Basin development north of Great Salt Lake and implications for Neogene structural history of northern Utah
- Geological Survey, Menlo Park, CA (United States)
Cenozoic deposits within and near the North Promontory Mountains comprise a tilted Miocene basin (Sand Hollow basin), Pliocene overlap deposits, and varied Quaternary deposits. The Sand Hollow basin contains the Salt Lake Formation, a complex tuffaceous unit deposited in lacustrine, fluvial, alluvial, eolian, and volcanic environments. Isotopic ages of tuffs indicate deposition spanning the middle Miocene. Initial deposition within sub-basins accounts for about 600 m of locally-derived conglomerate, sedimentary breccia, and finer grained tuffaceous materials. Moderate down-to-the-east tilting led to an eastward-deepening basin with deposits over 2.5 km thick. Subsequent tilting and erosional beveling of the tuffs took place before loess and alluvium, which contain little volcanic material, were deposited at [approximately]5 Ma. The Pliocene strata in turn were faulted to produce the basic physiographic and structural framework of the northern Great Salt Lake. Isotopic ages, correlations of tephra chemistry, and lithologic correspondence establish that several basins across northern Utah contain the Salt Lake Formation and are temporally equivalent. In several piedmont exposures, the formation was tilted and eroded much like the deposits in Sand Hollow basin. On the basis of this regional correlation, the authors suggest that Basin and Range magmatism and basin development began at about 18 Ma. Basins received thick deposits of tuffaceous sediment until about 9 Ma. Between [approximately]8 and 5 Ma, strata in some locations were uplifted, tilted, and eroded, presumably as adjacent basins deepened. Lower Pliocene overlap strata were faulted during the late Pliocene to form depocenters that coincide with present basins, suggesting that current topography is Pliocene and younger.
- OSTI ID:
- 5128588
- Report Number(s):
- CONF-9305259--
- Journal Information:
- Geological Society of America, Abstracts with Programs; (United States), Journal Name: Geological Society of America, Abstracts with Programs; (United States) Vol. 25:5; ISSN GAAPBC; ISSN 0016-7592
- Country of Publication:
- United States
- Language:
- English
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