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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 63 (1979)

Issue: 3. (March)

First Page: 538

Last Page: 539

Title: Middle Cretaceous Oxygen-Deficient Paleoenvironments in Mid-Pacific Mountains and on Hess Rise, Central North Pacific Ocean: ABSTRACT

Author(s): Jorn Thiede, T. L. Vallier, E. Vincent, R. R. Schmidt, A. Schaaf, C. A. Sancetta, P. Cepek, A. Boersma, N. Fujii, W. O. Sayre, K. E. Windom, K. E. Seifert, D. K. Rea, V. I. Koporulin, W. E. Dean, C. G. Adelseck

Article Type: Meeting abstract


Cores collected during Leg 62 of the Deep Sea Drilling Project recovered organic-rich rocks of early Aptian age in the Mid-Pacific Mountains and of late Albian age on the southern Hess Rise. Concentrations of organic carbon in these rocks range from a few tenths of 1% to more than 9%. The organic-rich strata in the Mid-Pacific Mountains are in a 45-m-thick sequence of carbonaceous and tuffaceous limestone that lies on interbedded

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pelagic limestones and clastic limestones containing locally derived shallow-water carbonate debris. The carbonaceous-tuffaceous sequence is overlain by cyclic interbeds of green, gray, and pink limestone. The organic-rich strata on southern Hess Rise are dark-olive laminated limestone with a few clay-rich intervals that may contain altered volcanic ash. The association of volcanogenic sediments with organic-rich strata on Hess Rise is not as striking as in the Mid-Pacific Mountains, but the occurrences do suggest a coincidence of mid-plate volcanic activity and accumulation of organic matter at intermediate water depths in the tropical North Pacific during the middle Cretaceous. These organic-rich rocks are equivalent in age to organic-rich lithofacies elsewhere in the world ocean. >

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