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Tectonic evolution of Hanna Basin, Wyoming: Laramide block rotation in the Rocky Mountain foreland

Thesis/Dissertation ·
OSTI ID:5631330

From late Early Cretaceous through late Early Eocene time the Hanna Basin area of south-central Wyoming developed in response to regional and local tectonic forces. Subsidence history, flexural modeling, depositional setting and history, coal moisture content of Tertiary coal and fission-track thermochronology document the evolutionary history of this small ({approx}2600 km{sup 2}), deep ({approx}16 km offset on the Precambrian basement) intermontane basin. The present geologic configuration of Hanna Basin is the result of five evolutionary phases: (1) initial regional subsidence ({approx}119 Ma) as part of the expanding foredeep in front of the Sevier Orogenic belt, (2) breakup of this foredeep into discrete depocenters and nascent uplifts began between 88.5 Ma and 97.5 Ma (locally, uplift of the Sweetwater Arch and downwarp of the Hanna trough are most important), (3) breakup of the Hanna trough and development of the Hanna Basin by basement block rotation facilitated by sediment loading (began at 68-70 Ma and continued through {approx}52 Ma), (4) late Early Eocene - early Middle Eocene uplift of Shirley Mountains area and final destruction of the old Hanna trough (final movement on the Shirley Thrust) and (5) post Early Eocene sedimentary fill of about 2.4 km and its subsequent erosion prior to {approx}29 Ma.

Research Organization:
Wyoming Univ., Laramie, WY (USA)
OSTI ID:
5631330
Country of Publication:
United States
Language:
English