[en] Three oil exploration wells were drilled within 20 km of Yucca Mountain in 1991. Conodont samples from two of these new wells and 190 locations near Yucca Mountain and have been analyzed for color alteration indices (CAI), which can be correlated to thermal maturity and petroleum generation. Cambrian through Triassic rocks in the vicinity of Yucca Mountain have experienced temperatures too high to be capable of generating oil, except for a narrow zone (20 x 100 km) northeast of Yucca Mountain, where Mississippian through Triassic rocks are just within the upper limit of the oil generating window. Organic geochemical samples from the Mississippian Eleana Formation in this zone have low total organic carbon and low hydrogen indices, which, combined with overall pattern of CAI values, indicates that the entire Cambrian through Triassic sedimentary column is unfavorable as oil source rocks. While much of the Cambrian through Triassic rocks have thermal potential for gas, extensive Late Tertiary faulting at Yucca Mountain suggest that seals might be inadequate for retaining gas. No commercial gas fields have been found to date in Nevada or adjacent parts of California. Organic geochemistry on samples from a few Tertiary lacustrine deposits do show high carbon and hydrogen indices. However, the lacustrine deposits in these basin and range type valleys lack long range continuity and none of the present Nevada oil fields produce from such Tertiary valley-fill

[en] Six multichannel seismic-reflection profiles taken across the Atlantic continental margin off the northeastern United States show an excess of 14 km of presumed Mesozoic and younger sedimentary rocks in the Baltimore Canyon trough and 8 km in the Georges Bank basin. Beneath the continental rise, the sedimentary prism thickness exceeds 7 km south of New Jersey and Maryland, and it is 4.5 km thick south of Georges Bank Stratigraphically, the continental slope--outer edge of the continental shelf is a transition zone of high-velocity sedimentary rock, probably carbonate, that covers deeply subsidized basement. The spatial separation of magnetic and gravity anomalies on line 2 (New Jersey) suggests that in the Baltimore Canyon region the magnetic-slope anomaly is due to edge effects and that the previously reported free-air and isostatic gravity anomalies over the outer shelf may be due in part to a lateral increase in sediment density (velocity) near the shelf edge. The East Coast magnetic anomaly and the free-air gravity high both coincide over the outer shelf edge on line 1 (Georges Bank) but are offset by 20 km from the ridge on the reflection profile

[en] Two wildcat oil and gas exploration holes drilled in 1991 on the northern edge of the Amargosa Desert penetrated Tertiary and Quaternary sedimentary rocks, alluvium, and basalt, possible Tertiary volcanic or volcaniclastic rocks, and Tertiary (?) and Paleozoic carbonate rocks. The easternmost of the two holes, Felderhoff-Federal 5-1, encountered about 200 feet of alluvium, underlain by 305 feet of basalt breccia and basalt, about 345 feet of probable Tertiary tuffaceous sedimentary rocks, and 616 feet of dense limestone and dolomite of uncertain age. Drill hole 25-1 penetrated 240 feet of alluvium and marl (?), and 250 feet of basalt breccia (?) and basalt, 270 feet of tuff (?) and/or tuffaceous sedimentary rocks, 360 feet of slide blocks (?) and large boulders of Paleozoic carbonate rocks, and 2,800 feet of Paleozoic limestone and dolomite. The two drill holes are located within a northerly trending fault zone defined largely by geophysical data; this fault zone lies along the east side of a major rift containing many small basalt eruptive centers and, farther north, several caldera complexes. Drill hole 25-1 penetrated an inverted paleozoic rock sequence; drill hole 5-1 encountered two large cavities 24-inches wide or more in dense carbonate rock of uncertain, but probable Paleozoic age. These openings may be tectonic and controlled by a regional system of northeast-striking faults