Journal of Research of the U. S. Geological Survey, 1977, volume 5, issue 4
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More than 50 percent of the U.S. population currently live within 50 miles of an ocean, Great Lake, or major estuary. According to forecasts, the concentration of people along our coastlines will continue to increase into the 21st century. In addition to residential and commercial buildings and facilities worth tens of billions of dollars, the coasts and associated wetlands are natural resources of tremendous value, with estimates in excess of $13 billion per year for commercial and recreational fisheries alone. Human activities and natural processes are stressing the coastal environment. * Each of the coastal states and island territories is suffering problems related to coastal erosion. * Deterioration of wetlands is widespread and of great public concern. * Pollutants carried by rivers or runoff are discharged directly into coastal waters and accumulate in the sediments on the sea floor, in some areas causing damage to living resources and presenting a threat to public health. * Onshore sources for hard-mineral resources, such as sand and gravel used for construction purposes, are becoming increasingly difficult to find. New sources are being sought in coastal waters. Coastal issues will become even more important into the next century if sea level is significantly influenced by climate change and other factors.
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By proclamation of the President on March 10, 1983, the United States claimed sovereign rights and jurisdiction within an Exclusive Economic Zone (EEZ). The United States is responsible for wisely developing and managing the EEZ and its marine resources and for protecting its environment. The U.S. Exclusive Economic Zone is a region that extends seaward 200 nautical miles from the coast and brings within the national domain over 3 million square nautical miles of submarine lands. The EEZ contains vital natural resources, both living and nonliving, of the seabed, subsoil, and overlying water. Because most of the EEZ has not been explored, its resources and their potential remain undefined
Geologic mapping of the Port Moller, Stepovak Bay, and Simeonof Island quadrangles was begun under the auspices of the Alaska Mineral Resource Assessment Program (AMRAP) in 1983 . Two important mineral deposits are located in the Port Moller quadrangle; the Pyramid prospect is the largest copper porphyry system in the Aleutian Arc, and the Apollo Mine is the only gold mine to reach production status in the Aleutian Arc.
Landsat images were digitally processed to facilitate assessment of the mineral resources of the Port Moller, Stepovak Bay, and Simeonof Island 1:250,000 quadrangles. Field mapping and assessment of these quadrangles were begun in 1983 as part of the Alaska Mineral Resource Assessment Program (AMRAP). It was quickly realized that time and budget constraints would limit mapping coverage. Therefore, at the suggestion of Roger Ashley, we used existing Landsat multispectral scanner imagery to aid in locating surface alteration, which could be field checked or related to stream-sediment or hand-sample geochemical data.
Geologic mapping and potassium-argon dating by R. L. Detterman, F. H. Wilson, J. E. Case, and Nora Shew in the Ugashik and western part of the Karluk quadrangles have shown that the Eocene and Oligocene volcanic arc continues into these quadrangles from the south in the Chignik and Sutwik Island quadrangles. Surface exposures of the arc extend northward to approximately 57°30'N., or midway through the Ugashik quadrangle, but none are observed north of that point. Subsurface drill-hole data (Brockway and others, 1975) indicate continuation of the arc, possibly offset to the northwest of the northernmost known surface exposures. In the extreme northern part of the Ugashik and Karluk quadrangles, volcanic rocks again become important. These volcanic rocks are as yet undated; however, they may be related to the Katmai late Tertiary volcanic centers. Like the early Tertiary volcanic arc, the present-day Aleutian arc is also offset to the northwest in the northern part of the Ugashik and Karluk quadrangles. No major offset of the Mesozoic rocks is indicated through the offset zone; this fact suggests a change in the Tertiary tectonic regime in the area of the offset.
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