Abstract: The Evolution of the Earth's Crust and Sedimentary Basin Development

By

Arthur R. Green

The earth's crust is a thin, dynamic shell that changes in both thickness and composition through time. It is postulated that the changes that alter the crust are primarily the result of subcrustal processes and lateral interactions of crustal plates. The type of crust that underlies a sedimentary basin determines the physical framework, stability, manner of structuring, and conditions of sedimentation and environment throughout the evolution of the basin. Thus, as sediments are deposited, they record the tectonic history of the basin. These stratigraphic data can be used to develop conceptual, genetic models that put the evolution of oceanic, continental, and transitional types of crust into perspective. An orderly cycle of crustal evolution is proposed which suggests that oceanic crust is thickened and continental crust is thickened and thinned by a number of natural processes. The resulting transitional crustal types, which represent intermediate steps in the continuum, occupy a realm between thin, basic oceanic crust and thick, acidic continental crust. These transitional, somewhat unstable crustal types host most of the world's sedimentary basins. An attempt is made to step back from the detail of the complex interplay involved in the process of crustal genesis and sedimentary basin development and look at the overall natural system. A set of hypothetical, genetic models depicting the proposed origin of various crustal types is presented so that geophysical data can be compared and tested against them.

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