8. CLAY MINERAL STRATIGRAPHY OF THE RIO GRANDE RISE AND SOUTHERN BRAZIL BASIN, WESTERN SOUTH ATLANTIC OCEAN1

Clay mineral facies of DSDP Sites (Legs 39 and 72) in the western South Atlantic Ocean reflect the region's tectonic and paleoceanographic events. An abrupt change to a smectite-dominated assemblage occurs in the lower Tertiary and represents the onset of extensive volcanic activity at that tim...

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Bibliographic Details
Other Authors: The Pennsylvania State University CiteSeerX Archives
Format: Text
Language:English
Subjects:
Core materials from the Deep Sea Drilling Project
Antarctic
Antarc*
South Atlantic Ocean
Online Access:http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.622.8874
http://www.deepseadrilling.org/72/volume/dsdp72_08.pdf
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Summary:Clay mineral facies of DSDP Sites (Legs 39 and 72) in the western South Atlantic Ocean reflect the region's tectonic and paleoceanographic events. An abrupt change to a smectite-dominated assemblage occurs in the lower Tertiary and represents the onset of extensive volcanic activity at that time. In the Coniacian-Campanian section of Site 516, a well-crystallized kaolinite suggests the presence of a deeply weathered continental remnant at the crest of the Rio Grande Rise and strongly opposed current systems at shallow and mid-water depths on the northern flanks of the Rise. Within the Rio Grande Gap, initiation of Antarctic Bottom Water flow occurs within the time span represented by an early Eocene-Oligocene unconformity in the sediment section of Site 515 at the northern terminus of the Vema Channel.

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