 |
| Titel |
Impact of Himalayas and Tibetan plateau uplift on regional climate and isotopic lapse rate |
| VerfasserIn |
Svetlana Botsyun, Pierre Sepulchre, Yannick Donnadieu |
| Konferenz |
EGU General Assembly 2014
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250091564
|
| Publikation (Nr.) |
 EGU/EGU2014-5866.pdf |
|
|
|
|
|
| Zusammenfassung |
| The Himalayan-Tibet barrier dominates atmospheric circulation over central Asia and
influences global climate. The current high Tibetan Plateau owes gradually during the
north-northeastward penetration of the Indian subcontinent into the Eurasian continent and in
2 main stages of abrupt uplift due to break of Neo-Tethyan slab ~45 Ma and convective
removal of Lhasa lithospheric root ~30-26Ma. Therefore, the northern plateau may have
attained its present-day elevation not earlier than ~13Ma. Nevertheless, several
studies based on stable-isotope paleoaltimetry call for paleoelevations at ~35Ma
comparable with present-day. Understanding variation of isotopic lapse rate through
the time and with changing of absolute value of elevations is critical to estimate
paleoelevations and consequently carry on reliable paleoclimate reconstructions. For
the purpose of simulating changes in isotopic composition of precipitation due to
uplift of the Himalayas and Tibetan plateau the atmospheric general circulation
model LMDZ-iso has been used. This model captures the spatial and temporal
patterns of precipitation δ18O and their relationships with moisture transport from the
westerlies and Indian monsoon. Three sensitivity experiments with modern and
reduced elevations over the Himalayas-Tibet show changes in precipitation rate,
precipitation δ18O, as well as moisture sources over India, East-Southern Asia and
Himalaya and Tibetan plateau areas. Moreover, our results allow to capture changing in
isotopic lapse rate with shifts of mountains height. This result has implications for
the region uplift history, because oxygen isotope paleoaltimetry assumes that the
modern δ18O lapse rate is representative of times when the mountains were lower. |
|
|
|
|
|
|