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| Titel |
Rain shadow development and paleoenvironmental change in the southern Central Anatolian Plateau |
| VerfasserIn |
Maud J. M. Meijers, Andreas Mulch, Gilles Y. Brocard, Donna L. Whitney |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250107535
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| Publikation (Nr.) |
 EGU/EGU2015-7239.pdf |
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| Zusammenfassung |
| Ongoing Arabia-Eurasia convergence in the eastern Mediterranean region has led to the
westward escape of the Anatolian microplate and the formation of the Central Anatolian
Plateau (CAP). The US-NSF CD-CAT (Continental Dynamics-Central Anatolian Tectonics)
project aims at understanding the surface-to-mantle coupling during the transition from
collision to escape tectonics and plateau formation in Anatolia. Within the CD-CAT project,
this study aims at determining the paleoenvironmental conditions and the age of plateau
(margin) uplift by integrating stable isotope geochemistry and absolute dating techniques
(40Ar/39Ar geochronology and magnetostratigraphy) on middle Miocene to Pliocene
lacustrine sedimentary rocks.
The low-relief CAP (~1.5 km average elevation) is characterized by high-relief mountain
ranges at its southern and northern margins. The Tauride mountain belt forms the southern
plateau margin of the CAP with a relief of up to 3 km. Uplift of Tortonian marine
sediments in the central Taurides to modern elevations of up to 2 km constrain the
onset of surface uplift of the southern plateau margin to ~8 Ma (Schildgen et al.
2012a,b).
Proxy records of oxygen isotopes (δ18O) in precipitation allow to reconstruct the
development of the present-day Tauride rain shadow and hence the surface elevation
history of the southern plateau margin. Here we evaluate δ18O and δ13C records of
seven lacustrine basins situated along a SW-NE swath in the lee of the modern
Tauride mountains in order to track the development of a Tauride rain shadow and
changes in open to closed lake conditions through the late Miocene to Pliocene. We
focus on lacustrine sections with available mammal ages and integrate these with
40Ar/39Ar geochronology of widespread volcanics of the Central Anatolian Volcanic
Province and magnetostratigraphy where possible. Our results from seven sections
of ~12-4 Ma in lacustrine deposits and pedogenic soil carbonates of ~3-2.5 Ma
show a decrease of δ18O values between ~12 and ~6 Ma of ca. 3o followed by a
period of remarkably stable δ18O values around 21.5‰ until about 2.5 Ma. The
latter coincides with modern δ18O values of the least-evaporative rinds of modern
pedogenic carbonate. The observed 3‰ decrease in δ18O of lacustrine carbonate
accounts for about 50 % of the present-day effect of orographic rainout on δ18O of
precipitation (Schemmel et al. 2013) along the southern plateau margin. This might
indicate the presence of a ~1000m high plateau prior to the formation of the Tauride
chain.
Schildgen et al., EPSL 317-118, 2012a; Schildgen et al., Tectonics 31, 2012b; Schemmel
et al., AJS 313, 2013 |
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