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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 67 (1983)

Issue: 8. (August)

First Page: 1351

Last Page: 1352

Title: Mesozoic and Early Tertiary Paleostructure and Sedimentology of Central Wasatch Mountains, Uinta Mountains, and Uinta Basin: ABSTRACT

Author(s): M. Dane Picard, Ronald L. Bruhn, Susan L. Beck

Article Type: Meeting abstract


During latest Cretaceous-Eocene time, 5,000 m (16,000 ft) of beds were deposited in central and northeast Utah. In the Late Cretaceous, sediment derived from the Sevier-Laramide thrust belt was transported to the east and southeast. Southerly paleocurrent directions in the base of the Currant Creek Formation (Maestrichtian) raise the possibility that uplift of the Uintas may have begun by then. The thrust belt continued as a major highland during the early Paleocene, and major uplift of the Uintas occurred. By the middle Paleocene there was an extensive lake which regressed during the late Paleocene as uplift of the Uintas continued. Lake Uinta reached its maximum size during the middle Eocene. During the late Eocene, Lake Uinta regressed and, near the end of the epoch, t e lake expired. Major sediment influx was from the east and southeast. Lower (early Duchesnean) and upper (Late Duchesnean) conglomeratic intervals record major episodes of uplift in the Uintas during latest Eocene.

Structurally, the Wasatch Mountains are part of a marginal foreland fold and thrust belt. In the northern Wasatch Mountains, pre-Late Cretaceous thrust fault plates were folded in part of a large, ramp-anticline that is cored by allochthonous, crystalline basement. Foreland thrust belt structures in the central Wasatch Mountains were folded about the east-trending Uinta axis as the Uinta Mountains formed. Eastward movement on the Hogsback thrust during the Paleocene was transferred onto the adjacent Uinta axis and Uinta Mountains structure, causing about 20 km (12 mi) of sinistral slip in the western Uinta Mountains. Deformation in the Uinta Mountains continued following cessation of movement on the Hogsback thrust system. A south-dipping fault ramp was located beneath the Uinta Mount ins and extended to depths of 15 to 20 km (9 to 12 mi).

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Oblique-slip on this ramp probably resulted in about 20 km (12 mi) of crustal shortening perpendicular to the trend of the mountains.

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