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Accueil du site → Master → Etats Unis → 2000 → Combined remote sensing and field investigations of major lithospheric compression in the Turkmenistan-Iran region of central Asia

San Diego State University (2000)

Combined remote sensing and field investigations of major lithospheric compression in the Turkmenistan-Iran region of central Asia

DeGross, Shane

Titre : Combined remote sensing and field investigations of major lithospheric compression in the Turkmenistan-Iran region of central Asia

Auteur : DeGross, Shane

Université de soutenance : San Diego State University

Grade : Master of Science in Geological Sciences 2000

Résumé
The Kopet Dag Mountains are a northwest-trending range that formed during the closure of the Tethys Sea and represent the boundary of the Turan and Iranian plates. The Central Kopet Dag is an example of world-class, fault-bend folds that are beautifully displayed on Landsat, Corona and space shuttle imagery. The imagery can be used to determine exactly how strain is being transferred from strike-slip faults to imbricate thrust sheets and fold systems. Understanding this complex array of fault and fold mechanisms offers a suitable platform for extending subsurface geometries out into the topographically flat Karakum Desert to the north. The ’’rigid indentor" style interaction of the Lut block with the 3-D, wedge-shaped fold and thrust belt into which it impinges provides an array of regionally plunging structures that expose an inclined structural view through the orogenic belt. Field studies reveal a three-dimensional, heterogeneously distributed amount of overall horizontal shortening. The Kopet Dag represents a three-dimensional model of the oblique convergence of two continental plates. The Kopet Dag fault as normally viewed in a two-dimensional map representation has been thought by most workers to be purely a strike-slip fault in the western Nebit Dag area. When viewed in a three-dimensional or four-dimensional model, however, an alternative model involving strike-slip faults as sidewall ramps in an imbricate thrust stack being differentially deformed by the Lut block appears more attractive. The incredible exposure of plunging structures allows a more sophisticated reconstruction than is traditionally done with most two-dimensional studies of orogenic belts. The Kopet Dag fault thus appears to represent the frontal boundary of oblique fault-bend fold tectonics between the Iranian plate and Central Asia. Major implications of this study apply to petroleum exploration and overall seismic safety for the densely populated city of Ashgabat, Turkmenistan.

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