Triassic-Jurassic Geodynamics and Basin Evolution ...

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Dec 2, 2015 - Triassic-Jurassic Geodynamics and Basin Evolution during the Breakup of Pangea. KRAUS, JEFFREY U., ROBERT, J. PAUKEN, and J.
ABSTRACT: Triassic-Jurassic Geodynamics and Basin Evolution durin... http://www.searchanddiscovery.com/abstracts/html/1997/annual/abstrac...

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Triassic-Jurassic Geodynamics and Basin Evolution during the Breakup of Pangea KRAUS, JEFFREY U., ROBERT, J. PAUKEN, and J. GOLONKA A quantitative analysis of a revised plate tectonic model, which is based on C. R. Scotese's (PALEOMAP Project) model, was undertaken to determine plate motions from 255-145 Ma, at 5 m.y. intervals. A key element of this analysis was the capability of calculating plate motion relative to an objective reference frame in the Earth's core. The results of this work are shown as vectors on a series of 4 global plate reconstructions. When combined with empirical geologic data, such as the orientation of tectonic/structural trends and measurements of paleolithospheric stress, plate-scale paleostress regimes may be estimated. These regimes provide improved understanding of known tectonic/structural trends, particularly rift basins. This analysis was also used to examine the tempo of Pangean fragmentation and its influence on sedimentary basins. By calculating the amount of change in plate motion rate and direction over 5 m.y. time steps, a pattern of "normal" plate behavior punctuated by several episodes of short-lived and dramatic change appears. These events, some of which correspond to episodes of plate reorganization, were compared to a variety of geologic phenomena to verify their existence. Perturbations in plate motion, when correlated with the burial histories of Australian and African basins, are shown to have profound effects on subsidence patterns. Such events are commonly recorded by episodes of rapid subsidence along extensional margins. Structural inversion in these basins also correlates with changes in plate motion and abrupt transition from extensional to compressional stress regime. AAPG Search and Discovery Article #91021©1997 AAPG Annual Convention, Dallas, Texas.

2015-12-02 12:40