crustal movements of the submerged southeastern United 

States Atlantic Coastal Plain, pt. 1: Geological Society of 

America Bulletin, v. 92, p. 812-833.

Cronin, T. M., and Hazel, J. E., 1980, Ostracode biostratigraphy 

of Pliocene and Pleistocene deposits of the Cape Fear Arch 

region, North and South Carolina: U.S. Geological Survey 

Professional Paper 1125-B, 25 p.

Cronin, T. M., Bybell, L. M., Poore, R. Z., Blackwelder, B. W., 

Liddicoat, J. C., and Hazel, J. E., 1984, Age and correlation 

of emerged Pliocene and Pleistocene deposits, U.S. Atlantic 

Coastal Plain: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 47, p. 21-51.

Dall, W. H., and Harris, G. D., 1892, Correlation papers: 

Neocene: U.S. Geological Survey Bulletin 84, 349 p.

Daniels, R. B., and Gamble, E. E., 1967, The edge effect in some 

Ultisols in the North Carolina Coastal Plain: Geoderma, v. 1, 

p. 117-124.

 1974, Surficial deposits of the Neuse-Cape Fear divide 

above the Surry Scarp, North Carolina, in Oaks, R. Q., and 

Dubar, J. R., eds., Post-Miocene stratigraphy, central and 

southern Atlantic Coastal Plain: Logan, Utah, Utah State University Press, p. 88-101. 

-1978, Relations between stratigraphy, geomorphology,

and soils in Coastal Plain areas of southeastern U.S.A.: Geoderma, v. 21, p. 41-65.

Daniels, R. B., Gamble, E. E., Wheeler, W. H., and Nettleton, 

W. D., 1966, Coastal Plain stratigraphy and geomorphology 

near Benson, North Carolina: Southeastern Geology, v. 8, 

no. 4, p. 159-181.

Daniels, R. B., Gamble, E. E., and Buol, S. W., 1969, Eolian 

sands associated with Coastal Plain River valleys Some 

problems in their age and source: Southeastern Geology, 

v. 11, no. 2, p. 97-110.

Daniels, R. B., Gamble, E. E., and Wheeler, W. H., 1971, Stability of Coastal Plain surfaces: Southeastern Geology, v. 13, 

no. 2, p. 61-75.

Daniels, R. B., Gamble, E. E., andHolzey, C. S., 1976, Humate, 

Bh soil horizons, in wet sands of the North Carolina Coastal 

Plain: Southeastern Geology, v. 18, no. 2, p. 61-81.

Daniels, R. B., Gamble, E. E., and Wheeler, W. H., 1978a, Age 

of soil landscapes in the Coastal Plain of North Carolina: Soil 

Science Society of America Journal, v. 42, no. 1, p. 98-105.

Daniels, R. B., Gamble, E. E., Wheeler, W. H., Gilliam, J. W., 

Wiser, E. H., and Welby, C. W., 1978b, Water movement in 

surficial Coastal Plain sediments, inferred from sediment 

morphology: North Carolina Agricultural Experiment Station 

Technical Bulletin 243, 31 p.

DeConinck, F., 1980, Major mechanisms in the formation of 

spodic horizons: Geoderma, v. 24, p. 101-124.

Delcourt, P. A., and Delcourt, H. R., 1979, Late Pleistocene and 

Holocene distributional history of the deciduous forest in the 

southeastern United States: Veroffentlichungen des Geobotanischen Institutes der E.T.H. Stiftung Rubel (Zurich), 

v. 68, p. 79-107.

Doering, J. A., 1960, Quaternary surface formations of southern 

part of the Atlantic Coastal Plain: Journal of Geology, v. 68, 

p. 182-202.

Douglas, L. A., 1977, Vermiculites, in Dixon, J. B., and Weed, 

S. B., eds., Minerals in soil environs: Madison, Wis., Amer26 Pedologic Studies in the Eastern United States
ican Association for the Advancement of Science, p. 259- 

288.

DuBar, J. R., 1971, Neogene stratigraphy of the lower Coastal 

Plain of the Carolinas: Atlantic Coastal Plain Geological Association Annual Field Conference, 12th, Myrtle Beach, 

S.C., 1971, 127 p.

DuBar, J. R., and Chaplin, J. R., 1963, Paleoecology of the 

Pamlico Formation (late Pleistocene); Nixonville quadrangle, 

Horry County, South Carolina: Southeastern Geology, v. 4, 

no. 3, p. 127-165.

DuBar, J. R., and Howard, J. F., 1963, Paleoecology of the type 

Waccamaw (Pliocene?) outcrops, South Carolina: Southeastern Geology, v. 5, no. 1, p. 27-68.

DuBar, J. R., Johnson, H. S., Thorn, B., and Hatchell, W. O., 

1974a, Neogene stratigraphy and morphology, south flank of 

the Cape Fear Arch, North and South Carolina, in Oaks, 

R. Q., and DuBar, J. R., eds., Post-Miocene stratigraphy 

central and southern Atlantic Coastal Plain: Logan, Utah, 

Utah State University Press, p. 139-173.

DuBar, J. R., Solladay, J. R., and Howard, J. F., 1974b, Stratigraphy and morphology of Neogene deposits, Neuse River 

estuary, North Carolina, in Oaks, R. Q., and DuBar, J. R., 

eds., Post-Miocene stratigraphy, central and southern Atlantic Coastal Plain: Logan, Utah, Utah State University 

Press, p. 102-122.

DuBar, J. R., DuBar, S. S., Ward, L. W., and Blackwelder, 

B. W., 1980, Cenozoic biostratigraphy of the Carolina Outer 

Coastal Plain, with contributions by W. H. Abbott and P. F. 

Huddlestun: Geological Society of America Guidebook, Field 

Trip No. 9, 236 p.

Fenneman, N. M., 1938, Physiography of the eastern United 

States: New York, McGraw-Hill, 714 p.

Flanagan, F. J., 1976, Descriptions and analyses of eight new 

USGS rock standards: U.S. Geological Survey Professional 

Paper 840, 192 p.

Flint, R. F., 1940, Pleistocene features of the Atlantic Coastal 

Plain: American Journal of Science, v. 238, no. 11, p. 557- 

587.

Gamble, E. E., 1965, Origin and morphogenetic relations of sandy 

surficial horizons of upper Coastal Plain soils of North Carolina: Raleigh, N.C., North Carolina State University, unpublished Ph.D. dissertation, 254 p.

Gamble, E. E., Daniels, R. B., and McCracken, R. J., 1970, A2 

horizons of Coastal Plain soils, pedogenic or geologic origin: 

Southeastern Geology, v. 11, no. 3, p. 137-152.

Harris, W. B., Zullo, V. A., and Baum, G. R., 1979, Tectonic 

effects on Cretaceous, Paleogene and early Neogene sedimentation, North Carolina, in Baum, G. R., Harris, W. B., and 

Zullo, V. A., eds., Structural and stratigraphic framework for 

the Coastal Plain of North Carolina: Carolina Geological Society and Atlantic Coastal Plain Geological Association Field 

Trip Guidebook, October 1979, Wrightsville Beach, N.C., 

p. 19-29.

Hatcher, P. G., Maciel, G. E., and Dennis, L. W., 1981, Allophatic structure of humic acids; a clue to their origin: Organic Geochemistry, v. 3, p. 43-48.

Hazel, J. E., 1971, Ostracod biostratigraphy of the Yorktown 

Formation (upper Miocene and lower Pliocene) of Virginia 

and North Carolina: U.S. Geological Survey Professional 

Paper 704, 13 p.

 1977, Distribution of some biostratigraphically diagnostic 

ostracodes in the Pliocene and lower Pleistocene of Virginia 

and northern North Carolina: U.S. Geological Survey Journal 

of Research, v. 5, no. 3, p. 373-388. 

-1983, Age and correlation of the Yorktown (Pliocene) and

Croatan (Pliocene and Pleistocene) formations at the Lee 

Creek, North Carolina, open pit mine, in Ray, C. E., ed., 

Geology and paleontology of the Lee Creek Mine, North 

Carolina, v. I: Smithsonian Contributions to Paleobiology, 

no. 53, p. 81-199.

Ingram, R. L., Robinson, Maryanne, and Odum, H. T., 1959, 

Clay mineralogy of some Carolina bay sediments: Southeastern Geology, v. 1, no. 1, p. 1-10.

Jenny, Hans, 1941, Factors of soil formation: New York, 

McGraw-Hill, 281 p.

Johnson, H. S., and DuBar, J. R., 1964, Geomorphic elements of 

the area between the Cape Fear and Pee Dee Rivers, North 

and South Carolina: Southeastern Geology, v. 6, no. 1, 

p. 37-48.

Karathanasis, A. D., Adams, Fred, and Hajek, B. F., 1983, Stability relationships in kaolinite, gibbsite, and Al-hydroxyinterlayered vermiculite soil systems: Soil Science Society of 

America Journal, v. 47, no. 6, p. 1247-1251.

Leenheer, J. A., 1980, Origin and nature of humic substances in 

the waters of the Amazon River basin: Acta Amazonica, 

v. 10, no. 3, p. 513-526.

MacNeil, F. S., 1950, Pleistocene shore lines in Rorida and Georgia: U.S. Geological Survey Professional Paper 221-F, 

p. F95-F107.

Malcolm, R. L., 1964, Mobile soil organic matter and its interpretations with clay minerals and sesquioxides: Raleigh, N.C., 

North Carolina State University, unpublished Ph.D. dissertation, 148 p.

Markewich, H. W., 1985, Geomorphic evidence for PliocenePleistocene uplift in the area of the Cape Fear Arch, North 

Carolina, in Morisawa, M., and Hack, J. T., eds., Tectonic 

geomorphology, Proceedings of the Annual Binghamton Geomorphology Symposium, 15th, Binghamton, N.Y., 1984: 

Boston, Alien and Unwin, p. 279-298.

Markewich, H. W., and Soller, D. R., 1983, The Cape Fear River: 

A late Quaternary drainage [abs.]: Geological Society of 

America (Southeastern Section) Abstracts with Program, 

v. 15, no. 2, p. 56.

Markewich, H. W., Pavich, M. J., Mausbach, M. J., Hall, R. L., 

Johnson, R. G., and Hearn, P. P., in press, Age relations 

between soils and geology in the Coastal Plain of Maryland 

and Virginia: U.S. Geological Survey Bulletin 1589-A, 34 p.

McCartan, L., Owens, J. P., Blackwelder, B. W., Szabo, B. J., 

Belknap, D. F. Kriausakul, N., Mitterer, R. M., and Wehmiller, J. F., 1982, Comparison of amino acid racemization 

geochronometry with lithostratigraphy, uranium series coral 

dating, and magnetostratigraphy in the Atlantic Coastal Plain 

of the southeastern United States: Quaternary Research, 

v. 18, p. 337-359.

McCollum, R. E., andMcCaleb, S. B., 1954, Chemical properties 

of some Coastal Plain soils of North Carolina: Soil Science, 

v. 78, p. 435-443.

Mixon, R. B., Szabo, B. J., and Owens, J. P., 1982, Evaluation 

of uranium-series dating of mollusks and corals and age of

Soils and Morphostratigraphy in Horry County, S.C. 27
Pleistocene deposits, Chesapeake Bay area, Virginia and 

Maryland: U.S. Geological Survey Professional Paper 1067- 

E, 18 p.

Moss, A. J., and Green, P., 1975, Sand and silt grains: Predetermination of their formation and properties by microfractures 

in quartz: Journal of Geological Society of Australia, v. 22, 

p. 485-495.

Oaks, R. Q., and DuBar, J. R., 1974, Tentative correlation of 

post-Miocene units, central and south Atlantic Coastal Plain, 

in Oaks, R. Q., and DuBar, J. R., eds., Post Miocene stratigraphy central and southern Atlantic Coastal Plain: Logan, 

Utah, Utah State University Press, p. 232-245.

Owens, J. P., Hess, M. M., Denny, C. S., and Dwornik, E. J., 

1983, Postdepositional alteration of surface and near-surface 

minerals in selected Coastal Plain formations of the Middle 

Atlantic States: U.S. Geological Survey Professional Paper 

1067-F, 45 p.

Pavich, M. J., 1985, Appalachian piedmont morphogenesis: 

Weathering, erosion, and Cenozoic uplift, in Morisawa, M., 

and Hack, J. T., eds., Tectonic geomorphology, Proceedings 

of the Annual Binghamton Geomorphology Symposium, 

15th, Binghamton, N.Y., 1984: Boston, Alien and Unwin, 

p. 299-320.

Pye, K., 1983, Early post-depositional modification of aeolian 

dune sands, in Brookfield, M. E., and Ahlbrandt, T. S., eds., 

Eolian sediments and processes: Developments in sedimentology: New York, Elsevier, v. 38, p. 197-221.

Schnitzer, M., 1977, Recent findings on the characterization of 

humic substances extracted for the soils from widely differing 

climatic zones, in Proceedings of the Third International 

Symposium on Soil Organic Matter: Vienna, International 

Atomic Energy Agency, v. II, p. 117-132.

Soil Survey Staff, 1972, Soil Survey investigations report no. 1: 

Soil Survey laboratory methods and procedures for collecting 

samples: Washington, D.C., U.S. Department of Agriculture 

Soil Conservation Service, 63 p.

 1975, Soil taxonomy: U.S. Department of Agriculture Soil 

Conservation Service Agriculture Handbook No. 436: Washington, D.C., U.S. Government Printing Office, 754 p.

 1981, Soil survey manual no. 1: Washington, D.C., U.S. 

Department of Agriculture Soil Conservation Services, unpublished revision of Agriculture Handbook No. 18, 107 p.

Soller, D. R., 1983, The Quaternary history and stratigraphy of the 

Cape Fear River valley: Washington, D.C., George Washington University, unpublished Ph.D. dissertation, 192 p.

 in press, Geology and tectonic history of lower Cape Fear 

River valley, southeastern North Carolina: U.S. Geological 

Survey Professional Paper.

Swanson, V. E., and Palacas, J. G., 1965, Humate in coastal 

sands of northwest Florida: U.S. Geological Survey Bulletin 

1214-B, 29 p.

Thorn, B. G., 1967a, Coastal and fluvial landforms, Horry and 

Marion Counties, South Carolina: Louisiana State University 

Studies, Coastal Studies Series, no. 19, 75 p.

 1967b, Humate in coastal geomorphology: Louisiana State 

University Studies, Coastal Studies Series Bulletin, v. 1, 

p. 15-17. 

-1970, Carolina bays in Horry and Marion Counties, South

Carolina: Geological Society of America Bulletin, v. 81, 

p. 783-814.

Thorn, B. G., Adams, R. D., Cazeau, C. J., and Herron, S. D., 

1972, Aspects of the texture and mineralogy of surficial sediments, Horry and Marion Counties, South Carolina: Southeastern Geology, v. 14, no. 1, p. 39-58.

Vita-Finzi, C., and Smalley, I. J., 1970, Origin of quartz silt: 

Comments on a note by P. H. Kuenen: Journal of Sedimentary Petrology, v. 40, p. 1367-1369.

Ward, L. W., Lawrence, D. R., and Blackwelder, B. W., 1978, 

Stratigraphic revision of the middle Eocene, Oligocene, and 

lower Miocene Atlantic Coastal Plain of North Carolina: 

U.S. Geological Survey Bulletin 1457-F, 23 p.

Weaver, R. M., 1975, Quartz presence in relationship to gibbsite 

stability in some highly weathered soils of Brazil: Clays and 

Clay Minerals, v. 23, p. 431-436.

Weems, R. E., and Lemon, E. M., Jr., 1984, Geologic map of 

Mount Holly quadrangle, Berkley and Charleston Counties, 

South Carolina: U.S. Geological Survey Geologic Quadrangle Map GQ-1579, scale 1:24,000.

Winker, C. C., and Howard, J. D., 1977, Correlation of tectonically deformed shorelines on the southern Atlantic Coastal 

Plain: Geology, v. 5, p. 124-127.

Wright, J. R., and Schnitzer, M., 1963, Metallo-organic interactions associated with podzolization: Soil Science Society of 

America Proceedings, v. 27, p. 171-176.

28 Pedologic Studies in the Eastern United States
Tables 1-18

Soils and Morphostratigraphy in Horry County, S.C. 29
Table 1 . Correlation of upper Tertiary formations with morphostratigraphic units on the southwestern limb of the Cape Fear Arch 

[ , unit not cited]

Thorn

Barrierback-barrier 

system

Con way ----

(1967a)

Associated 

glacial and 

interglacial 

stage

-- Unnamed

-- Sangamon 

- - Yarmouth or

Aftonian. 

- - Yarmouth or

Aftonian. 

- - Aftonian or

prePleistocene.

DuBar (1971), DuBar and 

others (1980)

Barrier-backbarrier system

Recent 

Myrtle Beach

Jaluco-Cainhoy 

Conway

Pleasant HillNakina. 

Horry

LakeviewOrrum.

Formation

Unnamed 

Socastee or 

Canepatch. 

Canepatch

Canepatch

Waccamaw 

Waccamaw

Bear Bluff

J. P. Owens (oral 

communication, 1984)

Barrier-backbarrier system

Recent 

Not recognized. 

Jaluco

Conway

Conway backbarrier flat. 

Daisy StrandNakina. 

Horry

Formation

Unnamed 

Wando (if present)

Socastee 

Socastee 

Socastee 

Penholoway 

Bear Bluff

Age

0-33 ka 

70 ka

200 ka 

200 ka 

200 ka 

800 ka 

2.5-3.0 Ma

Table 2A. Correlation of pedon number with morphostratigraphic unit and topographic position

Pedon number

S80SC-05 1-001- - -

S80SC-05 1-002- - -

S80SC-05 1-003- - -

S80SC-05 1-004- - -

S8 1SC-05 1-006---

S81SC-051-007---

S81SC-051-008---

S8 1SC-05 1-009- - -

S8 1SC-05 1-010- - -

S8 1SC-05 1-011---

S81SC-051-012---

S81SC-051-013---

S81SC-051-014---

S81SC-051-015---

Morphostratigraphic unit

Horry barrier system

Horry barrier system

Conway barrier system

Conway barrier system

Conway barrier system

Conway barrier system

Jaluco barrier system

Jaluco barrier system

Pee Dee fluvial terrace

Pee Dee fluvial terrace

Horry barrier system

Horry barrier system

Horry barrier system

Horry barrier system

Topographic 

position

Barrier

Barrier

Barrier

Barrier

Back barrier

Back barrier

Barrier

Back barrier

Rim of Carolina

bay.

Rim of Carolina

bay.

Back barrier

Back barrier

Back barrier

Back barrier

30 Pedologic Studies in the Eastern United States
Table 2B. Analytical methods and units of expression for 

analyses conducted at the Soil Conservation Service National 

Soil Survey Laboratory, Lincoln, Nebr.

Analysis Method 

code1 Unit of expression

Particle size ------------- 3A1 Weight percent <2 mm

material. 

Organic carbon ----------6A 1C Weight percent <2 mm

material. 

Dithionite-citrate --------- 6C2A Weight percent <2 mm

material. 

Iron -------------------- 6C2B Weight percent <2 mm

material.

Aluminum -------------- 6G7A Weight percent <2 mm

material.

Manganese -------------- 6D2A Weight percent <2 mm

material. 

Bulk density ------------- 4A1D g/cm3 <2 mm material

COLE2 ----------------- 4D1 cm/cm whole soil

15-bar tension ----------- 4B2A Weight percent <2 mm

material. 

WRD3 ----------------- 4C1 cm/cm whole soil

Extractable bases --------- 5B5A meq/100 g <2 mm

material. 

Cation exchange capacity

(CEC): 

Sum of cations ------- 5 A3 A meq/100 g <2 mm

material. 

NH4OAC ----------- 5A8B meq/100 g <2 mm

material. 

Al + bases4 ---------5A3B meq/100 g<2 mm

material. 

Base saturation:

Sum of cations ------- 5C3 Percent

NH4OAC ----------- 5C1 Percent

PH:

CaCl2 -------------- 8C1E Negative Iog10

H2O ---------------8C1A Negative Iog10

Method codes from Soil Survey Staff (1972). 

Coefficient of linear extensibility. 

3Water-retention difference.

4Aluminum precipitates from solution at pH 4.5 to 4.8. For pH ^ 5, 

extractable aluminum is not measured.

Soils and Morphostratigraphy in Horry County, S.C. 31
Table 3A. Field description of pedon S80SC-051-001

[Location: 18.3 km north of Conway, Horry County, South Carolina; 34°02' N., 79°05' W. Temperature: 17 °C mean annual, 26 °C mean summer. 

Elevation: 30 m above mean sea level. Physiography: Barrier bar. Geomorphic position: Crest of interfluve. Slope and aspect: 0 percent plane. Precipitation: 

137 cm, udic moisture regime. Drainage: Moderately well drained. Land use: Cropland. Parent material: Moderately weathered marine sand and clay. No 

entry indicates no data]

Depth 

(cm)

0-33 ----

33 45

45 74 ----

74 98 ----

no 117

117 141 ---

141 177 ---

Horizon

---_. /\pAn

_._.- F2

TJtl

Rt9

Q*1

----- C

Moist color1

10YR4/2

10YR7/6

10YR7/6

Tftvi?s/8

1OVR7/1

1OVR7/1

iftvi?7/'>

Texture2

Id

Isd

Is

sl

sl

sl

Id

Structure3 Clay skins

Ifgr 

Imsbk

Imsbk

1m + csbk

Icshk

O/"1

Roots4

mf

mf

fm

cm

Boundary5

oc

g»

5»<y^

£W

'Munsell notation.

2sl, sandy loam; Is, loamy sand.

3 1, weak; f, fine; m, medium; c, coarse; gr, granular; sbk, subangular blocky; SG, single grain.

^f, few fine; fm, few medium; mf, many fine; cm, common medium.

5cs, clear smooth; as, abrupt smooth; gs, gradual smooth; gw, gradual wavy; ci, clear irregular.

Table 3B. Textural analysis of pedon S80SC-051-001

[Grain sizes in millimeters; all other values in weight percent. VF, very fine; F, fine; M, medium; C, coarse; VC, very coarse; TR, trace; , analyzed

but below detectable limits]

Depth 

(cm) Horizon

0-33 ----Ap 

33-45 ----El 

45-74 ----E2 

74_98 ----Btl 

98-117 ---Bt2 

117-141 ---Bt3 

141-177 ---C

Clay 

«.002)

1.6 

2.0 

2.8 

12.5 

16.1 

12.1 

9.2

Total

Silt 

(.002-.05)

6.8 

5.8 

6.1 

4.4 

2.7 

1.2 

2.4

Sand

(.05-2)

91.6 

92.2 

91.1 

83.1 

81.2 

86.7 

88.4

Clay

F 

«.0002)

1.2 

1.2 

8.9 

10.5

7.7 

4.8

Silt

F 

(.002-.02)

3.6 

3.6

2.8 

.8

C

(.02-.05)

6.8 

2.2 

2.5 

1.6 

1.9 

1.2 

2.4

VF 

(.05-.10)

3.4 

3.4 

3.4 

2.8 

2.5 

2.5 

3.4

F 

(.10-.25)

81.1 

81.8 

80.5 

74.3 

72.4 

74.0 

78.0

Sand

M 

(.25-.50)

6.1

5.7 

5.9 

5.1 

4.7 

6.8 

5.0

C

(.5-1)

1.0 

1.2 

1.3 

.9 

1.5 

3.3 

1.8

VC

(1-2)

TR

0.1 

TR 

TR

.1 

.1

.2

32 Pedologic Studies in the Eastern United States
Table 3C. Physical and chemical analyses of pedon S80SC-051-001

[Units of measure for all values given in table 2B. , not detected; no entry, not analyzed; TR, trace]

Dithionite-citrate

Depth

(cm) Horizon

0-33 -----Ap 

33 45 c 1

45 74 -

74 98 -

98-117 

117-141 

141-177

CO

Rtl

----Bt2 

----Bt3 

----C

Organic 

C

0.69 

.24 

.13 

.16 

.10 

.05 

.05

Total

N

0.033 

.015 

.012 

.020

Extractable 

P

Total 

S

Bulk density

Depth 

(cm)

0-33 -

33 45 -

45 74 -

74 98 -

98-117 

117-141 

141-177

Depth 

(cm)

0-33 -

33-45 -

45 74 -

74 98 -

98-117 

117-141 

141-177

Horizon

------ APAn

...... E2

T3t1

RfO

Rfl

---... rV--

Horizon

----An/\p

- - - - E2

TJtl

----Bt2 

----Bt3 

----C

Field 

moist

NH4OAC

Ca Mg

0.9 0.2 

.1 .1 

.1 .1 

.1 .1 

.4 .3 

.9 .2 

.6 .1

1/3 

bar

.57 

.60 

.67 

.55 

.66 

1.67 

1.67

Oven 

dry

1.57

1.67 

1.56 

1.66 

1.69 

1.68

COLE3

0.002

.004 

.004

Extractable 

Fe

0.1 

.1 

.2 

.9 

.5 

.1 

.1

Extractable Extractable 

Al Mn

Water content

Field 

moist

1/3 

bar

6.7

7.2 

8.4 

9.5 

7.2 

6.2

extractable bases

Na

TR 

TR 

TR 

TR

K

0.1 

TR 

TR 

.2 

.2 

.1 

TR

Sum of 

bases

1.2 

.2 

.2 

.4 

.9 

1.2 

.7

Acidity

1.2 

1.0 

.2 

3.3 

3.1 

1.6 

1.4

Extractable 

Al

0.1 

.2 

.3 

1.1 

1.4 

.7 

.9

Sum of 

cations

2.4 

1.2 

.4 

3.7 

4.0 

2.8 

2.1

15 

bar2

1.4 

1.1 

1.4 

5.2 

6.5 

4.8 

3.8

CEC1

NH4 

OAC

2.4 

.9 

.7 

2.2 

3.0 

2.5 

2.2

WRD4

0.08

.10 

.05 

.04 

.04

NH4CI

1.6 

.9

.7 

1.6 

2.4 

2.4 

1.9

Ratio clay

CEC1

1.50 

.45 

.25 

.18 

.19 

.21 

.24

CaCl 2 

(.01 M) 

1:2

4.9 

4.8 

4.4 

4.0 

4.0 

4.2 

4.2

15 

bar2

0.88 

.55 

.50 

.42 

.40 

.40 

.41

PH

H2O 

1:1

5.6

5.4 

4.8 

4.3 

4.5 

4.8 

4.8

Base saturation

Sum

50 

17 

50 

11 

23 

43 

33

NH4OAC

50

22 

29 

18 

30 

48 

32

'Cation exchange capacity. 

2Water content at 15-bar pressure. 

Coefficient of linear extensibility. 

4Water-retention difference.

Table 3D. Bulk chemistry of pedon S80SC-051-001

Horizon

Major oxide

SiQ2 --------

A12O3 -- ------

Fe2O3 -------

MnO --------

TiO2 --------

CaO--------

K20 ----- -

MgO -------

Total --------

Ap

---97.4

---- 1.6

--- <.01

--- <.01

----- .3

----- .20

----- .10

 <1

--99.6

A21

99.8

.7

<.01

<.01

.3

.16

.09

<.l

101.0

A22

97.5

2.0

<.01

<.01

.4

.16

.10

<.l

100.1

Bt1

92.3

5.7

1.12

<.01

.5

.16

.14

<.l

99.9

Bt2

90.4

7.2

.58

<.01

.4

.17

.12

<.l

98.8

Bt3

93.4

5.5

<.01

<.01

.2

.18

.09

<.l

99.3

C

97.4

4.4

<.01

<.01

.2

.18

.13

<.l

102.3

Soils and Morphostratigraphy in Horry County, S.C. 33
Table 4A. Field description of pedon S80SC-051-002

[Location: 18.3 km north of Conway, Horry County, South Carolina. Location: 34°02' N., 79°02' W. Temperature: 17 °C mean annual, 26 °C mean 

summer. Elevation: 33 m above mean sea level. Physiography: Barrier bar. Geomorphic position: Crest of interfluve. Slope and aspect: 10 percent plane. 

Precipitation: 137 cm, udic moisture regime. Drainage: Well drained. Land use: Cropland. Parent material: Moderately weathered marine sand and clay. 

No entry indicates no data]

Depth

(cm)

n 11

H AS.

48 69 --- 

fjQ QO

(V) iin

i in i if.

1 1£. \ Ty

Horizon

..._ ----- ApAn

pp

-----Cl

-_._-C2

. ...-C3

Moist color1

10YR4/2

10YR5/6

i AVD « ic.

TftVPS/8

inVPT/l

1HVP8/1

10YR4/4

Texture2

Is

Is

dl

Isd

Is

Is

sl di.

Structure3

Ifgr 

Imsbk

Imsbk

Icsbk

MAivi/\

Clay skins Roots4

mf

cm

fm

Boundary5

QO

5»

'Munsell notation.

2ls, loamy sand; si, sandy loam.

3 1, weak; f, fine; m, medium; c, coarse; gr, granular; sbk, subangular blocky; MA, massive.

^f, few fine; mf, many fine; fm, few medium; cm, common medium.

5cs, clear smooth; as, abrupt smooth; gs, gradual smooth.

Table 40. Textural analysis of pedon S80SC-051-002

[Grain sizes in millimeters; all other values in weight percent. VF, very fine; F, fine; M, medium; C, coarse; VC, very coarse; , analyzed but below

detectable limits]

Depth 

(cm) Horizon

0-33 ----Ap

33_48 ----E

48-69 ----Bt

69-92 ----BC

92-120 ---Cl

120-136 ---C2

136-173 ---C3

Clay 

(<.002)

2.0

4.4

4.8

2.0

1.6

.8

8.4

Total

Silt 

(.002-.05)

5.0

3.9

3.8

2.6

7.6

8.3

8.9

Sand

(.05-2)

93.0

91.7

91.4

95.4

90.8

90.9

82.7

Clay

F 

(<.0002)

1.6

.8

1.2

.8

.4

Silt

F 

(.002-.02)

1.6

2.0

1.6

3.2

4.4

C

(.02-.05)

3.4

1.9

2.2

2.6

4.4

8.3

4.5

VF 

(.05-. 10)

1.9

1.4

1.3

1.7

3.5

3.4

2.2

Sand

F 

(.10-.25)

65.7

61.2

62.7

66.9

74.4

73.9

66.6

M 

(.25-.50)

20.8

22.6

21.3

20.9

11.1

11.8

11.7

C

(.5-1)

4.5

6.4

6.0

5.8

1.6

1.7

2.0

VC

(1-2)

0.1

.1

.1

.1

.2

.1

.2

34 Pedologic Studies in the Eastern United States
Table 4C. Physical and chemical analyses of pedon S80SC-051-002

[Units of measure for all values given in table 2B. , not detected; no entry, not analyzed; TR, trace]

Dithionite-citrate

Depth 

(cm)

0 33 -

33 48 -

48 69 -

69 92 -

92-120 

120-136 

136-173

Horizon

- - - - APAn

A ^

- - - - A2

RfO

TJ1

----Cl 

----C2 

----2C3

Organic 

C

0.79 

.23 

.22 

.10 

.08 

.07 

.12

Total

N

0.040 

.016 

.018 

.007

Extractable 

P

Total 

S

Bulk density

Depth 

(cm)

0-33 -

33 48 -

48 69 -

69 92 -

92-120 

120-136 

136-173

Horizon

---. /\pAn

---- A2

RtO

TJ1

----Cl 

----C2 

----2C3

Field 

moist

1/3 

bar

1.58 

1.81 

1.59 

1.55 

1.60 

1.68 

1.79

Oven 

dry

1.59 

1.82 

1.60 

1.57

1.68 

1.79

COLE3

0.002 

.002 

.002 

.004

Extractable 

Fe

0.2 

.3 

.4 

.2 

.1 

.1 

.7

Extractable Extractable 

Al Mn

TR 

TR

Water content

Field 

moist

1/3 

bar

5.1 

1.7 

6.1

4.3

3.7 

6.4

NH4OAC extractable bases

Depth

(cm)

0 33 -

33 48 -

48 69 -

69 92 -

92-120 

120-136 

136-173

Horizon

.-.- /\pAn

A9

RtO

TJ1

----Cl 

----C2 

----2C3

Ca Mg

0.9 0.3 

.1 .3 

.2 

TR 

TR

TR

_ j

Na K

TR 

 TR

Sum of 

bases

1.2 

0.4 

0.2

.1

Acidity

2.2 

.7 

.8

.1

Extractable

Al

0.3 

.4 

.6 

.3 

.2 

.1 

.7

Sum of 

cations

3.4 

1.1 

1.0

15 

bar2

1.5 

2.0 

2.1 

.9 

.6 

.4 

3.5

CEC1

NH4 

OAC

2.5 

1.3 

1.4 

.4 

.3 

.2 

1.7

WRD4

0.06

.06 

.05

.06

.05

NH4CI

1.8 

1.1 

1.7 

.9 

.6 

.4 

1.3

Ratio clay

CEC1

1.25 

.30 

.39 

.20 

.19 

.25 

.20

CaCl 2 

(.01 M) 

1:2

4.8 

4.6 

4.2 

4.3 

4.6 

4.7 

4.2

15 

bar2

0.75 

.45 

.44 

.45 

.38 

.50 

.42

PH

H2O 

1:1

5.4 

5.2 

4.8 

4.7 

4.9 

5.1 

4.8

Base saturation

Sum

35 

36 

20

NH4OAC

48 

31 

14 

5 

7 

10 

6

'Cation exchange capacity. 

2Water content at 15-bar pressure. 

Coefficient of linear extensibility. 

4Water-retention difference.

Table 4D. Bulk chemistry of pedon S80SC-051-002

Horizon

Major oxide

SiQ2 ------------

A1203 ----------

Fe203 -----------

MnO -----------

Tif~»

PaO

K

/~)

Na2O-----------

MgO -----------

Total -----------

Ap

------- 99.7

1C.

....... <.oi

--.-... <.Ql

-----._-_ 33

10

-----.... .06

.-.-... <.io

....... <.io

------ 100.6

A2

98.90 

1.78 

<.01 

<.01 

.39 

.17 

.08 

<.10 

<.10 

101.3

B2t

98.70 

2.06 

.12 

<.01 

.37 

.16 

.09 

<.10 

<.10 

101.5

B3 1

99.50 

1.35 

<.01 

<.01 

.37 

.16 

.05 

<.10 

<.10 

101.4

'Analysis of <63-(jLm fraction.

Soils and Morphostratigraphy in Horry County, S.C. 35
Table 5A. Field description of pedon S80SC-051-003

[Location: 8 km southwest of Conway, Horry County, South Carolina. Location: 33°48' N., 79°06' W. Temperature: 17 °C mean annual, 26 °C mean 

summer. Elevation: 14 m above mean sea level. Physiography: Barrier bar. Geomorphic position: Crest of interfluve. Aspect and slope: 1 percent plane. 

Precipitation: 137 cm, udic moisture regime. Drainage: Moderately well drained. Land use: Cropland. Parent material: Moderately weathered marine sand 

and clay. No entry indicates no data]

Depth

(cm)

0 23 --- 

23 37 ---

-37 «

55 73 ---

70 Ql

91 105 --

105 126 --

126 169 ---

169 190 -- 

Horizon

.....An/\p 

--.-. A21

A99

RH

RfO

.....A'?

-----Bhl

"DU^

tthl

Moist color1

10YR4/1

10YR6/4

1flYR7/4

10YR6/4

10YR6/4

i nvpd/^

7.5YR3/4

invpo/i

1fiVR9/9

Texture2

Is

fc

Is

Is

Is

Structure3

O/"1

O/"1

0/~1

Icshk

O/"1

MA ivi/\ 

MA

MA

Clay skins Roots4

cf

cf

ff

ff

cf

ff

Boundary5

53

'Munsell notation.

2sl, sandy loam; Is, loamy sand; s, sand; fs, fine sand.

3 1, weak; c, coarse; sbk, subangular blocky; SG, single grain; MA, massive.

4ff, few fine; cf, common fine.

5cs, clear smooth; cw, clear wavy; gs, gradual smooth.

Table 5fi. Textural analysis of pedon S80SC-051-003

[Grain sizes in millimeters; all other values in weight percent. VF, very fine; F, fine; M, medium; C, coarse; VC, very coarse; TR, trace; , analyzed

but below detectable limits]

Depth

(cm) Horizon

0-23 ----Ap

23-37 -

37-55 -

55-73 -

73-91 -

91-105

105-126

126-146

146-169

169-190

---A21

---A22

---Btl

---Bt2

---A'2

---Bhl

---Bh21

---Bh22

---Bh3

Clay 

(<.002)

2.4

2.4

4.8

12.5

8.5

1.6

.8

Total

Silt 

(.002-.05)

3.6

6.3

5.2

4.4

3.1

2.4

2.4

2.1

1.4

1.3

Clay Silt

Sand

(.05-2)

94.0

91.3

90.0

83.1

88.4

96.0

97.6

97.9

97.8

98.7

F F 

K.0002) (.002-.02)

0.8

2.8

2.0

1.2

 

0.8 .8

C

(.02-.05)

2.8

3.5

3.2

3.2

3.1

2.4

2.4

2.1

.6

1.3

VF 

(.05-.10)

1.1

.9

1.2

1.2

1.1

.6

.4

.5

.4

.4

F 

(.10-.25)

68.5

65.6

66.5

61.1

64.4

69.8

67.7

72.2

70.5

76.6

Sand

M 

(.25-.50)

23.2

23.6

21.1

19.8

21.8

24.7

27.9

24.1

26.3

19.2

C

(.5-1)

1.2

1.2

1.2

1.0

1.0

.9

1.6

1.1

.6

2.5

VC

(1-2)

TR

TR

0.1

TR

TR

TR

Table 5D. Bulk chemistry of pedon S80SC-051-003

Major oxide

Si02 --

A1203 ----------

TJ» fe2r\U3 - --------- 

MnO ----------

Tin

PaO

K

r\

Na2O----------

MgO ---------- 

Total ----------

Bt1

---- 52 40

1 f. GO

----- 6.47

------ .05

----- i 45

07

------ 51

------ .20

C. 1^

78 Q

Bt2

48.80

17 51

9 A ^

f\C.

1.43

.31

AA

.23

25

78.4

Horizon

A'2 1

42 75

14.88

9 on

.05

1.70

.37

.37

.30

<.10

70.3

Bh21 2

31 22

19.50

110

.05

1.77

.49

f.i

.30

<.10

55.1

Bh3 1

97.93

22

fS)

.01

.05

<.10

.05

< 20

<.10

99.3

'Analysis of <63-|wn fraction.

36 Pedologk Studies in the Eastern United States
Table 5C. Physical and chemical analyses of pedon S80SC-051-003

[Units of measure for all values given in table 2B. , not detected; no entry, not analyzed; TR, trace]

Dithionite-citrate

Depth 

(cm)

0-23 -

23 37 -

37 55 -

55 73 -

73 91 -

91-105 

105-126 

126-146 

146-169 

169-190

Depth 

(cm)

n 9^

23 37 -

37 55 -

55 73 -

73 91 -

91-105 

105-126 

126-146 

146-169 

169-190

Horizon

--.- A22

Rtl

----A'2 

----Bhl 

----Bh21 

----Bh22 

----Bh3

Horizon

TJOIt

-----A'2

-----Bhl

"DU^^

'DU'}

Organic 

C

0.73 

.23 

.17 

.24 

.18 

.36 

.34 

.68 

.68 

.39

Field 

moist

Total

N

0.045 

.018 

.014 

.024 

.018 

.020 

.011 

.016 

.022 

.008

Bulk density

1/3 

bar

1.60 

1.63 

1.55 

1.57 

1.60 

1.68 

1.70 

1.70 

1.67 

1.67

Extractable Total Extractable Extractable Extractable 

P S Fe Al Mn

0.1 

.2 

.2 

.7 

.6 

.3 

.1 

.1 

TR

0.1 

.1 

.1 

.3 

.2 

.2 

.2 

.3 

.2

Water content

Oven 

dry

1.64 

1.55 

1.57

1.68

1.75 

1.67 

1.67

COLE3

0.002 

.001

Field 1/3 

moist bar

4.7 

5.6

7.4

3.8

4.3 

3.7 

4.0

NH4OAC extractable bases

Depth 

(cm)

0-23 - 

23-37 - 

37-55 - 

55-73 - 

73-91 - 

91-105 

105-126 

126-146 

146-169 

169-190

Horizon

--Ap

---A21 

---A22 

---B21t 

---B22t 

---A'2 

---Bhl 

---Bh21 

---Bh22 

---Bh3

Ca Mg

0.3 0.1 

.1 TR 

.1 TR 

TR .1 

TR 

TR TR 

.1 TR 

TR TR

TR TR

Na K

 0.1 

TR TR 

 TR 

.1 

 TR

Sum of 

bases

0.5 

.1 

.1 

.2 

TR 

TR 

.1 

TR

TR

Acidity

1.4 

1.1 

1.3 

3.5 

1.9 

3.5 

2.7 

5.9 

5.5 

3.3

Extractable Sum of 

Al cations

0.5 1.9

.5 1.2 

.6 1.4 

1.3 3.7 

.9 1.9 

.4 3.5 

.3 2.8 

.4 5.9 

.4 5.5 

.3 3.3

CEC1

15 

bar2

1.4 

1.4 

1.6 

4.6 

3.3 

1.3 

.8 

1.2 

1.1 

.7

NH4 Bases 

OAC +AI

2.2 

1.1 

1.1 

2.4 

1.5 

1.3 

1.0 

2.0 

1.9 

1.0

1.0 

.6

.7 

1.5 

.9 

.4 

.4 

.4 

.4 

.3

WRD4

0.05 

.06 

.04

.04

.05 

.04 

.06

Al 

saturation

50 

83 

86 

87 

100 

100 

75 

100 

100 

100

Ratio clay

CEC1

0.92 

.46 

.23 

.19 

.18 

.81

2.38

CaCI 2 

(.01 M) 

1:2

4.1 

4.3 

4.2 

4.1 

4.3 

4.8 

5.0 

4.9 

4.9 

4.9

15 

bar2

0.58 

.58 

.33 

.37 

.39 

.81

1.38

PH

H2O 

1:1

4.4 

4.6 

4.6 

4.6

4.7 

5.2 

5.4 

5.4 

5.3 

5.3

Base saturation

Sum

26 

8 

7

5

4

NH4OAC

23 

9 

9 

8 

1 

2 

10 

1 

1 

2

'Cation exchange capacity. 

2Water content at 15-bar pressure. 

Coefficient of linear extensibility. 

4Water-retention difference.

Soils and Morphostratigraphy in Horry County, S.C. 37
Table 6A. Field description of pedon S80SC-051-004

[Location: 17.6 km northeast of Conway, Horry County, South Carolina; 33°52' N., 78°57' W. Temperature: 17 °C mean annual, 26 °C mean summer. 

Elevation: 14 m above mean sea level. Physiography: Barrier bar. Geomorphic position: Crest of interfluve. Aspect and slope: 10 percent plane. 

Precipitation: 137 cm, udic moisture regime. Water table: 169 cm. Drainage: Moderately well drained. Land use: Cropland. Parent material: Moderately 

weathered marine sand and clay. No entry indicates no data]

Depth 

(cm)

0 24 --- 

24 35 ---.

35-48 --- 

48 61 --- 

61 95 --- 

QC lOI

m l 10

1 1O 1 £f\

Horizon

.__.. ----- Ap An

. . . . . E2

-----BA

TJP1

D/~"1

-----C

Moist color1

10YR4/2 

10YR6/4 

10YR7/4 

10YR7/6 

10YR5/8 

10YR6/8 

10YR6/6 

10YR6/6

Texture2

Is 

Is 

Is 

Is 

si 

Is 

Is 

s

Structure3 Clay skins

Im+cgr 

SG 

SG 

Ifsbk 

If+msbk 

MA 

MA 

MA

Roots4

cf 

cf 

cf 

cf 

ff

Boundary5

as 

cs 

cs

gs 

cs 

cs 

cs

'Munsell notation.

2sl, sandy loam; Is, loamy sand; s, sand.

3 1, weak; f, fine; m, medium; c, coarse; gr, granular; sbk, subangular blocky; SG, single grain; MA, massive.

*ff, few fine; cf, common fine.

5cs, clear smooth; as, abrupt smooth; gs, gradual smooth.

Table 6fi. Textural analysis of pedon S80SC-051-004

[Grain sizes in millimeters; all other values in weight percent. VF, very fine; F, fine; M, medium; C, coarse; VC, very coarse; , analyzed but below

detectable limits]

Total Clay Silt Sand

Depth Clay Silt Sand F F C VF F M C VC 

(cm) Horizon (<.002) (.002-.05) (.05-2) (<.0002) (.002-.02) (.02-.05) (.05-.10) (.10-.25) (.25-.50) (.5-1) (1-2)

0-24 -

24-35 -

35-48 -

48-61 -

61-95 -

95-121

121-138

138-169

 Ap

---El

 E2

---BA

---Bt

---BC1

---BC2

---C

1.6

3.6

2.8

6.0

10.5

4.0

4.8

3.6

3.4

3.4

5.0

4.9

2.9

2.0

1.2

1.5

95.0

93.0

92.2

89.1

89.6

94.0

94.0

94.0

1.2

.8

.8

2.8

4.0

2.0

2.4

1.6

1.2

2.4

3.2

4.0

2.0

.8

1.2

1.5

2.2

1.0

1.8

.9

.9

1.2

1.1

.9

1.0

1.2

.9

.8

.5

.6

61.4

54.2

58.3

56.7

56.1

60.4

58.3

62.2

29.5

33.6

29.9

28.1

26.6

30.0

31.8

29.3

2.9

4.2

2.9

2.9

2.8

2.6

3.3

2.8

0.1

.1

.1

.2

.2

.2

.1

38 Pedologic Studies in the Eastern United States
Table 6C. Physical and chemical analyses of pedon S80SC-051-004

[Units of measure for all values given in table 2B. , not detected; no entry, not analyzed; TR, trace]

Depth 

(cm)

0 74 -

24 35 -

35-48 -

48 61 -

61 95 -

95-121 

121-138 

138-169

Depth 

(cm)

0 24 -

24 35 -

35-48 -

48 61 -

61 95 -

95 121

121-138 

138-169

Organic 

Horizon C

----Ap 

mil

0.74 

C1 1 f.

----BA .14

----Bt .14

----BC1 .06 

----BC2 .07 

----C .06

Field 

Horizon moist

 -Ap

---.-F2

-----BA

PPI

Rf~")

-----C

Total Extractable

N P

0.047 

.018 

.013 

.013 

.017

Bulk density

1/3 Oven 

bar dry

1.60 

1.60 

1.60 

1.61 1.64 

1.70 1.70 

1.62 1.65 

1.73 1.74 

1.70

Total Extractable 

S Fe

0.1

.2 

.2 

.4 

.7 

.5 

.7 

.4

Dithionite-citrate

Extractable 

Al

Water content

Field 

COLE3 moist

0.006

.006 

.002

NH4OAC extractable bases

Depth 

(cm)

0-24 -

24 35 -

35-48 -

48 61 -

61 95 -

95-121 

121-138 

138-169

Horizon Ca Mg

----Ap 0.8 0.3

m TD 1

PO TP

----BA .1 .1

m i i

----BC1 .2 .1 

----BC2 .1 .1 

----C .1 TR

Sum of 

Na K bases

 TR 1.1 

_ _ 1

TR

TR 9

TR 0.3 .8

.2 .5 

.2 .4 

.2 .3

Extractable 

Acidity Al

2.0 0.3 

1.0 .5 

.7 .4 

1.2 .5 

2.4 .7 

.4 .1

1 _

1/3 15 

bar bar2

1.3 

1.1 

1.1 

4.8 1.8 

5.4 3.7 

3.4 1.7 

6.4 1.9 

1.4

CEC1

Sum of NH4 

cations OAC

3.1 2.1 

1.1 .8 

.7 .7 

1.4 1.0 

3.2 1.9 

.9 .7 

.4 .4 

.4 .3

Ratio clay

Extractable 

Mn CEC1

1.31

 .22 

 .25 

.17 

TR .18 

.18 

.08 

.08

CaCI 2 

(.01 M) 

WRD4 1 :2

4.2 

4.3 

4.3 

0.05 4.2 

.03 4.3 

.03 4.8 

.08 4.9 

4.9

15 

bar2

0.81 

.31 

.39 

.30 

.35 

.43 

.40 

.39

PH

H2O 

1:1

4.5 

4.3 

4.4 

4.4 

4.8 

5.3 

5.3 

5.3

Base saturation

NH4CI Sum

1.6 35 

.7 9 

.5 

1.1 14 

1.6 25 

.8 56 

.5 100 

.5 75

NH4OAC

52 

12 

8 

20 

42 

71 

100 

100

'Cation exchange capacity. Coefficient of linear extensibility. 

2Water content at 15-bar pressure. 4Water-retention difference.

Table 6D. Bulk chemistry of pedon S80SC-05 1 -004

Major oxide

SiO2 ------------

A1203 ---------- 

Fe2O3 -----------

MnO -----------

Tifk

PaO

K

r\

Na2O----------- 

MgO -----------

Total -----------

B1 1

%

1'J

.--_.--.- 1 34

.....--.. 1.46

.......... .01

.......... .70

.......... .09

.......... .09

^ on

........ <.io

QQ 8

Horizon

Bt2

92.29 

2.60 

1.96 

.01 

.64 

.01 

.11 

<.20 

<.10 

97.6

B31 1

92.17 

2.02 

1.48 

.01 

.72 

.03 

.07 

<.20 

<.10 

96.5

B31 1

91.27 

1.10 

1.56 

.01 

.42 

.03 

.07 

<.20 

<.10 

94.4

'Analysis of <63-|«n fraction.

Soils and Morphostratigraphy in Horry County, S.C. 39
Table 7A. Field description of pedon S81SC-051-006

[Location: 4.8 km northeast of Conway, Horry County, South Carolina; 35°52'30" N., 79°05'56" W. Temperature: 17 °C mean annual, 26 °C mean 

summer. Elevation: lira above mean sea level. Physiography: Back-barrier flat. Geomorphic position: Interfluve summit. Slope and aspect: 1 percent 

plane. Precipitation: 137 cm, udic moisture regime. Drainage: Moderately well drained. Land use: Cropland. Parent material: Weathered marine sand 

and clay. No entry indicates no data]

Depth 

(cm) Horizon

0-23 --------Ap

O-3 OC Tjfl

IS AQ DfO

AQ 71 Rt't

71 104 -------Btg 

104 1S9 -------fVI

152 193 -------fV2

Moist color1 Texture2 Structure3 Clay skins

10YR4/3 fsl Ifgr 

7.5YR5/6 cl Imsbk

7.5YR5/6 cl 2msbk Common, thin, patchy

10YR5/4 c 3msbk Common, thin, patchy

10YR5/2 c 3csbk Common, thin, patchy

10YRS/9 r MA

Boundary4

oc

gw

'Munsell notation.

2fsl, fine sandy loam; cl, clay loam; c, clay; sc, sandy clay.

3 1, weak; 2, moderate; 3, strong; f, fine; m, medium; c, coarse; gr, granular; sbk, subangular blocky; MA, massive.

4cs, clear smooth; as, abrupt smooth; cw, clear wavy; gs, gradual smooth.

Table 7B. Textural analysis of pedon S81SC-051-006

[Grain sizes in millimeters; all other values in weight percent. VF, very fine; F, fine; M, medium; C, coarse; VC, very coarse; , analyzed but below

detectable limits]

Total Clay Silt Sand

Depth Clay Silt Sand F F C VF F M C VC 

(cm) Horizon «.002) (.002-.05) (.05-2) K.0002) (.002-.02) (.02-.05) (.05-.10) (.10-.25) (.25-.50) (.5-1) (1-2)

0-23 ----Ap

23-35 ----Btl

35_48 ----Bt2

48-71 ----Bt3

71-104 ..-Btg

104-152 ---Cgl

152-193 ---Cg2

152-193 ---Cg3

17.3

52.7

46.7

40.4

46.3

25.1

24.3

21.4

33.8

27.7

31.8

33.9

26.8

20.1

13.3

15.4

48.9

19.6

21.5

25.7

26.9

54.8

62.4

63.2

11.1

34.6

27.5

24.1

26.2

16.6

18.2

12.9

22.6

21 .4

24.2

25.7

20.9

14.2

8.9

10.5

11.2

6.3

7.6

8.2

5.9

5.9

4.4

4.9

8.9

4.3

4.3

5.3

4.4

5.3

4.2

4.8

26.1

10.1

11.1

13.1

14.6

30.9

34.2

35.4

8.9

3.4

3.9

4.4

5.3

11.7

15.0

14.5

3.9

1.3

1.6

2.2

2.1

5.4

7.1

6.4

1.1

.5

.6

.7

.5

1.5

1.9

2.1

40 Pedologic Studies in the Eastern United States
Table 7C. Physical and chemical analyses of pedon S81SC-051-006

[Units of measure for all values given in table 2B. , not detected; no entry, not analyzed; TR, trace]

Depth Organic Total Extractable Total 

(cm) Horizon C N P S

0-23 -----Ap 1.09 0.069

JT, ^S ----.Rtl 47 O^Q

35_48 -----Bt2 .35 .034

/IB "71 D*"J 1<; All

71-104 ----Btg .27 

104-152 ----Cgl .12 

152-193 ----Cg2 .10 

152-193 ----Cg3 .10

Bulk density

Depth Field 1/3 Oven 

(cm) Horizon moist bar dry COLE3

0-23 ------Ap 1.76 1.39 1.44 0.012

T-J -JC T}f1 1 CA

35_48 ------Bt2 1.61 1.50 1.59 .020

48 71 ------Bt3 1.50

71-104 -----Btg 1.72 1.58 1.69 .023

104 152 -----Cgl 1.60

1*9 iqa Po9 18^ 1 79 1 77 filfi

152 193 -----Cfr^ 1 70

NH4OAC extractable bases

Depth Sum of 

(cm) Horizon Ca Mg Na K bases Acidity

0 23 -----Ap 2.9 1.2 TR 0.3 4.4 6.2 

23 35 -----Btl 2.6 1.3 0.6 .1 4.6 13.9

7* Ay no i i o TD i T "7 n «

48-71 -----Bt3 .6 .7 .1 TR 1.4 12.7

71-104 ----Btg .5 .8 .1 .1 1.5 15.2 

104-152 ----Cgl .3 .4 TR TR .7 8.8 

152-193 ----Cg2 .4 .4 TR TR .8 8.9 

152-193 ----Cg3 .4 .3 TR TR .7 7.4

Nation exchange capacity. 

2Water content at 15-bar pressure. 

Coefficient of linear extensibility. 

4 Water-retention difference.

Table ID. Bulk chemistry of pedon S81SC-05 1-006

Major oxide Bt1 Bt2

oir~\ ai ^o 4^1 IT

A12O3 ------------------ 18.40 16.15 

Fe2O3 ------------------- 8.76 7.80

MnO -------------------- .01 .01

Tifv 1 SA 1 fvl

CaO--------------------- .36 .34

K c\ aa £i

Na2O------- ----------- <.20 <.20

MgO -------------------- .18 .10

Tntal Q1? 0 Q1? 8

Dithionite-citrate

Extractable Extractable 

Fe Al

1.2 

3.8 

3.5 

3.4 

4.9 

1.5 

.2 

1.9

Water content

Field 1/3 15 

moist bar bar2

5.1 15.3 7.8 

21.1 

14.0 23.7 19.3 

17.4 

10.2 22.4 19.8 

9.9 

7.6 13.8 9.1 

8.9

CEC1

Extractable Sum of NH4 

Al cations OAC

10.6 4.0 

3.6 18.5 10.8 

4.0 15.2 9.2 

5.0 14.1 9.4 

7.5 16.7 11.3 

4.8 9.5 7.0 

5.2 9.7 7.0 

4.0 8.1 5.7

Horizon

Bt3

71.79 

14.50 

7.60 

.01 

1.65 

.31 

.62 

<.20 

.10 

96.5

Ratio clay

Extractable 

Mn CEC1

0.23 

.21 

.20 

.23 

.24 

.28 

.29 

.27

CaCl2

(.01 M) 

WRD4 1 :2

0.10 5.0 

4.1 

.07 4.2 

4.3 

.04 4.3 

4.1 

.08 3.9 

3.9

15 

bar2

0.45 

.40 

.41 

.43 

.43 

.39 

.37 

.42

pH

H2O 

1:1

5.7 

4.6 

4.6 

4.7 

4.6 

4.6 

4.6 

4.7

. . Base saturation Al

saturation Sum

42 

44 25 

60 18 

78 10 

83 9 

87 7 

87 8 

85 9

Btg

61.92 

17.69 

11.40 

.01 

1.48 

.30 

.68 

<.20 

.10 

93.5

NH4OAC

100 

43 

29 

15 

13 

10 

11 

12

Soils and Morphostratigraphy in Horry County, S.C. 41
Table 8/4. Field description of pedon S81SC-051-007

[Location: 1.6 km west of Conway, Horry County, South Carolina; 33°50' N., 79°05'30" W. Temperature: 17 °C mean annual, 26 °C mean summer. 

Elevation: 10 m above mean sea level. Physiography: Back-barrier flat. Geomorphic position: Interfluve summit. Slope and aspect: 1 percent plane. 

Precipitation: 137 cm, udic moisture regime. Drainage: Moderately well drained. Land use: Cropland. Parent material: Weathered marine sand and clay. 

No entry indicates no data]

Depth 

(cm)

0 20 ----

on OQ

29 46 ----

46 60 ----

60 71 ----

71 Qfi ._._

96 142 ---

142 170 ---

Horizon

_.._ An /\p

AR

Df'J

H/"*~1 ----BCgl

----BCg2

Moist color 1

10YR3/1 

10YR4/4 

10YR6/6 

10YR5/6 

10YR5/8 

10YR6/1 

10YR6/1 

10YR6/1

Texture2

Ifs 

fsl 

fsl 

scl 

scl 

scl 

scl 

c

Structure3 Clay skins

Ifgr 

Ifgr 

Ifgr 

Imsbk Common, thin, patchy 

2msbk Common, thin, patchy 

2msbk Common, thin, patchy 

Icpr- Imsbk 

Icpr

Boundary4

aw 

cs 

cs 

cs 

cs 

cw 

gw

'Munsell notation.

2fsl, fine sandy loam; scl, sandy clay loam; Ifs, loamy fine sand; c, clay.

3 1, weak; 2, moderate; f, fine; m, medium; gr, granular; sbk, subangular blocky; pr, prismatic.

4cs, clear smooth; cw, clear wavy; aw, abrupt wavy; gw, gradual wavy.

Table 8fl. Textural analysis of pedon S81SC-051-007

[Grain sizes in millimeters; all other values in weight percent. VF, very fine; F, fine; M, medium; C, coarse; VC, very coarse; TR, trace; , analyzed

but below detectable limits]

Depth 

(cm)

0-20 -

20-29 -

29-46 -

46-60 -

60-71 -

71-96 -

96-142

142-170

Horizon

 Ap

---AB

---E

---Btl

---Bt2

---Bt3

---BCgl

---BCg2

Clay 

K.002)

4.1

4.1

7.3

33.8

37.6

31.3

31.7

65.5

Total

Silt 

(.002-.05)

25.6

25.6

26.2

19.5

15.8

11.7

15.3

30.5

Sand 

(.05-2)

70.3

69.3

66.5

46.7

46.6

57.0

53.0

4.0

Clay

F 

K.0002)

1.7

1.6

1.6

21.2

22.5

17.9

17.9

40.7

Silt

F 

(.002-.02)

17.0

17.1

17.4

13.0

10.6

8.5

10.2

24.5

C

(.02-.05)

8.6

9.5

8.8

6.5

5.3

3.2

5.1

6.0

VF 

(.05-.10)

11.3

10.9

10.2

6.8

5.1

5.7

13.6

1.5

F

(.10-.25)

47.2

25.9

44.3

30.7

30.5

37.0

32.3

1.9

Sand

M 

(.25-.50)

11.6

12.2

11.6

9.0

10.8

14.1

7.0

.5

C

(.5-1)

0.2

.3

.3

.2

.1

.2

.1

.1

VC

(1-2)

TR

TR

.1

TR

.1

TR

TR

TR

42 Pedologic Studies in the Eastern United States
Table 8C. Physical and chemical analyses of pedon S81SC-051-007

[Units of measure for all values given in table 2B. , not detected; no entry, not analyzed; TR, trace]

Dithionite-citrate

Depth

(cm)

0-20 - 

20 29 -

9Q A.f\

46 60 -

60-71 -

71 Qf,

96-142 

142-170

Horizon

---Ap 

----AB

Rf 1

----Bt2

D»1

----BCgl 

---BCg2

Organic 

C

1.67 

.83 

.33 

.36 

.29 

.24 

.16 

.19

Total

N

0.072 

.033 

.014 

.026

Extractable Total Extractable Extractable Extractable 

P S Fe Al Mn

0.3 

.4 

.4 

2.4 

3.6 

3.8 

4.5 

1.8

Bulk density

Depth

(cm)

0 20 -

20 29 -

9Q df\

46 60 -

60 71 -

71 96 -

96-142 

142-170

Depth 

(cm)

Horizon

--.._ An j\p 

-----AB

---.-F

TJf 1

Rt')

n»1

-----BCgl

-----BCg2

Horizon

0-20 ----Ap 

20-29 ----AB 

29-46 ----E 

46-60 ----Btl 

60-71 ----Bt2 

71-96 ----Bt3 

96-142 ---BCgl 

142-170 ---BCg2

Field 

moist

1.60

1.68 

1.53

NH4OAC

Ca Mg

1.6 0.4 

.3 TR 

.2 TR 

1.0 .3 

50.8 .5 

28.7 .3 

.8 .7 

3.3 2.4

1/3 

bar

.43 

.50 

.52 

.60 

.60 

.62 

.60 

.23

Oven 

dry

1.44 

1.52

1.70 

1.73

COLE3

0.002

.016 

.120

Field 

moist

4.0

14.1 

23.6

Water content

1/3 

bar

14.0 

12.1

20.2 

39.6

extractable bases

Na K

 0.1 

 TR 

TR TR 

.1 

TR TR 

TR .1 

0.1 .1 

.2 .3

Sum of 

bases

2.1 

.3 

.2 

1.4 

51.3 

29.1 

1.7 

6.2

Acidity

8.1 

7.3 

3.9 

9.9 

11.1 

10.4 

10.3 

22.7

Extractable 

Al

0.6 

1.0 

.8 

3.9 

5.3 

4.7 

5.6 

15.2

Sum of 

cations

10.2 

7.6 

4.1 

11.3 

62.4 

39.6 

12.0 

28.9

15 

bar2

3.3 

3.4 

3.6 

14.9 

15.5 

13.5 

14.0 

25.0

CEC1

NH4 Bases 

OAC +AI

6.1 2.7 

2.9 1.3 

1.7 1.0 

8.2 5.3 

9.5 56.6 

8.3 33.9 

9.4 7.3 

24.7 21.4

WRD4

0.15 

.13

.11 

.18

Al 

saturation

22 

77 

80 

74 

9 

14 

77 

71

Ratio clay

CEC1

1.49 

.71 

.23 

.24 

.25 

.27 

.30 

.30

CaCl2

(.01 M) 

1:2

4.4 

4.4 

4.4 

4.3 

4.2 

4.1 

3.9 

4.2

15 

bar2

0.80 

.83 

.49 

.44 

.41 

.43 

.44 

.38

pH

H2O 

1:1

4.9 

4.9 

5.0 

4.6

4.7 

4.7 

4.7 

4.5

Base saturation

Sum

21 

4 

5 

12 

82 

74 

14 

21

NH4OAC

34 

10 

12 

17 

100 

100 

18 

25

'Cation exchange capacity. 

2Water content at 15-bar pressure. 

Coefficient of linear extensibility. 

4Water-retention difference.

Table 8D. Bulk chemistry of the <63-|Am fraction, pedon S81SC-051-007

Major oxide

SiO2 ----------

A12O3 ---------

TJ- O

MnO ---------

TiC\

PaO

K p\

Ma n

MgO --------- 

Total ---------

E

. _ . . . 90 84

------ 5.17

i on

------- .02

1 78

------- .30

....... .41

----- <.20

----- <.10

---- 100.4

Btl

£- 7 fr-i

1 f. «O

8 1 ^

.02

1 59

.33

f-Q

< 20

.21

95 2

Horizon

Bt3

M. 75/ j 

19.96

15.95

.02

1.33

.32

oc

< 20

.16

93.3

BCgl

53.37

17.80

1 B 78

.02

1.34

32

.84

<.20

.13

O1 £.

BCg2

£*r\ i o

20 25

7.39

.01

1 24

40

1.15

< 25

52

93.1

Soils and Morphostratigraphy in Horry County, S.C. 43
Table 9/4. Field description of pedon S81SC-051-008

[Location: 1.6 km southwest of Conway, Horry County, South Carolina; 33°48' N., 79°01' W. Temperature: 17 °C mean annual, 26 °C mean summer. 

Elevation: 10 m above mean sea level. Physiography: Barrier bar. Geomorphic position: In slight depression. Slope and aspect: 0 percent plane. 

Precipitation: 137 cm, udic moisture regime. Drainage: Somewhat poorly drained. Land use: Forest, ungrazed. Parent material: Weathered marine sand 

and clay. No entry indicates no data]

Depth 

(cm)

0 1 8

IB 71

31-41 ----

41 61 ----

r 1 --r^r

76 91 ----

91 122 ---

Horizon

----A

----Bh

_ _- -Rw

----Bhl

T»h7

Moist color1 Texture2

1 f\ VD 1/1 c

10YR6/1 s

^VDO/1 o

10YR3/4 s

S

S VI? 0/1 c

Structure3

o/ »

O/"*

Imsbk

MA

MA

MAivi/\ 

MA

Clay skins Boundary4

aw

aw

gw

'Munsell notation.

2s, sand.

3 1, weak; m, medium; sbk, subangular blocky; SG, single grain; MA, massive.

4cw, clear wavy; aw, abrupt wavy; gw, gradual wavy.

Table 9fi. Textural analysis of pedon S81SC-051-008

[Grain sizes in millimeters; all other values in weight percent. VF, very fine; F, fine; M, medium; C, coarse; VC, very coarse; , analyzed but below

detectable limits]

Total Clay Silt Sand

Depth Clay Silt Sand 

(cm) Horizon (<.002) (.002-.05) (.05-2)

F F C VF F M C VC 

K.0002) (.002-.02) (.02-.05) (.05-.10) (.10-.25) (.25-.50) (.5-1) (1-2)

0-18 -

18-31 -

31-41 -

41-61 -

61-76 -

76-91 -

91-122

---A

---E

---Bh

---Bw

---Bhl

---Bh2

---Bh3

0.4

.4

3.4

2.4

.4

2.0

1.2

7.8

3.3

9.6

3.9

3.3

7.6

1.6

91.8

96.3

87.0

93.7

96.3

90.4

97.2

1.8

1.6

5.9

3.2

1.6

5.7

1.5

6.0

1.7

3.7

.7

1.7

1.9

.1

0.4

.5

.4

.6

.6

.2

.3

22.4

32.3

28.2

29.4

30.8

23.0

33.6

48.1

50.9

45.3

45.7

46.4

45.5

39.3

20.6

12.2

12.6

16.9

17.7

21.0

20.6

0.3

.4

.5

1.1

.8

.7

3.4

44 Pedologic Studies in the Eastern United States
Table 9C. Physical and chemical analyses of pedon S81SC-051-008

[Units of measure for all values given in table 2B. , not detected; no entry, not analyzed; TR, trace]

Dithionite-citrate

Depth 

(cm)

A 10

10 01

31-41 --

41 61 --

f\ is

76 91 --

91 122 -

Horizon

A

----Bh

- _ - - Rw

----Bhl

out

Dkl

Organic 

C

5.31 

.30 

2.62 

.48 

.68 

1.15 

1.90

Total

N

0.122 

.006 

.154 

.011 

.011 

.019 

.023

Extractable Total Extractable Extractable Extractable 

P S Fe Al Mn

0.1 

TR 

.1 

.2 

TR 

.1 

TR

Bulk density

Depth 

(cm)

A 10

18 ^1

31-41 -

41 61 -

61 76 -

76 91 -

91-122

Field 

Horizon moist

----- A

-----E

-----Bh

-----Bhl

DV>T

TJU-J

1.02

1.63 

1.88

1/3 

bar

0.67 

1.70 

1.67 

1.61 

1.60 

1.60 

1.64

Oven 

dry

0.84

1.68 

1.61

1.66

COLE3

0.078 

.002

TR

0.3

.2 

.1 

.3 

.3

Water content

Field 1/3 

moist bar

18.3

8.6 

1.0

NH4OAC extractable bases

Depth 

(cm)

0-18 - 

18-31 - 

31-41 - 

41-61 - 

61-76 - 

76-91 - 

91-122

Horizon

---A 

---E 

---Bh 

---Bw 

---Bhl 

---Bh2 

---Bh3

Ca Mg

0.4 1.0 

 TR 

.1 TR

TR 

Na K

TR 0.2 

0.1 

.2 

.5 

.1 

Sum of 

bases

1.6 

.1

 3

.5 

.1

Extractable 

Acidity Al

20.5 

1.3 

24.8 

6.6 

6.4 

12.6 

15.0

1.2 

.1 

5.7 

1.1 

1.4 

1.8 

1.6

Sum of 

cations

22.1 

1.4 

25.1 

6.6 

6.9 

12.6 

15.1

15 

bar2

10.2 

.2 

5.5 

2.0 

.8 

2.4 

2.1

CEC 1

NH4 

OAC

16.6 

1.1 

12.4 

1.8 

2.4 

4.1 

6.3

Bases 

+AI

2.8 

.2 

6.0 

1.1 

1.9 

1.8 

1.7

WRD4

0.23

.13 

.08

.09

Al 

saturation

43 

50 

95 

100 

74 

100 

94

Ratio clay

CEC1

41.50 

2.75 

3.65 

.75 

6.00 

2.05 

5.25

CaCl 2

(.01 M) 

1:2

2.8 

3.4 

3.4 

4.4 

3.7 

4.2 

4.3

15 

bar2

25.50 

.50 

1.62 

.83 

2.00 

1.20 

1.75

pH

H2O 

1:1

3.4 

3.9 

4.0 

4.7 

4.0 

4.5 

4.6

Base saturation

Sum

7 

7 

1

7 

1

NH4OAC

10 

9 

2 

1 

21 

TR 

2

'Cation exchange capacity. 

2Water content at 15-bar pressure. 

Coefficient of linear extensibility. 

4Water-retention difference.

Table 9D. Bulk chemistry of the <63-jun fraction, pedon S81SC-051-008

Horizon

Major oxide

SiOz 

A12O3 ---------

rec~ 2f\U3 -- ------ 

MnO ---------

TiO2 - ---------

PaO

K

p\

Na2O---------

MgO --------- 

Total ---------

E

OT cn

. --. 9 97

. -._. 91

----- .05

1 ^8

------.29

1 8

---- <.20

---- <.10

Of f\

Bh

72.31 

1.22 

1.04 

.03 

.46 

.29 

.22 

<.20 

<.10 

75.5

Bw

78.04 

7.69 

2.83 

.02 

1.06 

.31 

.39 

<.20 

<.10 

90.3

Bh1

76.26 

3.72 

<.01 

.05 

1.03 

.29 

.21 

<.20 

<.10 

81.5

Bh2

78.56 

5.65 

.16 

.01 

2.20 

.29 

.22 

<.20 

2.41 

89.5

Bh3

91.69 

<.10 

.70 

.01 

.20 

.05 

.01 

.70 

.50 

93.8

Soils and Morphostratigraphy in Horry County, S.C. 45
Table 10/4. Field description of pedon S81SC-051-009

[Location: 4.8 km east of Conway, Horry County, South Carolina; 33°53'30" N., 79°54'40" W. Temperature: 17 °C mean annual, 26 °C mean summer. 

Elevation: 10 m above mean sea level. Physiography: Back-barrier flat. Geomorphic position: In slight depression. Slope and aspect: 1 percent plane. 

Precipitation: 137 cm, aquic moisture regime. Drainage: Somewhat poorly drained. Land use: Cropland. Parent material: Weathered marine sand and 

clay. No entry indicates no data]

Depth 

(cm) Horizon

0-22 ------- Ap 

22 42 ------- Rtl

42 84 ------- Bt2

84-134 ------Bt3

134 180 ------ BCg 

1 80 204 ------ 1C

Moist color1

10YR3/2 

10YR5/2 

10YR4/2 

10YR5/8 

10YR7/2 

10YR5/8

Texture2

fsl 

cl 

c 

c 

scl 

si

Structure3

Imsbk 

2fsbk 

2fsbk 

2msbk 

2msbk 

MA

Clay skins

Common, thin, patchy 

Common, thin, patchy 

Common, thin, patchy

Roots4

cvf+f 

ff 

ff 

fvf

Boundary5

as 

cw 

cw

gs 

gw

'Munsell notation.

2sl, sandy loam; scl, sandy clay loam; fsl, fine sandy loam; cl, clay loam; c, clay; s, sand.

3 1, weak; 2, moderate; f, fine; m, medium; sbk, subangular blocky; MA, massive.

^f, few fine; fvf, few very fine; cvf, common very fine; f, fine.

5as, abrupt smooth; cw, clear wavy; gs, gradual smooth; gw, gradual wavy.

Table 10fl. Textural analysis of pedon S81SC-051-009

[Grain sizes in millimeters; all other values in weight percent. VF, very fine; F, fine; M, medium; C, coarse; VC, very coarse; TR, trace; , analyzed

but below detectable limits]

Depth

(cm)

0-22 -

22-42 -

42-84 -

84-134

134-180

180-204

Horizon

---Ap

---Btl

---Bt2

---Bt3

---BCg

---2C

Clay

K.002)

14.1

35.2

44.7

43.0

26.8

11.3

Total

Silt

(.002-.05)

20.8

15.6

13.6

12.2

11.7

2.9

Sand

(.05-2)

65.1

49.2

41.7

44.8

61.5

85.8

Clay

F

K.0002)

9.1

25.4

30.8

30.4

18.7

8.5

Silt

F

(.002-.02)

13.7

10.2

9.0

7.4

6.1

.4

C

(.02-.05)

7.1

5.4

4.6

4.8

5.6

2.5

VF

(.05-.10)

4.4

3.3

2.8

2.8

3.4

3.5

F

(.10-.25)

56.2

42.5

35.9

39.0

38.7

22.7

Sand

M

(.25-.50)

3.4

2.7

2.4

2.4

15.9

41.0

C

(.5-1)

0.9

.6

.6

.6

3.4

7.5

VC

(1-2)

0.2

.1

TR

.1

.1

46 Pedologic Studies in the Eastern United States
Table 10C. Physical and chemical analyses of pedon S81SC-051-009

[Units of measure for all values given in table 2B. , not detected; no entry, not analyzed; TR, trace]

Dithionite-citrate

Depth

(cm) Horizon

0-22 -----Ap 

22-42 -----Btl 

42 84 nt^

84-134 

134-180 

180-204

----Bt3 

---BCg 

----2C

Organic 

C

1.55 

.49 

.46 

.43 

.16 

.13

Total

N

0.076 

.040 

.042

Extractable Total Extractable Extractable Extractable 

P S Fe Al Mn

1.0

2.3 

4.3 

4.6 

.7 

.7

Bulk density

Depth

(cm)

O 77

22-42 -

42 84 -

84-134 

134-180 

180-204

Horizon

----- /\pAn

Htl

RO

D*"J

_-.--BCe *JV-&

. . . . . 2C

Field 

moist

1.50 

1.42 

1.72

1/3 

bar

1.51 

1.40 

1.32 

1.30 

1.71 

1.70

Oven

dry

1.54 

1.456 

1.78

COLE3

0.007 

.057 

.013

Field 

moist

7.5 

26.1 

13.1

Water content

1/3 

bar

NH4OAC extractable bases

Depth 

(cm)

0-22 - 

22-42 - 

42-84 - 

84-134 

134-180 

180-204

Horizon

 Ap 

---Btl 

---Bt2 

---Bt3 

---BCg 

---2C

Ca Mg

2.8 1.1 

1.3 .6 

1.3 .6 

1.5 .7 

1.1 .4 

1.4 .3

Na K

 0.4 

0.3 .2 

TR .1 

TR .1 

.1 .1 

TR .1

Sum of 

bases

4.3 

2.4 

2.0 

2.3 

1.7 

1.8

Acidity

7.6 

10.2 

13.3 

12.5 

8.5 

4.0

Extractable 

Al

0.3 

4.2 

5.3 

4.2 

4.9 

1.7

Sum of 

cations

11.9 

12.6 

15.3 

14.8 

10.2 

5.8

15 

bar2

6.8 

14.4 

18.7 

19.2 

11.0 

5.1

CEC1

NH4 Bases 

OAC +AI

7.7 4.6 

8.9 6.6 

10.5 7.3 

10.1 6.5 

8.2 6.6 

4.1 3.5

WRD4

0.11 

.21 

.07

Al 

saturation

7 

64 

73 

65 

74 

49

Ratio clay

CEC 1

0.55 

.25 

.23 

.23 

.31 

.36

CaCl2 

(.01 M) 

1:2

5.1 

4.1 

4.2 

4.2 

4.0 

4.0

15 

bar2

0.48 

.41 

.42 

.45 

.41 

.45

pH

H2O 

1:1

5.5 

4.4 

4.4 

4.6 

4.6 

4.5

Base saturation

Sum

36 

19 

13 

16 

17 

31

NH4OAC

56

27 

19 

23 

21 

44

'Cation exchange capacity. 

2Water content at 15-bar pressure. 

Coefficient of linear extensibility. 

4Water-retention difference.

Table 10D. Bulk chemistry of pedon S81SC-051-009

Major oxide

SiQ2 ----------------

AlzOs 

reCo 2C\ U3- -------------- 

MnO ---------------

Tin

PaO

if /~\

Na2O---------------

MgO --------------- 

Total ---------------

Bt1

.._-__-._. 53 92

..-..-.-.. 17.54

8 Qf\

rj-j

1 7]

ia

........... .46

<r- 7(\

........... .24

89 7

Horizon

Bt3

58.05

in TO

18 7*i

.01

1 18

.35

CO

.20

.10

Q8 n

BCg

<9 OR

17.39

« nn

.02

110

.34

89

i no

.10

78 7

Soils and Morphostratigraphy in Horry County, S.C. 47
Table 11/4. Field description of pedon S81SC-051-010

[Location: 8 km southwest of Floyds, Horry County, South Carolina; 34°08' 10" N., 79°08'20" W. Temperature: 17 °C mean annual, 26 °C mean summer. 

Elevation: 20 m above mean sea level. Physiography: Rim of Carolina bay. Geomorphic position: Interfluve summit. Slope and aspect: 1 percent plane. 

Precipitation: 137 cm, aquic moisture regime. Drainage: Moderately well drained. Land use: Cropland. Parent material: Weathered marine or fluvial sand 

and clay. No entry indicates no data]

Depth

(cm)

ft TO

oo 4ft

40 63 ----

63 96 ----

96 134 ---

134 162 ---

Horizon

__-. /\pAn

----Bhl

DUT

Moist color1

lftYR^/9

IftVU^/1}

10YR5/6

10YR6/2

SYP^n

i n VP ^ /^

Texture2

Is13

Structure3

O/"1

O/"1

O/"1

Q/~"

MA

MA

Clay skins Boundary4

gw

gw

5\V

'Munsell notation.

2ls, loamy sand; s, sand.

3SG, single grain; MA, massive.

4cs, clear smooth; as, abrupt smooth; gw, gradual wavy.

Table 116. Textural analysis of pedon S81SC-051-010

[Grain sizes in millimeters; all other values in weight percent. VF, very fine; F, fine; M, medium; C, coarse; VC, very coarse; , analyzed but below

detectable limits]

Total Clay Silt Sand

Depth Clay Silt Sand F F C VF F M C VC 

(cm) Horizon (<.002) (.002-.05) (.05-2) (<.0002) (.002-.02) (.02-.05) (.05-.10) (.10-.25) (.25-.50) (.5-1) (1-2)

0-28 --

28-40 --

40-63 --

63-96 --

96-134 -

134-162 -

--Ap

--E

--BW

--Bt

--Bhl

--Bh2

0.8

2.0

1.2

6.4

3.3

2.5

4.6

4.3

4.2

14.5

7.3

5.7

94.6

93.7

94.6

79.1

89.4

91.8 

0.8

.4

.8

9.2

3.7

1.6

3.8

3.9

3.4

5.3

3.6

4.1

0.6

1.0

1.0

1.6

.7

.8

8.3

13.1

11.6

13.2

9.0

10.0

48.0

51.2

49.8

41.1

43.8

50.0

35.5

27.1

30.2

21.7

32.3

28.8

2.2

1.3

2.0

1.5

3.6

2.2

48 Pedologic Studies in the Eastern United States
Table 11C. Physical and chemical analyses of pedon S81SC-051-010

[Units of measure for all values given in table 2B. , not detected; no entry, not analyzed; TR, trace]

Depth

(cm)

Organic 

Horizon C

0-28 -----Ap 0.68 

28-40 -----E .20 

40-63 -----Bw .16

96-134 

134-162

Depth

(cm)

n TO

98 40 -

40 63 -

f/l Qf.

96-134 

134-162

----Bhl .96 

----Bh2 1.26

Field 

Horizon moist

.

P

"Dt 1 Q1

-----Bhl

-----Bh2 1.49

Total

N

0.023 

.006 

.005 

.006 

.010 

.018

Bulk density

1/3 

bar

1.70 

1.70 

1.70 

1.67 

1.70 

1.69

Dithionite-citrate Ratio clay

Extractable Total Extractable Extractable Extractable 

P S Fe Al Mn

Oven 

dry

1.67 

1.69

NH4OAC extractable bases

Depth

(cm)

0-28 - 

28-40 - 

40-63 - 

63-96 - 

96-134 

134-162

Horizon Ca Mg

---Ap 0.7 0.2 

---E .1 TR 

. . _BW 

- - -Bt TR 

---Bhl 

___Bh2 

Na K

 0.1 

 TR 

 TR 

 TR 

 TR 

 TR

Sum of 

bases

1.0 

.1 

TR 

TR 

TR 

TR

0.1 0.1 

TR TR 

.1 TR

.1 .1 

TR .2 

.1 .3

Water content

Field 1/3 15 

COLE3 moist bar bar2

1.0 

.8 

.5 

1.5 2.0 

2.8 

12.5 2.9

CEC1

Extractable Sum of NH4 Bases 

Acidity Al cations OAC +AI

2.1 0.2 3.1 1.9 1.2 

1.1 .2 1.2 .4 .3 

.5 .2 .5 .1 .2 

1.6 .5 1.6 .8 .5 

8.7 .9 8.7 2.8 .9 

12.3 1.1 12.3 4.5 1.1

WRD4

.07 

.15

Al 

saturation

17 

67 

100 

100 

100 

100

CEC1

2.38 

.20 

.08 

.13 

.85 

1.80

CaCl 2 

(.01 M) 

1:2

4.9

4.4 

4.4 

4.3 

4.5 

4.5

Base

Sum

32 

8

15 

bar2

1.25 

.40 

.42 

.31 

.85 

1.16

PH

H2O 

1:1

5.4 

4.8 

4.8 

4.7 

4.9 

4.8

saturation

NH4OAC

53 

25 

20 

2 

1 

TR

'Cation exchange capacity. 

2Water content at 15-bar pressure. 

Coefficient of linear extensibility. 

4Water-retention difference.

Table 11 D. Bulk chemistry of pedon S81SC-051-010

Horizon

Major oxide

SiOz-- -------

A12O3 -----------

Fe203 ----------

MnO -----------

TiO2 ------------

CaO------------

K20--- --

Na2O-----------

MgO -----------

Total -----------

Bw1

--...--94.55

-------- 3.27

......... .60

.-...---. .02

-------- 1.42

--....--. .30

......... .26

-.....--. .20

......... jo

------ 100.7

Bt

92.23

4.78

.40

.01

1.68

.29

.27

.22

.10

99.9

Bhl 1

78.27

8.25

.17

.02

2.31

.29

.30

.34

<.10

89.9

Bh2'

48.63

17.79

14.99

.02

1.10

.34

.49

.30

.15

83.8

'Analysis of 63-jim fraction.

Soils and Morphostratigraphy in Horry County, S.C. 49
Table 12/4. Field description of pedon S81SC-051-011

[Location: 6.4 km southwest of Floyds, Horry County, South Carolina; 34°08'10" N., 79°08'20" W. Temperature: 17 °C mean annual, 26 °C mean 

summer. Elevation: 21 m above mean sea level. Physiography: Back-barrier flat. Geomorphic position: Interfluve summit. Slope and aspect: 1 percent 

plane. Precipitation: 137 cm, udic moisture regime. Drainage: Poorly drained. Land use: Forest, ungrazed. Parent material: Weathered marine or fluvial 

sand and clay. No entry indicates no data]

Depth

(cm)

A 10

1 O -J-J

33 51 ----

51 79 ----

7Q 119-

m i *i'2

163 204 ---

Horizon

----A

----F2

----Btg 

----Cel v-gi

.... v^g^, Co2

f\r~* ^

----2Cg

Moist color1

«YP'7/'>

1ftVP7/'7

i n VD a / 1

10YR4/2

10YR4/1

IftVP'*/'?

invpo/i

Texture2

Is

si

Structure3

Ifgr 

Imsbk

2msbk

3msbk

MA

MA

Clay skins Boundary4

PQ

PQ

PQ

'Munsell notation.

2sl, sandy loam; Is, loamy sand; fsl, fine sandy loam; s, sand.

3 1, weak; 2, moderate; 3, strong; f, fine, m, medium; c, coarse; gr, granular; sbk, subangular blocky; MA, massive.

4cs, clear smooth.

Table 12fi. Textural analysis of pedon S81SC-051-011

[Grain sizes in millimeters; all other values in weight percent. VF, very fine; F, fine; M, medium; C, coarse; VC, very coarse; , analyzed but below

detectable limits]

Total Clay Silt Sand

Depth Clay Silt Sand F F C VF F M C VC 

(cm) Horizon (<.002) (.002-.05) (.05-2) (<.0002) (.002-.02) (.02-.05) (.05-.10) (.10-.25) (.25-.50) (.5-1) (1-2)

0-18 ----A

18-33 ----El

33-51 ----E2

51_79 -..-Btg

79-112 ---Cgl

112-163 ---Cg2

163-204 ---2Cg

3.2

.8

1.6

4.0

2.0

2.0

13.3

40.2

10.7

20.9

20.0

16.4

16.0

25.7

56.6

88.5

77.5

76.0

81.6

82.0

61.0

24.3

4.5

12.9

12.1

10.5

9.7

15.5

15.9

6.2

8.0

7.9

5.9

6.3

10.3

3.5

1.1

1.8

2.0

1.5

.9

4.6

15.3

16.6

16.3

16.6

16.1

14.4

15.4

27.1

52.9

43.1

41.8

45.8

46.2

25.6

9.6

17.0

15.4

14.8

17.3

19.4

14.0

1.1

.9

.9

.8

.9

1.1

1.4

50 Pedologic Studies in the Eastern United States
Table 12C. Physical and chemical analyses of pedon S81SC-051-011

[Units of measure for all values given in table 2B. , not detected; no entry, not analyzed; TR, trace]

Depth 

(cm) Horizon

0-18 -----A

10 -3-3 pi

'j'j <;i co

51 79 -----Btg 

79_112 ----Cgl 

112-163 ----Cgl 

163-204 ----2Cg

Depth 

(cm) Horizon

0-18 ------A

1 0 'J'2 t71

13 Si ... -F?

51 79 ......Btg

O

79 112 -----Cgl

112 163 -----Cg2

1 £.*} ^f\A ^/~*

Organic 

C

11.50 

1.07 

.26 

.53 

.39 

.55 

.21

Field 

moist

2.03 

1.99

Total

N

0.578 

.031 

.006

.006 

.141

Bulk density

1/3 

bar

1.00 

1.70 

1.98 

1.99 

1.70 

1.70 

1.30

Dithionite-citrate Ratio clay

Extractable Total Extractable Extractable Extractable 

P S Fe Al Mn CEC1

Oven 

dry

1.98 

1.99

NH4OAC extractable bases

Depth 

(cm) Horizon Ca

0-18 ----Ap 14.8 

18-33 ----El .5 

33-51 ----E2 .1 

51-79 ----Btg .4 

79-1 12 ---Cgl .3 

112-163 ---Cg2 .4 

163-204 ---2Cg 11.3

Mg

0.9 

.2 

TR 

.1 

.1 

.2 

.4

Na K

0.2 0.5 

 TR 

.4 TR 

.1 

TR TR 

 TR 

.2 .2

Sum of 

bases

16.4 

.7 

.5 

.6 

.4 

.6 

12.1

0.1 

TR 

TR 

TR 

TR 

TR 

.1

Water content

Field 1/3 15 

COLE3 moist . bar bar2

22.1 

1.8 

2.0 .6 

5.1 1.3 

.8 

1.1 

10.9

CEC1

Extractable Sum of NH4 Bases 

Acidity Al cations OAC +AI

37.6 0.4 54.0 50.2 16.8 

2.2 .1 2.9 1.7 .8 

.7 TR 1.2 .6 

1.4 .2 2.0 1.4 .8 

1.1 TR 1.5 .9 

1.1 TR 1.7 1.2 

16.3 28.4 19.2

15.69 

2.13 

.38 

.36 

.45 

.60 

1.44

CaCl 2 

(.01M) 

WRD4 1 :2

4.4 

4.1 

0.13 4.6 

.15 4.6 

4.6 

4.6 

4.9

15 

bar2

6.91

2.25 

.38 

.33 

.40 

.55 

.82

pH

H2O 

1:1

4.4 

4.7 

5.1 

5.3 

5.3 

5.3 

5.5

Base saturation

Al 

saturation Sum

2 30 

12 24 

42 

25 30 

27 

35 

43

NH4OAC

33 

41 

83 

43 

44 

50 

63

'Cation exchange capacity. 

2Water content at 15-bar pressure. 

Coefficient of linear extensibility. 

4Water-retention difference.

Table 12D. Bulk chemistry of the <63-|xm fraction, pedon 

S81SC-051-011

Major oxide Btg horizon

Si02 -- 

A1203 - 

Fe203 - 

MnO - 

Ti02 -- 

CaO-- 

K20-- 

Na2OMgO - 

Total -

95.15

2.44

- .05

1.59 

.34 

.49 

.40

100.4

Soils and Morphostratigraphy in Horry County, S.C. 51
Table 13/4. Field description of pedon S81SC-051-012

[Location: 16 km northwest of Floyds, Horry County, South Carolina; 34°12'20" N., 79°04'55" W. Temperature: 17 °C mean annual, 26 °C mean summer. 

Elevation: 21 m above mean sea level. Physiography: Back-barrier flat. Geomorphic position: Interfluve summit. Slope and aspect: 1 percent plane. 

Precipitation: 137 cm, udic moisture regime. Drainage: Well drained. Land use: Cropland. Parent material: Weathered marine sand and clay. No entry 

indicates no data]

Depth 

(cm) Horizon

0-25 --------Ap 

o<: <;i TJ*I

<:i 01 TJ*T

o 1 Oft D+O

99 119 -_-____Bt4

119 145 -------BC

i/i<; ion TTJ<^I

1 8n TIQ *mt~"}

Moist color1

10YR4/2

i f\ V~D <; m

10YR5/8

invps/8

10YR6/1

2 SVPA/8

Texture2

Ifs lid

oWl

oWl

Ljl/1

OW1

Ol

Structure3

Ifgr 

Imsbk

Imsbk

Imsbk

2msbk

2msbk

2msbk

Clay skins Boundary4

QC

O

CS

'Munsell notation.

2lfs, loamy fine sand; scl, sandy clay loam; si, sandy loam.

3 1, weak; 2, moderate; f, fine; m, medium; gr, granular; sbk, subangular blocky; MA, massive.

4as, abrupt smooth; gw, gradual wavy; gs, gradual smooth; cs, clear smooth; cw, clear wavy.

Table 13B. Textural analysis of pedon S81SC-051-012

[Grain sizes in millimeters; all other values in weight percent. VF, very fine; F, fine; M, medium; C, coarse; VC, very coarse; , analyzed but below

detectable limits]

Total Clay Silt Sand

Depth Clay Silt Sand F F C VF F M C VC 

(cm) Horizon (<.002) (.002-.05) (.05-2) (<.0002) (.002-.02) (.02-.05) (.05-.10) (.10-.25) (.25-.50) (.5-1) (1-2)

0-25 -

25-51 -

51-81 -

81-99 -

99-119

119-145

145-180

180-219

 Ap

---Btl

---Bt2

---Bt3

---Bt4

---BC

---2BC1

---2BC2

2.8

21.1

20.7

21.0

21.1

27.1

36.2

23.0

19.2

19.3

18.7

20.2

20.4

20.3

20.9

12.5

78.0

59.6

60.6

58.8

58.5

52.6

42.9

64.5

0.8

14.6

15.0

15.0

12.2

19.0

21.6

14.1

5.7

7.7

8.9

10.1

10.5

10.5

10.6

6.5

13.5

11.6

9.9

10.1

9.9

9.8

10.3

6.0

28.4

22.9

23.4

23.3

22.7

22.0

24.5

11.8

43.2

31.9

32.5

31.5

31.3

26.9

15.7

49.4

4.5

3.0

3.3

2.9

3.0

2.5

1.4

2.8

1.5

1.2

1.0

.9

1.0

.9

.9

0.5

0.4

.6

.4

.2

.5

.3

.4

52 Pedologic Studies in the Eastern United States
Table 13C. Physical and chemical analyses of pedon S81SC-051-012

[Units of measure for all values given in table IB. , not detected; no entry, not analyzed; TR, trace]

Dithionite-citrate

Depth

(cm) Horizon

0-25 -----Ap 

25 51 -- mi

SI 81

o 1 oo

99-119 - 

119-145 - 

145-180 - 

180-219 -

Rf?

Rt7?

---Bt4 

---BC 

---2BC1 

---2BC2

Organic 

C

0.57 

.30 

.18 

.17 

.18 

.16 

.16 

.11

Total

N

0.027 

.024 

.010

Extractable Total Extractable Extractable Extractable 

P S Fe Al Mn

0.2 

1.7 

1.8 

2.1 

2.4 

2.6 

3.4 

1.7

Bulk density

Depth

(cm)

0 25 -

25 51 --

C| 01

01 QQ

99 119 -

119 145 -

145 180 -

180 219 -

Horizon

-- - - - - - /\pAn

D*1

Rtl

Df3

----Bt4

'Of

ORPI

Tf>C"1

Field 

moist

1.64 

1.62

1/3 

bar

1.70 

1.60 

1.64 

1.60 

1.60 

1.55 

1.50 

1.60

NH4OAC extractable

Depth

(cm) Horizon

0-25 ----Ap 

25-51 ----Btl 

51-81 ----Bt2 

81-99 ----Bt3 

99-119 ---Bt4 

119-145 ---BC 

145-180 ---2BC1 

180-219 ---2BC2

Ca Mg

1.1 0.2 

1.8 .4 

1.8 .4 

1.7 .4 

1.6 .5 

1.4 .6 

1.3 .9 

.2 .3

Na K

 0.2 

.4

_ 2

TR .1 

0.1 .1 

.2 .1 

.3 .1 

.5 .1

Oven 

dry

1.65 

1.64

bases

Sum of 

bases

1.5 

2.6 

2.4 

2.2 

2.3 

2.3 

2.6 

1.1

COLE3

0.002 

.019

Acidity

2.0 

4.7 

4.6 

4.8 

4.8 

6.5 

11.7 

6.8

Field 

moist

13.6 

17.6

Extractable 

Al

0.1 

.6 

.6 

.8 

1.1 

2.6 

5.1 

4.0

Water content

1/3 

bar

15.5 

21.9

Sum of 

cations

3.5 

7.3 

7.0 

7.0 

7.1 

8.8 

14.3 

7.9

15 

bar2

1.6 

8.5 

8.8 

9.6 

10.5 

13.2 

16.4 

9.6

CEC1

NH4 Bases 

OAC +AI

1.9 1.6

4.1 3.2 

3.6 3.0 

3.8 3.0 

4.5 3.4 

6.2 4.9 

9.1 7.7 

5.2 5.1

WRD4

0.11 

.13

Al 

saturation

6 

10

2 

27 

32 

53 

66 

78

Ratio clay

CEC1

0.68 

.19

.17 

.18 

.21

.23 

.25 

.23

CaCI 2 

(.01 M) 

1:2

4.8 

4.6 

4.5 

4.5 

4.5 

4.2 

4.2 

4.3

15 

bar2

0.57 

.40 

.43 

.46 

.50 

.49 

.45 

.42

pH

H2O 

1:1

5.3 

4.8 

4.8 

4.7 

4.6 

4.5 

4.5 

4.5

Base saturation

Sum

43 

36 

34 

31 

32 

26 

18 

14

NH4OAC

79 

63 

67 

58 

51 

37 

29 

21

'Cation exchange capacity. 

2Water content at 15-bar pressure. 

Coefficient of linear extensibility. 

4Water-retention difference.

Table 13D. Bulk chemistry of the <63-|xm fraction, pedon S81SC-051-012

Horizon

Major oxide

SiQ2 ---------

A12O3 --------

Fe203 -------- 

MnO --------

T;<"I

TaH

K C\

Na2O--------

MgO -------- 

Total --------

Bt1

---69.18

--- 15.08

. ... fi 46

tvy

1 89

----- 39

----- .41

--- <.20

----- .10

- - - 93 4

Bt2

68.99 

15.88 

7.08 

.02 

1.93 

.38 

.34 

<.20 

<.10 

94.6

Bt3

69.08 

15.79 

8.05 

.02 

1.92 

.38 

.36 

<.20 

<.10 

95.6

Bt4

67.67 

16.47 

8.36 

.02 

1.93 

.37 

.40 

.30 

.10 

95.6

BC

62.56 

19.12 

9.60 

.02 

1.77 

.35 

.50 

<.20 

.10 

94.0

2BC1

61.00 

20.18 

9.93 

.03 

1.62 

.33 

.72 

.30 

.36 

94.4

2BC2

63.93 

18.52 

10.16 

.03 

1.35 

.29 

.84 

<.20 

.38 

95.5

Soils and Morphostratigraphy in Horry County, S.C. 53
Table 14/4. Field description of pedon S81SC-051-013

[Location: 0.8 km north of Floyds, Horry County, South Carolina; 34°12' N., 79°03'50" W. Temperature: 17 °C mean annual, 26 °C mean summer. 

Elevation: 28 m above mean sea level. Physiography: Back-barrier flat. Geomorphic position: Interfluve summit. Slope and aspect: 1 percent plane. 

Precipitation: 137 cm, udic moisture regime. Drainage: Well drained. Land use: Cropland. Parent material: Weathered marine sand and clay. No entry 

indicates no data]

Depth

(cm)

0 23 ----

23 35 -..-

35 73 .-._

73-109 "71 1 f\f\ ---

109 124 ---

124 147 ---

147 173 ---

173 196 ---

196 243 ---

Horizon

.-._ /\p An

_..-F

Rtl

Rf?

Rtl

RP1

Rf"">

ID/"1

- - - - 2C

Moist color1

10YR4/2

10YR6/4

10YR5/6

10YR6/8

1 flVD £. Hi

10YR6/6

10YR5/6

1HVP7/1

2.5YR4/6

Texture2 Structure

Ifs

Ifs lid

dVi,

cl

Wl

cl Wl

t3Vl

Clay skins Boundary3

oc

gs o

gwo

oc

'Munsell notation.

2lfs, loamy fine sand; scl, sandy clay loam; cl, clay loam; s, sand.

3as, abrupt smooth; cs, clear smooth; gs, gradual smooth; cw, clear wavy; gw, gradual wavy.

Table 14B. Textural analysis of pedon S81SC-051-013

[Grain sizes in millimeters; all other values in weight percent. VF, very fine; F, fine; M, medium; C, coarse; VC, very coarse; , analyzed but below

detectable limits]

Depth 

(cm)

0-23 -

23-35 -

35-73 -

73-109

109-124

124-147

147-173

173-196

196-243

Horizon

 Ap

---E

---Btl

---Bt2

---Bt3

---BC1

---BC2

---2BC

---2C

Clay 

K.002)

1.6

4.0

16.9

20.6

26.0

32.1

35.3

42.4

19.3

Total

Silt 

(.002-.05)

22.6

27.2

23.3

23.3

25.2

26.7

24.4

32.0

7.3

Sand 

(.05-2)

75.8

68.8

59.8

56.1

48.8

41.2

40.3

25.6

73.4

Clay

F 

«.0002)

1.2

2.8

11.3

14.2

16.2

18.7

20.3

22.0

12.1

Silt

F 

(.002-.02)

11.3

16.1

12.5

13.0

13.0

13.8

15.0

19.2

4.4

C

(.02-.05)

11.3

11.6

10.8

10.3

12.2

12.9

9.4

12.8

2.9

VF 

(.05-.10)

27.0

24.9

21.7

21.7

19.6

16.2

10.6

9.0

6.3

F 

(.10-.25)

45.0

40.1

35.4

31.3

25.8

18.1

14.5

9.3

55.9

Sand

M 

(.25-.50)

2.5

2.2

1.7

1.7

1.6

2.0

3.9

2.7

5.5

C

(.5-1)

1.1

1.0

.8

.9

1.1

3.3

7.9

3.3

2.4

VC

(1-2)

0.2

.6

.2

.5

.7

1.6

3.4

1.3

3.3

54 Pedologic Studies in the Eastern United States
Table 14C. Physical and chemical analyses of pedon S81SC-051-013

[Units of measure for all values given in table IB. , not detected; no entry, not analyzed; TR, trace]

Depth Organic Total Extractable 

(cm) Horizon C N P

0-23 -----Ap 0.69 0.031

Tl "5<; t7 'ii nn;

35-73 -----Btl .22 .014

73-109 ----Bt2 .19 

109-124 ----Bt3 .20 

124-147 ----BC1 .18 

147-173 ----BC2 .20 

173-196 ----2BC .19 

196-243 ----2C .13

Bulk density

Dithionite-citrate

Total Extractable Extractable 

S Fe Al

0.2 

.4 

1.6 

2.3 

2.9 

3.8 

4.2 

3.4 

1.0

Water content

Depth Field 1/3 Oven Field 1/3 15 

(cm) Horizon moist bar dry COLE3 moist bar bar2

f\ 0-23 *T1 A ------Ap 

23-35 ------E

TC 70 TJfl

73-109 -----Bt2

109 124 -----Bt3

174 147 _ --Rfl

147 173 _.___BC2

m in/; 9R/"1

1Q6 743 -- --?r

NH4OAC extractable bases

1.6 

2.2 

7.7 

10.4 

13.3 

15.5 

16.8 

18.2 

8.1

CEC1

Depth Sum of Extractable Sum of NH4 Bases 

(cm) Horizon Ca Mg Na K bases Acidity Al cations OAC +AI

0-23 ----Ap 0.7 0.2 0.2 1.1 3.2 

23-35 ----E .5 .1 .1 .7 2.1 

35-73 ----Btl 1.4 .2 0.5 .2 2.3 4.7 

73-109 ---Bt2 1.6 .4 .9 .1 3.0 6.2 

109-124 ---Bt3 1.4 .6 TR .1 2.1 8.5 

124-147 ---BC1 .9 .8 .1 1.8 9.7 

147-173 ---BC2 .9 .7 .3 .1 2.0 11.2 

173-196 ---2BC 1.0 .8 .2 .2 2.2 12.4 

196-243 ---2C .1 .3 TR .1 .5 6.3

'Cation exchange capacity. 

2Water content at 15-bar pressure.

Table 14D. Bulk chemistry of the <63-|j,m

Major oxide Bt1 Bt2

SiO2 - ----------- 74.38 70.39

A12O3 - ---------- 12.64 14.52

Fe2O3 ------------ 5.88 7.53 

MnO ------------- .02 .02

Tin,,- -- - 1 OO 1 O4

f^nf\ is '5'7

K2O-------------- .36 .44

Na2O------------ <.20 <.20

MgO ------------ <.1Q .10 

Total ----------- 95.6 95.3

0.2 4.3 2.1 1.3 

.4 2.8 1.6 1.1 

.5 7.0 3.5 2.9 

1.3 9.2 4.8 4.3 

2.6 10.6 6.6 4.7 

4.5 11.5 8.7 6.3 

5.5 13.2 9.0 7.5 

7.6 14.6 11.5 9.8 

3.4 6.8 5.1 3.9

Coefficient of linear extensibility. 

4Water-retention difference.

fraction, pedon S81SC-051-013

Horizon

Bt3 BC1 BC2

66.87 65.41 60.69 

16.21 17.06 17.92 

8.85 9.98 12.40 

.02 .02 .02 

1.80 1.60 1.34 

.34 .31 .31 

.53 .81 .81 

<.20 <.20 <.20 

.10 .10 .10 

94.7 95.2 93.5

Ratio clay

Extractable 

Mn CEC1

1.31 

.40 

.21

.23 

.25 

.27 

.26 

.27 

.26

CaCl 2 

(.01 M) 

WRD4 1:2

4.8 

4.5 

4.5 

4.5 

4.3 

4.5 

4.4 

4.6 

4.2

15 

bar2

1.00 

.55 

.46 

.50 

.51 

.48 

.48 

.43 

.42

PH

H2O 

1:1

5.3 

5.0 

4.9 

4.7 

4.6 

4.6 

4.7 

4.6 

4.7

Base saturation

Al 

saturation Sum

15 26 

36 25 

21 33 

30 33 

55 20 

71 16 

73 15 

78 15 

87 7

2BC

66.47 

17.93 

7.37 

.02 

1.36 

.31 

.97 

<.20 

.30 

94.7

NH4OAC

52 

44 

66 

62 

32 

21 

22 

19 

10

Soils and Morphostratigraphy in Horry County, S.C. 55
Table 15/4. Field description of pedon S81SC-051-014

[Location: 0.8 km south of Floyds, Horry County, South Carolina; 34°11' N., 79°02' W. Temperature: 17 °C mean annual, 26 °C mean summer. 

Elevation: 29 m above mean sea level. Physiography: Back-barrier flat. Geomorphic position: Interfluve summit. Slope and aspect: 1 percent plane. 

Precipitation: 137 cm, udic moisture regime. Drainage: Moderately well drained. Land use: Cropland. Parent material: Weathered marine sand and clay. 

No entry indicates no data]

Depth

(cm)

n 9^

23 35 --.-

35 53 ....

5^ 81 --

01 irvQ

109 135 ---

T3S 18"3

Horizon

A

Ktl

DO

Dl""!

----C\~f

Moist color1

10YR4/2

10YR5/6

i nvr> < if.

10YR5/6

10YR5/6

10YR5/6

7

^^/"D ^ /4?

Texture2

Is

tjl/1

di

Structure3 Clay skins Boundary4

1 frrt* Q c

Imsbk cs

Imsbk cw

MA

'Munsell notation.

2ls, loamy sand; scl, sandy clay loam; si, sandy loam.

3 1, weak; f, fine; m, medium; gr, granular; sbk, subangular blocky; MA, massive.

4as, abrupt smooth; cs, clear smooth; gw, gradual wavy; cw, clear wavy.

Table 15B. Textural analysis of pedon S81SC-051-014

[Grain sizes in millimeters; all other values in weight percent. VF, very fine; F, fine; M, medium; C, coarse; VC, very coarse; TR, trace; , analyzed

but below detectable limits]

Total Clay Silt Sand

Depth Clay Silt Sand 

(cm) Horizon (<.002) (.002-.05) (.05-2)

F F C VF F M C VC 

K.0002) (.002-.02) (.02-.05) (.05-.10) (.10-.25) (.25-.50) (.5-1) (1-2)

0-23 ----Ap

23-35 ----Btl

35-53 ----Bt2

53-81 ----Bt3

81-109 ---BC1

109-135 ---BC2

135-183 ---C

6.6

15.4

16.6

15.3

18.6

22.7

31.2

29.8

33.8

33.5

33.0

30.2

25.4

18.8

63.6

50.8

49.9

51.7

51.2

51.9

50.0

4.6

11.8

5.7

12.9

13.0

15.8

17.1

14.5

20.7

19.8

18.9

18.2

15.0

10.5

15.3

13.1

13.7

14.1

12.0

10.4

8.3

15.7

12.2

12.1

12.4

11.6

10.3

9.4

45.5

36.7

35.6

27.4

37.7

39.6

37.7

1.9

1.4

1.7

1.5

1.5

1.6

2.1

0.4

.4

.4

.4

.3

.3

.6

0.1

.1

.1

TR

.1

.1

.2

56 Pedologic Studies in the Eastern United States
Table 15C. Physical and chemical analyses of pedon S81SC-051-014

[Units of measure for all values given in table IB. , not detected; no entry, not analyzed; TR, trace]

Dithionite-citrate

Depth

(cm)

0-23 - 

23 35 -

35 53 -

Si'1 01

81-109 

109-135 

135-183

Horizon

 -Ap

RH

Rf7

Rtl

----BC1 

----BC2 

----C

Organic 

C

1.66 

.34 

.22 

.18 

.16 

.16 

.12

Total

N

Extractable Total Extractable Extractable Extractable 

P S Fe Al Mn

0.6 

1.4 

1.5 

1.3 

1.7 

2.5 

5.9

Bulk density

Depth

(cm)

0 23 -

23 35 -

35 53 -

M 01

81-109 

109-135 

135-183

Horizon

----- /\pAn

RH

RfO

Rf2

R/"1 !

Rf"">

-----C\->

Field 

moist

1.57 

1.72 

1.63

1/3 

bar

1.60 

1.57 

1.60 

1.71 

1.70 

1.64

NH4OAC extractable

Depth

(cm) Horizon

0-23 ----Ap 

23-35 ----Btl 

35-53 ----Bt2 

53-81 ----Bt3 

81-109 ---BC1 

109-135 ---BC2 

135-183 ---C

Ca Mg

1.2 0.3 

.9 .4 

1.0 .3

.3 .2 

.2 .2 

.2 .2 

.2 .3

Na K

-- 0.3 

_ j

 TR 

 TR 

 TR 

TR TR 

1.2 TR

Oven

dry

1.60 

1.72 

1.69

bases

Sum of 

bases

1.8 

1.4 

1.3 

.5 

.4 

.4 

1.7

COLE3

0.006 

.002 

.010

Acidity

8.1 

6.0 

5.5 

4.3 

4.2 

5.4 

6.8

Field 

moist

10.8 

11.5 

15.1

Extractable 

Al

1.2 

1.4 

1.1 

1.3 

1.3 

2.0 

3.1

Water content

1/3 

bar

16.0 

15.4 

18.2

Sum of 

cations

9.9 

7.4 

6.8 

4.8 

4.6 

5.8 

8.5

15 

bar2

4.6 

7.6 

7.8 

7.5 

9.1 

11.3 

13.6

CEC1

NH4 Bases 

OAC +AI

6.5 3.0 

4.2 2.8 

3.8 2.4 

3.3 1.8 

3.5 1.7 

4.5 2.4 

5.4 4.8

WRD4

0.13 

.14 

.11

Ratio clay

CEC1

0.98 

.27 

.23 

.22 

.19 

.20 

.17

CaCI 2

(.01 M) 

1:2

4.6

4.3 

4.2 

4.4 

4.4 

4.3 

4.4

15 

bar2

0.70 

.49 

.47 

.49 

.49 

.50 

.44

pH

H2O

1:1

4.8 

4.6 

4.6 

4.7 

4.7 

4.7 

4.7

Base saturation

Al 

saturation

40 

50 

46 

72 

76 

83 

65

Sum

18 

19 

19 

10 

9 

7 

20

NH4OAC

28 

33 

34 

15 

11 

9 

31

'Cation exchange capacity. 

2Water content at 15-bar pressure. 

Coefficient of linear extensibility. 

4Water-retention difference.

Table 15D. Bulk chemistry of the <63-u.m fraction, pedon S81SC-051-014

Major oxide

SiQ2 ----------- 

A12O3 ----------

Fe2O3 - --------- 

MnO ----------

TiO2 - ----------

PaO

K

f\

Na2O--- -----

MgO ---------- 

Total ----------

Bt1

---- 80.51

---- 10.21

----- 4.57

------ .01

----- 1.66

------ 32 ,^JL*

------ .37

---- <.20

10

Q7 8

Bt2

80.07

10 40

4.99

.01

1.69

.33

35

<.20

.10

97.9

Horizon

Bt3

83.46

9.22

4 00

.01

1 73

30

.31

<.20

<.10

99.0

BC1

01 79

9.40

4.73

nfi

1.73

.29

31

<.20

<.10

no 9

BC2

68.41

9.79

6.15

<.01

1.49

.30

.29

<.20

<.10

86.4

Soils and Morphostratigraphy in Horry County, S.C. 57
Table 16/4. Field description of pedon S81SC-051-015

[Location: 1.6 km south of Floyds, Horry County, South Carolina; 34°02'50" N., 78°53' W. Temperature: 17 °C mean annual, 26 °C mean summer. 

Elevation: 30 m above mean sea level. Physiography: Back-barrier flat. Geomorphic position: Interfluve summit. Slope and aspect: 1 percent plane. 

Precipitation: 137 cm, udic moisture regime. Drainage: Well drained. Land use: Cropland. Parent material: Weathered marine sand and clay. No entry 

indicates no data]

Depth 

(cm)

ft_?^

23 41 

41 71 -----

71 104 ---

104 142 ---

1/1 9 10Q

189 204 ---

Horizon

_____ - - - - - /\pAn

Rtl

RtO

IK""!

D/~">

-----C

Moist color1

10YR4/2

invp*;/'}

i HVT> < m

10YR6/8

10YR6/8

10YR6/8

10YR6/8

Texture2

Is

k

si -31

sl

k

Structure3

Ifgr 

Ifgr

Imsbk

Imsbk

Imsbk

MA

MA

Clay skins Boundary4

QC

5W

5W

gw

'Munsell notation.

2ls, loamy sand; scl, sandy clay loam; si, sandy loam.

3 1, weak; f, fine; m, medium; gr, granular; sbk, subangular blocky; MA, massive.

4as, abrupt smooth; cs, clear smooth; gw, gradual wavy.

Table 16B. Textural analysis of pedon S81SC-051-015

[Grain sizes in millimeters; all other values in weight percent. VF, very fine; F, fine; M, medium; C, coarse; VC, very coarse; , analyzed but below

detectable limits]

Total Clay Silt Sand

Depth Clay Silt Sand F F C VF F M C VC 

(cm) Horizon (<.002) (.002-.05) (.05-2) «.0002) (.002-.02) (.02-.05) (.05-.10) (.10-.25) (.25-.50) (.5-1) (1-2)

0-23 -

23-41 -

41-71 -

71-104

104-142

142-189

189-204

 Ap

---E

---Btl

---Bt2

---BC1

---BC2

---C

2.0

2.8

24.8

24.7

18.2

18.6

9.3

8.0

10.4

8.4

7.2

3.7

2.3

3.6

90.0

86.8

66.8

68.1

78.1

79.1

87.1

0.4

14.6

15.8

10.5

13.7

5.6

4.9

7.2

5.7

4.5

2.4

1.2

2.4

3.1

3.2

2.7

2.7

1.3

1.1

1.2

5.2

4.7

3.6

3.4

3.0

2.4

3.3

78.3

75.2

56.6

59.2

69.6

62.8

80.2

4.2

4.0

3.5

3.3

3.5

7.1

2.5

2.0

2.6

2.6

1.9

1.9

5.6

.8

0.3

.3

.5

.3

.1

1.2

.3

58 Pedologic Studies in the Eastern United States
Table 16C. Physical and chemical analyses of pedon S81SC-051-015

[Units of measure for all values given in table 2B. , not detected; no entry, not analyzed; TR, trace]

Dithionite-citrate Ratio clay

Depth 

(cm)

0-23 - 

23-41 - 

41 71 -

71-104 

104-142 

142-189 

189-204

Depth 

(cm)

0 23 -

23 41

41 71 -

71-104 

104-142 

142-189 

189-204

Depth

(cm)

Horizon

----Ap 

----E

Rtl

----Bt2 

----BC1 

----BC2 

----C

Horizon

.-__. --/\p An

-----P - - - c,

D»l

D*O

Rfi

Rr">

-----C

Horizon

0-23 ----Ap 

23-41 ----E 

41-71 ----Btl 

71-104 ---BC2 

104-142 ---BC1 

142-189 ---BC2 

189-204 ---C

Organic 

C

0.63 

.20 

.24 

.21 

.15 

.13 

.14

Field 

moist

NH4OAC

Ca Mg

0.7 0.1 

.2 TR 

1.9 .6 

1.6 .6 

1.2 .5 

.8 .6 

.3 .2

Total Extractable Total Extractable Extractable Extractable 

N P S Fe Al Mn CEC1

0.036 

.009 

.020 

.013

Bulk density

1/3 Oven 

bar dry

extractable bases

Sum of 

Na K bases

0.1 0.1 1.0 

TR .1 .3 

.3 .2 3.0 

.1 .1 2.4 

.1 TR 1.8 

.3 TR 1.7 

TR TR .5

0.2 0.90 

.3 .25 

2.4 .13 

2.6 .11 

1.8 .13 

1.8 .15 

2.3 .15

Water content _ . , TarU

Field 1/3 15 (.01 M) 

COLE3 moist bar bar2 WRD4 1:2

1.5 4.7 

1.3 4.7 

9.8 5.4 

10.3 5.5 

8.6 5.0 

8.5 4.4 

5.4 4.5

CEC1

15 

bar2

0.75 

.46 

.40 

.42 

.47 

.46 

.58

pH

H2O 

1:1

5.1 

5.2 

5.7 

5.8 

5.4 

5.1 

5.2

Base saturation Extractable Sum of NH4 Bases Al

Acidity Al cations OAC +Al saturation Sum

2.1 0.2 3.1 1.8 1.2 17 32 

.6 .1 .9 .7 .4 25 33 

4.4 7.4 3.3 41 

3.9 6.3 2.8 38 

2.6 4.4 2.4 41 

3.1 .5 4.8 2.7 2.2 23 35 

3.0 .1 3.5 1.2 .6 17 14

NH4OAC

56 

43 

91 

86 

75 

63 

42

'Cation exchange capacity. 

2Water content at 15-bar pressure. 

Coefficient of linear extensibility. 

4Water-retention difference.

Table 16D. Bulk chemistry of the <63-|xm fraction, pedon S81SC-051-015

Major oxide

SiO2 -----------

A1203 ---- 

Fe203 ---------- 

MnO ----------

Tin

faO

K

r\

Na2O---------- 

MgO ----------

Total ----------

E

---- 80.47

----- 4.26

----- 1.55

------ .01

----- 1.50

 3-3

------ .39

<* on

---- <.10

88 S

Bt1

39 24

27 29

10.22

f\0

1 «iS

.41

.48

<.20

<.10

79.3

Horizon

Bt2

0« AO

f\t~ -50

12.50

<.10

1.74

.41

.43

<.20

<.10

76.5

BC1

34 63

26.50

14.63

.05

1.24

.40

.56

<.20

.47

78.4

BC2

34 93

25 84

16.59

.05

88

37

1.02

<.20

.50

on 1

Soils and Morphostratigraphy in Horry County, S.C. 59
Table 17. Clay mineral trends-peak height ratios: 14.2 A/ 

7.2 A+4.85 A for pedons 001, 002, 003, 004, 010, 012, and 

014

Pedon Horizon

Horry barrier

S80SP OS 1-001 A

Btl

Bt2

C

o orvo/*"1 f\c 1 /V\O A «

Bt2

BC

C2

2C3

Conway barrier

SROSr 051-003 A

Bt2

Bt3

S80SC 051-004

BA

Bt2

BC

C

Carolina bay

S81SC-051-010 An

BA

Bt

Bhl

Horry back barrier

oolov_ ooiop UJl nsi-fn? Uli. /\pA

Btl

Bt2

Bt3

Bt4

BC

2BC1

S81SC-05 1-014----- ------Ap 

Btl

Bt3

BC2

C

Peak height ratio

1.9

1.1

.2

.2

2.4

1.2

.9

1.0

1.6

1.9

1.5

.7

1.6

1.7

.6

.9

1.2

2.1

2.0

1.7

1.3

1.5

2.5

1.1

1.0

.7

.4

.1

1.9

1.4

1.0

1.0

.4

66 Pedefcjgic Studies in the Eastern United States
Table 18. Altitude, age, and estimated uplift rates for individual barrier systems in Horry County, South Carolina

Barrier system 

(formation)

Altitude 

(meters)

Age

(years)

Uplift rate 

(meters/m.y.)

Average altitude

difference

between units

(meters)

Uplift rates in 

interval between

deposition of 

units (meters/m.y.)

Horry (Bear Bluff) - - - -33-50 2.5 xlO6- 

3.0 x 106

13-20 

11-17

(2.5 Ma) (3.0 Ma)

Lscuay ouoiiu ------ --^i j\j

Nakina

(Penholoway). 

Conway-Jaluco ------ - 17-20

(Canepatch 

or Socastee).

Unnamed (Myrtle -- - - -3-10

Beach of 

Crisp (1971) 

or Wando).

*

500,000 or 

200,000

70,000 or 

30,000 or 

10,000

j*i jo f ~ iv u.v -r.j

-/

K

34-40 

85-100

-/

40-140 

100-330 

300-1,000

J

(500 ka) (200 ka) 

10 33 17

(70 ka) (30 ka) (10 ka)

y 10 25 21 20

77 59 53

ft OS GOVERNMENT PRINTING OFFICE 1986 - 181-407 - 226/40030 Soils and Morphostratigraphy in Horry County, S.C. 61