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| Titel |
500,000 years of water table fluctuations recorded in Devils Hole 2 cave from southwestern Nevada, USA |
| VerfasserIn |
Kathleen A. Wendt, Gina E. Moseley, Yuri V. Dublyansky, Christoph Spötl, R. Lawrence Edwards |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250130871
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| Publikation (Nr.) |
 EGU/EGU2016-11194.pdf |
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| Zusammenfassung |
| Evidence for large reoccurring Pleistocene lakes in the Great Basin region of North America
suggests that this modern day arid landscape underwent drastic climate fluctuations in the
past. We aim to reconstruct the history of water table fluctuations in the discharge area of
the Ash Meadow groundwater flow system since 500 ka BP. To do so, we have
analyzed a series of carbonate cores drilled at varying elevations above the modern
day water table from the walls of Devils Hole 2 cave in southwest Nevada, USA.
Petrographic and morphologic differences between calcite precipitated below (mammillary
calcite) or at (folia) the water table in this cave record past variations in water table
elevation. A total of ten cores were drilled between 0.8 and 15.1 m above the modern
day water table. Each core includes alternations between mammillary calcite to
folia, with an increasing occurrence of folia in higher elevation cores, suggesting
multi-meter variations in past water table elevation. Over 50 high-precision 230Th dates
have been measured at the mammillary calcite to folia boundaries of each core.
Preliminary results show multi-meter water table fluctuations which appear to follow
interglacial-glacial cycles from 500 ka to present day, such that water table high-stands
coincide with glacial periods. Observed maxima in water table levels are likely correlated to
periods of increased precipitation within the catchment area during glacial (pluvial)
periods, which is consistent with paleoclimate records in this region. Preliminary
results suggest water table levels peaked (reaching +5.5 m or higher than present
day water table) at 461 kyr, between 320 and 250 kyr, between 196 and 137 kyr,
and between 67 and 20 kyr BP, largely coinciding with glacial periods. Periods in
which water table levels reached the lowest elevation sampled (+0.8 m) occurred
at 240 kyr, 116 kyr, and 5.7 kyr BP, largely coinciding with interglacial periods. |
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