Paleogeographic Evolution and Non-Glacial Eustasy, Northern South America
Paleogeographic Evolution and Non-Glacial Eustasy Northern South America - Published eustatic cycle charts commonly call for eustatic fluctuations of more the 40 m every few million years or less. These cycles are interpreted as eustatic, but, so far, waxing and waning of continental glaciations is the only known mechanism which clearly has the ability to drive such large, short-term eustatic fluctuations. High-magnitude, high-frequency ?glacio-eustatic cyclicity? may be a valid concept for times of continental glaciations, but what about times when such glaciations was absent from Earth? Why do cycle charts have a similar form and style for time periods with and without glaciation? Is it that we have missed the identification of a fundamental driving cause which is as important as glaciation and which might have operated during non-glacial times? Or, is it that we are confusing local and eustatic drivers of relative sea-level change? These persistent questions, and others, continue to cast doubt on the entire subject of sequence correlatability. The papers in this book collectively address these questions.
Sequence Stratigraphy and Relative Sea-Level History of the Cretaceous to Eocene Passive Margin of Northeastern Venezuela and the Possible Tectonic and Eustatic Causes of Stratigraphic Development
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Published:January 01, 1998
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CiteCitation
Johan P. Erikson, James L. Pindell, 1998. "Sequence Stratigraphy and Relative Sea-Level History of the Cretaceous to Eocene Passive Margin of Northeastern Venezuela and the Possible Tectonic and Eustatic Causes of Stratigraphic Development", Paleogeographic Evolution and Non-Glacial Eustasy, Northern South America
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Abstract
Passive-margin strata of Cretaceous through Eocene age are exposed in northeastern Venezuela and provide a rare opportunity for the study of the eustatic and tectonic controls of stratigraphic development. The sequence stratigraphy of these strata has been analyzed in conjunction with paleogeographic analysis, and seven regionally extensive sequence boundaries are identified between Hauterivian and late Eocene time: latest ? Hauterivian, two in Early-Middle Albian, Middle-Late Albian, Late Santonian, mid-Maastrichtian, and late middle Eocene. These sequence boundaries have an average spacing of ~ 16 my (typical of second-order sequences). Stratigraphic development and sequences were controlled by both tectonism and eustasy. Three tectonic episodes are most relevant to the stratigraphic development of the northeastern Venezuelan passive margin: (1) a Hauterivian (anomaly MIO) plate motion change between North America and South America-west Africa; (2) Aptian-Albian rifting and opening of the Equatorial Atlantic; and (3) Tertiary, eastward migration with respect to South America of the Caribbean plate. The effects of these tectonic events can at least partially account for Early Cretaceous and Eocene sedimentologic events and sequence development in northeastern Venezuela. Eustatic control of sequence stratigraphic, lithostratigraphic, and paleogeographic development is most probable in Late Cretaceous time. Eustatic fluctuations appear to be less frequent or of much smaller magnitude than is typically concluded from other more tectonically active areas.
- Cenozoic
- Cretaceous
- eustasy
- lithostratigraphy
- marine environment
- Mesozoic
- paleo-oceanography
- paleoenvironment
- Paleogene
- paleogeography
- passive margins
- pelagic environment
- plate tectonics
- reconstruction
- sea-level changes
- sequence stratigraphy
- South America
- tectonics
- Tertiary
- Venezuela
- northeastern Venezuela