Detail Tectonic and stratigraphic modeling of the evolution of continental rift basins Bibliografi Author: Conteras, Juan ; Scholz, Christopher H. (Advisor) Topik: GEOLOGY Bahasa: (EN )    ISBN: 0-599-51200-8     Penerbit: Columbia University     Tahun Terbit: 1999     Jenis: Theses - Dissertation Fulltext: 9948960.pdf (0.0B; 0 download) Abstract This work investigates two aspects of the history of continental rift basins: their temporal stratigraphic evolution and how extension and subsidence is accommodated along the series of normal faults that bound these basin on one side. The first aspect is examined through a series of numerical simulations based on a three-dimensional physical model that incorporates the effects of fault growth, flexure, erosion, sedimentation, and isostasy. It also incorporates two feedback mechanisms. The first one is between isostasy and redistribution of mass due to erosion-sedimentation; and the second one is between topography and erosion and sedimentation rates. Numerical experimentation shows that the displacement rate of the bounding fault plays a major role in reproducing the sedimentation rates observed in Newark basin, a typical continental rift basin, and the commonly observed stratigraphy, which consists of a upsection progression of deep lacustrine beds to fluvio-lacustrine sandstones and siltstones. Initially, it is required high displacement rates followed by a gradual decrease in its magnitude with time. To simulate this behavior, faults in the model grow at constant seismic moment rate, consistent with an extension at a constant areal strain rate. The second aspect is investigated through an analysis of the growth history of the Usisya normal fault system of the Lake Malawi basin. Using the patterns of sediment infill observed on seismic lines, has shown that there is an initial stage of isolated fault growth. This is marked by the symmetric growth of individual fault segments. Once fault segments start interacting with each other, growth of fault segments is characterized by (i) an asymmetric enlargement with higher displacement gradients toward the regions of the overlap and (ii) a gradual evolution of the fault system to a common displacement versus length ration of 0.03, the value expected for a single fault. This demonstrates that linkage of faults is a self-similar process as suggested by other authors. Further numerical simulations using these observations, i.e., a decreasing slip rate through time and asymmetric enlargement of faults once interaction has been established, have yielded solutions with stratigraphy and structure similar to those observed in the East African Rift System. Opini Anda Klik untuk menuliskan opini Anda tentang koleksi ini! Lihat Sejarah Pengadaan  Konversi Metadata   Kembali

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