Western Cordillera and Adjacent Areas
This volume includes guides for 15 of the field trips held in conjunction with the 2003 GSA Annual Meeting in Seattle. Topics covered include Glacial Lake Missoula and the Clark Fork Ice Dam; the Sauk Sequence in western Utah; the geology of wine in Washington state; the Columbia River basalt and Yakima Fold Belt; Alpine glaciation of the North Cascades; and recent geoarchaeological discoveries in central Washington. Quaternary geology of Seattle, engineering geology in the central Columbia Valley, and the tephrostratigraphy and paleogeography of southern Puget Sound also are covered, as are trips to central Cascade Range and the White River.
Sequence stratigraphy of the Sauk Sequence: 40th anniversary field trip in western Utah
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Published:January 01, 2003
Abstract
The Sauk Sequence comprises more than 5 km of mixed carbonate and siliciclastic strata on the Paleozoic miogeocline of the eastern Great Basin. Rapid, post-rifting subsidence was the single most important factor for providing accommodation for accumulation of sediments. Despite the enormous thickness of strata and the tendency for unconformities to die out toward the margin of the continent, bounding surfaces of the Sauk Sequence and several sequence boundaries within this interval are preserved in mountain ranges of western Utah. The base and top of the Sauk Sequence are thick sandstones. The development of microkarst or truncation surfaces associated with major facies disclocations and deposition of major influxes of siliciclastics are the hallmarks of sequence boundaries and correlative conformities in this setting. The style of sequence boundary development was mostly a function of magnitude and duration of sea-level fall but was also influenced by tectonic features such as the House Range Embayment.