Ch. 2— Resource Assessments and Expectations • 51 



Figure 2-5.— Atlantic EEZ Heavy {Minerals 



28°Pi 



78° 74" 70° 



Several areas of the Atlantic EEZ contain high concentrations 

 of heavy minerals in the surficial sediments. Further research 

 is needed to determine the extent of these deposits and 

 possible economic potential. 



SOURCES: Office of Technology Assessment, 1987; A,E. Grosz, J.C. Hatfiaway, 

 and E.G. Escowitz, "Placer Deposits of Heavy Minerals in Atlantic Con- 

 tinental Shelf Sediments," Proceedings of the 18th Annual Offshore 

 Technology Conference, Houston, Texas, OTC 5198, May 1986. 



sediments of the southern Atlantic region contain 

 lower concentrations of heavy minerals, but the as- 

 semblage becomes progressively more mature to 

 the south and, hence, more concentrated in heavy 

 minerals of more economic interest such as tita- 

 nium." This situation suggests that the mineral 

 composition of the southern Atlantic shelf region 

 holds the best prospects for economically attractive 

 deposits. 



Precious Metals 



Although, in general, the north Atlantic region 

 may have relatively poor prospects for economic 

 placer deposits compared to the southern region. 



it might possibly be the most favorable area along 

 the Adantic EEZ for gold placers. Gold occurrences 

 have been found in a variety of rocks along the Ap- 

 palachians and in the maritime provinces of Can- 

 ada, and both lode and placer gold deposits have 

 been worked in areas that drain toward the coast . 

 Because of its high specific gravity, placer gold is 

 expected to be near its point of origin, which would 

 be nearer to the coast in the New England area than 

 in southern areas where broad coastal plains are 

 developed. Further, glacial scouring and movement 

 could have brought gold-bearing sediment offshore 

 where it could be reworked and the gold concen- 

 trated by marine processes. WhUe the prospects for 

 gold placers are poor in the Atlantic EEZ, gold 

 placers have been found on the coastal plain in the 

 mid- and south Atlantic regions. To reach the EEZ 

 in those regions, gold would have been transported 

 by fluvial processes a considerable distance from 

 its source and, if found, probably would be very 

 fine-grained. 



Heavy Minerals — Titanium Sands 



The major area of interest for economic placer 

 deposits, particularly titanium minerals, would be 

 the middle and south Atlantic EEZ. Again the cri- 

 teria in table 2-3 are useful. Concentrations of the 

 commercially sought heavy minerals have been 

 found in the sediments offshore (criterion 1) and 

 titanium minerals mined onshore (criterion 2). In 

 addition, several other criteria are also evident. 

 These indicators would suggest a good potential for 

 placer deposits offshore. An interesting aspect of 

 this, however, is a reconnaissance study by the U.S. 

 Geological Survey (USGS) that found significant 

 concentrations of heavy minerals in surface grab- 

 samples offshore of Virginia, where no economic 

 deposits are found onshore.'^ However, rich rutile 

 and ilmenite placer deposits have been mined in 

 the drainage basin of the James River, a tributary 

 of Chesapeake Bay. These deposits had their source 

 in anorthosite and gneisses of the Virginia Blue 

 Ridge. '^ An earlier study, which had found high 



"A.E. Grosz, J.C. Hathaway, and E.G. Escowitz, "Placer Deposits 

 of Heavy Minerals in Atlantic Gontinental Shelf Sediments," Proceed- 

 ings of the 18th Annua] Offshore Technology Conference, Houston, 

 TX, May 5-8, 1986, pp. 387-394. 



'^A.E. Grosz and E.G. Escowitz, "Economic Heavy Minerals of 

 the U.S. Atlantic Gontinental Shelf," W.F. Tanner (ed.). Proceed- 

 ings of the Sixth Symposium on Coastal Sedimentology, Florida State 

 University, Tallahassee, FL, 1983, pp. 231-242. 



"J. P. Minard, E.R. Force, and G.W. Hayes, "Alluvial Ilmenite 

 Placer Deposits, Gentral Virginia," U.S. Geological Survey Profes- 

 sional Paper 959-H, 1976. 



