Gianniny, Gary L.; Thackray, Glenn D. (1997): Lacustrine sedimentation and paleoclimate, Pleistocene-Holocene Lake Terreton, northeastern Snake River plain, Idaho. Geological Society of America (GSA), Boulder, CO, United States, In: Anonymous, Geological Society of America, 1997 annual meeting, 29 (6), 437, georefid:1998-051654
Abstract:
Linkages between continental glacial records and deep-sea records of climatic fluctuations have been limited by the discontinuity of continental sedimentation and by the scarcity of chronological control. The nature of western North American climate response to climatic events recognized in DSDP cores may be enhanced by a high resolution record of lacustrine sedimentation recovered from four 50 meter-deep cores near the margin of Pleistocene-Holocene Lake Terreton on the northeastern Snake River Plain. Like other closed Great Basin lakes, precipitation/evaporation balances are the primary control on lake depth such that inferred Lake Terreton depth can be used as a first-order proxy for climate variability. In each of the cores basal lacustrine sediments are overlain by two basalt flows (10 m thick), which are overlain by 35 m of lacustrine, eolian and fluvial sediments. Within the upper 35 m, six post 150 ka pulses of lacustrine deposition are recorded. Clays and silts below the basalts were thermally altered and yield preliminary thermoluminescence ages of 136+ or -13 ka and 153+ or -13 ka. Additional dating in progress will further constrain the temporal framework of these deposits. These dates provide minimum average sedimentation rates for this portion of the Lake Terreton basin approaching 0.5-1.0 mm/100 years. The thickest accumulation of well-laminated lacustrine clays occurs between core depths of 20 m to 14 m and may be associated with pluvial conditions of isotope stage 4 or late stage 6. Ostracodes (Candona, Cypridopsis) from this interval suggest well circulated lacustrine conditions. A shift to more sand-rich sediments with abundant rounded clay intraclasts in the upper 14 m of core is inferred to indicate higher energy deposition in shallow lakes and playas. Thus, deep lake conditions appear to have characterized isotope stages 6 and/or 4, while shallow lake conditions characterized stage 2. These preliminary results concur with other climate proxies suggesting that isotope stage 2 was relatively dry in the northern Rocky Mountains.
Coverage:
West: -155.0000 East: -103.0000 North: 65.0000 South: 32.0000
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