GEOLOGICAL SURVEY CIRCULAR 669 

Mineral Resources Off the 

Northeastern Coast of 

the United States 

Mineral Resources Off the 

Northeastern Coast of 

the United States 

By Frank T. Manheim 

GEOLOGICAL SURVEY CIRCULAR 6 6 9 

Washington 19 72 
United States Department of the Interior 

ROGERS C. B. MORTON, Secretary 

Geological Survey 

V. E. McKelvey, Director 

Free on application to the U.S. Geological Survey, Washington, D.C. 20242 
CONTENTS 

~~:~:~~:::~===========================================================j= Offshore extensions of land deposits ----------------------------------------

Manganese nodules, phosphorite, and other authigenic minerals formed on or 

below the sea floor ------------------------------------------~--------­

Deeper in-place ore deposits -----------------------------------------------

Sand, gravel, and mud ----------------------------------------------------

Environmental factors ----------------------------------------------------

References cited ----------------------------------------------------------

ILLUSTRATIONS 

Page 

1 

1 

7 

11 

11 

13 

13 

18 

27 

FIGURE 1. Simplified bathymetric map of northeastern offshore region, United States and maritime 

Page 

Canada --------------------------------------------------------------------------- 2 

2. Schematic diagram showing maximum glacial advance off Northeastern United States ------ 3 

3. Map showing distribution of calcium carbonate in bottom sediments off Northeastern United 

States ---------------------------------------------------------------------------- 4 

4. Generalized geologic map of coastal Northeastern United States and part of the Maritime 

Provinces of Canada --------------------------------------------------------------- 5 

5. Structure cross sections of the Gulf of Maine ------------------------------------------- 6 

6. Maps showing location of sampling stations of the U.S. Geological Survey-Woods Hole 

Oceanographic Institution Continental Margin Program ----------------------------- 9 

7. Map showing distribution of middle Tertiary phosphate-bearing sediments along the eastern 

continental margin of North America ------------------------------------------------ 12 

8. Schematic drawing showing transport of material from outcrop by glacial action ---------- 13 

9-17. Maps showing: 

9. Copper and zinc content of moraine near the Noranda ore body, Canada ----------- 14 

10. Distribution of spotted schist pebbles on the southeastern Scotian Shelf ---------- 15 

11. Distribution of sand on the continental margin off Northeastern United States ---- 16 

12. Distribution of sand and gravel off New Jersey --------------------------------- 17 

13. Distribution of sand in the inner Gulf of Maine and Massachusetts Bay ------------ 19 

14. Distribution of gravel on the continental margin off Northeastern United States ----- 20 

15. Distribution of gravel in the inner Gulf of Maine and Massachusetts Bay ---------- 21 

16. Offshore distribution of sediments that can be used in an innovative ceramic manufacturing process ---------------------------------------------------------- 22 

17. Directions of residual current along the bottom on the continental shelf and directions 

and magnitudes of sand movement on the beaches ---------------------------- 24 

18. Diagram showing balance of dredge spoil and consumption of sand and gravel for Atlantic Coast 

States ---------------------------------------------------------------------------- 26 

III 
TABLES 

Page 

TABLE 1. Chemical and modal analyses of typical sea-floor deposits on the northeastern continental margin 

of the United States ---------------------------------------------------------------- 11 

2. Quantity and value of sand and gravel production for various uses in the United States in 1970 14 

3. Quantity and value of sand and gravel and stone produced by some northeastern States, 1970 _ 14 

IV 
Mineral Resources off the Northeastern Coast 

of the United States 

By Frank T. Manheim 

ABSTRACT 

Sand, gravel, and mud represent not only the largest 

potential but also the most immediately useful.sea-floor 

resources off the coast of the Northeastern United 

States. Reserves of surficial sand grading 75 percent or 

more amount to more than 400 billion tons in the upper 

3 meters (10 ft) of the sea floor; this is enough to 

supply the sand needs of the Northeastern States of 

the United States and Maritime Provinces of Canada 

for several thousand years. 

Utilization of fine muds may be possible through 

innovative technology and should be encouraged. The 

mounting quantity of spoils produced by dredging of 

harbors and waterways otherwise poses a threat to the 

environment. 

Significant placer or other ores are not promising in 

surficial deposits. In the Gulf of Maine the existence of 

ores beneath glacial deposits remains unknown in the 

absence of core drilling to probe pre-Tertiary sedimentary and metamorphic rocks. 

No leasing is now permitted pending reevaluation of 

Federal and State regulatory guidelines. Improved 

investigatory and regulatory systems are essential to 

determine the guidelines for and to permit judicious 

and environmentally compatible management of offshore 

resources. 

INTRODUCTION 

The area off the coast of the Northeastern 

United States to the edge of the continental 

shelf encompasses about 250,000 km2 (square 

kilometers) or about 100,000 square miles 

(fig. 1). This area is only a little smaller than 

the combined area of New Jersey, New York, 

Connecticut, Rhode Island, Massachusetts, New 

Hampshire, and Maine. Except for bays and 

estuaries, and basins within the Gulf of Maine, 

most of the area is covered with relic sand, silt, 

and gravel, which are remnants of glacial or 

glachil-outwash deposits. As may be seen in 

figure 2, the entire area was either covered by 

1 

glaciers some 15,000 years ago or was affected 

by outwash from melting glaciers. Ice-rafted 

material that ranges in size from sand to 

boulders is found on the sea bottom well beyond 

the shelf break into the continental-slope region. 

The shelf break generally begins at a depth of 

from 120 to 140 m (meters), but most of the 

shelf is considerably shallower than this, except 

for basins deeper than 200 m in the Gulf of 

Maine. Below the shelf break, finer and more 

carbonate-rich sediments dominate (fig. 3). 

Oil, gas, and sulfur are not included in this 

summary, which focuses on relatively shallow 

earth materials found on the shelf and in bays, 

estuaries, and tidal rivers along the coast. The 

kinds of sediment found in the offshore sea 

bottom reflect in part the geology of the adjoining land (fig. 4), but some long distance 

transport is involved, and an enormous amount 

of mixing and homogenization was performed 

by the scraping actions of the ice sheets, combined with the postmelting processes of deposition by streams and transport and winnowing 

by waves and currents. 

Because of the blanket of glacially related 

sediments over much of the shelf, knowledge of 

the subsurface is based chiefly on geophysical 

(seismic, gravity, magnetic) measurements, 

samples from outcrops of bedrock in submarine 

canyons at the shelf break, and extrapolation of 

land geology. The subsurface geology off New 

Jersey and New York consists largely of 

Quaternary-to-Mesozoic sedimentary layers dipping seaward. North of Long Island, however, 

only shallow layers of sediment, a few tens or 

hundreds of meters thick, overlie complex preTriassic metamorphic or crystalline rocks in 
100 200 KM 

FIGURE 1.-Simplified bathymetric map of northeastern offshore region, United States and maritime Canada 

(modified from Emery and others, 1970). Solid circles indicate seamounts off New England. 1, gold deposits 

near Lunenberg Bay, Nova Scotia; 2, coal mines off Sydney-Glace Bay, Cape Breton Island; 3, copper-zinc 

district, Penobscot Bay, Maine. Contours in meters. 

the nearshore region (fig. 5) . Farther offshore, 

wedges of Tertiary-to-Mesozoic sedimentary 

rocks thicken rapidly seaward. Petroleum prospects are restricted to the thicker sedimentary 

rocks, as noted by Maher (1971) and work 

cited therein and by Tucker. 1 

The largest body of data on the sediments of 

the shelf region has been accumulated through 

surface-sediment samplings by the U.S. Geological Survey-Woods Hole Oceanographic Institution Continental Margin Program, which 

1 L. R. Tucker, 1971, East coast oil and gas potential: Report 

presented at Conference on World Ocean Resources, New York 

Univ., November 1971. 

2 

began in 1962.2 Location of the sampling stations, raw data from which are available in a 

recent computerized compilation (Hathaway, 

1971), are given in figure 6. These collections 

were largely made by surface grab samples 

which obtained material from a depth of 10 to 

about 30 em (centimeters). Gravity and piston 

cores have been obtained chiefly by coring in 

muddy basins in the Gulf of Maine, Buzzards 

Bay, canyons, and estuaries; such coring is 

2 The Bureau of Commercial Fisheries, Woods Hole (now North 

Atlantic Fisheries Research Center, National Oceanic and Atmospheric Administration), also collaborated in the program and has 

tabulated faunal populations noted in the bottom sediments. 
1:1:) 

I 

-----' 

I 

I 

25 0 25 50 75 100 KILOMETERS 

CONTOURS IN METERS 

FIGURE 2.-Schematic diagram showing maximum glacial advance off Northeastern United States. Arrows indicate major currents of movement of the 

ice sheet. From Schlee and Pratt (1970, fig. 15). 
.... 

\r 

~)~ "&"~, 

@ 

GEO"JES {I 

BANK v 

90.. 

0 IOOKM l 

FIGURE 3.-Distribution of calcium carbonate in bottom sediments off Northeastern United States (from Htilsemann, 1967; reprinted from "Sedimentology': with permission of Elsevier Publishing Co.). Concentrations are in percent air dry weight; 

depth contours in meters. 
72" 

01 

38" 

70" 

EXPLANATION 

Schist, argillite, • quartzite, gneiss. 

metavolcanic rocks, and limestone 

of Precambrian and Paleozoic age ~ 

c 

~ • Quaternary, Tertiary, and 

::a Cretaceous I :1! 

1 

~ Triassic 

Carboniferous • 

Granite, felsite, and in Canada, 

volcanic rocks 

• Intrusive and extrusive rocks of 

Triassic age 

D Volcanic rocks of Paleozoic age 

(United States only) 

68' 

s 

"' 

~ 

I 

J 

38' 

4.l ~ 

f,/" 

25 0 25 I I ''I I 

Contact 25 0 25 50 75 100 KILOMETERS 

~~--L--L~ 

CON TOURS IN METf.'<:S 

66' 40' 64' 4 ,;- b , '" 

FIGURE 4.-Generalized geologic map of coastal Northeastern United States and part of the Maritime Provinces of Canada. Modified from Goldsmith (1964) and Canada Geological Survey (1949), in Schlee and Pratt (1970). 
Cf) 

K~OMETERS 100 

PLEISTOCENE-HOLOCENE B 

0.4 

tr4. r/ ~ -_ 

r."' / -

TRIASSIC'_:-'..- ,... ' , -

~ 0 rB . PLEISTOCENE-HOLOCENE • c ~ ~ ~~~~~~~~ ____ . ,-;:-:..---:-,_--___ :: - ____-:,___________ TERTIARY "" ,_/_, ...... _.....-_ ........ (-, /--- ~ ... -:;: -=~ --.... ,-- ( ... --!,....._-:.... --=--====-

~ PiLE:ozolc , ,/ -- ,'- ---- -- ~ ·,~ cRETAcEous 

V) 0.4 

~ :::::;: 

~ 

~ G 

I 0 re;;;;n:;=-->--....--

~I~ I 

~ 0.2 ,, 

0:53 

~ 

0.2 

PALEOZOIC 

H 

~--· 

' ;;:5)~',~~ ·~ 4:·(j44• i1 .. ~ ·: :·-

' ' .. ;, ~ ~ '. c coo . , I ' F 142° 

-' G"oRG£5 ~ {INK • 

66° 

FIGURE 5.-Structure cross sections of the Gulf of Maine (from Uchupi, 1966; reprinted from "Journal of Geophysical Research" with pennission of 

American Geophysical Union). 
difficult in sands or coarser materials on the 

shelf proper. However, the U.S. Army Coastal 

Engineering Research Center (Washington, 

D.C.) has taken more than 300 vibro cores that 

reached depths of about 6 m, from New Jersey 

northward. With the exception of their program in Cape Cod Bay, most of the Corps of 

Engineers' work is directed toward beach-sand 

replenishment sources within 10 miles of land 

or shallower than 100 feet (30 m) of water. 

This work is summarized briefly by Duane 

( 1969). 

Few deeper samplings are available. Schlee 

(1968) listed the following drill holes and information from them: 

Ambrose Light Station ___ 20-196 ft of silty sand to 

and Scotland Light towers gravel above gray clay. 

at the approaches to New 

York Harbor. 

Texas tower site, south ___ 70 ft of coarse sand and 

of Moriches Bay, Long fine gravel overlying silty 

Island. clay. 

Nantucket Shoals ________ 80-90 ft of sand and gravelly sand above silty clay. 

Georges Shoal (250 km ___ As much as 120ft of fine to 

northeast of above) . coarse sand. 

In addition to the above, E. H. Goodwin, U.S. 

Coast Guard, Boston, Mass. (oral commun., 

1972), provided data on several other foundation borings made for the Coast Guard in the 

New England offshore region: 

Portland, Maine, lat ______ Bedrock encountered from 

43°30'42" N., long 70°4' just below sea bottom to 

57" W. (about 11 nautical some 11 ft or more below 

miles southeast of Port- sea bottom. 

land). 

800 feet off tip of ________ 50 ft of chiefly medium to 

Monomoy Point, Mass. coarse sand with trace of 

gravel. 

Cross Rip light, south of __ Q-10 ft, sand; 10-20, shell 

Hyannisport, Mass., lat fragments; at 20, silt; 

41 °26'39" N., long 17°17' 35, many shell fragments; 

36" W. Measurements are 46, less shell fragments; 

in feet below sea bottom. 59, fine gravel and sand; 

65, dense gray medium 

sand; 85, fine stiff clay, 

silty clay; 99-100, sand 

layers; 109, stiff gray 

silty to clayey sand; 119, 

silty sand; 125, less silt; 

135, shell fragments and 

coarse sand; 149 very fine 

gray sand. 

Buzzards Bay tower ______ Bottom (61 ft) to 91 ft, 

sand; at 91 ft, gravelly 

7 

layers, 1 to 2 inches thick; 

91-268 ft, clay, sand, gravel and possible boulders; 

268 ft, bedrock. 

Brenton Reef, lat 41 °25'35" _Bedrock at 77 ft water 

N., long 71 °23'20" W., off depth (no sediment); 77-

N ewport, R.I. 112 ft, metamorphic rock. 

No mineral deposits are now being exploited 

on the offshore sea floor, except for coastal 

dredge and fill operations and beach restoration. 

The future value of mineral resources in the 

area is great, but as several researchers have 

indicated, the immediate promise is not in 

valuable metal ores, but in such unglamorous 

or apparently uninteresting materials as sand, 

gravel, and mud, which are available in huge 

quantities. However, to develop these resources 

and meet the anticipated needs of the northeastern coastal communities, several still unfulfilled conditions will probably have to be met. 

Chief among these is a positive, fully implemented and well-coordinated investigatory and 

regulatory system involving both state and 

federally controlled offshore lands. The purpose 

of this paper is to sketch some of the facts and 

factors involved in achieving these goals. 

I am indebted most of all to J. S. Schlee (U.S. 

Geological Survey, Woods Hole), who provided 

the core of published and unpublished information on which this paper is based. K. 0. Emery 

(Woods Hole Oceanographic Institution) also 

provided much help and useful discussion. 

Others who have been helpful are R. Wigley, 

North Atlantic Fisheries Research Center, 

Woods Hole; D. B. Duane, Corps of Engineers, 

Washington, D.C.; V. L. Andreliunas and D. 

Leifer, Corps of Engineers, North Atlantic Div.; 

R. Blumberg, Massachusetts Department of 

Natural Resources; J. I. Tracey, Jr., U.S. Geological Survey, Washington, D.C.; R. H. Meade, 

U.S. Geological Survey, Woods Hole, Mass.; 

Frank Shea of the Nova Scotia Department of 

Mines; and E. H. Goodwin of the U.S. Coast 

Guard in Boston. 

PLACER ORES 

The term "offshore mineral resources" frequently conjures up valuable commodities or 

raw materials such as phosphorite, placer 

(transported by running water) gold, platinum, 

diamonds, tin, monazite (thorium-rare earth 
8 
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COW TOUR$ 1111 ME TEllS 

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FIGURE 6.-Location of sampling stations of the U.S. Geological Survey-Woods Hole Oceanographic Institution Continental Margin Program 

(documented in Hathaway, 1971). Top: Stations as of January 1, 1967. Bottom: Stations added after January 1, 1967. Numbered areas 

contain additional sampling stations that are too closely spaced to show at this scale. These stations are given in Hathaway (1971). 
phosphates), zircon, and titanium ores such as 

rutile and ilmenite. However, although all of 

the above occur offshore and have either been 

sought, considered for exploitation, or mined 

somewhere in the world (McKelvey and Wang, 

1969), only tin (Indonesia-Malaya) and diamonds (Southwest Africa-production now 

abandoned) have yielded as much as a million 

dollars in value per year (Emery, 1966; Emery 

and Noakes, 1968) . 

The prospects for finding significant beach 

or offshore placer deposits along the northeastern coast of North America are diminished 

by the repeated glaciation of the area. The vast 

amount of ground-up country rock supplied 

from moraines and outwash plains in glacial 

areas tends to dilute segregations of heavy 

minerals. 3 Many sites of uneconomic dark 

(heavy) mineral concentrations were reported 

along Cape Cod beaches by Trumbull and 

Hathaway (1968), who covered 255 km (kilometers) or about 160 miles of shoreline from 

Scituate to the Elizabeth Islands, Mass., in 2 

days by helicopter survey. The accumulations 

were mainly thin surface dustings or deposits of 

limited thickness, concentration, or extent. The 

dark minerals consisted largely of small garnets 

which are not of gem quality and very common 

in low- to medium-grade metamorphic rocks 

such as schists. 

Total concentration of heavy minerals (that 

is, heavier than a specific gravity of about 3.0) 

ranges generally from 1 to 4 percent in surficial shelf s~diments off the Northeastern 

United States. Of the heavy minerals, 30 to 50 

percent are generally opaque grains (Ross, 

1970, and cited in Hathaway, 1971) such as 

magnetite, ilmenite (iron-titanium oxide), and 

limonite (hydrous iron oxide). In the nonopaque 

fraction, garnets and iron-magnesium-calciumaluminum silicates such as amphiboles, epidote, 

augite, and staurolite dominate. Mineral and 

chemical analyses of a typical heavy mineral 

fraction from sand south of Long Island are 

given in table 1, along with the composition of 

other typical offshore sediments. Some dark 

minerals are not heavy. These include glauconite 

(iron-potassium-aluminum silicate related to 

3 Glacial action, however, may sometimes aid in prospecting for. 

in-place ore bodies. See "Deeper In-Place Ore Deposits." 

10 

potassium micas), iron-stained quartz, and 

artificially introduced products such as coal and 

slag particles. 

Rather ordinary beach sands are sometimes 

mined for heavy minerals such as rutile, 

ilmenite, zircon, and monazite, even though 

total heavy minerals amount to as little as 1112 

percent. This may be done under stable price 

conditions where large-scale mining and advanced techniques for separating the minerals 

are -applied, as in coastal Georgia and the east 

coast of Australia (Emery and Noakes, 1968). 

For the A-ustralian deposits the cutoff grade is 

about 0.3 percent rutile (Ti02) and 0.3 percent 

zircon (ZrSi04). Offshore, however, higher 

costs and the impracticability of selective mining suggest that overall grades must be higher, 

even for shallow waters. 

Rutile and zircon are scarce in shelf sands 

from the present area of interest and normally 

are less than 0.05 percent of the total sediment 

(from data by D. A. Ross in Hathaway, 1971). 

Though not investigated mineralogically, the 

opaque fraction of the heavy minerals must 

contain appreciable titanium minerals, probably 

largely ilmenite, to judge from the typical heavy 

mineral sample .analyzed and presented in 

table 1, sample 4 (12 percent Ti02 ), and from 

the several tenths of a percent Ti02 generally 

found in shelf sands. Nevertheless, this titanium 

concentration is no doubt well below concentrations necessary to offer mining potential. 

Though not rich enough in valuable minerals 

to attract commercial interest, the sands are too 

impure to serve as "glass" sands for glassmaking. Such sands must be very low in iron 

and other metals which can impart undesirable 

color and other properties to the glass. Other 

aspects of the sands are mentioned later. 

Thus, no valuable placer deposits have been 

found or are currently likely on the continental 

margin of the United States, but attempts to 

explore for and mine placer gold were made by 

a commercial firm off the south shore of Nova 

Scotia near Lunenberg Bay (south of Halifax). 

A small seagoing dredge was employed less than 

1 mile seaward of the coast (fig. 1) to mine 

placer gold in submerged stream deposits presumably eroded from the known gold-bearing 

Halifax slates and Goldenville quartzites of 

Ordovician age. Values of up to $4 per cubic 
TABLE 1.-Chemical and modal analyses of typical seafloor deposits on the northeastern continental margin 

of the United States 

[Data from J. A. Hathaway (X-ray analysis), D. A. Ross (heavy 

minerals). and F. T. Manheim (chemical), compiled in Hathaway 

(1971), and unpublished data. All data in weight percent; values 

in parentheses are approximate. Location of stations shown in upper part of fig. 6] 

2 3 

Chemical analyses 

Si02 ----------------- Ti02 ----------------- AbOa ---------------- Fe:Oa ----------------

FeO ----------------- MgO ----------------- CaO -----------------· MnO ----------------- NazO ---------------- K20 ----------------- P20s ----------------- H20- ---------------- H20+ ---------------- C02 ------------------ C (organic) ---------

N ------------------- Volatiles other than -- C02 and H202• 

64.2 .67 10.8 

.54 

2.6 

1.7 

.84 

.04 13.3 

2.0 

.18 

2.3 

4.3 

.12 

3.5 

.17 

6.4 

Sum ----------- 100 

50.4 

.69 

15.9 

3.2 

3.0 

3.0 

1.3 

.11 13.8 

3.6 

.20 

3.3 

5.6 

.69 

1.9 

.27 

4.4 

399 

92.6 

.23 2::o} 

.25 

99 

.4 

.18 

.03 

.50 

.63 

.03 

.02 

.98 

.06 

.05 

.004 

Modal analyses of sediments 

Clay (total) --------- 58 

Illite ------------- Chlorite ---------- Kaolinite --------- Quartz --------------- 26 

Plagioclase feldspar -- 14 Potassium feldspar <1 

Calcium carbonate ---- <1 

Pyrite --------------- 1 Heavy minerals (total) (2) 

Opaque ---------- Nonopaque -------

83 

42 

17 

8 

6 

7 

<1 

<1 

1 

0.0 

93 

4 

2 

III 

<1 

1.6 

t Most of the sodium is present as dried sea salt. 2 Includes organic carbon and nitrogen. 

28.8 

12.0 

19.1 

21.5 

4.4 

9.1 

1.0 

.3 

.47 

.26 

.1 

.05 

51.4 

.60 

lt~ 

1.6 

2.0 

8.9 

14.0 

2.2 

.14 

2.4 

3.7 

5.5 

.7 

.11 

5.8 

99 

0.0 62 

96 19 

<1 <1 

<1 7 2 9 

<1 <1 

5.3 •(.5) 

1.5 

63.6 71 

3 Also contains S, 0.52; HCl-soluble sulfate reported as SOa, 0.15; 

and F, 0.12. 4 Also contains Sr, 0.01, Ni, 0.01, Zn, 0.062, Ba, 0.0·1. 11 Aragonite from broken mollusk shells. 6 Composition of nonopaque fraction, in percent: garnet, 42; 

staurolite, 30; augite, 8; amphiboles, 8; tourmaline, 5; epidote, 

hypersthene, kyanite, and titanite, 2 to 4 each; and zircon 1. 1 Horn blend e. 

1. Sta. 1913, river mouth estuarine mud, Penobscot River, Maine, 

lat 44°28.7' N., long 68°47.7' W.; water depth, 18 m; silty 

gray-brown clay with twigs, worms, and shell fragments. 

2. Sta. 2197, terrigenous mud, Wilkinson Basin, Gulf of Maine, lat 

42°34.7' N., long 69°32.6' W.; depth, 290m; very fine gray clayey 

mud. 

3. Sta. N14, shelf sand off Nantucket, lat 40°43' N., long 69°45' W.; 

depth, 47 m; tan-gray clean sand. 

4. Sta. 1387, shelf sand south of Long Island, lat 40°30.3' N., long 

73°30.8' W.; depth, 20 m; chemical analysis on heavy-mineral 

fraction. In modal analysis, sum of more than 100 is probably due in part to sample inhomogeneity. 

5. Sta. P15, continental slope sediment off Cape Cod, lat 39°44' N., 

long 69°18' W.; depth, 1,580 m; silty to sandy foraminiferal clay. 

yard of sediment were reported in a rather 

glowing account (Libby, 1969). Since then, 

however, mining activities have evidently ceased 

(Frank Shea, Nova Scotia Department of 

Mines, oral commun., 1971). Instead, large beds 

of sea clams and scallops which were found during the gold search are being exploited. 

OFFSHORE EXTENSIONS OF LAND DEPOSITS 

In many parts of the world, mineral deposits 

known or mined on land extend into the adjoin11 

ing submerged shelf. In some cases, boreholes 

or other workings are directed under the sea 

floor from the land itself. Coal mining under the 

sea adjoining Cape Breton Island (Canada) is 

the only such activity currently known off the 

coast of northeastern North America. Near 

Sydney and Glace Bay on the northern coast of 

Cape Breton Island (fig. 1) up to 2 million tons 

of coal worth about $18 per ton is mined yearly 

from workings whose inclined submarine shafts 

extend as far as 6 miles seaward off the coast. 

The only metalliferous area which has exposure close enough to the sea on the United 

States coast to warrant serious offshore interest 

is the copper and zinc district in and around 

Penobscot Bay, Maine (fig. 1). Known workings 

include the Blue Hill and Black Hawk areas 

(sphalerite-chalcopyrite) (W. A. Anderson, 

Maine Geological Survey, oral commun., 1971). 

MANGANESE NODULES, PHOSPHORITE, AND 

OTHER AUTHIGENIC MINERALS FORMED ON 

OR BELOW THE SEA FLOOR 

Millions of tons of both manganese-iron oxide 

nodules and phosphorite are known from the 

Blake Plateau, off the coast between Florida 

and South Carolina (Pratt and McFarlin, 1966; 

Manheim and Pratt, 1968; Pratt, 1971). These 

deposits have been repeatedly investigated by 

private firms, but their poor grade and the 

difficulty of recovery under the Gulf Stream at 

depths of 500 to 1,000 m relegate them to the 

status of potential resources for the relatively 

distant future. Study of the regional geological 

setting of the phosphorite deposits indicates 

that the phosphorite-enriched zones were developed in late Oligocene to middle Miocene 

time along the entire North American continental margin (fig. 7). Economic deposits, 

such as those in Florida, South Carolina~ and 

North Carolina have been enriched partly by 

selective leaching and erosion. Residual phosphorite grains often become remobilized or 

reprecipitated to form slabs, cobbles, crusts and 

other forms (Cathcart, 1968, and works cited 

therein). 

Normal marine or continental sediments such 

as shale, sand, and limestone contain less than 

0.2 percent P 205. Middle Tertiary sediments 

containing significant phosphate enrichments 

(more than 1 percent P205) extend far north-
ward, even to the Grand Banks area, and are 

noted in those areas where Tertiary sediments 

are exposed to erosion, such as the shelf break 

and especially submarine canyons, as well as in 

EXPLANATION 30° 

---- \ \ ~il9001~~ 

~ 

KNOWN CONTINUOUS PHOSPHATIC 

SEDIMENTS (>1 PERCENT P205) 

0 200 I I I 

goo 

~ PROBABLE CONTINUOUS 

I::L:LL.J PHOSPHATIC SEDIMENTS 

~OLIGOCENE-MIOCENE SEDIMENTS 

~OF UNKNOWN P205 CONTENT 

[[[[[].OLIGOCENE-MIOCENE NONPHOSPHATIC SEDIMENTS 

REPORTED PHOSPHATIC OCCURRENCES 

PHOSPHATIC OCCURRENCES ON 20° 

SEAMOUNTS 

FIGURE 7.-Distribution of middle Tertiary phosphate-bearing sediments along the eastern continental margin of 

North America (from F. T. Manheim and R. M. Pratt, unpub. data). Queries indicate areas of possible 

phosphatic sediments. 

12 
recent boreholes in the Canadian offshore region. 

So far, however, these phosphatic sediments 

remain of scientific (lithostratigraphic and 

paleooceanographic) rather than economic interest, as there is little evidence that marked 

enrichments occur north of Cape Hatteras. Even 

less is known of the Eocene and Cretaceous 

phosphorites which are reported from scattered 

localities on the continental margin. 

Of scientific interest are peculiar phosphatic 

and iron-rich concretions on Georges Bank 

(Stanley and others, 1967), which appear to be 

formed from fossil bones, and phosphatic deposits and manganese-iron crusts and nodules 

on the New England Seamounts (fig. 1) 

(Uchupi, 1968). The purer manganese iron 

deposits are found on the farther offshore seamounts, where continuing metal-oxide precipitation is less diluted with ordinary· sediments 

than closer to sources of sediment influx. 

DEEPER IN-PLACE ORE DEPOSITS 

As pointed out by Emery (1966) and Uchupi 

(1966), deeper rocks underlying the Gulf of 

Maine are to a considerable extent deformed 

and metamorphosed and are therefore inhospitable for oil or gas. Through geophysical studies 

which penetrate the blanket of glacial and 

postglacial sediments, some of the major rock 

types and structural relationships have been 

delineated, but the economic potential for 

metalliferous or other ores is unknown. More 

intensiv~ study, including shallow core-drilling, 

needs to be performed before estimates of 

potential can be made. Because the costs of 

undersea mining greatly exceed those on land 

at present, only very substantial deposits could 

be mined. 

Although glaciation normally complicates the 

geological study of a region, glacial action does 

provide at least one mechanism which may 

expose rather than conceal valuable or interesting rock formations. Ice sheets tend to scrape 

up and disperse fragments of ground-up materials from point sources. Unidirectional glacial 

action thus tends to form typical fan-shaped 

residues of material pointing to the source 

(figs. 8 and 9) . In some cases, the distributions 

of residues of material may reveal bodies or 

rock formations which would oth~rwise be 

overlooked. A large-scale example of dispersion 

13 

Plan 

. .. 

Ice movement 

Section . : :. . . . . . . . . 

. .-..<ii.·:.)// (:._: :·:· : .· ·. . ... 

·. Glacial 

Bedrock 

FIGURE 8.-Schematic drawing showing transport of 

material from outcrop by glacial action (from Hawkes 

and Webb, 1962, fig. 8-4; reprinted from "Geochemistry In Mineral Exploration" with permission of 

Harper & Row, Publishers). 

of a given rock material in the Gulf of Maine 

is shown in figure 10 (Schlee and Pratt, 1970, 

fig. 16). 

SAND, GRAVEL, AND M.UIJ 

As pointed out by Emery (1968), Rexworthy,4 

Schlee (1968), and Schlee and Pratt (1970), 

sand and gravel represent not only a very 

large, but probably the most immediate, resource likely to be exploited on the offshore 

Atlantic margin of the United States. Offshore 

sand and gravel production around the United 

Kingdom now amounts to about 14 million tons 

per year or 13 percent of total production, and 

demand and production continue to grow (Hess, 

1971). 

In the United States, sand and gravel production makes up about one-fifth of the total nonmetallic industry in value, amounting to about 

4 S. R. Rexworthy, 1968, The sand and gravel industry of the 

United States of America with special reference to exploiting the 

deposits offshore the eastern seaboard: Unpub. rept. for Ocean 

Mining Aktiengesell., 48 p. 
N 

0 

0 

0 

0 

0 0 

0 

{j 0 

0 

0 

0 

0 

0 

0 

0 

Quemont ~__... 

ore body_..,. 

~ 0 

0 

0 0 0 0 

0 0 0 

0 

0 

~Cu>75 ppm ~ Zn>175 ppm 

0 

Sample locality 

141<'---2 KILOMETERS---1~ 

FIGURE 9.-Copper and zinc content of moraine (glacial 

deposits) near the Noranda ore body, Canada (from 

Hawkes and Webb, 1962, fig. 10-6; reprinted from 

"Geochemistry In Mineral Exploration" with permis-· 

sion of Harper & Row, Publishers) . 

1 billion tons and about $1.1 billion value in 

1970. In addition, somewhat less than 1 billion 

tons of crushed stone and other aggregate 

competed with sand and gravel for use in building and paving of roads (tables 2 and 3). 

In spite of the current standstill in offshore 

leasing or exploration activities preparatory to 

exploitation (see "Environmental Factors"), 

several factors combine to exert pressure toward 

the mining of building aggregates offshore in 

the near future. Spreading urban areas continue 

to encroach on or exhaust sand and gravel 

quarries, which must normally be located close 

to the major-use sites. This is so because transportation is the principal factor in the cost of 

sand and gravel. Moreover, restrictions arising 

14 

from enviromental and esthetic concern, rural 

zoning, and rise in land values decrease the 

availability and increase the cost of quarries. 

This is even more true of hard-rock quarries, 

which utilize blasting and are regarded as locally 

undesirable. 

Most sand and gravel is used for construction 

(building and road) purposes, and value and 

production have increased over the last few 

decades at about 4 to 5 percent per year, on the 

average. Cement, prestressed concrete, readymixed concrete, and other special products all 

depend on constant and convenient supplies of 

aggregate materials. 

Data on sand and gravel production in the 

United States and some northeastern States for 

1970 are given in tables 2 and 3. Telephone 

inquiries were made in April1972 to dealers in 

TABLE 2.-Quantity and value of sand and gravel 

production for various uses in the United States 

in 1970 

[Quantity in millions of short tons; value in millions of dollars at point of production. Data from Walter Pajalich, U.S. Bureau of 

Mines (oral commun., 1972)] 

Use 

Construction: 

Building ---------- Paving ----------- Fill --------------- Railroad ballast __ _ 

Other -------------

Total ----------- Total industrial use, ground and 

unground -----------

Total, all 

purposes 1 -----

Quantity Value 

Sand Gravel Sand Gravel 

166 130 $198 $191 

139 364 149 384 

33 43 21 27 

1.2 2.8 .73 2.4 

14.4 12.4 16.0 14.6 

906 $1,003 

29 101 

944 $1,116 

1 Data do not add to totals shown because they do not include 

miscellaneous uses. 

TABLE 3.-Quantity and value of sand and gravel and 

stone produced by some northeastern _States, 1970 

[Data from Walter Pajalich (sand and gravel) and H. J. Drake 

(stone) of the U.S. Bureau of Mines (oral commun., 1972). 

Where data for 1970 are unavailable, data for 1969 (U.S. Bureau of Mines, 1971, p. 1027) are given in parentheses. Quantity in 

millions of short tons; value in millions of dollars. W, withheld to avoid disclosing individual company data] 

Sand and gravel Stone 

State Quantity Value Quantity Value 

Maine ---------------- 13.0 $6.9 w 1$2.3 

-... 8 (1.1) (3.8) 

New Hampshire ___ .,. __ 6.5 tW 1.845 

(.32) (2.9) 

Massachusetts 17.9 22.2 18.0 24.3 

Rhode Island _::::::::: 2.4 2.9 w w 

-6.8 -9.2 (W) (1.4) 

Connecticut ----------- 8.3 16.9 

New York 35.5 38.8 37.6 68.1 

New Jersey-::::::::::: 16.7 31.6 15.2 40.6 

1 State total incomplete to avoid disclosing individual company 

data. 
0 + 

+ + 

+ 

• 

+ 

+ 

0 

+ 

+ 

0 + 

---- SH£LF -----, ___ , ~ & 

..... ,-..::~~ 

""" '"iil+ 

\ 

' 

NOVA ~(;OTIA 

+ + 

0 

• 

10 

+ 

• 

0 

• 

0 

10 0 I , I 

10 

• 

10 

I 

20 

EXPLANATION 

Spotted schist in 8-16-mm size class, in percent 

40-79 

• 20-39 

10-19 

• S-9 

Trace- • 4 

0 No spotted schist 

+ 

Gravelly sample too small to make a pebble count 

No gravel 

~---8----

Mo\'ing average contour 

Duslu>d where npprorimntely/o('(tfed 

N 

I 30 40 STATUTE MILES 

20 30 40 KILOMETERS I I I 

FIGURE 10.-Distribution and abundance of spotted schist pebbles (8-16-mm size class) in gravels on the southeastern Scotian Shelf. Computed by moving-average technique (from Schlee and Pratt, 1970, fig. 16). 

major east coast centers to obtain the price of 

sand (concrete quality) and gravel. Prices were 

quoted f.o.b. plant. Some of the sand and gravel 

pits are at a considerable distance from the 

metropolitan areas. The following prices (per 

short ton) vary relatively little from 1971 

prices: Boston, sand $2.00, gravel $3.00; New 

York, sand $0.75 at plants in southern New 

Jersey to $1.50, gravel $3.00; Philadelphia, 

15 

sand $1.35 ($3.50 delivered; transport cost 

about $0.40 per ton mile), crushed stone $3.50; 

Washington, D.C., sand $2.75, gravel, truck 

loads $3.50, larger quantities $3.00. Production 

for New York and New Jersey slumped in 

1969-70 owing partly to a decline in supplies 

but largely because of a decrease in construction activities in the greater New York City 

area. The latter factor probably accounts for 
1-' 

a') 

74° 

50-75 

0 

<50 CONTOURS IN MIETERS 

700 68° 38° 66° 40° 64° 42° 62° 

FIGURE H.-Distribution of sand on the continental margin off Northeastern United States (redrawn from Schlee and Pratt, 1970, pl. 5A). 

44° 

62° 
the low prevailing prices in this area. 

Existing- sand deposits on the shelf are very 

large (fig. 11) . In the area shown in figure 11, 

surficial sand deposits grading 75 percent or 

more cover 112,000 km2 • One can get an idea of 

the sand resources contained in this area by 

assuming a dredging depth of 3m (10ft) and 

50 percent porosity ( 1.35 tons of dry sand per 

cubic meter of wet sediment) . The total of about 

450 billion tons of dry sand obtained is enough 

NEW JERSEY 

0 10 

NAUTICAL MILES 

at current consumption rates to meet the needs 

of all the northeastern coastal states of the 

United States and the Maritime Provinces of 

Canada for several thousand years. Though 

poorly known at present, actual thicknesses are 

probably at least 10 times greater. Drill cores 

will be required to establish depths and characteristics of the sand. 

A few sand deposits, such as those off New 

Jersey (fig. 12) (Schlee, 1964), have been 

-~- . :_·::_·_· .. ·.·.· . . ·.·::. 

·-·--:::·:_::·_ ... 

-:.· .. X: -: ->: . <· :-·.:-.: 

·,.:<·:·· :· :..:-

.. -.:.·:- ·.-:-

:-:. ·:' .. :.:::·~:-: . 

. . . -. :-. ·::- ~·-:-~~- ':'; ':. · ..-.-

EXPLANATION 

X 

SAMPLE LOCATION 

• SAND 

SANOY GRAVEL 

fSl:j 

~ 

PEBBLY SAND 

MAXIMUM PEBBLE SIZE 

0 

64-32mm 

0 

32-16mm 

0 

16-8mm 

0 

8-4mm 

••••••• 

BOUNDARY OF LIMONITESTAINED SEDIMENT 

--66--

SUBMARINE CONTOUR 

SHOWING DEPTH IN FEET 

FIGURE 12.-Distribution of sand and gravel off New Jersey (from Schlee, 1964). 

17 
sufficiently well delineated to indicate their direct suitability for immediate exploitation. 

Leases have been requested, but activities await 

promulgation of clear regulatory guidelines by 

State and Federal agencies. Other sand supplies 

north of Cape Cod also offer clear potential 

(fig. 13) . Another prime target for dredging, 

though farther offshore, is Nantucket Shoals, 

which has been a major hazard to navigation, 

as attested to by the hundreds of wrecks still 

located there. 

Gravels are much less abundant than sands 

on the shelf and generally would require longer 

transport to consumer areas (figs. 14 and 15). 

However, gravels have greater value and, as 

has been pointed out by recent lively discussions 

on the question of offshore sand and gravel 

mining (Davenport, 1971; Taney, 1971), distance is a much less important factor at sea 

than on land. Whereas the capital costs to 

initiate viable commercial dredging operations 

offshore are much higher than on land, say on 

the order of $5 million dollars, the barging and 

delivery of materials to coastal urban centers 

is much less costly than trucking (main land 

means) or even rail. With efficient technology 

and good organization, there seems little doubt 

that rnajor centers could begin to utilize seafloor aggregates within the next 5 or 10 years. 

Sediments containing more than 50 percent 

gravel cover about 15,000 km2 in the area shown 

in figure 14. In the smaller a-rea in figure 15, 

presumably a potential supplier to the Greater 

Boston and Massachusetts shore communities, 

sediments containing more than 60 percent 

gravel cover 345 km2 , which, under assumptions 

previously made for sand dredging, would 

yield 1.4 billion tons. 

In the United Kingdom, subsidies of about 20 

percent of costs were offered earlier to stimulate 

building of offshore dredging equipment, but 

these have been discontinued as no longer necessary (Hess, 1971). Private surveys of conditions in the United States also indicate that 

subsidy of offshore sand and gravel production 

would not be needed, given a stable and appropriate legal climate. 

Sand and gravel are not the only potentially 

valuable sediments in the offshore bottoms. The 

natural grading of materials by grain size and 

18 

mineralogic and chemical compositions offers a 

wide range of earth materials which might find 

uses through technologic innovations. A recent 

discovery (patent pending) by D. C. Rhoads, 

R. B. Gordon, and M. A. Ruggiero (Bingham 

Laboratory, Yale University, New Haven, 

Conn.) is that ceramic material of superior 

quality can be made by firing fine marine sediment that contains less than 1t) percent calcium 

carbonate and between 1 and 3 percent organic 

matter. Advantages of the marine material are 

that it need not be subjected to complex blending processes involving different raw material 

sources, it can be obtained in very large volumes 

by simple surface dredging of deposits in Long 

Island Sound, Buzzards Bay, and other areas 

along the northeast continental margin, and it 

has much lighter finished weight than brick or 

other comparable ceramics. Channel dredging 

materials may be suitable, as may be muds in 

contaminated bays or tidal water bodies, for 

the excess organic carbon attributable to pollution products actually promotes favorable attributes in the finished ceramic; the gases released 

on firing create high porosity and therefore 

lightness. The sea salt incorporated in the raw 

mud also aids in the fluxing of the ceramic to 

create desirable strength and other properties. 

One may point out that muddy basins where 

the indicated materials occur (fig. 16) are generally poor fishing grounds and otherwise play 

a subordinate role in the marine biologic cycle 

offshore, insofar as present information permits 

assessment. Under certain conditions, removal 

and use of the mud from polluted areas, such 

as inner Long Island Sound (Gro_ss and others, 

1971), may actually improve the local aquatic 

habitat much more rapidly than could be done 

by the slow process of natural deeutrophication after the input of pollutants is stopped. 

This kind of innovative and coordinated use of 

offshore resources needs especial encouragement and stimulation. 

ENVIRONMENTAL FACTORS 

Shelf sands and gravels are metastable deposits on the northeastern continental margin 

and are undergoing erosion and winnowing by 

natural forces such as bottom currents. In contrast to widespread impressions to the contrary, 
43°~------~------------------------~------------------------~------~ 

EXPLANATION 

SAND, IN PERCENT 

0 

~ 

~ 

>90 

70-90 

10 20 

KILOMETERS 

CONTOURS IN METERS. 

FIGURE 13.-Distribution of sand in the inner Gulf of Maine and Massachusetts Bay (redrawn from Schlee and others, 1971). 

19 
1:\:) 

0 

5-50 

0 

<25 CONTOURS IN METERS 

38° 40° 64° 

FIGURE 14.-Distribution of gravel on the continental margin off Northeastern United States 'redrawn from Schlee and Pratt, 1970, pl. 5B). 
43°r-------~------------------------~------------------------~------~ 

,.· 

EXPLANATION 

GRAVEL, IN PERCENT 

~ >60 

m~~~~~:::~j 4 o- 6 o 

0 10 20 

I 

I 

I 

\ 

\. 

" 

/ 

/ / 

( 

(.,L~-, 

( J 

1 

I 

i 

\ 

\ 

/ 

'\ 

\ 

~ v, 

/ / 

'\ 

\ 

I 

I 

I 

/ / 

'"' ........ 

" \. 

) 

' ~ 

\ 

'\ 

') 

l, 

"'.l 

\." ' ) '-so----

FIGURE 15.-Distribution of gravel in the inner Gulf of Maine and Massachusetts Bay (redrawn from Schlee and others, 1971) . 

21 
~ 

~ 

420 

41° 

7. 7~ 1 -, 

EXPLANATION 

~High silt-clay content mud 

0 50 100 KILOMETERS 

<j> I I I I ~0 MILES 

sL.•fil 

I( I 

B"-ocsou~o 

1J BLOCK 

OISLAND 

71° 

sosro>~~ BAY ~ 

.... 

\$' 

'0 

FIGURE 16.-0ffshore distribution of sediments that· can be used in an innovative ceramic manufacturing process. 

700 
most estuaries on the continental margin may 

not have a net loss of sediment to the shelf and 

open ocean; rather, sediment moving into the 

estuaries by bottom transport from the shelf 

is tending to fill them up on a net basis 

(fig. 17 A) even though outward transport of 

river sediments does take place at the same time 

(Meade, 1969). Thus, the dredging of a harbor 

mouth, as in the case of Savannah Harbor, has 

not increased outward loss of sediment, but 

rather has accelerated the silting up to the 

harbor, because movement of bottom material 

inward is facilitated (H. B. Simmons, cited in 

Meade, 1969). From this point of view, mining 

of offshore sands may be taking materials which 

are tending to move into the continent in any 

event (fig. 17B). 

A different problem is posed by beach and 

shore erosion. Whether or not the taking of sand 

from one area might promote erosion in another 

coastal zone must be assessed separately for 

each case. On the one hand, experience in the 

United Kingdom, where offshore sand and 

gravel have been mined since World War II, 

has brought to light only a few cases where 

coastal erosion has been attributed to sand 

mining, and these occurred where the mining 

was in relatively close proximity to. the affected 

shore. On the other hand, studies of actual 

movement of bottom materials in the Atlantic 

offshore region are still very limited. Moreover, 

though the data are still inadequate, it can be 

shown qualitatively that storms and hurricanes 

have a much greater influence on beach erosion 

and coastal modification in many areas than day 

to day action (Hayes, 1967; Coastal Plains 

Center for Marine Development Services, 1970, 

and publications cited therein). Thus, there 

will continue to be coastal erosion with or without mining operations. 

Marine life is potentially affected by marine 

mining and other activities that modify sediments. For example, Massachusetts oyster production has declined from 24 million pounds 

(meat) annual production in 1910 to only a few 

tens of thousands of pounds per year in recent 

years. Discussion with officials of the Massachusetts Department of Natural Resources and 

other observers indicates that the major causes 

of the destruction of oyster fisheries include 

dredge and fill operations and no or inadequate 

23 

management of oyster beds in the public (that 

is, town) domain: For example, in some places 

oysters are taken without returning the shell 

to provide cultch or other hard surfaces needed 

by oyster spat as substrates. Marine biologists 

familiar with shelf fauna and flora indicate that 

mining operations on the shelf are not inherently incompatible with proper maintenance 

of marine life and commercial and sports 

fisheries. However, they indicate that proper 

design of operations and coordination with 

fisheries authorities are important factors in 

assuring ecologically judicious development. For 

example, mining operations might be shifted to 

different areas according to seasons of the year, 

in order to avoid the spawning grounds of 

given fish species. 

A serious problem at present is the expanding pressure on existing sites for dumping of 

dredge spoils. For example, dredgings in Delaware Bay amounted to nearly 20 million cubic 

yards per year until a few years ago, when 

damming off of the spoils reduced the need for 

dredging to about 10 million cubic yards per 

year. However, in the foreseeable future all 

available dumping space will be exhausted if 

d1:1mping is not to be done where environmental 

damage will result or where exorbitant transport costs are incurred. Extracts from the 

earlier U.S. Commission on Marine Science, 

Engineering and Resources (Coastal Research 

Notes, 1971) indicated that the draft requirements of the new super tankers (up to 70 ft) 

are so great that in some areas channels extending as much as 60 miles from shore or 

deep-water terminals would be needed to accommodate the vessels. Even medium-sized 

super tankers cannot be accommodated by any 

present-day Atlantic ports. Alternatives to 

dredging may not be simple or cheap because 

they involve the possibility of declining port 

usage and the necessity of supplying energy and 

essential fuels by other means. According to 

the reports, dredgings even at current rates 

would fill most currently available disposal 

sites in 8 to 10 years. 

If innovative and efficient technological means 

could be found to utilize dredge spoils to supply 

aggregate needs (other than fill), then a dual 

advantage would be gained; the destruction of 

land areas for sand and gravel mining purposes 
could be reduced, at least for coastal communi- turned to productive uses. The ceramic process 

ties, and a troublesome waste product could be mentioned earlier is an example of innovation 

A 

100 KM 

24 
which has promise in this direction. The approximate regional balance of dredge spoils 

and sand and gravel consumption is shown in 

figure 18. 

Innovative use of offshore bottoms might 

even improve the aquatic or biologic environment under certain conditions. An example of 

the "surgical removal" and utilization of polluted mud has already been mentioned. D. C. 

Rhoads (oral commun., 1971) has also pointed 

out that mud bottoms (especially if they are 

highly organic owing to deposition of sewage 

or other organic matter of primary or secondary origin) might serve as sources of food to 

nourish an intensive above-bottom aquaculture 

(for example, mussels, clams, oysters). Freed 

from predators, and with good substrates provided, the organisms could use excess organic 

matter and nutrients not only to produce marketable protein, but help deeutrophicate previously contaminated basins. Pilot studies for 

analogous types of aquaculture are being carried 

on by J. H. Ryther and his coworkers at the 

Woods Hole Oceanographic Institution. 

The history of the Atlantic offshore region 

shows that we are now at a crossroads. Before, 

when mining leases could have been obtained at 

nominal cost, there was little incentive to prospect offshore. Now, when the growth of coastal 

populations and increased demand for products 

potentially available from the sea bottom 

renders such exploration and exploitation attractive, there is virtually a complete moratorium on leasing while State, Federal, and 

local regulatory agencies reassess their operations procedures in response to the growth in 

environmental concern, as well as improved 

knowledge of the natural environment itself. 

Massachusetts, for example, has recently enacted a moratorium on all offshore leasing within the State boundaries (Mass. Sen. 737, Ch. 567, 

1971), and another bill (Sen. 1445, Ch. 742, 

1971) provides a natural sanctuary around the 

entire Cape Cod region, stipulating that no 

dredging or dumping of whatever kind may be 

performed, except for ·beach restoration purposes. The legislature has also allocated $200,000 

to the Department of Natural Resources to 

study the environmental aspects of the Massachusetts offshore region with a view to preparing guidelines for leasing when and if the Department deems that offshore exploitation can 

safely be carried out. 

Keys to proper and environmentally judicious 

management of offshore resources lie in improving presently uncertain or overlapping jurisdiction and coordination and effectiveness of 

investigatory and regulatory bodies. With 

limited resources, regulatory bodies must have 

broad knowledge or access to expertise in many 

overlapping fields: marine biology, geology, 

engineering practice, economics, law, politics, 

and psychology. A short account and bibliography of problems potentially affecting marine 

mining is provided by McKelvey, Tracey, 

Stoertz, and Vedder ( 1969) and Battelle 

Memorial Institute Staff ( 1971), respectively. 

If regulation is inadequate, damage or public 

loss of confidence leading to prohibitory legislation or crippling litigation may result. If regulation is unnecessarily rigid or if its inadequacy 

leads to blanket prohibition, needed and useful 

goods and services may be denied the public, or 

unfavorable environmental developments may 

occur by default. It is often pointed out that 

offshore work requires adequate capital, technology, and organization; responsible organizations possessing these prerequisites will hesitate 

to take political risks over and above the usual 

economic risks involved in new ventures. They 

need dependable guidelines under which to 

work. 

FIGURE 17 (left) .-Directions of general residual current (A) along the bottom on the continental shelf (from 

Bumpus, 1965), and (B) directions and magnitudes of sand movement on the beaches (from Meade, 1969, 

fig. 9; reprinted from "Journal of Sedimentary Petrology" with permission of Society of Economic Paleontologists and Mineralogists). Width of arrow shaft in part B indicates estimated amounts of sand; the widest 

represents about 370,000 m3 per year. 

25 
92.4 

35.6 

33.4 

65.1 

NEW 

ENGLAND 

5.2 

MIDDLE 

ATLANTIC STATES 

SOUTHERN 

ATLANTIC STATES 

EXPLANATION 

I . 

Sand and gravel 

consumption 

Dredge spoils 

FIGURE 18.-Balance of dredge spoil and consumption of sand and gravel (in millions of tons) in Atlantic Coast 

States. Dredge spoil data from V. L. Andreliunas, U.S. Army Corps of Engineers (oral commun., 1972) refers 

to 1971 dredging in and around navigable waterways. Sand and gravel consumption from U.S. Bureau of 

Mines (1969, p. 986-987). 

26 
REFERENCES CITED 

Battelle Memorial Institute Staff, 1971, Environmental 

disturbances of concern to marine mining research, 

a selected annotated bibliography: U.S. Natl. 

Oceanic and Atmospheric Adm. Tech. Memo. ERL 

MMTC-3, 72 p. 

Bumpus, D. F., 1965, Residual drift along the bottom on 

the continental shelf in the Middle Atlantic Bight 

area: Limnology and Oceanography, v. 10, supp. 

(Redfield Volume), p. R50-R53. 

Canada Geological Survey, 19:49, Geologic map of the 

Maritime Provinces (New Brunswick, Nova Scotia, 

and Prince Edward Island): Canada Geol. Survey 

Map 910A. 

Cathcart, J. B., 1968, Phosphate in the Atlantic and 

Gulf Coastal Plains, in Forum on geology of industrial minerals, 4th, Austin, Tex., 1968, Proceedings: Austin, Texas Univ. Bur. Econ. Geology, 

p. 23-24. 

Coastal Plains Center for Marine Development Services, 

Washington, D.C., 1970, Bibliography on hurricanes 

and severe storms of the coastal plains region: 

Coastal Plains Center Marine Devel. Services 

Pub. 70-2, 71 p. 

Coastal Research Notes, 1971, [On port-dredging problems]: Coastal Research Notes, v. 3, no. 6, p. 3. 

Davenport, J. M., 1971, Incentives for ocean mining: a 

case study of sand and gravel: Marine Technology 

Soc. Jour., v. 5, p. 35-40. 

Duane, D. B., 1969, A study of New Jersey and northern 

New England coastal waters: Shore and Beach, 

v. 37, no. 2, p. 12-16. 

Emery, K. 0., 1966, Geological methods for locating 

mineral deposits on the ocean floor, in Exploiting 

the ocean: Marine Technology Soc. Conf. and 

Exhibit, 2d Ann., 1966, Trans., p. 24-43. 

--- 1968, The continental shelf and its mineral 

resources, in Selected papers from the Governor's 

Conference on Oceanography, New York, 1967: 

[Albany, New York State Dept. Commerce] p. 36-

51. 

Emery, K. 0., and Noakes, L. C., 1968, Economic placer 

deposits of the continental shelf: U.N. Econ. Comm. 

Asia Far East Comm. Coord. Joint Prosp. Mineral 

Resources Asian Offshore Areas Tech. Bull., v. 1, 

p. 95-111. 

Emery, K. 0., Uchupi, Elazar, Phillips, J. D., Bowin, 

C. 0., Bunce, E. T., and Knott, S. T., 1970, Continental rise off eastern North America: Am. 

Assoc. Petroleum Geologists Bull., v. 54, p. 44-108. 

Goldsmith, Richard, 1964, Geologic map of New England: U.S. Geol. Survey open-file rept., 3 sheets, 

scale 1:1,000,000. 

Gross, M. G., Black, J. A., Schramel, R. J ., and Smith, 

R. N., 1971, Survey of marine waste deposits, New 

York Metropolitan region: New York State Univ., 

Stony Brook, Marine Sci. Research Center Tech. 

Rept. 8, 72 p. 

27 

Hathaway, J. C., 1971, Data File, Continental Margin 

Program, Atlantic Coast of the United States, 

Volume 2, Sample collection and analytical data: 

Woods Hole Oceanog. Inst. Ref. 71-15, 496 p. 

Hawkes, H. E., and Webb, J. S., 1962, Geochemistry in 

mineral exploration: New York, Harper and Row, 

Publishers, 415 p. 

Hayes, M. 0., 1967, Hurricanes as geological, age~ts, 

south Texas coast: Am. Assoc. Petroleum Geologists 

Bull., v. 51, no. 6, p. 937-942. 

Hess, H. D., 1971, Marine sand and gravel mining 

industry of the United Kingdom: U.S. Natl. 

Oceanic and Atmospheric Adm. Tech. Rept. ERL 

213-MMTC 1, 176 p. 

Hiilsemann, Jobst, 1967, The continental margin off the 

Atlantic coast of the United States; carbonate in 

sediments, Nova Scotia to Hudson Canyon: Sedimentology, v. 8, p. 121-145. 

Libby, F., 1969, Searching for alluvial gold deposits 

off Nova Scotia: Ocean Industry, v. 4, no. 1, p. 43-

47. 

Maher, J. C., 1971, Geologic framework and petroleum 

potential of the Atlantic Coastal Plain and continental margin: U.S. Geol. Survey Prof. Paper 659, 

98 p., 17 pis. 

Manheim,. F. T., and. Pratt, R. M., 1968, Geochemistry 

of manganese-phosphorite deposits on the Blake 

Plateau, in Woods Hole Oceanographic Institution 

Summary of investigations in 1967: Woods Hole 

Oceanog. Inst. Ref. 68-32, p. 49. 

McKelvey, V. E., Tracey, J. 1., Jr., Stoertz, G. E., and 

Vedder, J. G., 1969, Subsea mineral resources and 

problems related to their development: U.S. Geol. 

Survey Circ. 619, 26 p. 

McKelvey, V. E., and Wang, F. F. W., 1969, World 

subsea mineral resources: U.S. Geol. Survey Misc. 

Geol. Inv. Map I-632. 

Meade, R. M., 1969, Landward transport of bottom 

sediments in estuaries of the Atlantic Coastal 

Plain: Jour. Sedimentary Petrology, v. 39, no. 1, 

p. 222-234. 

Pratt, R. M., 1971, Lithology of rocks dredged from the 

· Blake Plateau: Southeastern Geology, v. 13, p. 19-

38. 

Pratt, R. M., and McFarlin, P. F., 1966, Manganese 

pavements on the Blake Plateau: Science, v. 151, 

p. 1080-1082. 

Ross, D. A., 1970, Atlantic continental shelf and slope 

of the United States-Heavy minerals of the 

continental margin from southern Nova Scotia to 

northern New Jersey: U.S. Geol. Survey Prof. 

Paper 529-G, 40 p. 

Schlee, John, 1964, New Jersey offshore gravel deposit: 

Pit and Quarry, v. 57, p. 80-81. 

--- 1968, Sand and gravel on the continental shelf 

off the northeastern United States: U.S. Geol. 

Survey Circ. 602, 9 p. 

Schlee, John, Folger, D. W., and O'Hara, C. J., 1971, 

Bottom sediments on the continental shelf of the 
northeastern United States, Cape Cod to Cape Ann, 

Massachusetts: U.S. Geol. Survey open-file rept. 

Schlee, John, and Pratt, R. M., 1970, Atlantic continental shelf and slope of the United StatesGravels of the northeastern part: U.S. Geol. Survey 

Prof. Paper 529-H, 39 p. 

Stanley, D. J., Swift, D. J. P., and Richards, H. G., 

1967, Fossiliferous concretions on Georges Bank: 

Jour. Sed. Petrology, v. 37, p. 1070-1083. 

Taney, N. E., 1971, Comments on "Incentives for Ocean 

Mining": Marine Technology Soc. Jour., v. 5, 

p. 41-43. 

Trumbull, J. V. A., and Hathaway, J. C., 1968, Darkmineral accumulations in beach and dune sands of 

28 

Cape Cod and vicinity, in Geological Survey research 1968: U.S. Geol. Survey Prof. Paper 600-B, 

p. B178-B184. 

U chupi, Elazar, 1966, Structural framework of the 

Gulf of Maine: Jour. Geophys. Research, v. 71, 

p. 3013-3028. 

--- 1968, Long lost Mytilus: Oceanus, v. 14, no. 3, 

p. 2-7. 

U.S. Bureau of Mines, 1969, Minerals yearbook, 1968, 

Volumes 1-2, Metals, minerals, and fuels: Washington, D.C., U.S. Govt. Printing Office, 1208 p. 

--- 1971, Minerals yearbook, 1969, Volumes 1-2, 

Metals, minerals and fuels: Washington, D.C., U.S. 

Govt. Printing Office, 1194 p. 

GP 0 935-568