HR: 1340h
AN: PP23A-1078    [Abstracts]
TI: Preliminary Geophysical and Sedimentological Data From Peiku Co Tibet
AU: * Ricketts, R D
EM: ricketts@d.umn.edu
AF: Large Lakes Observatory, University of Minnesota Duluth, Duluth, MN 55812, United States
AU: Henderson, A C
EM: ahenders@life.uiuc.edu
AF: Institute of Geography and Earth Sciences, University of Wales, Aberystwyth Llandinan Building, Penglais Campus, Aberystwyth, SY23 3DB, United Kingdom
AU: Yu, S
EM: syu@d.umn.edu
AF: Large Lakes Observatory, University of Minnesota Duluth, Duluth, MN 55812, United States
AB: Peiku Co (N28°46; E85°30, 4595 m a.s.l, surface area =<280km²) is located in a fault- bounded basin on the northern side of the Himalayas. The lake, which has been little explored prior to our Spring 2007 field expedition, is an excellent site for reconstructing past hydrological and monsoon variability as paleo- shorelines attest to effective-moisture-driven changes in lake level and ~70% of precipitation in the region is from the southwest Asian monsoon. In addition, the nearby Dasuopu ice core provides a record of climate variability and Indian subcontinent drought, which can be used to evaluate our Peiku Co record. We recovered over 40km of Chirp sub-bottom seismic profiles and three 4.5 meter long cores from Peiku Co. The cores were all collected from the same site in the southern basin from a water depth of approximately 40 meters. The Chirp data collected near the core site indicate that there is a least 9 meters of sediment in this part of the southern basin, which is twice the amount of sediment collected during our coring operations. A radiocarbon date from the bottom of one of the cores indicates that the core bottom (~4.5m) was deposited ~ 14,500 calendar years BP. Chirp data collected from the northern basin found the deepest water depth in the entire basin (~70m) and also sections of the northern basin containing at least 15 meters of sediment. A few strong reflectors occur throughout the lake and if our interpretation is correct these reflectors imply that the basal sediment found in the northern basin is older than the basal sediment found in the southern basin. In addition, in-filled channels and faults are found in many of the seismic profiles. Higher magnetic susceptibility values near the middle and bottom of the sediment cores suggest that there may have been more detrital input to the core site in the older part of the sediment record, possibly indicating more glacial runoff to the system. Additional analyses and radiocarbon dates will be necessary to validate this initial interpretation.
DE: 4914 Continental climate records
DE: 4942 Limnology (0458, 1845, 4239)
DE: 9320 Asia
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting