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| Titel |
Spatial patterns of erosion and landscape evolution in the central Menderes
Massif (Western Turkey) revealed by cosmogenic 10Be |
| VerfasserIn |
Caroline Heineke, Ralf Hetzel, Nils-Peter Nilius, Christoph Glotzbach, Andreas Wölfler, Andrea Hampel, Cüneyt Akal, Marcus Christl |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250138972
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| Publikation (Nr.) |
 EGU/EGU2017-2123.pdf |
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| Zusammenfassung |
| In regions undergoing active crustal shortening, rock exhumation occurs exclusively by
erosion, whereas in extensional tectonic settings rocks are exhumed by both erosion
and normal faulting (e.g. Ring et al., 1999). An ideal region to study the relative
contribution of normal faulting vs. erosion to rock exhumation is the central Menderes
Massif in Western Turkey, which is bounded by the low-angle Gediz and Büyük
Menderes detachment faults (e.g. Gessner et al., 2013). Recent thermochronological
data show that the two detachments faults were active contemporaneously during
the Pliocene (Buscher et al., 2013; Wölfler et al., in revision). Here we present
10Be erosion rates for 37 catchments to resolve the spatial pattern of erosion across
the central Menderes Massif. Our results show that erosion rates for catchments
located in the footwall of the Gediz detachment range from 40 to 150 mm/kyr. These
relatively low rates indicate that the thick (20-50 m) cataclasites associated with
this detachment fault have protected the footwall from significant erosion, which
explains why the Gediz detachment is such an outstanding geomorphic feature. A
comparison with thermochronological data (Buscher et al., 2013) shows that erosion
contributed 10-20% to rock exhumation (0.6-2.0 km/Myr). In contrast, erosion rates from
catchments in the footwall of the Büyük Menderes detachment are generally higher, with
rates ranging from 140 to 400 mm/kyr. These higher rates are consistent with
the observation that the respective catchments expose mechanically weak mica
schists and phyllites and have rather steep hillslopes. Together with the fact that the
Büyük Menderes detachment is associated with only a relatively thin layer of fault
gouge and cataclasite, this explains why the Büyük Menderes detachment is less
well preserved than the Gediz detachment despite the contemporaneous activity of
both detachments. Furthermore, our data show that erosion contributed 20-40% to
the total exhumation rate of ∼1 km/Myr in the footwall of the Büyük Menderes
detachment (Wölfler et al, in revision). Our results imply that normal faulting played
the dominant role for rock exhumation at both detachments but that the relative
contribution of erosion is higher at the Büyük Menderes detachment than at the Gediz
detachment.
References
Buscher, J.T., Hampel, A., Hetzel, R., Dunkl, I, Glotzbach, C., Struffert, A., Akal, C.,
Rätz, M. 2013. Quantifying rates of detachment faulting and erosion in the central Menderes
Massif (western Turkey) by thermochronology and cosmogenic 10Be. J. Geol. Soc. Lond.
170, 669–683.
Gessner, K., Gallardo, L.A., Markwitz, V., Ring, U., Thomson, S.N., 2013.
What caused the denudation of the Menderes Massif: Review of crustal evolution,
lithosphere structure, and dynamic topography in southwest Turkey. Gondwana Res. 24,
243–274.
Ring U., Brandon, M.T., Lister, G.S., Willett, S.D. 1999. Exhumation processes. In: Ring
U., Brandon, M.T., Lister, G.S., Willett, S.D. (eds.). Exhumation processes: normal faulting,
ductile flow, and erosion. Geol. Soc. Lond. Spec. Publ. 154, 1–27.
Wölfler, A., Glotzbach, C., Heineke, C., Nilius, N.P., Hetzel, R., Hampel, A., Akal, C.,
Dunkl, I., Christl, M. (manuscript in revision for Tectonophysics). Late Cenozoic cooling
history of the central Menderes Massif: timing and slip rate of the Büyük Menderes
detachment and the relative contribution of normal faulting and erosion to rock exhumation. |
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