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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 65 (1981)

Issue: 5. (May)

First Page: 991

Last Page: 991

Title: Changing Patterns of Phosphogenesis in Mesozoic and Cenozoic: ABSTRACT

Author(s): Richard P. Sheldon, William C. Burnett

Article Type: Meeting abstract


During the Mesozoic and Cenozoic Eras, major global phosphogenic episodes occurred during the Upper Cretaceous-Eocene and Miocene Epochs. A minor phosphogenic episode occurred during the Jurassic Period.

The Jurassic and Miocene phosphogenic provinces were primarily located on the eastern sides of oceans on continental shelves where upwelling ocean paleocurrents were associated with paleotrade winds. Major exceptions are the Miocene phosphorites of the southeastern United States which probably were associated with the paleo-Gulf Stream, and the Miocene phosphorites of the Chatham Rise, New Zealand, which possibly were associated with the Antarctic circumpolar paleocurrent. The Miocene phosphorites probably were the result of increased vertical oceanic circulation, mainly trade-wind belt coastal upwelling. Jurassic phosphorites appear to be paleo-oceanographically analogous to the Miocene phosphorites.

The Late Cretaceous-Eocene phosphogenic province was primarily an east-west equatorial circumglobal province of Tethys and Pacific seamounts. The Upper Cretaceous-Eocene phosphorites of the Atlantic paleo-ocean continental shelves in Togo, Gabon, Senegal, and Brazil are an exception to this distribution. The major Upper Cretaceous-Eocene phosphorites probably were the result of vertical circulation due to equatorial divergent upwelling.

Tertiary and Mesozoic phosphogenic episodes appear to be due to a combination of the onset of increased rates of oceanic circulation after periods of oceanic stability, periods of high sea level, and favorable paleogeography.

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