Azambuja Filho, N. C. and Azevedo, R. L. M. (1996): Cyclostratigraphy and stable isotopes in the Oligocene-Miocene succession of the Campos Basin, Brazil

Leg/Site/Hole:
Identifier:
1997-016396
georefid

Creator:
Azambuja Filho, N. C.
Petrobras Research Center, Rio de Janeiro, Brazil
author

Azevedo, R. L. M.
author

Identification:
Cyclostratigraphy and stable isotopes in the Oligocene-Miocene succession of the Campos Basin, Brazil
1996
In: Anonymous, American Association of Petroleum Geologists 1996 annual convention
American Association of Petroleum Geologists and Society of Economic Paleontologists and Mineralogists, Tulsa, OK, United States
5
7-8
The Oligocene-Miocene succession of Campos Basin consists of rhythmical interbedding of marlstones and mudstones, with few chalk and turbidite layers, deposited in a bathyal environment. The hemipelagic sedimentation has recorded the orbital beat of precession, obliquity and eccentricity, based on spectral analyses of calcium carbonate content data, taken from core samples. A study of oxygen stable isotopes has allowed the recognition of significant fluctuations in d (super 18) O values for the Oligocene/lower Miocene succession. These sediments have recorded important oceanographic events such as the Oi1, Oi2, and Oi2a recognized by Miller et al. (1991) in DSDP boreholes, and the influence of the Antarctic glaciations. The results of this study confirm that global geochemical changes in the marine environment provide means for reliable chronostratigraphic correlations between oceanic and marginal basins, which is thought to contribute to a more accurate evaluation of biologic, sedimentologic and tectonic events. The existence of intervals with in-and out-of-phase d (super 18) O related to %CaCO (sub 3) , reflects the importance of regional events of carbonate productivity versus siliciclastic dilution in the deep-water and its relationship with the global oscillations of the d (super 18) O record. The combination of cyclostratigraphy and chemostratigraphy has shown that there still is a vast area to be explored in order to understand ancient sedimentary records.
English
Coverage:Geographic coordinates:
North:5.1500
West:-74.0000East: -34.0000
South:-34.0000

Stratigraphy; Isotope geochemistry; Atlantic Ocean; Brazil; calcium carbonate; Campos Basin; carbonate rocks; Cenozoic; chalk; chemostratigraphy; chronostratigraphy; clastic rocks; correlation; cyclostratigraphy; Deep Sea Drilling Project; deep-water environment; eccentricity; glaciation; hemipelagic environment; isotope ratios; isotopes; marine environment; marl; Miocene; mudstone; Neogene; O-18/O-16; Oligocene; oxygen; Paleogene; productivity; sedimentary rocks; siliciclastics; South America; South Atlantic; stable isotopes; Tertiary; turbidite; variations;

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