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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 65 (1981)

Issue: 5. (May)

First Page: 996

Last Page: 997

Title: Late Pleistocene and Holocene Sedimentary History of Great Salt Lake, Utah: ABSTRACT

Author(s): R. J. Spencer, H. P. Eugster, K. Kelts

Article Type: Meeting abstract


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Piston cores to 6 m in length from the South Arm of Great Salt Lake, Utah, have been correlated. Radiocarbon ages indicate a record greater than 30,000 y.b.p. Sediments are divided into 4 units (I to IV, top to bottom). Units I, II, and IV contain laminated mud and pelleted mud with brine shrimp egg capsules; III consists of disrupted (bioturbated) sediment containing two ostracod assemblages.

The position of a volcanic ash (Mt. Mazama, Oregon, ~ 7,000 y.b.p.) has been traced across eleven cores. Aligned pellets and ooids are deposited at the lake margins as parallel flat laminae or thin beds; basinward flaser laminae are present and toward the center disrupted intervals occur. A similar variation is seen in the surface sediment today. The aligned pellets and ooids are interpreted as shallow (< ~ 5 m) nearshore current deposits, the flaser laminae as wave-worked deposits, and the disruption is attributed to intrasediment salt growth. Lateral and vertical variations indicate that Unit I sediments have been deposited under relatively shallow (< 25 m) saline conditions. The fine laminae of Unit II sediments are wavy and discontinuous. Toward the basin edge carbonate crus s are present. Reworked clasts of soft sediment are evidence that the sediments were bound, while clasts and scours indicate current activity. Unit III sediments are disrupted (bioturbated) with short intervals of primary layering. The ostracod assemblages have wide salinity and depth tolerances, but indicate a deeper fresher lake. Unit IV contains fine parallel flat, wavy and lenticular laminae and is interpreted as a shallow, saline subfacies.

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