Climate variability in the last interglacial: new evidence using a high-resolution speleothem stable isotope record from Lancaster Hole caves, North Yorkshire.
by
E.J. Hodge
Department of Geographical Sciences, University of Bristol
Coauthors: P.L.Smart (University of Bristol), D.A.Richards (University of Bristol), D.P.Mattey (Royal Holloway, University of London), M.A.Maslin (University College London)

A speleothem (LH-90-12) from Lancaster Hole, North Yorkshire is used to reconstruct medium and short-term climate change during the last interglacial period. High-resolution records of 18-O and 13-C determined using Laser Ablation Gas Chromatography Isotope Ratio Mass Spectrometry (LA-GC-IRMS) are used as potential palaeoclimate proxies. We compare LA-GC-IRMS technique with results from conventional methods and demonstrate that this new technique is both accurate and successful in rapidly obtaining very high-resolution isotopic profiles.

TIMS U-Th dates suggest the main phase of deposition was between 130.4 to 115.5 ka BP with a clearly defined depositional hiatus at around ~120 ka BP. Variations of 18-O and 13-C suggest that climate was unstable throughout the last interglacial period. Results indicate a cooling and-or drying from ~126.5 to 120.9 ka BP, followed by a period during which conditions were considerably cold and-or arid. Rapid warming from 119.8 until ~119 ka BP was then followed by another cooling and-or drying trend until the end of the growth period at 115.5 ka BP. The timing of 18-O variation is tentatively linked with North Atlantic circulation and-or SSTs and the GRIP ice-core record. The preliminary chronology also reveals a possible 1500 year 18-O cycle, the first evidence of such periodicity during the last interglacial period.

Carbonate Processes and Palaeoenvironments Research Group, University of Bristol

Date received: May 15, 2001

Copyright © 2001 by the author(s). The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Conferences Inc. Document # cahi-95.