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Publications

Publications from the staff of the Geology, Minerals, Energy, and Geophysics Science Center

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Southern hemisphere origin of the Cretaceous Laytonville Limestone of California

New paleomagnetic, paleontologic, and stratigraphic data from outcrops of the Laytonville Limestone (101 to 88 million years old) support a Southern Hemisphere orgin. A paleomagnetic megaconglomerate test is statistically significant and suggests magnetization at 14?? ?? 5?? south, predating Late Cretaceous to Eocene (70 to 50 million years ago) accretion. Rapid Kula plate movement or the existenc
Authors
J.A. Tarduno, M. McWilliams, W.V. Sliter, H. E. Cook, M. C. Blake, I. Premoli-Silva

Equivalent radiolarian ages from ophiolitic terranes of Cyprus and Oman

Radiolarian biostratigraphy shows that umberiferous strata overlying the Troodos ophiolite in Cyprus are Turonian in age and are thus essentially contemporaneous with similar strata that overlie the Samail ophiolite in Oman. However, this radiolarian age is markedly older than Campanian isotopic ages measured on the underlying rocks of the Troodos ophiolite. The revised age for the umbers indicate
Authors
Charles D. Blome, William P. Irwin

Origin and tectonic evolution of the Maclaren and Wrangellia terranes, eastern Alaska Range, Alaska

Major portions of the eastern Alaska Range, south of the Denali fault, in the McCarthy, Nabesna, Mount Hayes, and eastern Healy quadrangles, consist predominantly of the Maclaren and Wrangellia tectono-stratigraphic terranes. The Maclaren terrane consists of the Maclaren Glacier metamorphic belt and the regionally deformed and metamorphosed East Susitna batholith. The Maclaren Glacier metamorphic
Authors
Warren J. Nokleberg, D. L. Jones, Norman J. Silberling

Geologic setting, petrology, and geochemistry of stratiform sphalerite-galena-barite deposits, Red Dog Creek and Drenchwater Creek areas, northwestern Brooks Range, Alaska

Similar stratiform sphalerite-galena-barite deposits occur in the Red Dog Creek area, De Long Mountains quadrangle, and in the Drenchwater Creek area, Howard Pass quadrangle, northwestern Brooks Range, Alaska. The deposits, located approximately 180 km apart, are hosted by Mississippian and Pennsylvanian strata of the Kagvik structural sequence of late Paleozoic and early Mesozoic age. This sequen
Authors
Ian M. Lange, Warren J. Nokleberg, J.T. Plahuta, H.R. Krouse, B. R. Doe
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