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The Valley and Ridge Province of eastern Pennsylvania - Stratigraphic and sedimentologic contributions and problems The Valley and Ridge Province of eastern Pennsylvania - Stratigraphic and sedimentologic contributions and problems

Many contributions that have led to a better understanding of Appalachian geology have resulted directly from work in the folded Appalachian Mountain and Great Valley sections of the Valley and Ridge physiographic province of eastern Pennsylvania. Disagreements have been common since H.D. Rogers first described the geology of the area in 1858. Many differing opinions still exist...
Authors
Jack B. Epstein

Pacific Enewetak Atoll Crater Exploration (PEACE) program, Enewetak Atoll, Republic of the Marshall Islands. Part 1: Drilling operations and descriptions of boreholes in vicinity of KOA and OAK craters Pacific Enewetak Atoll Crater Exploration (PEACE) program, Enewetak Atoll, Republic of the Marshall Islands. Part 1: Drilling operations and descriptions of boreholes in vicinity of KOA and OAK craters

From mid-1984 through mid-1985, the United States Geological Survey (USGS) engaged in an investigation of two craters formed from high-yield, near-surface nuclear bursts in the Marshall Islands at Enewetak Atoll (figures 1 and 2). Supported by the Defense Nuclear Agency (DNA), this cooperative venture is referred to by the acronym PEACE, derived from its official name, Pacific Enewetak...
Authors
Thomas W. Henry, Bruce R. Wardlaw, Betty Skipp, Richard P. Major, Joshua I. Tracey

Age of biostratigraphic horizons within the Ordovician and Silurian systems Age of biostratigraphic horizons within the Ordovician and Silurian systems

Three samples that have a bearing on the age of horizons within the Ordovician and Silurian systems, two previously dated by the conventional K-Ar method and one by the 40Ar/39 Ar total-fusion method, have been reanalysed using the 40Ar/39Ar age-spectrum method. Conventional K-Ar and total-fusion 40Ar/39Ar ages can always be questioned because of the relative ease with which the K-Ar...
Authors
Michael J. Kunk, J. Sutter, J. D. Obradovich, Marvin A. Lanphere

Age of the Comfort Member of the Castle Hayne Formation, North Carolina Age of the Comfort Member of the Castle Hayne Formation, North Carolina

The biostratigraphic and chronostratigraphic position of the Comfort Member of the Castle Hayne Formation has been the subject of much debate. At the Martin-Marietta Quarry at Castle Hayne, New Hanover County, North Carolina, the planktic foraminifers indicate an assignment within an interval of the uppermost Turborotalia frontosa Zone to the Turborotalia pomeroli Zone. The calcareous...
Authors
J. E. Hazel, Laurel M. Bybell, Lucy E. Edwards, G. D. Jones, L. W. Ward
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