Geological Society of America

T218 Recent Advances and Future Directions in Paleoaltimetry and Paleoclimate

Tuesday, 6 November 2018
1:30 PM - 5:30 PM
Room 240-241

HOW ACCURATE ARE STABLE ISOTOPE BASED ESTIMATES OF PALEOALTIMETRY: RESULTS FROM ISOTOPE ENABLED CLIMATE MODELS

Paper number: T218-14
Program: Technical Sessions
Time: 4:55 PM – 5:10 PM

Authors

Alexander Farnsworth
Bristol University, Bristol
Paul Valdes Presenting Author
Bristol University, Bristol
Robert Spicer
Open University, Milton Keynes
Tao Su
Xishuangbanna Tropical Botanical Garden, CAS, Yunnan
Dan J. Lunt
Bristol University, Bristol
Ding Lin
Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing

Abstract

Stable isotope based estimates of paleoaltimetry require a number of assumptions, many of which are difficult to assess through data alone. We use an isotope-enabled fully coupled atmosphere-ocean general circulation model (the Hadley centre climate model, HadCM3L) to investigate the role of changing circulation and local recycling in determining the isotopic signature over the Tibetan plateau. The model is configured with Early Eocene (Lutetian, ~45Ma) paleogeographies and a number of topographic scenarios are modelled. The different topographic scenarios represent uncertainties in the reconstructions, and include representation of valley systems and differences in the southern part of the plateau. Even with these relatively modest changes in the height, changes in delta-18O can be large. Typical variations can be +/- 3 per mille which corresponds to an elevation uncertainty of about 1km. Larger changes to the topography can make even bigger differences to the estimated elevations, with changes in circulation altering the best location for estimating the low altitude reference site.

Geological Society of America Abstracts with Programs. Vol. 50, No. 6

doi: 10.1130/abs/2018AM-321963

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