Prepared in cooperation with the

NATIONAL PARK SERVICE

Geochemistry of the Johnson River,

Lake Clark National Park and 

Preserve, Alaska

Water-Resources Investigations Report 03-4252

U.S. DEPARTMENT OF THE INTERIOR

U.S. GEOLOGICAL SURVEY
Cover photograph: View of the Johnson River upstream from the gaging station. Photograph by Tim Brabets, U.S. Geological Survey, July 1999.
U.S. Department of the Interior

U.S. Geological Survey

Geochemistry of the Johnson River, 

Lake Clark National Park and Preserve, 

Alaska

By Timothy P. Brabets and James R. Riehle

Water-Resources Investigations Report 03-4252

Prepared in cooperation with the 

NATIONAL PARK SERVICE

 Anchorage, Alaska

 2003
U.S. DEPARTMENT OF THE INTERIOR

GALE A. NORTON, Secretary

U.S. GEOLOGICAL SURVEY

Charles G. Groat, Director

Use of trade names in this report is for identification purposes only and does not constitute 

endorsement by the U.S. Geological Survey

For additional information: Copies of this report may be purchased from:

Alaska Science Center

Chief, Water Resources Office U.S. Geological Survey

U.S. Geological Survey Branch of Information Services

4230 University Drive, Suite 201 Box 25286

Anchorage, AK 99508-4664 Denver, CO 80225-0286

http://ak.water.usgs.gov
i

CONTENTS

Abstract.................................................................................................................................................................................. 1

Introduction............................................................................................................................................................................ 1

Purpose and scope ............................................................................................................................................................4

Acknowledgements ..........................................................................................................................................................4

Description of study area ....................................................................................................................................................... 4

Methods of data collection and analysis................................................................................................................................ 4

Bedrock geology of the Johnson River study area ................................................................................................................ 8

Geologic setting................................................................................................................................................................8

Modifications to the geologic map...................................................................................................................................9

Flow and water-quality characteristics of the Johnson River................................................................................................ 9

Discharge..........................................................................................................................................................................9

Specific conductance........................................................................................................................................................9

pH.....................................................................................................................................................................................12

Water temperature............................................................................................................................................................12

Dissolved oxygen .............................................................................................................................................................14

Alkalinity..........................................................................................................................................................................14

Nutrients...........................................................................................................................................................................14

Organic carbon .................................................................................................................................................................16

Suspended sediment .........................................................................................................................................................16

Geochemistry and water quality of the study area................................................................................................................. 16

Chemical composition and classification of rocks...........................................................................................................16

Mineralization at the Johnson River Prospect..................................................................................................................16

Alteration at the Johnson River Prospect and elsewhere in the study area ......................................................................17

Discussion of geochemical data .......................................................................................................................................17

Discussion of water-quality data......................................................................................................................................19

Summary and conclusions ..................................................................................................................................................... 26

References ............................................................................................................................................................................. 26

Appendix 1. Trace element concentrations measured in 18 water samples collected from Johnson River above Lateral 

Glacier near Tuxedni Bay, Alaska .................................................................................................................................. 29

Appendix 2. Trace element concentrations measured in streambed sediment samples collected from sites located in the 

Johnson River Basin, Alaska........................................................................................................................................... 31

FIGURES

Figures 1-6. Maps showing:

1. Location of Lake Clark National Park and Preserve, Johnson River and Cook Inlet Basin, Alaska .................. 2

2. Location of Johnson River Prospect in the upper Johnson River Basin.............................................................. 3

3. Locations of water quality and discharge measurement sites.............................................................................. 5

4. Locations of geologic field sites and geology map of the study area.................................................................. 6

5. Geology of the study area.................................................................................................................................... 10

Figures 6-19. Graphs showing:

6. Discharge hydrograph of the Johnson River above Lateral Glacier near Tuxedni Bay, Alaska, 1995-2002...... 12

7. Average monthly discharge for the Johnson River above Lateral Glacier near Tuxedni Bay ............................ 12

8. Relation between instantaneous discharge and instantaneous suspended sediment for the Johnson 

River above Lateral Glacier near Tuxedni Bay, 1999-2001............................................................................... 16

9. Classification of chemically analyzed samples of the Talkeetna Formation and of the Alaska–Aleutian 

Ranges batholith ................................................................................................................................................. 16

10. Photographs of the Johnson River Prospect gossan and secondary veins ......................................................... 18

11. Trilinear diagrams of water samples from the Johnson River Basin................................................................. 20

12. Relation between total aluminum, total iron, and total manganese, and suspended sediment at Johnson 

River above Lateral Glacier near Tuxedni Bay, Alaska..................................................................................... 23
ii

TABLES

1. Selected minerals present in the Johnson River Basin ..................................................................................................... 3

2. Water-quality and discharge measurement sites in the Johnson River study area ........................................................... 8

3. Major elements as oxides in percent of Johnson River rock samples .............................................................................. 11

4. Discharge and physical properties measured at selected sites in the Johnson River study area ...................................... 13

5. Discharge, physical properties, and suspended sediment measured at Johnson River above Lateral Glacier near 

Tuxedni Bay, Alaska......................................................................................................................................................... 13

6. Nutrient and organic carbon concentrations measured in 18 water samples collected from Johnson River above 

Lateral Glacier near Tuxedni Bay, Alaska........................................................................................................................ 15

7. Alteration minerals of the Johnson River Prospect and associated gossans in the nearby Talkeetna Formation and 

batholith ............................................................................................................................................................................ 19

8. Major dissolved inorganic constituents measured in 18 water samples collected from Johnson River above Lateral 

Glacier near Tuxedni Bay, Alaska.................................................................................................................................... 21

9. Major dissolved inorganic constituents measured in water samples collected from sites in the Johnson River 

study area, July 2000 ........................................................................................................................................................ 21

10. Dissolved trace element concentrations measured in water samples collected from sites in the Johnson 

River study area, July 2000............................................................................................................................................... 22

11. Concentrations of selected trace elements in streambed sediments from various studies.............................................. 24

12. Concentrations of trace elements, percent organic carbon, and mean PEC quotient for streambed sediments at 

sites located in the Johnson River study area ................................................................................................................... 25

13. Results of acid based accounting tests on 11 rock samples from the Johnson River study area.................................... 25

CONVERSION FACTORS, VERTICAL DATUM, AND WATER-QUALITY INFORMATION

Multiply by To obtain

inch (in.) 25.4 millimeter 

foot (ft) 0.3048 meter

mile (mi) 1.609 kilometer

cubic foot per second (ft3/s) 0.02832 cubic meter per second

In this report, temperature is reported in degrees Celsius (°C), which can be converted to degrees Fahrenheit (°F) by the 

following equation:

°F = 1.8 (°C) + 32

ABBREVIATED WATER-QUALITY UNITS

Chemical concentration and water temperature are given only in metric units. Chemical concentration in water is given in 

milligrams per liter (mg/L) or micrograms per liter (μg/L). Milligrams per liter is a unit expressing the solute mass per unit 

volume (liter) of water. One thousand micrograms per liter is equivalent to 1 milligram per liter. For concentrations less than

7,000 milligrams per liter, the numerical value is about the same as for concentrations in parts per million. Specific conductance is given in microsiemens per centimeter (μS/cm) at 25°C.

VERTICAL DATUM

Sea level: In this report, “sea level” refers to the National Geodetic Vertical Datum of 1929—A geodetic datum derived from 

a general adjustment of the first-order level nets of the United States and Canada, formerly called Sea Level Datum of 1929.
1

Geochemistry of the Johnson River, Lake Clark National Park and 

Preserve, Alaska

By Timothy P. Brabets and James R. Riehle

ABSTRACT

The Johnson River Basin, located in Lake Clark National 

Park and Preserve, drains an area of 96 square miles. A private inholding in the upper part of the basin contains a gold 

deposit that may be developed in the future. To establish a 

natural baseline to compare potential effects on water quality if development were to occur, the upper part of the 

Johnson River Basin was studied from 1999 to 2001 as part 

of a cooperative study with the National Park Service.

Two basic rock types occur within the drainage basin of 

the study: the Jurassic Talkeetna Formation of interbedded 

volcanic and volcaniclastic rocks, and the slightly younger 

plutonic rocks of the Aleutian-Alaska Ranges batholith. The 

Johnson River gold prospect reflects widespread, secondary 

mineralization and alteration of the Talkeetna Formation. 

Metals found at the prospect proper are: arsenic, cadmium, 

copper, gold, iron, lead, mercury, molybdenum, selenium, 

silver, and zinc.

The Johnson River Prospect is located in the East Fork 

Ore Creek Basin, a 0.5 square mile watershed that is a tributary to the Johnson River. Water quality data from this 

stream reflect the mineralization of the basin and the highest 

concentrations of several trace elements and major ions of 

the water column were found in this stream. Presently, pH in 

this stream is normal, indicating that there is sufficient buffering capacity. At the Johnson River streamgage, which 

drains approximately 25 mi2

 including the East Fork Ore 

Creek, concentrations of these constituents are significantly 

lower, reflecting the runoff from Johnson Glacier and Double Glacier, which account for approximately 75 percent of 

the total discharge.

Streambed concentrations of cadmium, lead, and zinc 

from East Fork Ore Creek and its receiving stream, Ore 

Creek, typically exceed concentrations where sediment 

dwelling organisms would be affected. Similar to the water 

column chemistry, concentrations of these elements are 

lower at the Johnson River streamgage, reflecting the fine 

sediment input from the glacier streams draining Johnson 

Glacier and Double Glacier. The amount of organic carbon 

present in the study area is relatively low and most sites indicate that some degree of toxicity is present even though 

these basins do not contain mineralized areas.

Acid based accounting tests on rock samples in the study 

area indicate a neutralizing capacity in the Talkeetna Formation rocks. These results should be used with caution 

because similar tests were not done on rocks from narrow 

veins or faults that could have acid generating potential. In 

addition, based on field tests during the study, carbonatebearing rocks in streambeds are armored by a carbonatedepleted shell and would not readily neutralize acidic water.

INTRODUCTION

The Johnson River is located in Lake Clark National 

Park and Preserve, on the west side of Cook Inlet, Alaska 

(fig. 1). Like many rivers and streams in the park, the 

Johnson River supports resident and anadromous fish populations. Coho salmon, chum salmon, and Dolly Varden char 

can all be found in the river. The intertidal estuary and mud 

flats near the mouth of the river are important to resident and 

migratory birds, especially shorebirds. Bald eagle and peregrine falcon nests are found along the Johnson River and the 

river valley supports the largest breeding population of 

trumpeter swans in western Cook Inlet.

In 1975, Resource Associates of Alaska, under contract 

to Cook Inlet Region, Incorporated (CIRI), an Alaska 

Native corporation, discovered a mineral prospect in the 

Johnson River Basin (fig. 2) (Steefel, 1987). In 1976, CIRI 

selected the land, including the mineral rights underlying 

the Johnson River Prospect, under the Alaska Native Claims 
2

Lake Clark National Park and Preserve

63o

152o 63o

146o

60o

154o

149o

60o

Johnson 

River

Tuxedni

Bay

Anchorage 

75 100 MILES

100 KILOMETERS

50

75

25

25 50

0

0

EXPLANATION COOK INLET

Figure 1. Location of Lake Clark National Park and Preserve, Johnson River and Cook Inlet Basin, Alaska.

LAKE CLARK 

NATIONAL PARK

AND PRESERVE

Cook Inlet Basin 

ALASKA

Glacier
3

Gaging Station

EXPLANATION

Glacier

0

0 1

1

2

2

3

3

4

4

5 KILOMETERS

5 MILES

Figure 2. Location of Johnson River Prospect in the upper Johnson River Basin.

Johnson Glacier

Lateral Glacier

Double Glacier

Johnson River

Prospect

Private inholding

Johnson River

152o50' 152o 153 40' o

60o

06'

60o

09'

60o

02'

Settlement Act (ANCSA, 1971). This 33 mi2 area of land 

became known as the “Johnson River Tracts.” In 1981, a 

joint-venture agreement was signed between CIRI and Anaconda Minerals Company to evaluate the mineral potential 

of the prospect. One drill hole intersected about 160 feet of 

ore, grading 0.59 ounces of gold per ton, 9.4 percent zinc, 

2.8 percent lead, and 1.1 percent copper. Overall, Anaconda 

Minerals Company estimated 1-2 million tons of ore grading 0.27 ounces of gold per ton, 7 percent zinc, and lesser 

amounts of copper and lead (Steefel, 1987). Other metalbearing minerals known to occur in the area have been documented by Steefel (1987) and Gray (1988) (table 1).

If the Johnson River Tracts were developed, the National 

Park Service is concerned about the effects of development 

on the water quality of the Johnson River. Weathering and 

breakdown of rocks in the natural environment usually takes 

place over an extended period of time; however, the breakdown process in physically and chemically treated tailings 

and wastes from mines is accelerated. If ore and waste rock 

 Table 1. Selected minerals present in the Johnson River Basin (modified from Steefel (1987), and Gray (1988))

Element Symbol Mineral associations

Arsenic As Possibly as arsenopyrite with iron

Cadmium Cd Probably dissolved in sphalerite

Copper Cu Chalcopyrite

Gold Au Native gold

Iron Fe Pyrite

Lead Pb Galena

Mercury

Hg

Several possible forms (sulfide, sulfate, chloride, or native mercury), most likely as either 

trace amounts of cinnabar or dissolved in 

sphalerite.

Molybdenum Mo Probably molybdenite

Selenium

Se

Typically occurs dissolved in sulfides, in 

gossans developed from sulfides, can also be 

adsorbed on surfaces of clays or iron-manganese oxides.

Silver Ag Possible native silver.

Zinc Zn Sphalerite
4

Kona Creek were studied. The Johnson River Prospect is 

located in the East Fork Ore Creek drainage basin (fig. 3).

METHODS OF DATA COLLECTION AND ANALYSIS

The primary factors that could affect the water quality in 

the Johnson River study area include the type of bedrock, 

occurrence of altered rock, and streamflow characteristics. 

For example, altered or mineralized rocks are important in 

geochemical studies because toxic metals and acids formed 

during weathering typically originate in these rocks. If metals and acids enter the stream, they may or may not be 

diluted, depending on the flow characteristics. Thus, efforts 

were made towards collecting and analyzing these types of 

data.

Geologic mapping of the study area was first done by 

Detterman and Hartsock (1966). Because the authors 

focused on the sedimentary rocks and their potential for 

hydrocarbons, the Johnson River Prospect was not studied 

or mapped in further detail. Additional geologic mapping 

and interpretation of the area was done by Detterman and 

Reed (1980). In addition to detailed geologic mapping, a 

cross section of the Johnson River Prospect was developed 

by Steefel (1987). The Johnson River Prospect is included in 

the summary work by Nokleberg and others (1994). Aerial 

photography obtained in 1995 provided additional information on the geology of the area for this study.

Field work was done in the summer of 2000 to enhance 

and build upon the previous geology studies. Thirty-eight 

study sites were selected to examine the geology (fig. 4). 

From these sites, 69 rock samples were collected and submitted for trace element analysis. Analytical procedures for 

trace elements are outlined in Baedecker (1987). Fourteen 

of the samples also were analyzed for major-element content for use in rock classification. The major-element content of the rocks was determined by x-ray fluorescence at the 

USGS laboratory in Lakewood, Colorado (Taggert and others, 1987).

Discharge data have been collected during open water 

periods (May through October) at one site located on the 

Johnson River since 1995 (fig. 3, site number 52, USGS station ID 15294700, Johnson River above Lateral Glacier near 

Tuxedni Bay, Alaska). These data provide a good overview 

of the flow characteristics of the Johnson River. In addition, 

discharge measurements were obtained at tributaries to the 

Johnson River located in the study area during 2000 to characterize their respective flow characteristics (table 2).

were kept near the mine site or near the Johnson River floodplain, the material could potentially increase the metal load 

and acidity of water in the Johnson River, resulting in acid 

mine drainage.

Purpose and Scope

This report summarizes the results of a cooperative study 

by the National Park Service (NPS) and the U.S. Geological 

Survey (USGS) during 1999 through 2001 to study the 

water quality of the Johnson River. The purpose of this study 

was to characterize the geochemistry of the Johnson River 

Prospect, to identify potential environmental hazards, and to 

determine baseline levels for selected water-quality constituents. The area of study is limited to the upper part of the 

Johnson River in the vicinity of the Johnson River Prospect 

(fig. 2).

Acknowledgements

The authors gratefully acknowledge the assistance of 

Cory Stephens and Peter Oswald of the U.S. Geological 

Survey with field work done in 2000. Additional resources 

were provided to the study from the U.S. Geological Survey 

National Water-Quality Assessment (NAWQA) Program, 

Cook Inlet Basin Study Unit. The authors gratefully appreciate Cook Inlet Region, Inc. for allowing access to corporation lands.

DESCRIPTION OF STUDY AREA

The Johnson River Basin, located on the west side of 

Cook Inlet in south central Alaska, drains an area of about 

96 mi2(fig. 2). Glaciers cover approximately 20 mi2 of the 

entire basin. The topography of the watershed ranges from 

relatively steep in the upper part of the basin to relatively flat 

in the lower part of the basin. Precipitation is also variable. 

Mean annual precipitation is about 67 inches, but ranges 

from 70 inches in the headwaters to about 55 inches at the 

mouth at Cook Inlet. Snow accounts for about one-half the 

precipitation. The primary land cover is alpine tundra, and 

inceptisols are the primary soils. Vegetative cover and soils 

are generally discontinuous and thinly developed in the 

upper portion of the basin.

The study area, located upstream of the gaging station 

(site 52, fig. 3), is approximately 25 mi2. The area includes 

the Johnson River Prospect, several small tributaries, and 

two glaciers, Johnson Glacier and Double Glacier that cover 

approximately 9 mi2

 of the study area. Only the small basins 

in the vicinity of the Johnson River Prospect, Ore Creek, and 
5

52

113

112

110

111

114

115

116

117

118

Johnson River 

Prospect

USGS 

Gaging Station 

15294700

Kona Cr.

Ore Cr.

Double Glacier

Johnson Glacier

Johnson River

East Fork

Ore Cr.

North Fork

Ore Cr.

0

0 1

1

2 KILOMETERS

2 MILES

Johnson River drainage basin

Secondary drainage divide

EXPLANATION

Glacier

52 Water quality and Discharge

sampling site (see table 2) 

Gravel

Small drainage basins

Figure 3. Locations of water quality and discharge measurement sites (see table 2 for station names).

152o 153 55' o

60o

09'

60o

05'

Water samples were collected from the Johnson River at 

the gaging station (site number 52, fig. 3) from 1999-2001. 

These samples were collected over a range of discharge and 

provided a broad overview of the water quality of the 

Johnson River. Additional water samples were collected at 

nine sites located near the Johnson River Prospect during 

summer 2000 to determine the water-quality characteristics 

of these small streams and their relative contributions to the 

total discharge in the Johnson River (fig. 3, table 2).

Water samples were analyzed for major ions, dissolved 

solids, nutrients, trace elements, organic carbon, and sus-
6

152o 152 50' o 153 55' o

60o

05'

60o

10'

1P

2P

R101

R100 15P

5P R117

R118

8P

16P

9P

19P

R120

18P

17P

R119

7P R107

4P

R105 R106

3P

R104

R103

R102

R116

6P

R108

R109

R110

10P

R111

14P

13P

R114

R115

R113

11P, R112 12P

Bruin Bay fault

Bruin Bay 

 fault

Johnson R

Kona Creek

Jtkm

Jtkm

Jtkm

USGS

Gage

EXPLANATION

3P Geologic field station occupied during 

 2000 fieldwork

Boundary of drainage basin

Johnson River Prospect drainage basin

R106

Figure 4. Locations of geologic field sites and geology map of the study area.

0 1 2 34 5 MILES

0 12 34 5 KILOMETERS

CONTOUR INTERVAL 100 FEET

DATUM IS MEAN SEA LEVEL
7

Metamorphic rocks: metamorphosed limestone, sandstone, 

 siltstone, volcanic tuff, and greenstone; protoliths presumably

 mainly of Triassic (ie, pre-Talkeetna Formation) age

Marsh Creek breccia member: massive volcanic breccia and lava 

 flows, in part marine; interbedded siltstone and tuff. Low-rank

 metamorphism of lower part

Portage Creek agglomerate member: massive agglomerate, some

 breccia, minor lava flows; interbedded metasedimentary rocks

Horn Mountain tuff member: andesitic tuff, tuffaceous sandstone, 

 and siltstone; locally, some lava flows

Mainly biotite- and hornblende-bearing quartz diorite (plutonic rock)

Medium- to coarse-grained quartz monzonite (plutonic rock)

Talkeetna

Formation

 Alaska-Aleutian

Ranges batholith

Reverse or thrust fault, teeth on upthrown side

Other faults, dashed where approximately located, dotted where concealed. 

 U on upthrown side, D on downthrown side.

Contact of geologic unit, dashed where approximately located or indefinite

27

Strike and dip in degrees of bedded rocks

Qal, Qo, Qgt etc: unconsolidated, mainly sand and gravel deposits 

 of streams, mass movements, and glaciers; details not relevent to 

 this study

Triassic Lower Jurassic Middle Jurassic

and younger

Quaternary

Trm

Jtkm

Jtkp

Jtkh

Jqd

Jqm

Explanation for the base geology map of the Johnson River area, Alaska 

(Detterman and Hartsock, 1966). Base used in Figures 4 and 5.

Note: Line weights shown as on enlarged base for Figure 5 .

pended-sediment. The field-collection and processing 

equipment used was made from Teflon, glass, or stainless 

steel to prevent sample contamination and to minimize analyte losses through adsorption. All sampling equipment was 

cleaned prior to use with a non-phosphate laboratory detergent, rinsed with distilled water, and rinsed with stream 

water just prior to sample collection. Depth-integrated 

water samples were collected across the river by using the 

equal-width-increment method (Edwards and Glysson, 

1988) and processed onsite using methods and equipment 

described by Shelton (1994). Samples for organic-carbon 

analysis were collected separately by dipping a baked glass 

bottle in the centroid of flow. Samples to be analyzed for 

dissolved constituents were filtered either onsite or at the 

USGS office in Anchorage through 0.45 -um capsule filters. 

Water samples were sent to the USGS National Water-Quality Laboratory in Lakewood, Colorado, for analysis using 

standard USGS analytical methods (Fishman and Friedman, 

1989; Patton and Truitt, 1992; Fishman, 1993). Suspendedsediment samples were sent to the USGS Sediment Analy-
8

sis Laboratory in Vancouver, Washington, for concentration 

and particle size analysis.

Streambed sediments were sampled at the gaging site 

and at the sites near the Johnson River Prospect. At each 

site, sediments were collected from the surface of the streambed at several depositional areas using Teflon tubes or 

Teflon coated spoons and composited in glass bowls 

(Shelton and Capel, 1994). This ‘composite sample’ was 

then sieved through a 0.063-mm Nylon sieve and analyzed 

for trace elements. About 250 mL of stream water was used 

for sieving the trace-element sample. Water included in the 

trace elements was decanted after very fine-grained sediments had settled. Arbogast (1990) describes laboratory 

procedures for processing streambed sediment samples for 

trace element analysis.

Since mining has yet to occur in the study area, there are 

no mined rock piles that could be studied to determine their 

neutralizing capacity or acid-generating capacity. Instead, 

eleven of the rock samples, representing different suites of 

minerals, were analyzed by acid-base accounting (ABA) 

techniques. ABA is a method developed in the 1960’s and 

1970’s (Sobek and others, 1978) and is based on the 

assumption that drainage chemistry is a net result of reacting 

minerals and that the minerals that last longest and react 

fastest will determine long-term and overall chemistry. 

Samples were crushed, then soaked in strong acid to determine neutralizing capacity and analyzed for sulfur content 

to determine acid-generating capacity. In reality, the fastest 

reacting minerals often do not last long and thus affect only 

short-term chemistry. ABA simplifies this complexity to 

predict the outcome as “acidic”, “near-neutral”, or “alkaline” drainage based primarily on mineral balance (Morin 

and Hutt, 1997).

After the data were collected, checked, and compiled, 

data analysis was undertaken. Geologic data collected during 2000 were used to update the original Detterman and 

Hartsock (1966) map, and to determine the chemical composition of the Johnson River Prospect. Analyses of the rock 

samples were compared to the water-quality data to determine the effects of geology on water quality. Water quality 

changes were examined in a downstream direction from Ore 

Creek and Kona Creek to the Johnson River streamgage for 

dilution effects. Flow statistics from the Johnson River 

streamgage were analyzed and compared to flow values 

from the small tributaries near the Johnson River Prospect to 

determine their relative contribution to the total streamflow. 

ABA tests determined whether a particular rock type would 

be acidic or alkaline.

BEDROCK GEOLOGY OF THE JOHNSON RIVER STUDY 

AREA

Geologic Setting 

 The study area is part of the Peninsular Terrain, which 

is thought to have attached to mainland Alaska by the end of 

the Cretaceous Period 55-65 million years ago (Hillhouse 

and Coe, 1994). Late Paleozoic and Triassic, marine sedimentary and volcanic rocks are the oldest known rocks of 

the terrain. Although not well exposed in the vicinity of 

Johnson River (fig. 4), these Paleozoic and Triassic rocks 

crop out to the south of the study area where limestone, 

chert, and greenstone (metamorphosed oceanic basalt 

flows) were described by Detterman and Reed (1980). 

Table 2. Water-quality and discharge measurement sites in the Johnson River study area.

Site identifier1 

(figure 3)

1The Cook Inlet NAWQA study unit established a uniform numbering system for all surface water sites in the study basin. For a complete list of stations and 

numbers see http://alaska.usgs.gov/projects/Nawqa/water.sites.htm

Latitude/longitude or USGS station 

number Sampling site Drainage area (mi2)

52 15294700 Johnson River above Lateral Glacier near Tuxedni Bay 24.8

110 60o

08’26” 152o55’44” Kona Creek 3 miles above mouth near Tuxedni Bay 2.3

111 60o

08’03” 152o55’24” Kona Creek 2.5 miles above mouth near Tuxedni Bay 2.7

112 60o06’35” 152o55’09” Kona Creek tributary above Lateral Glacier near Tuxedni Bay 0.2

113 60o

06’36” 152o55’14” Kona Creek 0.8 miles above mouth near Tuxedni Bay 5.5

114 60o

07’39” 152o57’07” Unnamed Spring

115 60o07’15” 152o57’28” East Fork Ore Creek near mouth near Tuxedni Bay 0.5

116 60o

07’13” 152o57’40” North Fork Ore Creek near mouth near Tuxedni Bay 0.5

117 60o

06’58” 152o58’14” Ore Creek near mouth near Tuxedni Bay 1.1

118 60o

06’09” 152o56’11” Johnson River tributary above Lateral Glacier near Tuxedni Bay 0.1
9

These rocks are overlain by deposits of a major oceanic volcanic arc, the Talkeetna Formation of Lower to Middle 

Jurassic age (Detterman and Harstock, 1966, Detterman and 

Reed, 1980). Two major rocks units are exposed in the 

Johnson River study area: the Lower-to-Middle Jurassic Talkeetna Formation, and the Middle Jurassic and younger 

intrusive rocks of the Alaska-Aleutian Ranges batholith.

A major regional fault on the Alaska Peninsula, the 

Bruin Bay fault, trends north to south through the study area 

(fig. 4). The Bruin Bay fault is a thrust fault of vertical offset 

to the west and may also have had some left-lateral offset. 

The close succession of the intrusions to the volcanic-arc 

activity is interpreted (Reed and Lanphere, 1969 and 1973) 

to mean that the Jurassic part of the batholith is probably the 

intrusive equivalent of the Talkeetna Formation volcanic 

rocks, the geologically slightly younger ages reflecting 

slower cooling of the intrusions. Rather than a single fault, 

Detterman and Hartsock (1966) show multiple individual 

fault strands.

Modifications to the Geologic Map

 Based on our 2000 field work, the Detterman and Hartsock (1966) geologic map was modified to show an intrusive 

body between Kona Creek and Ore Creek (fig. 5). The modified geologic map (fig. 5) shows other outlying domes that 

are separate from the main dome at the ground surface, but 

that may connect in the subsurface to the main body. Both 

Steefel (1987) and Gray (1988) refer to this body as “dacite” 

(intermediate-silica, fine-grained volcanic rock); although 

the two analyzed samples (R117-A and 10P-A) are low-silica dacite and low-silica rhyolite (table 3). A second modification to the Detterman and Hartsock (1966) map was the 

removal of the unit Trm (Triassic metamorphic rocks) that 

straddles Kona Creek at the Bruin Bay fault. Rocks examined at three stations (11P, R112, and R113, fig. 4) where 

Detterman and Hartsock (1966) mapped this unit could not 

be distinguished from typical Talkeetna Formation.

FLOW AND WATER-QUALITY CHARACTERISTICS OF 

THE JOHNSON RIVER

The following section is intended to provide background 

on the flow and water-quality characteristics of the Johnson 

River study area. Water-quality data dealing with the 

geochemistry of the Johnson River are provided in a later 

section of the report.

Discharge

Continuous discharge records for May through October 

are available from the streamgage at the Johnson River (station ID 15294700, site number 52, fig. 3) from 1995 through 

2002 (URL: http://ak.waterdata.usgs.gov/nwis). Discharge 

records are not available during the winter due to logistical 

considerations. However, since the Johnson River is a glacial-fed river, flow is probably close to or equal to 0 ft3

/s 

during this period. The available flow records at the Johnson 

River indicate that daily discharge has ranged from 1.5 ft3

/s 

to 5,020 ft3/s (fig. 6). High flows occur in late June or early 

July due to snowmelt. Ice melt from Johnson Glacier and 

Double Glacier sustain the flow during July and August. 

High flows may also occur during the summer due to rainfall. Based on a per unit runoff basis, runoff can ranged from 

0 ft3

/s/mi2 to 202 ft3/s/mi2. Monthly average discharge from 

May through October for 1995 to 2002 ranged from 183 

ft3

/s in May to 719 ft3/s in July (fig. 7). The highest instantaneous peak discharge for this period was 8,800 ft3/s.

During late July 2000, measured discharge at the 

selected sites ranged from 0.04 ft3/s to 123 ft3/s (table 4). 

Discharges measured on July 24 at Ore Creek and Kona 

Creek were 24 ft3

/s and 123 ft3/s, respectively. Based on the 

concurrent flow at the Johnson River streamgage, 603 ft3/s, 

the flows at Ore Creek and Kona Creek represent 4 percent 

and 20 percent respectively, of the total flow measured at the 

streamgage. The remaining flow is derived from Johnson 

Glacier and Double Glacier. Flow conditions at this time 

probably represented average flow and the flows were not 

affected by rainfall or snowmelt. Depending on flow conditions, the relative contributions could change.

Specific Conductance

Specific conductance is determined by the type and concentration of ions in solution. It is a readily measured property that can be used to indicate the dissolved-solids or ion 

content in water. Values of conductance ranged from 32 to 

105 μs/cm at the Johnson River streamgage (table 5). Higher 

values of specific conductance were measured at the lowest 

discharge, usually in May, reflecting contributions from 

groundwater or snowmelt. As discharges increase due to 

snow and ice melt, values of conductance were lower than 

the May values. In September, when there is no discharge 

from ice or snowmelt, values of conductance increased.

At the sites visited in 2000, conductance values showed 

some variation (table 4). Values measured at the two sites on 

Kona Creek above Kona Creek tributary ranged from 22- 26 

μs/cm. The water from Kona Creek tributary (conductance 
10

152o 153 55' o

60o

07'

60o

09'

EXPLANATION

Dacite dome; margins approximate

Talkeetna Formation, undifferentiated

Photointerpreted Features:

Physiographic lineaments

Prominent gossan

Johnson River

Prospect

Figure 5. Geology of the study area (modified from Detterman and Hartsock, 1966).

Kona Creek

Ore 

Creek

Prospect

Gossan

Kona

Gossan

Johnson

Gossan

0 1 2 3 MILES

0 1 2 3 KILOMETERS

CONTOUR INTERVAL 100 FEET

DATUM IS MEAN SEA LEVEL
11

Table 3. Major elements as oxides in percent of Johnson River rock samples.

[Analyses by USGS Denver laboratory. All by x-ray fluorescence (Taggart and others, 1987) except FeO by titration (Jackson and others, 1987), values shown are in percent]

Site 

identifier 

(figure 4)

Sample 

Description Latitude Longitude Al2O3 CaO Fe2O3 FeO K2O MgO MnO Na2O P2O5 TiO2 SiO2 CO2 H2O+ H2O- Total

SiO2 

(normalized, 

volatile-free)

K20 + Na2O 

(volatile-free)

R105-A fine grained 

diorite or hornfels

60°07′31′′ 152°57′53′′ 19.2 9.93 6.53 6.61 0.18 4.51 0.22 2.93 0.26 1.11 48.1 0 0.9 0.1 100.58 48.3 3.12

R109 pillow lava 

flow

60°07′43′′ 152°54′27′′ 19.5 11.7 3.36 5.27 0.09 4.83 0.16 1.59 0.15 0.65 49.7 0.08 1.4 0.9 99.38 51.2 1.73

R111-B2 lava flow 

within tuff-breccia

60°08′22′′ 152°55′40′′ 17.8 5.75 3.99 5.65 0.57 5.47 0.26 4.37 0.16 0.68 48.2 2.19 4.1 0.5 99.69 51.9 5.32

R117-A dacite plug 60°07′00′′ 152°55′19′′ 16 4.42 2.58 2.89 1.33 3.5 0.03 3.23 0.21 0.6 59.8 0.02 5.2 0.5 100.31 63.2 4.821P-A granodiorite 60°07′00′′ 152°57′58′′ 12.2 2.44 0.86 0.64 1.14 0.4 0.04 3.64 0.13 0.18 77.4 0 0.5 0.1 99.67 78.1 4.83

3P-B lava flow 60°07′42′′ 152°56′53′′ 12.2 2.11 1.49 4.75 0.39 2.02 0.19 3.37 0.16 0.6 69.2 1.4 2.6 0.1 100.58 71.7 3.90

4P-A granodiorite 

w/ pyrite

60°07′30′′ 152°58′37′′ 15.4 5.26 2.38 1.99 0.29 1.19 0.08 3.22 0.2 0.42 67.9 0 0.7 0.1 99.13 69.1 3.57

4P-B granodiorite 60°07′30′′ 152°58′37′′ 12.5 7.54 5.15 7.32 0.29 5.89 0.23 1.73 0.23 1.08 57.3 0 1.3 0.1 100.66 -- --

6P-G mafic 

granodiorite

60°08′02′′ 152°56′48′′ 16.5 7.38 2.69 4.94 0.55 3.81 0.16 2.97 0.24 0.76 58 0 1.4 0.1 99.5 59.2 3.59

6P-H felsic 

granodiorite

60°08′02′′ 152°56′48′′ 16.6 8.67 4.68 5.2 0.51 5.3 0.2 2.6 0.18 0.77 52.9 0 1.5 0.1 99.21 54.2 3.19

9P-J lava flow 60°07′28′′ 152°54′04′′ 19.6 11.5 4.32 4.94 0.28 4.47 0.15 1.79 0.17 0.71 49.1 0.47 1.6 0.9 100 50.6 2.13

10P-A dacite plug 60°08′05′′ 152°53′39′′ 13.6 1.15 3.02 0.96 3.34 2.11 0.04 3.83 0.16 0.44 68 0.46 1.8 0.3 99.21 70.4 7.42

10P-E mafic dike 60°08′05′′ 152°53′57′′ 19.6 11 6.09 3.4 0.17 5.26 0.16 1.79 0.17 0.73 46.9 0.16 2.3 1.5 99.23 49.2 2.06

14P-D mafic dike 60°08′34′′ 152°54′56′′ 17.6 4.08 3.79 4.49 1.32 4.56 0.16 3.56 0.2 0.69 54.4 0.55 3.5 0.4 99.3 57.4 5.14
12

Figure 6. Discharge hydrograph of the Johnson River above Lateral Glacier near 

Tuxendi Bay, Alaska, 1995-2002.

1

2

5

10

20

50

100

200

500

1000

2000

5000

8000

MEAN DAILY DISCHARGE, IN CUBIC FEET PER SECOND

Oct

14 28

Nov

14 28

Dec

14 28

Jan

14 28

Feb

14 28

Mar

14 28

Apr

14 28

May

14 28

Jun

14 28

Jul

14 28

Aug

14 28

Sep

14 28

No Record

Maximum daily discharge

Average daily discharge

Minimum daily discharge

Figure 7. Average monthly discharge for the Johnson 

River above Lateral Glacier near Tuxedni Bay, 1995-2002.

AVERAGE MONTHLY DISCHARGE, 

IN CUBIC FEET PER SECOND

100

500

1000

JOHNSON RIVER ABOVE LATERAL GLACIER NEAR TUXEDNI BAY

OND J FMA M J J A S

No Record

from the unnamed spring in the North Fork Ore Creek 

watershed (227μs/cm).

pH

The pH of water is a measure of its hydrogen-ion activity 

and can range from less than zero (very acidic) to 14 (very 

alkaline) standard units. The pH of river water not affected 

by contamination is typically between 6.5 and 8.0 standard 

units (Hem, 1985) and for fish growth and survival, the pH 

should remain in the 6.5 - 9.0 standard unit range. Values of 

pH at the Johnson River streamgage ranged from 6.9 to 7.9 

for the period of sampling. Similar values were found at the 

other sites measured in 2000. (tables 4-5).

Water Temperature

Water temperature determines the amount of oxygen 

water can contain when at equilibrium with the atmosphere 

and it also controls the metabolic rates of fish and their rates 

of growth. Ranges in water temperature at the Johnson 

River were highly seasonal (tables 4-5). Measured water 

temperatures were the coldest in May (0.0 o

C, 0.2 oC, and 

of 111 μs/cm) elevated the conductance at the site near the 

mouth of Kona Creek (40 μs/cm). At the Ore Creek sites, 

values of conductance were consistent and ranged from 78-

80 μs/cm. The highest conductance value measured was 
13

 Table 4. Discharge and physical properties measured at selected sites in the Johnson River study area.

[ft3/s, cubic feet per second, us/cm, microsiemens per centimeter at 25 degrees Celsius]

Site identifier 

(figure 3) Station Name Date Discharge (ft3/s) Specific Conductance (μs/cm) Dissolved Oxygen (mg/L) Water Temperature (oC) pH (standard units) Alkalinity (mg/L as CaCO3)

110 Kona Creek 3 miles above mouth 7-26 56 26 13.0 2.0 6.7 5111 Kona Creek 2.5 miles above mouth 7-26 67 22 13.0 3.4 7.4 6112 Kona Creek tributary 7-27 2.3 111 13.0 4.5 7.2 32113 Kona Creek 0.8 miles above mouth 7-24 123 40 12.8 3.9 7.5 9115 East Fork Ore Creek near mouth 7-25 16 80 13.2 2.6 6.8 6116 North Fork Ore Creek near mouth 7-25 7.8 78 13.1 3.1 7.5 29117 Ore Creek near mouth 7-24 24 78 13.3 3.5 7.2 18118 Johnson River tributary 7-27 0.04 46 10.0 9.8 7.3 16114 Unnamed Spring 7-25 -- 227 -- 4.8 7.9 95

Table 5. Discharge, physical properties, and suspended sediment measured at Johnson River above Lateral Glacier near Tuxedni Bay, Alaska (site 52).

 [ft3/s, cubic feet per second; ft3/s/mi2, cubic feet per second per square mile; mg/L, milligrams per liter; oC, degree Celsius;]

Date Discharge (ft3/s) Unit Discharge (ft3/s/mi2) Specific Conductance (us/cm) Dissolved Oxygen (mg/L) Water Temperature (oC) pH (standard units) Alkalinity (mg/L as CaCO3) Suspended sediment (mg/L)

5-17-99 20.0 0.8 69 13.7 0.0 7.1 15 56-10-99 602 24.3 57 13.1 2.5 7.6 16 1746-30-99 580 23.4 45 -- 6.0 7.6 14 647-21-99 627 25.3 37 13.2 5.0 7.8 -- 728-6-99 2460 99.2 32 12.0 3.0 7.9 12 8828-24-99 521 21.0 41 11.9 6.7 7.0 12 339-16-99 451 18.2 55 14.2 2.8 7.1 15 1310-7-99 200 8.1 78 12.7 4.3 7.5 21 25-9-00 45.0 1.8 105 15.2 0.2 7.2 15 136-15-00 497 20.0 64 15.3 2.1 7.0 14 227-26-00 603 24.3 42 13.2 3.0 7.1 12 478-16-00 439 17.7 42 13.6 3.8 7.2 13 609-18-00 89.0 3.6 87 12.4 2.2 7.5 19 45-23-01 174 7.0 93 14.2 1.2 7.2 18 256-26-01 1220 49.2 45 12.8 2.5 7.2 12 1188-1-01 827 33.3 38 12.9 5.8 7.1 10 759-3-01 693 27.9 46 11.5 4.3 7.2 12 169-27-01 280 11.3 58 13.3 3.3 6.9 14 5
14

1.2 oC), reflecting the beginning of snowmelt. By June, 

water temperatures had risen to 2.0 oC or higher. From June, 

temperatures varied, ranging from 3.0 o

C to 6.7 oC. By midto-late September, water temperatures had cooled to 3.3 o

C 

or lower. 

At other sites visited in the summer of 2000, water temperatures ranged from 2.0 to 9.8 oC (table 4). The highest 

water temperatures were found at the unnamed spring, and 

at tributaries to Kona Creek and the Johnson River (site 

numbers 112 and 118). Since discharge was relatively low at 

these two sites, water temperature was likely influenced by 

air temperature. Water temperature at the sites on Kona 

Creek and Ore Creek was similar to the water temperature at 

the Johnson River gage.

Dissolved Oxygen

The dissolved-oxygen concentration in a stream is controlled by several factors, including water temperature, air 

temperature and pressure, hydraulic characteristics of the 

stream, photosynthetic or respiratory activity of stream 

biota, and the quantity of organic matter present. Salmon 

and other fish require well-oxygenated water at every stage 

in their life, but young fish are more susceptible to oxygen 

deficiencies than adult fish. Dissolved oxygen concentrations at the Johnson River ranged from 11.9 to 15.3 mg/L. 

and from 10.0 to 13.3 mg/L at other sites visited in the summer of 2000 (tables 4-5). Measured concentrations of dissolved oxygen were sufficient to support fish.

Alkalinity

Alkalinity is a measure of the capacity of the substances 

dissolved in water to neutralize acid. In most natural waters, 

alkalinity is produced mainly by bicarbonate and carbonate 

(Hem, 1985), which are ions formed when carbon dioxide or 

carbonate rocks dissolve in water. Alkalinity concentrations 

(reported as equivalent concentrations of calcium carbonate 

(CaCO3)) for the Johnson River ranged from 12 to 21 mg/L 

(table 5). These alkalinity concentrations indicate that water 

in the Johnson River has a low buffering capacity and limited availability of inorganic carbon (Hem, 1985). Also, 

given the range of pH values of the Johnson River, all of the 

alkalinity can be assigned to dissolved bicarbonate (Hem, 

1985).

At the sites visited in the summer of 2000, alkalinity concentrations ranged from 5 mg/L to 95 mg/L (table 4). Sites 

in the Kona Creek Basin had relatively low alkalinity (less 

than 10 mg/L) while the small tributary to Kona Creek, 

North Fork Ore Creek, and the unnamed spring had relatively high values of alkalinity (29 mg/L).

Nutrients

In aquatic ecosystems, nitrogen commonly occurs in the 

following forms: nitrate (NO3), nitrite (NO2), and ammonium (NH4). In the laboratory, ammonium is analyzed as 

ammonia (NH3); thus nitrogen concentrations are reported 

as total and dissolved ammonia plus organic nitrogen (often 

called Kjeldahl nitrogen), dissolved ammonia, dissolved 

nitrite plus nitrate, and dissolved nitrite. Nitrite readily oxidizes to nitrate in natural water; therefore nitrate is generally 

more abundant than nitrite in water bodies. Total ammonia 

plus organic nitrogen concentrations represent the ammonium and organic nitrogen compounds in solution and associated with colloidal material. Nitrite and nitrate are 

oxidized forms of inorganic nitrogen that together make up 

most of the dissolved nitrogen in well-aerated streams.

All concentrations of the various nitrogen forms were 

less than 1.0 mg/L (table 6). Due to its toxicity to freshwater 

aquatic life, the U.S. Environmental Protection Agency 

(USEPA, 1976) suggests a limitation of 0.02 mg/L of 

ammonia (as un-ionized ammonia, NH3) for waters to be 

suitable for fish propagation. Based on the values of pH, 

water temperature, and ammonia in the Johnson River (table 

5) the un-ionized ammonia, was calculated as 0.2 percent of 

dissolved ammonia (interpolated from table 3, United States 

Environmental Protection Agency, 1976, p. 11). Thus, even 

at the maximum concentration of dissolved ammonia (0.056 

mg/L), the concentration of un-ionized ammonia is well 

below the recommended criteria for fish propagation.

Phosphorus is an essential element in the growth of 

plants and animals. It occurs as organically bound phosphorus or as phosphate. High concentrations of phosphorus in 

water are not considered to be toxic to human or aquatic life. 

However, its presence can stimulate the growth of algae in 

lakes and streams. It was first noted by Sawyer (1947) that 

nuisance algal conditions could be expected in lakes when 

concentrations of inorganic nitrogen (NH3 + NO2 + NO3 as 

N) as low as 0.3 mg/L are present in conjunction with as 

much as 0.01 mg/L of phosphorus.

Phosphorus concentrations are reported as total phosphorus, dissolved phosphorus, and dissolved orthophosphate. The orthophosphate ion, PO4, is the most important 

form of phosphorus because it is directly available for metabolic use by aquatic plants. Concentrations of total phosphorus and dissolved phosphorus were less than 0.6 mg/L 

for all samples collected at the Johnson River (table 6).
15

Table 6. Nutrient and organic carbon concentrations measured in 18 water samples collected from Johnson River above Lateral Glacier near Tuxedni Bay, Alaska (site 52). 

[all values in mg/L; NO2 + NO3, nitrite plus nitrate, E, estimated, <, less than].

Date Nitrogen nitrite, dissolved Nitrogen NO2 + NO3, dissolved Nitrogen ammonia, dissolved Nitrogen ammonia + organic, total Nitrogen ammonia + organic, dissolved Phosphorus, total Phosphorus, dissolved Phosphorus ortho, dissolved Organic carbon, dissolved Organic carbon, particulate

5-17-99 0.001 0.300 0.004 E0.09 <0.10 0.006 <0.004 0.002 0.30 <0.20

6-10-99 0.001 0.130 0.003 <0.10 <0.10 0.089 <0.004 0.001 0.20 <0.206-30-99 0.001 0.048 0.003 <0.10 E0.06 0.045 <0.004 0.003 <0.10 <0.207-21-99 0.001 0.014 <0.002 0.11 0.15 0.058 <0.004 0.001 0.30 0.208-6-99 0.001 0.031 0.002 0.11 E0.05 0.594 <0.004 0.001 0.20 <0.208-24-99 <0.001 0.023 0.005 0.12 E0.05 0.021 <0.004 <0.001 0.20 <0.209-16-99 <0.001 0.030 0.007 <0.10 <0.10 0.016 <0.004 <0.001 0.39 <0.2010-7-99 <0.001 0.076 <0.002 E0.07 E0.05 E0.004 <0.006 0.008 0.36 <0.205-9-00 0.001 0.302 <0.002 E0.09 <0.10 0.038 <0.006 <0.001 0.90 <0.206-15-00 <0.001 0.160 0.056 <0.10 E0.05 0.013 <0.006 <0.001 <0.33 <0.207-26-00 0.001 0.032 <0.002 <0.10 <0.10 0.032 <0.006 0.002 <0.33 <0.208-16-00 0.001 0.047 0.011 <0.10 <0.10 0.029 <0.006 0.003 <0.33 <0.209-18-00 <0.001 0.030 0.004 <0.10 <0.10 <0.008 E0.003 <0.001 E0.24 <0.205-23-01 <0.001 0.181 <0.002 <0.08 <0.10 0.017 <0.006 <0.007 E0.19 0.106-26-01 <0.001 0.079 0.002 E0.06 <0.10 0.059 <0.006 <0.007 <0.30 0.308-1-01 <0.001 0.025 <0.002 <0.08 <0.10 0.042 <0.006 <0.007 <0.30 0.409-3-01 <0.001 E0.023 E0.005 <0.08 E0.06 0.012 <0.006 <0.007 <0.30 0.109-27-01 0.001 0.024 0.002 <0.08 <0.10 0.006 <0.006 <0.007 <0.30 <0.10
16

50 100 500 1000 3000

2.5

5.0

7.5

25

50

75

250

500

750

10

INSTANTANEOUS SUSPENDED SEDIMENT, 

IN MILLIGRAMS PER LITER

INSTANTANEOUS DISCHARGE, IN CUBIC FEET PER SECOND

Figure 8. Relation between instantaneous discharge and 

instantaneous suspended sediment for the Johnson River 

above Lateral Glacier near Tuxedni Bay, Alaska, 1999-2001.

Organic Carbon

Dissolved organic carbon (DOC) is commonly a major 

pool of organic matter in ecosystems. DOC is defined as 

organic carbon in the filtrate (dissolved and colloidal 

phases) that has passed through a 0.45 -μm pore-size filter. 

Generally, DOC is in greater abundance than particulate 

organic carbon (POC), accounting for approximately 90 

percent of the total organic carbon of most waters (Aiken 

and Cotsaris, 1995). In the aquatic system, the sources of 

DOC can be categorized as (1) allochthonous - entering the 

system from a terrestrial source, and (2) autochthonous - 

being derived from biota (algae, bacteria, macrophytes) 

growing in the water body.

At the Johnson River, concentrations of DOC ranged 

from less than 0.10 mg/L to 0.90 mg/L. All POC concentrations were less than 1.0 mg/L (table 6). The relatively low 

concentrations of DOC are likely related to the lack of well 

developed soil within the study area.

Suspended sediment

Suspended-sediment concentrations of the Johnson 

River ranged from 2 mg/L to 882 mg/L (table 5). Low concentrations of suspended sediment were usually noted at 

low flow or before snow melt begins. The Johnson River is 

relatively clear during these times. Greater suspended sediment concentrations are present in the river during high 

flows. Suspended sediment concentrations show a good 

correlation (R = 0.74) with discharges greater than 200 ft3

/s 

(fig. 8).

GEOCHEMISTRY AND WATER QUALITY OF THE 

STUDY AREA

Chemical Compositions and Classification of Rocks

Only one of the analyzed rock samples of the Talkeetna 

Formation is true andesite (fig. 9); most fall near the basaltbasaltic andesite boundary. The dome and its related tuffs 

and lava flows are low-silica dacite or low-silica rhyolite. 

Rock samples from the batholith range in silica content 

from basalt to rhyolite (fig. 9) and only two samples would 

be considered andesites. The older lava flows and tuffs are 

mafic (basaltic andesite) while the dome and equivalent 

tuffs--the youngest rocks and deposits of the Talkeetna 

arc—are the most silicic.

(Gabbro or Diorite)

Alaska-Aleutian Ranges batholith

Talkeetna Formation

Dacite dome Tuff or lava flow

Dike Average of 7 tuffs 

 (Steefel, 1987)

SiO2

40 50 60 70 80

weight percent

(Na2O + K2O) weight percent

10

8

6

4

2

Dacite

Rhyolite

Basalt

Andesite

Basaltic

 andesite

EXPLANATION

Alkalic Types

(Quartz and Diorite)

(Gabbro or Diorite)

(Tonalite)

(Granodiorite)

(Granite)

Figure 9. Classification of chemically analyzed samples 

of the Talkeetna Formation and of the Alaska-Aleutian 

Ranges batholith (Names of coarse-grained equivalents

given in parenthesis).

Mineralization at the Johnson River Prospect

The Johnson River Prospect is located within several 

square miles of orange-stained rocks, referred to as the Prospect and Kona gossans (fig. 5), developed in the Talkeetna 

Formation adjacent to and up to 2 mi east of the Bruin Bay 
17

fault (fig. 5). Upper-plate plutonic rocks of the batholith 

immediately west of the Bruin Bay fault also show gossan 

colors (fig. 10). “Gossan” is iron oxide formed during 

weathering oxidation of pyrite (iron sulfide). Oxidation of 

sulfur forms acid, which in turn increases the solubility of 

metals in surface waters. The major implication of gossans 

to geologists is that gossan rock has undergone enrichment 

of sulfur and also metals. Mineralization is divided by 

Steefel (1987) into two stages: an early anhydrite-pyritesericite-chlorite-calcite stage, and a later stage during which 

quartz, gold, barite, and sulfides were added. Metal minerals of the later stage--native gold, sphalerite, chalcopyrite, 

silver, and galena—are zoned with zinc and silver occurring 

near the top, followed next by a copper, gold, lead zone, and 

finally by a copper and pyrite zone.

Alteration at the Johnson River Prospect and Elsewhere in 

the Study Area

Alteration associated with the Johnson River Prospect 

mineralization and with the more extensive Prospect gossan 

is not easily identified in detail. Alteration minerals are typically very fine, occur in trace amounts, and comprise several mineral groups that each vary widely in chemical 

composition and environmental implications. Sericitic 

alteration is characterized by quartz, pyrite, and sericite (a 

potassium mica) and typically occurs at veins which were 

pathways (fractures) for acidic fluids that added sulfur and 

removed alkalis from the altered rock (table 7).

Pyrite is a common crustal mineral and its significance is 

dependent on the other minerals present with it. At the 

Johnson River Prospect, pyrite provided the iron that was 

later oxidized to create the striking color gossan on both 

sides of the Bruin Bay fault. A gossan typically involves 

secondary permeability (fractures and faults), which allows 

for later incursion of oxygenated ground water. In the case 

of intensive gossans, iron was probably added to the original rock, potentially along with other metals of economic 

interest. The orange color means that much of the pyrite has 

already been oxidized and cannot further contribute to acidity. The uncertainty, however, is how much unoxidized 

pyrite remains beneath the oxidized rock surface, awaiting 

exposure by landslides or human activity. Sulfur content of 

the rocks is one measure of this potential. A number of analyzed samples of the Talkeetna Formation were high in sulfur (analyses available at USGS office). This supports the 

likelihood that unoxidized Talkeetna Formation rocks in the 

subsurface have moderate to high pyrite contents.

Discussion of Geochemical Data

 Major-element analyses (table 3) provide a basis for 

classification of igneous rocks and have been previously discussed. Rock samples analyzed for minor elements were 

grouped according to rock type and the averages for each 

rock category were calculated (data available at USGS 

office). Rock samples from the fault-fracture-controlled 

mineralization at the Johnson River Prospect contained high 

amounts of gold, mercury, silver, arsenic, cadmium, copper, 

molybdenum, lead, zinc, and selenium. These include the 

same metals (gold, silver, copper, lead and zinc) noted by 

Steefel (1987) and Gray (1988). Molybdenum is not mentioned by Steefel, and it does not occur in significant concentrations in our samples. Mercury and arsenic are associated 

worldwide in shallow hot-springs deposits or commonly 

occur in trace amounts together with cadmium and selenium 

in a variety of precious- and base-metal deposits, especially 

those formed as veins with quartz or calcite (Rose and others, 1979; Levinson, 1974). Johnson River Prospect samples 

are also elevated in carbon dioxide and sulfur, indicative of 

calcite, sulfides, or anhydrite dissolution.

Non-mineralized samples from the Talkeetna Formation 

were compared with those from the Prospect and Kona gossans. Gossan samples are generally much higher in mercury, 

arsenic, cadmium, and zinc, and slightly higher in copper, 

manganese, molybdenum, lead (one sample), and selenium. 

The gossan Talkeetna Formation is also higher in carbon 

dioxide and sulfur. This suite of elevated elements is essentially identical to that of the Johnson River Prospect, suggesting that the broad areas of the Kona gossan in the 

Talkeetna Formation to the north and east of the Prospect 

drainage were formed by similar processes, such as, a combination of magmatic heat, sulfur, and seawater convecting 

through permeable deposits above and adjacent to intrusives.

 Sulfur content of gossan samples varies widely, reflecting both variable sulfur addition during mineralization as 

well as variable degree of oxidation of pyrite during subsequent weathering and consequent loss of sulfur from the 

rock. In general, sulfur in the rock samples is not extremely 

high, and the highest values are found in rock samples immediately adjacent to the Johnson River Prospect (Prospect 

Gossan). Sulfur in this area may not occur as pyrite, but as 

anhydrite, in which sulfur is already in its most oxidized 

state. However, future disturbance of gossan areas such as 

natural landslides, faulting in earthquakes, or human activity 

could expose higher levels of sulfur assuming that unoxidized pyrite is more abundant beneath the present weathering zone.
18

Secondary veins (white) can be seen clearly cutting fault-breccia pieces of Talkeetna Formation (dark gray) at the 

Johnson River Prospect. Very little oxidation of sulfides has occurred as indicated by the lack of orange staining. This 

may be because the rock surface was only recently exposed and has not yet weathered, or because the secondary 

vein minerals are chiefly carbonates and silicates and do not include many sulfides.

A section of the vein system at the Johnson River Prospect, that has much greater abundance of oxidized metals, 

which yield the bright orange stain (rust and other hydrated iron oxides). The entire region of the prospect shows 

such orange staining (a "gossan"), indicating pervasive enrichment, though at lower levels than the prospect proper, 

in iron, sulfur, and other metals.

Figure 10. Photographs of the Johnson River Prospect gossan and secondary veins.
19

Carbonate in the rocks provides the neutralizing capacity 

to affect the potential acidity generated by pyrite and sulfur. 

Calcite is the most soluble of the common carbonate minerals and was detected frequently during the fieldwork by 

applying hydrochloric acid to rocks. Calcite found in 

batholith rocks is confined to minor fractures and is not 

abundant. Carbonate xenoliths in batholith rocks derived 

from Triassic or Permian limestones are known to occur in 

the geologic column elsewhere on the Alaska Peninsula, but 

none were identified during this study nor reported by Detterman and Hartsock (1966). There is, however, an abundant 

amount of calcite in both lavas and volcaniclastic rocks of 

the Talkeetna Formation from the analyses of thin sections 

from the rock samples (analyses available at USGS office).

Discussion of Water-Quality Data

The water samples collected for this study have approximately the same anion and cation content (tables 8 and 9). 

At the Johnson River gage, calcium is the dominant cation 

while bicarbonate is the dominant anion (fig. 11). Samples 

from Kona Creek and Kona Creek tributary indicate the 

same type of cation/anion relation. In the Ore Creek Basin, 

there are differences that reflect the geology of the watershed. Calcium is the dominant cation and sulfate is the dominant anion in East Fork Ore Creek, which drains the 

Johnson River Prospect (fig. 11). The high sulfate reflects 

the elevated amounts of sulfur found in the Johnson River 

Prospect. North Fork Ore Creek and the unnamed spring 

adjacent to the Johnson River Prospect, however, have characteristics similar to the Kona Creek and Johnson River 

gage sites - calcium is the dominant cation and bicarbonate 

the dominant anion (fig. 11), reflecting the relatively low 

amounts of sulfur found in rock samples from these areas. 

Water from the North Fork Ore Creek has a dilution affect 

on the water of East Fork Ore Creek, which is indicated by 

the approximately equal percentage of the anions sulfate 

and bicarbonate found at the mouth of Ore Creek.

Water samples from the Johnson River gage site were 

analyzed for 23 trace elements, both in the dissolved phase 

and total content (appendix 1). These samples cover a range 

of discharge (20 ft3

/s to 2,460 ft3/s) for 1999-2001. Most of 

these same elements, though only in the dissolved phase, 

were analyzed from water samples collected from the sites 

visited during summer 2000 (table 10). 

At the Johnson River gage site, concentrations of about 

one-half the trace elements analyzed were less than 5.0 μg/L 

(appendix 1). At the other sites sampled in 2000, concentrations of 9 trace elements were less than 1.0 μg/L (table 10). 

In comparing the concentrations of the trace elements to 

published or known values and with standards that have 

been established for the protection of aquatic life, concentrations of all trace elements were within the normal ranges 

and did not exceed standards for protection of aquatic life 

(Smith and Huyck, 1999).

There were some notable characteristics of the trace element data from the water samples. The highest concentrations of several dissolved trace elements (aluminum, 

cadmium, copper, lead, manganese, and zinc) were found at 

East Fork Ore Creek, which drains the Johnson River Prospect, reflecting the mineralization of the basin. At Ore 

Creek, concentrations of these elements were lower, due to 

the dilution effect from North Fork Ore Creek. At the 

Johnson River gage site, concentrations of these elements 

were further diluted, reflecting the additional runoff from 

Johnson Glacier, Double Glacier, and Kona Creek. In addition, three trace elements (total aluminum, total iron, and 

total manganese) showed a strong correlation with suspended sediment that suggest these three elements are 

adsorbed onto the sediment (fig. 12).

Streambed sediments of the Johnson River at the gage 

site and at seven other sites in the study area were collected 

and analyzed for 39 trace elements (appendix 2). The highest concentrations of several trace elements (arsenic, 

Table 7. Alteration minerals of the Johnson River Prospect and associated gossans in the nearby Talkeetna Formation and batholith (identified by Gray, 1988).

Subtype Occurrence

Sericitic alteration: acidic fluids, addition of sulfur

Pyrite Low levels in Talkeetna Formation, including dacite dome; responsible for gossan

Quartz-sericitic-pyrite Veins/fractures in gossan areas of Talkeetna Formation; intensive at Johnson River 

Prospect where fault controlled

Anhydrite-chlorite-pyrite Intensive at Johnson River Prospect where fault controlled

Propylitic alteration: breakdown of plagioclase, addition of water and carbon dioxide

Chlorite-calcite (epidote) Pervasive and low levels throughout Talkeetna Formation

Zeolite Low levels, especially in porous silica-rich tuffs of Talkeetna Formation
20

Johnson River

Kona Creek

Ore Creek

Johnson River tributary

Unnamed Spring

East Fork

North

Fork

Ore

SULFATE PLUS CHLORIDE

CALCIUM PLUS MAGNESIUM

BICARBONATE

SODIUM PLUS POTASSIUM

MAGNESIUM

CALCIUM

PERCENT

CHLORIDE, FLUORIDE, NITRITE PLUS NITRATE

SULFATE

PERCENT

PERCENT

SULFATE PLUS CHLORIDE

CALCIUM PLUS MAGNESIUM

BICARBONATE

SODIUM PLUS POTASSIUM

MAGNESIUM

CALCIUM

PERCENT

CHLORIDE, FLUORIDE, NITRITE PLUS NITRATE

SULFATE

PERCENT

PERCENT

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Figure 11. Trilinear diagrams of water samples from the Johnson River Basin.
21

Table 8. Major dissolved inorganic constituents measured in 18 water samples collected from Johnson River above Lateral Glacier near Tuxedni Bay, Alaska (site 52). 

[all values in mg/L, E, estimated]

Date Calcium Magnesium Sodium Potassium Bicarbonate Sulfate Chloride Silica Dissolved Solids

5-17-99 9.5 0.92 1.3 0.18 18 12.0 1.0 4.2 426-10-99 8.1 0.73 0.9 0.27 17 8.4 0.7 3.2 416-30-99 6.8 0.62 0.8 0.30 16 6.4 0.5 2.6 517-21-99 5.3 0.43 0.6 0.22 -- 5.2 0.3 1.8 278-6-99 5.4 0.37 0.5 0.35 12 3.7 <0.1 1.8 268-24-99 6.6 0.52 0.7 0.29 15 5.8 0.3 2.3 239-16-99 7.8 0.64 0.8 0.28 18 8.8 <0.3 2.7 3410-7-99 11.2 0.98 1.1 0.35 26 13.5 0.6 4.4 465-9-00 15.0 1.24 2.5 E0.20 26 17.9 1.7 5.6 686-15-00 8.6 0.80 1.1 0.32 18 9.9 1.4 3.5 367-26-00 5.9 0.52 0.7 0.27 16 5.6 0.6 2.3 248-16-00 6.5 1.23 0.7 0.40 17 6.6 0.5 2.0 289-18-00 12.0 0.90 1.3 0.46 25 15.6 0.8 3.8 505-23-01 13.8 1.04 1.8 0.31 23 17.8 2.0 4.7 446-26-01 6.4 0.58 0.9 0.27 16 5.9 0.7 2.7 238-01-01 5.3 0.45 0.6 0.40 13 5.3 0.5 2.0 209-3-01 6.7 0.54 0.7 0.21 16 7.0 0.5 2.4 209-27-01 8.7 0.72 0.9 0.24 18 10.8 0.5 3.2 34

Table 9. Major dissolved inorganic constituents measured in water samples collected from sites in the Johnson River study area, July 2000. 

[all values in mg/L; E, estimated]

Site identifier

(figure 3) Sampling site Calcium Magnesium Sodium Potassium Bicarbonate Sulfate Chloride Silica

115 East Fork Ore Creek 9.4 1.3 0.9 <0.2 8 24 0.8 3.5

114 Unnamed Spring 29 12 1.6 0.3 124 14 5.0 5.1116 North Fork Ore Creek 8.7 3.2 1.0 <0.2 38 5.5 0.5 3.7117 Ore Creek 9.9 2.2 1.0 <0.2 23 17 0.6 3.9118 Johnson River tributary 6.7 0.4 0.6 <0.2 21 3.9 0.4 2.9110 Kona Creek 3 miles above mouth 2.8 0.4 0.6 <0.2 6 4.7 0.4 2.1111 Kona Creek 2.5 miles above mouth 2.9 0.4 1.8 <0.2 8 4.5 0.5 2.2112 Kona Creek tributary 19 0.9 1.0 0.4 42 17 0.6 4.6113 Kona Creek 0.8 miles above mouth 4.9 0.6 0.8 <0.2 12 5.9 0.8 2.8
22

Table 10. Dissolved trace element concentrations measured in water samples collected from sites in the Johnson River study area, July 2000. 

[all values in ug/L; E, estimated; M, presence verified, but not qantified]

Site identifier

(figure 3) Sampling site Aluminum Antimony Arsenic Barium Beryllium Boron Cadmium

115 East Fork Ore Creek 40 <1.0 <1 13 <1.0 <12 3.4

114 Unnamed Spring 25 <1.0 3 45 <1.0 57 <1.0116 North Fork Ore Creek 24 <1.0 1 23 <1.0 32 <1.0117 Ore Creek 47 <1.0 E1 20 <1.0 24 1.5118 Johnson River tributary 27 <1.0 <1 1.8 <1.0 E7.3 <1.0110 Kona Creek 3 miles above mouth 28 <1.0 <1 7.9 <1.0 E8.6 <1.0111 Kona Creek 2.5 miles above mouth 24 <1.0 <1 9.1 <1.0 E9.0 <1.0112 Kona Creek tributary 5.3 <1.0 <1 1.0 <1.0 22 <1.0113 Kona Creek 0.8 miles above mouth 31 <1.0 <1 7.3 <1.0 E8.7 <1.0

Site identifier

(figure 3) Sampling site Chromium Cobalt Copper Iron Lead Lithium Manganese

115 East Fork Ore Creek <0.8 <1.0 1.6 <10 1.6 M 28

114 Unnamed Spring <0.8 <1.0 <1.0 <10 <1.0 4 <1.0116 North Fork Ore Creek <0.8 <1.0 <1.0 <10 <1.0 1 <1.0117 Ore Creek <0.8 <1.0 <1.0 E6.7 <1.0 1 14118 Johnson River tributary <0.8 <1.0 <1.0 <10 <1.0 M <1.0110 Kona Creek 3 miles above mouth <0.8 <1.0 <1.0 <10 <1.0 <1 1.6111 Kona Creek 2.5 miles above mouth <0.8 <1.0 <1.0 <10 <1.0 <1 1.3112 Kona Creek tributary <0.8 <1.0 <1.0 <10 <1.0 M <1.0113 Kona Creek 0.8 miles above mouth <0.8 <1.0 <1.0 <10 <1.0 <1 2.0

Site identifier

(figure 3) Sampling site Molybdenum Nickel Selenium Silver Strontium Thallium Vanadium Zinc

115 East Fork Ore Creek <1.0 <1.0 <1 <1.0 39 <0.9 <1 687

114 Unnamed Spring 1.7 <1.0 <1 <1.0 72 <0.9 <1 6.5116 North Fork Ore Creek <1.0 <1.0 <1 <1.0 18 <0.9 <1 5.2117 Ore Creek <1.0 <1.0 <1 <1.0 33 <0.9 <1 303118 Johnson River tributary <1.0 <1.0 <1 <1.0 7.8 <0.9 <1 4.1110 Kona Creek 3 miles above mouth <1.0 <1.0 <1 <1.0 8.5 <0.9 <1 6.1111 Kona Creek 2.5 miles above mouth <1.0 <1.0 <1 <1.0 9.1 <0.9 <1 6.1112 Kona Creek tributary <1.0 <1.0 <1 <1.0 16 <0.9 <1 <1.0113 Kona Creek 0.8 miles above mouth <1.0 <1.0 <1 <1.0 10 <0.9 <1 9.0
23

Figure 12. Relation between (A) total aluminum, (B) total iron, 

and (C) total magnesium and suspended sediment at Johnson 

River above Lateral Glacier near Tuxedni Bay, Alaska.

SUSPENDED SEDIMENT, IN MILLIGRAMS PER LITER

TOTAL MANGANESE, IN MICROGRAMS PER LITER

2.5 7.5 25.0 50.0 250.0 750.0 6

10

50

100

500

C

200

500

1000

5000

10000

20000

200

1000

5000

10000

20000

30000

TOTAL IRON, IN MICROGRAMS PER LITER TOTAL ALUMINUM, IN MICROGRAMS PER LITER

B

A

mium, chromium, copper, lead, mercury, nickel, selenium, 

and zinc. Trace-element concentrations in the streambed 

sediments were compared with those of previous studies 

(table 11). Gilliom and others (1998) determined national 

median concentrations (in micrograms per gram, dry 

weight) for these elements. As part of the NAWQA program, a NAWQA data base has been established where 

users may retrieve water-quality data from other NAWQA 

study units based on criteria such as land use. From this data 

base, trace element data for basins listed as “mined” were 

retrieved and the median concentration values determined. 

The Canadian Council of Ministers of the Environment 

(1999) has established guidelines for some trace elements in 

unsieved streambed sediment. These guidelines use two 

assessment values: a lower value, called the “interim freshwater sediment quality guideline” (ISQG), is the

 concentration below which adverse effects are expected to 

occur rarely and the upper value, called the “probable effect 

level” (PEL), is the concentration above which adverse 

effects are expected to occur frequently. Because trace-element samples for the NAWQA program are from sediments 

finer than 0.063 mm where concentrations tend to be greatest, comparisons with the Canadian guidelines may overestimate the effects on aquatic organisms (Deacon and 

Stephens, 1998). However, it was felt that the PEL would be 

useful for comparative purposes when applied to the finer 

than 0.063 mm size fraction sediment samples analyzed for 

this study.

MacDonald and others (2000) established sediment 

quality guidelines (SQGs) for seven trace elements and Van 

Derveer and Canton (1997) established guidelines for selenium. These guidelines use the following two concentrations for a given trace element: the threshold effect 

concentration (TEC) and the probable effect concentration 

(PEC) and assume a one-percent organic carbon concentration. The TEC is the concentration below which sedimentdwelling organisms are unlikely to be adversely affected, 

and the PEC is the concentration above which toxicity is 

likely. In addition, MacDonald and others (2000) developed 

a Mean PEC Quotient (table 12) which is the toxicity of the 

combined trace element concentrations. This value is determined by summing the concentrations of all the trace elements analyzed and dividing by the number of elements. 

MacDonald and others found that sediments with mean 

PEC quotients of less than 0.5 accurately predicted the 

absence of toxicity in 83 percent of the samples they examined. Mean PEC quotients greater than 0.5 accurately predicted toxicity in 85 percent of the samples. 

Comparison of the concentrations of the bed sediments 

of the nine trace elements with median values from Gilliom 

and others (1998) and the NAWQA data base 

barium, cadmium, copper, lead, selenium, and zinc) were 

found in East Ore Creek and to a lesser extent, Ore Creek, 

reflecting the mineralization of the Johnson River Prospect. 

Concentrations of these trace elements were substantially 

lower at the most downstream site of the study area, the 

Johnson River gage. This suggests that discharge from Kona 

Creek, Johnson Glacier, and Double Glacier transport fine 

sediment that mixes with the sediment from Ore Creek.

The focus in the literature on criteria for streambed sediments has been limited to nine trace elements: arsenic, cad-
24

(http://water.usgs.gov/nawqa/data, accessed July, 2002) 

indicated that with the exception of chromium and nickel, 

concentrations of trace elements at East Fork Ore Creek and 

Ore Creek exceeded the median values (table 11). Concentrations of arsenic, copper, and mercury from the Kona 

Creek sites and the Johnson River gage sites also exceeded 

these median values (tables 11). Concentrations of cadmium, lead, and zinc from East Fork Ore Creek and Ore 

Creek exceeded the ISQG limits. PEL concentrations of 

arsenic, cadmium, lead, mercury, and zinc were exceeded 

only at East Fork Ore Creek and Ore Creek. There was some 

variation in TEC levels. TEC levels of arsenic and copper 

were exceeded at all sites and TEC levels of cadmium, lead, 

selenium, and zinc were exceeded only at East Fork Ore 

Creek and Ore Creek. Finally, only concentrations of 

arsenic, lead, and zinc at East Fork Ore Creek and Ore Creek 

exceeded the PEC (table 11).

Comparison of the concentrations of the trace elements 

with the percent organic carbon and PEC quotient offer 

some insights about the bioavailability of these elements 

(table 12). The highest concentration of organic carbon 

(1.30 percent) and the lowest PEC quotient (0.23) was found 

at Kona Creek Tributary. All other sites had organic carbon 

concentrations from 0.05 percent to 1.00 percent and PEC 

quotient values greater than 0.5, which would indicate some 

level of potential toxicity (table 12). As MacDonald and others (2000) noted, sites containing relatively low concentrations of organic carbon have higher potential toxicity.

As a preliminary survey of the neutralizing potential of 

Johnson River bedrock, 11 samples were submitted to an 

acid-base accounting (ABA) test. The samples (table 13) 

have low sulfur contents: 0.50 percent in a gossaned, 

sheared granodiorite and 0.58 percent in limey volcaniclastic sandstone from the upper part of the Talkeetna Formation 

were the only detectable abundances. Neutralizing potential 

ranged by two orders of magnitude, from 4 to 590. The highest values were three tuff-breccia samples and a volcaniclastic sandstone (Talkeetna Formation) and the gossaned 

granodiorite sample that also had 0.58 percent sulfur. Such 

high values in Talkeetna Formation volcaniclastic rocks 

reflect secondary veins and vesicles of calcite (propylitic 

alteration) as well as clasts of limestone that were probably 

eroded from reefs growing in the vicinity of the volcanic arc.

As noted previously, ABA maximizes the reported neutralizing potential by crushing the sample so that the entire 

volume is exposed to the test acid. Field tests for this study 

indicated that stream cobbles had lost most of the calcite 

originally in the outer shell, and, unless broken open, had little or no reaction to acid. Thus, in the case of a natural or 

manmade exposure of unweathered sulfide-bearing rock, 

the effect on downstream acidity will depend on how much 

calcite is also exposed or if the existing calcite is crushed. If 

sulfide significantly outweighs calcite, then bed sediments 

in the adjacent drainage may not be effective in buffering the 

resulting acidity because they are now armored by a calcitedepleted shell.

Table 11. Concentrations of selected trace elements in streambed sediments from various studies. 

[values in micrograms per gram; --; no data]

Trace element Gilliom and 

others (1998)1

1Median values 

NAWQA 

database2

2 Median values among mined sites 

Interim Freshwater 

Sediment Quality 

Guideline (ISQG)3

3

Canadian Council of Ministers of the Environment (1995)

Probable Effect 

Level3 (PEL)

Threshold Effect

 Concentration 

(TEC)4

4MacDonald and others (2000)

Probable Effect 

Concentration 

(PEC)4

East Fork Ore 

Creek Ore Creek

Arsenic 6.4 13.0 5.9 17.0 9.8 33.0 64 44

Cadmium 0.4 0.9 0.6 3.5 0.99 5.0 4.3 4.6

Chromium 62 68.5 37.3 90 43.4 111 14 23

Copper 26 36 35.7 197 31.6 149 76 92

Lead 24 41.5 35.0 91.3 35.8 128 230 180

Mercury 0.06 0.08 0.17 0.49 0.18 1.06 0.93 0.28

Nickel 25 38 -- -- 22.7 48.6 4.0 8.0

Selenium 0.7 0.8 -- -- 5

2.5

5VanDerveer and Canton (1997)

54.0 2.6 1.2

Zinc 110 235 123 315 121 459 1000 1800
25

Table 12. Concentrations of trace elements, percent organic carbon, and mean PEC quotient for streambed sediment at sites located in the Johnson River study area. 

[values in micrograms per gram; bold indicates values exceeds TEC or PEC when normalized for organic carbon content or value exceeds 0.5 for PEC quotient]

Site 

identifier 

(figure 3)

Sampling site Arsenic Cadmium Chromium Copper Lead Mercury Nickel Selenium Zinc

 Organic 

Carbon

 (percent)

Mean PEC 

quotient

52 Johnson River above Lateral Glacier 16 0.2 66 75 4 0.13 17 0.3 130 0.05 6.02

110 Kona Creek 3 miles above mouth 19 <0.1 38 56 6 0.75 11 0.6 120 0.25 1.27

111 Kona Creek 2.5 miles above mouth 18 0.1 42 57 5 0.16 11 0.6 140 0.26 0.98

112 Kona Creek tributary 18 <0.1 77 47 4 0.10 25 0.2 85 1.30 0.23113 Kona Creek 0.8 miles above mouth 16 0.4 48 63 17 0.28 14 0.7 150 0.49 0.62

115 East Fork Ore Creek 64 4.3 14 76 230 0.93 4 2.6 1,000 1.00 0.72

116 North Fork Ore Creek 34 <0.1 41 54 <1 0.53 15 0.2 120 0.16 2.21

117 Ore Creek 44 4.6 23 92 180 0.28 8 1.2 1,800 0.24 4.60

Table 13. Results of acid based accounting tests on 11 rock samples from the Johnson River study area. 

[units for MPA, NP, and NNP are kilograms CaCO3 per metric ton]

Site location 

(figure 4)

Sample 

identifier Sample type Sulfate (percent S) Sulfur (percent) Sulfur (percent total) Carbon dioxide (percent) Maximum poten- tial acidity (MPA)1

1MPA is determined by multiplying the percent total sulfur by 31.25

Neutralizing 

potential 

(NP)2

2NP is the capacity to neutralize acidity to pH 6.0

Net neutralizing 

potential

 (NNP)3

3NNP equals NP - MPA

Ratio

 (NP/MPA)

R107 B Lava <0.01 <0.01 <0.01 0.8 1 44 43 44R112 A Lava flow <0.01 <0.01 <0.01 0.2 1 4 3 4R113 A Tuff <0.01 <0.01 <0.01 1.6 1 94 93 94R117 A Dacite plug <0.01 <0.01 <0.01 0.6 1 13 12 13R107 C Granodiorite <0.01 <0.01 0.01 16.2 1 355 354 355R110 A Tuff <0.01 <0.01 <0.01 3.8 1 218 217 2183P C Lava flow <0.01 0.50 0.50 0.8 16 27 11 1.74P CA Granodiorite <0.01 0.07 0.07 0.4 2 7 5 3.55P C Dacite plug <0.01 <0.01 <0.01 <0.2 1 9 8 9.09P CB Lava flow 0.04 0.04 0.58 21.4 18 525 507 2912P CA Tuff <0.01 <0.01 <0.01 24.6 1 591 590 1591
26

SUMMARY AND CONCLUSIONS

The Johnson River Basin, located on the west side of 

Cook Inlet in south-central Alaska, drains an area of about 

96 mi2. In the upper part of the basin, a mineral deposit is 

located on a private inholding. Due to the possibility of 

developing the mineral prospect, the upper part of the 

Johnson River Basin was studied from 1999 through 2001 as 

part of a cooperative study with the National Park Service. 

The purpose of this study was to characterize the geochemistry of the Johnson River Prospect, to identify potential 

environmental hazards, and to determine baseline levels for 

selected water-quality constituents. Major findings are:

The two main rock units that occur in the study area are 

the Early Jurassic Talkeetna Formation and the Middle and 

Late Jurassic plutonic rocks of the Alaska-Aleutian Ranges 

batholith. Both show extensive areas of oxidation of previously mineralized, sulfide-rich rocks (gossans). The main 

structural feature of the study area is the Bruin Bay fault.

The widespread gossans in the volcanic Talkeetna Formation have a similar metal signature to the Johnson River 

Prospect (lead, zinc, cadmium, arsenic, copper, mercury, 

gold, and sulfur).

The average monthly discharge for the Johnson River 

during the open water period (May through October) ranges 

from 183 ft3

/s in May to 719 ft3/s in July. Most of the flow 

originates from Johnson Glacier and Double Glacier. Physical and chemical parameters (specific conductance, pH, 

water temperature, and dissolved oxygen) and concentrations of basic water-quality constituents indicate good water 

quality. Water type of the Johnson River is classified as calcium bicarbonate.

Water quality samples from various sites in the study 

area indicate that most trace metals occur at low concentrations in the dissolved phase. The low dissolved metal contents are most likely the result of a combination of natural 

buffering by available carbonate and current level of weathering of previously sulfur-bearing rocks. Concentrations of 

total aluminum, total iron, and total manganese collected at 

the Johnson River gage correlate with suspended-sediment 

concentration.

The highest concentrations of several trace elements 

from streambed sediments (arsenic, barium, cadmium, copper, lead, selenium, and zinc) were found at East Fork Ore 

Creek, which drains the Johnson River Prospect, and Ore 

Creek. Concentrations of these elements substantially 

decrease downstream, indicating the introduction of additional fine sediment from streams draining Johnson Glacier 

and Double Glacier.

Concentrations of several trace elements from streambed 

sediments of East Fork Ore Creek and Ore Creek exceed the 

Interim Freshwater Sediment Quality Guidelines, probable 

effect levels, threshold effect concentrations, and probable 

effect concentrations. Most sites sampled in the study area 

have low amounts of organic carbon and mean PEC quotients greater than 0.5, which indicates the presence of toxicity.

Acid-Base Accounting (ABA) tests on 11 rock samples 

indicated low acid-generating potential and high acidityneutralizing potential of most samples. ABA maximizes the 

reported neutralizing potential by crushing the sample so 

that the entire volume is exposed to the test acid. Conversely, field tests show that stream cobbles have lost most 

of the calcite originally in the outer shell and unless broken 

open, have little further reaction to acid. Thus, in the case of 

a natural or manmade exposure of unweathered sulfidebearing rock, the effect on downstream acidity will depend 

on how much calcite is newly exposed along with unweathered sulfide. If sulfide significantly outweighs calcite, then 

bed sediments in the adjacent drainage may be ineffective in 

buffering the resulting surge of acidity because they are now 

armored by a calcite-depleted shell.

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Aiken, G., and Cotsaris, E., 1995, Soil and hydrology-Their 

effect on NOM: American Water Works Association, January, p. 36-45.

Alaska Native Claims Settlement Act (ANCSA), 1971: 43 

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Arbogast, B.F., ed., 1990, Quality assurance manual for the 

Branch of Geochemistry, U.S. Geological Survey: U.S. 

Geological Survey Open-File Report 90-668, 184 p.

Baedecker, P.A., ed., 1987, Methods for geochemical analysis: 

U.S. Geological Survey Bulletin 1770, 11 chapters, independently paginated.

Canadian Council of Ministers of the Environment, 1995, 

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Canadian sediment quality guidelines for the protection of 

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Quality Guidelines, 1999: Winnipeg, Canadian Council of 

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streambed sediment and fish liver at selected sites in the 

Upper Colorado River Basin, Colorado, 1995-96: U.S. 

Geological Survey Water-Resources Investigations Report 

98-4124, 19 p.
27

Detterman, R.L., and Hartsock, J.K., 1966, Geology of the Iniskin-Tuxedni region, Alaska: U.S. Geological Survey Professional Paper 512, 78 p. 6 plates, scale 1:63,360.

Detterman, R.L., and Reed, B.L., 1980, Stratigraphy, structure, and economic geology of the Iliamna quadrangle, 

Alaska: U.S. Geological Survey Bulletin 1368-B, 86 p., 1 

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Edwards, T.K., and Glysson, G.D., 1988, Field methods for 

measurement of fluvial sediment: U.S. Geological Survey 

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28

APPENDIX 
29

Appendix 1. Trace element concentrations measured in 18 water samples collected from Johnson River above Lateral Glacier near Tuxedni Bay, Alaska (site 52).

[all values in ug/L; E, estimated, <, less than, --, no data; M, presence verified, but not quantified]

Date Aluminum, dissolved Aluminum, total Antimony, dissolved Antimony, total Arsenic, dissolved Arsenic, total Barium, dissolved Barium, total Beryllium, dissolved Beryllium, total Boron, dissolved Cadmium, dissolved

5-17-99 10 -- <1.0 -- <1.0 -- 9.1 -- <1.0 -- -- <1.06-10-99 18 6,460 <1.0 <1.0 <1.0 3 9.1 42.6 <1.0 <4.0 -- <1.06-30-99 28 2,670 <1.0 <1.0 <1.0 1 8.6 16.4 <1.0 <4.0 -- <1.07-21-99 22 2,870 <1.0 <1.0 <1.0 2 6.1 16.4 <1.0 <4.0 -- <1.08-6-99 24 24,400 <1.0 <1.0 <1.0 7 3.7 76.3 <1.0 <4.0 -- <1.08-24-99 21 1,940 <1.0 <1.0 <1.0 1 7.0 15.3 <1.0 <4.0 -- <1.09-16-99 19 1,420 <1.0 <1.0 <1.0 E1 8.8 14.0 <1.0 <5.0 -- <1.010-7-99 18 232 <1.0 <1.0 <2.0 <3 13.0 13.8 <1.0 <5.0 -- <1.05-9-00 <16 -- <1.0 -- <0.9 -- 14.0 -- <1.0 -- 23 <1.06-15-00 14 1,020 <1.0 <1.0 E0.6 <3 11.5 15.2 <1.0 <5.0 25 <1.07-26-00 70 2,010 <1.0 <1.0 E0.7 E1 6.5 13.0 <1.0 <5.0 17 <1.08-16-00 13 2,160 <1.0 <1.0 E0.8 E2 7.3 15.7 <1.0 <5.0 20 <1.09-18-00 22 -- <1.0 -- 1.2 -- 14.1 -- <1.0 -- 43 <1.05-23-01 11 -- 0.08 -- 0.4 -- 14.9 -- <0.06 -- 54 E0.036-26-01 33 4,070 0.07 -- 0.5 E1 8.8 27.0 <0.06 <2.5 17 E0.038-1-01 21 2,570 0.07 -- 0.7 E1 6.3 15.7 <0.06 <2.5 16 <0.049-3-01 20 706 0.06 -- 0.8 M 6.9 10.0 <0.06 <2.5 19 E0.029-27-01 19 353 0.10 -- 0.8 E1 8.7 10.1 <0.06 <2.5 33 0.04

Date Cadmium, total Chromium, dissolved Chromium, total Cobalt, dissolved Cobalt, total Copper, dissolved Copper, total Iron, dissolved Iron, total Lead, dissolved Lead, total Lithium, dissolved Lithium, total

5-17-99 -- <1.0 -- <1.0 -- 2.1 -- <10.0 -- <1.0 -- -- --6-10-99 <1.0 <1.0 1.0 <1.0 2.0 <1.0 E11.7 <10.0 5,120 <1.0 <1.0 -- <12.06-30-99 <1.0 <1.0 <1.0 <1.0 1.0 <1.0 E6.5 M 2,060 <1.0 <1.0 -- <12.07-21-99 <1.0 <1.0 <1.0 <1.0 1.0 <1.0 <12.0 <10.0 2,180 <1.0 <1.0 -- <12.08-6-99 <1.0 -- 5.0 <1.0 10 <1.0 38.7 <10.0 16,900 <1.0 2.0 -- E6.18-24-99 <1.0 <1.0 <1.0 <1.0 1.0 <1.0 <12.0 <10.0 1,610 <1.0 <1.0 -- <12.09-16-99 <0.11 <1.0 <1.0 <1.0 E1.0 <1.0 <20.0 <10.0 1,120 <1.0 <1.0 -- <7.010-7-99 <0.11 <0.8 <1.0 <1.0 <2.0 <1.0 <20.0 <10.0 180 <1.0 1 -- <7.05-9-00 -- -- -- <1.0 -- <1.0 -- <10 -- <1.0 -- E0.1 --6-15-00 <0.11 <0.8 <1.0 <1.0 <2.0 <1.0 <20.0 <10.0 840 <1.0 <1.0 0.4 <7.07-26-00 <0.11 <0.8 M <1.0 <2.0 <1.0 <20.0 30 1,590 <1.0 <1.0 0.5 <7.08-16-00 <0.11 E0.8 M <1.0 E1.0 <1.0 <20.0 <10.0 1,900 <1.0 <1.0 0.3 <7.09-18-00 -- E0.5 -- <1.0 -- <1.0 -- <10.0 -- <1.0 -- 0.9 --5-23-01 -- E0.4 -- 0.12 -- 0.6 -- <10.0 -- <0.08 -- 1.4 --6-26-01 E0.07 <0.8 M 0.07 E2.0 0.6 <20.0 10.0 3,510 E0.06 <1.0 E0.2 <7.08-01-01 <0.10 <0.8 <1.0 0.04 E1.0 0.5 <20.0 <10.0 2,240 <0.08 <1.0 E0.2 <7.09-3-01 E0.05 <0.8 <1.0 0.04 <2.0 <0.2 <20.0 M 540 <0.08 <1.0 E0.2 <7.09-27-01 <0.10 <0.8 <1.0 0.07 <2.0 0.4 <20.0 <10.0 310 <0.08 <1.0 0.4 <7.0
30

Appendix 1. Trace element concentrations measured in 18 water samples collected from Johnson River above Lateral Glacier near Tuxedni Bay, Alaska (site 52)—Continued.

Date Manganese, dissolved Manganese, total Mercury, total Molybdenum, dissolved Molybdenum, total Nickel, dissolved Nickel, total Selenium, dissolved Selenium, total Silver, dissolved Silver, total

5-17-99 3.6 -- -- <1.0 -- <1.0 -- <1.0 -- <1.0 --6-10-99 4.8 114 -- <1.0 <1.0 <1.0 1.0 <1.0 <1.0 <1.0 <1.06-30-99 4.2 45 -- <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.07-21-99 3.4 49 -- <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.08-6-99 8.7 395 -- <1.0 <1.0 <1.0 5.0 <1.0 <1.0 <1.0 <1.08-24-99 4.0 37 -- <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.09-16-99 3.9 27 -- <1.0 1.3 <1.0 <2.0 <1.0 <2.6 <1.0 <1.010-7-99 3.4 8.0 -- <1.0 <1.0 <1.0 <2.0 <2.4 <2.6 <1.0 <1.05-9-00 4.2 -- -- <1.0 -- 1.33 -- <0.7 -- <1.0 --6-15-00 2.9 21 <0.30 <1.0 <1.0 <1.0 <2.0 <0.7 <2.6 <1.0 <1.07-26-00 3.5 34 <0.30 <1.0 1.3 <1.0 <2.0 <0.7 <2.6 <1.0 <1.08-16-00 4.2 41 <0.30 <1.0 <1.0 <1.0 <2.0 <0.7 <2.6 <1.0 <1.09-18-00 3.6 -- -- <1.0 -- <1.0 -- E0.4 -- <1.0 --5-23-01 3.1 -- -- 0.4 -- 0.18 -- <0.3 -- <1.0 --6-26-01 4.9 79 0.03 0.3 <1.5 0.15 <2.0 <0.3 <3.0 <1.0 <0.408-1-01 4.8 52 <0.01 0.4 E0.8 <0.06 <2.0 <0.3 E0.2 <1.0 <0.409-3-01 2.6 16 <0.01 0.4 <1.5 <0.06 <2.0 E0.2 <3.0 <1.0 <0.409-27-01 2.2 8.0 <0.01 0.6 E1.1 <0.06 <2.0 <0.3 <3.0 <1.0 <0.40

Date Strontium, dissolved Strontium, total Thallium, dissolved Vanadium, dissolved Zinc, dissolved Zinc, total

5-17-99 -- -- -- -- 3.0 --6-10-99 -- 29.0 -- -- 4.0 E326-30-99 -- 18.9 -- -- 7.0 E227-21-99 -- 15.4 -- -- 3.0 <408-6-99 -- 65.2 -- -- <1.0 E408-24-99 -- 15.4 -- -- 3.0 <409-16-99 -- 17.0 -- -- 7.0 E1510-7-99 -- 22.3 -- -- 11 E175-9-00 24.5 -- <0.90 <1.0 <5.0 --6-15-00 19.4 19.0 <0.90 <1.0 7.0 E207-26-00 11.9 14.9 <0.90 <1.0 4.0 <318-16-00 12.5 15.6 <0.90 <1.0 2.0 <319-18-00 24.0 -- <0.90 <1.0 3.0 --5-23-01 26.3 -- <0.04 E0.2 4.0 --6-26-01 12.5 18.9 <0.04 0.5 3.0 E238-1-01 10.6 14.5 <0.04 0.5 3.0 E179-3-01 12.5 13.2 <0.04 0.6 4.0 <319-27-01 16.9 17.4 <0.04 0.6 8.0 <31
31

Appendix 2. Trace element concentrations measured in streambed sediment samples collected from sites located in the Johnson River Basin, Alaska.

[all values in micrograms per gram, dry weight; <, less than; M, presence verified, but not quantified]

Site identifier

(figure 3) Sampling site Aluminum Antimony Arsenic Barium Beryllium Bismuth Cadmium Cerium

52 Johnson River above Lateral Glacier near Tuxedni Bay 8.1 2.8 16 210 0.2 <0.1 0.2 21110 Kona Creek 3 miles above mouth above Lateral Glacier near Tuxedni Bay 8.5 1.4 19 250 M <1.0 <0.1 30111 Kona Creek 2.5 miles above Lateral Glacier near Tuxedni Bay 8.3 1.5 18 260 M <1.0 0.1 29112 Kona Creek tributary above Lateral Glacier near Tuxedni Bay 9.0 0.4 18 250 1.0 <1.0 <0.1 27113 Kona Creek 0.8 miles above mouth above Lateral Glacier near Tuxedni Bay 8.8 1.7 16 340 1.0 <1.0 0.4 25115 East Fork Ore Creek near mouth near Johnson Glacier near Tuxedni Bay 10 5.8 64 1100 1.0 <1.0 4.3 36116 North Fork Ore Creek near mouth near Johnson Glacier near Tuxedni Bay 8.0 10 34 200 1.0 <1.0 <0.1 22117 Ore Creek near mouth near Johnson Glacier near Tuxedni Bay 9.0 5.9 44 860 1.0 <1.0 4.6 27

Site identifier

(figure 3) Sampling site Chromium Cobalt Copper Europium Gallium Gold Holmium Iron

52 Johnson River above Lateral Glacier near Tuxedni Bay 66 33 75 1.0 16 <1.0 2.0 13110 Kona Creek 3 miles above mouth above Lateral Glacier near Tuxedni Bay 38 26 56 1.0 16 <1.0 2.0 8.2111 Kona Creek 2.5 miles above Lateral Glacier near Tuxedni Bay 42 27 57 1.0 16 <1.0 2.0 8.9112 Kona Creek tributary above Lateral Glacier near Tuxedni Bay 77 24 47 1.0 15 <1.0 1.0 4.8113 Kona Creek 0.8 miles above mouth above Lateral Glacier near Tuxedni Bay 48 23 63 1.0 16 <1.0 1.0 6.5115 East Fork Ore Creek near mouth near Johnson Glacier near Tuxedni Bay 14 18 76 2.0 20 <1.0 1.0 5.8116 North Fork Ore Creek near mouth near Johnson Glacier near Tuxedni Bay 41 44 54 1.0 18 <1.0 1.0 11117 Ore Creek near mouth near Johnson Glacier near Tuxedni Bay 23 24 92 1.0 18 <1.0 1.0 6.6

Site identifier

(figure 3) Sampling site Lanthanum Lead Lithium Manganese Mercury Molybdenum Neodymium

52 Johnson River above Lateral Glacier near Tuxedni Bay 9.0 4.0 10 1800 0.13 0.5 16110 Kona Creek 3 miles above mouth above Lateral Glacier near Tuxedni Bay 12 6.0 9.0 1600 0.75 2.0 20111 Kona Creek 2.5 miles above Lateral Glacier near Tuxedni Bay 12 5.0 9.0 1600 0.16 2.0 22112 Kona Creek tributary above Lateral Glacier near Tuxedni Bay 11 4.0 20 1200 0.10 3.0 16113 Kona Creek 0.8 miles above mouth above Lateral Glacier near Tuxedni Bay 10 17 12 1400 0.28 1.0 16115 East Fork Ore Creek near mouth near Johnson Glacier near Tuxedni Bay 15 230 17 1600 0.93 4.0 22116 North Fork Ore Creek near mouth near Johnson Glacier near Tuxedni Bay 8.0 <1.0 19 2000 0.53 <1.0 15117 Ore Creek near mouth near Johnson Glacier near Tuxedni Bay 12 180 16 1600 0.28 3.0 18
32

Appendix 2. Trace element concentrations measured in streambed sediment samples collected from sites located in the Johnson River Basin, Alaska—Continued. 

Site identifier

(figure 3) Sampling site Nickel Niobium Scandium Selenium Silver Strontium Tantalum Thallium

52 Johnson River above Lateral Glacier near Tuxedni Bay 17 <4.0 44 0.3 0.5 200 <1.0 <1.0110 Kona Creek 3 miles above mouth above Lateral Glacier near Tuxedni Bay 11 <4.0 49 0.6 <0.1 8.5 <1.0 <1.0111 Kona Creek 2.5 miles above Lateral Glacier near Tuxedni Bay 11 <4.0 49 0.6 <0.1 200 <1.0 <1.0112 Kona Creek tributary above Lateral Glacier near Tuxedni Bay 25 <4.0 29 0.2 <1.0 200 <1.0 <1.0113 Kona Creek 0.8 miles above mouth above Lateral Glacier near Tuxedni Bay 14 <4.0 36 0.7 0.1 190 <1.0 <1.0115 East Fork Ore Creek near mouth near Johnson Glacier near Tuxedni Bay 4 <4.0 31 2.6 0.8 74 <1.0 1.3116 North Fork Ore Creek near mouth near Johnson Glacier near Tuxedni Bay 15 <4.0 56 0.2 <0.1 140 <1.0 <1.0117 Ore Creek near mouth near Johnson Glacier near Tuxedni Bay 8 <4.0 36 1.2 0.2 110 <1.0 <1.0

Site identifier 

(figure 3) Sampling site Thorium Tin Titanium Uranium Vanadium Ytterbium Yttrium Zinc

52 Johnson River above Lateral Glacier near Tuxedni Bay 2.0 1.0 0.7 1.1 550 4.0 36 130110 Kona Creek 3 miles above mouth above Lateral Glacier near Tuxedni Bay 2.0 1.0 0.7 <1.0 300 4.0 42 120111 Kona Creek 2.5 miles above Lateral Glacier near Tuxedni Bay 2.0 1.0 0.8 <1.0 340 4.0 43 140112 Kona Creek tributary above Lateral Glacier near Tuxedni Bay <1.0 1.0 0.5 0.8 150 3.0 27 85113 Kona Creek 0.8 miles above mouth above Lateral Glacier near Tuxedni Bay 1.0 1.0 0.6 <1.0 220 3.0 31 150115 East Fork Ore Creek near mouth near Johnson Glacier near Tuxedni Bay 2.0 2.0 0.5 <1.0 140 4.0 34 1000116 North Fork Ore Creek near mouth near Johnson Glacier near Tuxedni Bay <1.0 1.0 0.8 <1.0 420 4.0 38 120117 Ore Creek near mouth near Johnson Glacier near Tuxedni Bay 1.0 1.0 0.5 1.0 220 4.0 33 1800