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Multi‐proxy reassessment of the paleolimnology of Lake Bonneville (western USA) as observed in the restricted Pilot Valley sub‐basin
Author(s) -
Nelson S. T.,
Rey K. A.
Publication year - 2018
Publication title -
journal of quaternary science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.142
H-Index - 94
eISSN - 1099-1417
pISSN - 0267-8179
DOI - 10.1002/jqs.3014
Subject(s) - geology , structural basin , pluvial , brackish water , marine transgression , oceanography , terrigenous sediment , paleolimnology , pleistocene , diatom , hydrology (agriculture) , paleontology , salinity , geotechnical engineering
Late Pleistocene sediments of pluvial Lake Bonneville of the western USA represent an important archive of climate and paleolimnological processes. Geochemical, mineralogical and diatom records from the Pilot Valley sub‐basin represent a complete multi‐proxy record of the Bonneville cycle, including closed‐basin transgressive, the Bonneville flood, open‐lake and closed‐basin regressive cycles. Diatoms record pH and salinity, and vary from alkalibiontic/brackish (early transgression), alkaliphilous/fresh‐brackish (deep lake) and back to alkalibiontic/brackish (late regression) conditions. Pennate diatoms reveal passage through and back into the euphotic zone due to the penetration of light through the water column supporting an active benthos. As such, the base of the euphotic zone (∼35 m depth) can be established through time. Restriction and evaporation within the Pilot Valley arm of Lake Bonneville during times of shallow water produced very high endogenic carbonate production, an order of magnitude higher than during deep water. This is shown by age–depth relations in the core, major element and isotopic variations, and sediment mineralogy, requiring a major re‐evaluation of the position of the Bonneville flood horizon within the sediments of Pilot Valley. In summary, lacustrine sediments from restricted arms of large pluvial lakes may vary significantly from complementary records from an open basin.