Date of Graduation

Summer 2025

Degree

Master of Science in Geography & Geology

Department

School of Earth, Environment & Sustainability

Committee Chair

Kevin Mickus

Abstract

The Jurassic-Tertiary Amu Darya Basin is mainly located within Turkmenistan and Uzbekistan with a small portion extending into Afghanistan and Iran. The basin is one of the largest petroleum systems in central Asia. The basin is located in the southeast corner of the Turan platform, where both the Middle Paleozoic Turkestan and Early Mesozoic Tethys oceans were closed during different orogenies. The southern boundary of the basin is along the Bande Turkestan fold belt, the Afghan-Tajik basin to the east, Paleozoic metamorphic terranes to the north, and the Karakum high (Paleozoic basement rocks) to the west. Several blocks and terranes were accreted during the late Paleozoic Hercynian orogeny in the late Permian and make up the basement of the basin. The makeup is relatively unknown due to the lack of drill holes and deep geophysical studies. Tectonism occurred initially from the late Permian through to the Middle Jurassic, during this time, a complex of faults and folds were created during this orogeny. During this time the basement was broken into a series of grabens that may be 6 km deep or deeper. Between the Jurassic to Eocene times, passive margin sedimentation occurred that increased in thickness toward the south. In the Eocene, the final tectonism created the basin as is known today following the collision of the Indian plate with the Asian plate and the subsequent Alpine-Himalayan orogeny. This final round of tectonism reactivated relict structures incongruently within the basin, however, not all structures were activated at the same rates, if at all. The present study uses available magnetic and gravity data to determine and location of these structures and to create a model that will show how the basin formed. The gravity and magnetic data were analyzed via residual, derivative and isostatic anomalies, 2-D forward modeling, upward continuation, and bandpass anomalies through areas of interest. Complete Bouguer gravity and magnetic maps revealed a large maximum in the south-central portion of the basin, near the Tajikistan-Uzbekistan border. 2-D gravity and magnetic forward modeling revealed the shape, orientation and extent of faults, folds, and other structures within the basin. Additionally, the 2-D forward modelling reveals that the basement of the basin may be deeper than previously assumed.

Keywords

geophysics, gravity, magnetic, uzbekistan, turkmenistan, amu-darya

Subject Categories

Geology | Geophysics and Seismology | Tectonics and Structure

Copyright

© Logan R. Rogers

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