Open Session - SWISS GEOSCIENCE MEETINGs

6
Symposium 2: Mineralogy-Petrology-Geochemistry
REFERENCES
Gerya, T., Stöckhert, B. & Perchuk, A.L. 2002: Exhumation of high-pressure
metamorphic rocks in a subduction channel: a numerical simulation, Tectonics 21, 1056.
Hu, N., Yang, J., An, S. & Hu, J. 1993: Metamorphism and tectonic evolution of the Shangdan fault zone, Shaanxi, China. J.
metamorphic Geol. 11, 537-548.
Ratschbacher, L., Hacker, B.R., Calvert, A., Webb, L.E., Grimmer, J.C., McWilliams, M., Ireland, T., Dong, S. & Hu, J. 2003:
Tectonics of the Qinling Belt (Central China): Tectonostratigraphy, geochronology, and deformation history.
Tectonophysics 366, 1-53.
Figure 1. left: garnet profile of sample 75261C, right: equilibrium phase diagram and P-T path of sample 75261C
2.3
New hints on the tectonometamorphic history of the Douling complex
(Qinling belt, central China)
Bader Thomas*, Franz Leander*, de Capitani Christian*, Ratschbacher Lothar**, Hacker Bradley R.***, Weise Carsten**,
Wiesinger Maria**, Popp Michael**
*Mineralogisch-Petrographisches Institut, Universität Basel, CH-4056 Basel
(thomas.bader@unibas.ch)
**Institut für Geologie, Technische Universität Bergakademie Freiberg, D-09599 Freiberg
*** Geological Sciences, University of California, Santa Barbara, CA-93106
The Douling complex, probably part of the Yangtze craton, is located in the Paleozoic-Mesozoic Qinling Belt of central China.
The Douling complex is composed of Proterozoic gneisses and schists with intercalated metabasites (Ratschbacher et al.
2003). Zhang et al. (1996) reported a probably Late Proterozoic metamorphism at P-T conditions of 650-700°C at 0.7-0.8 GPa
for the basement rocks. Together with the cover, the Late Proterozoic Yaolinghe schists, the basement was intensively folded
and underwent a low-grade metamorphism. This study presents new data on the basement and gives insight onto the late,
low-grade metamorphism.
Despite of the intensive low-grade overprint, several indications for the preceding high-grade metamorphism were found.
The absence of primary white mica and the presence of sillimanite and K-feldspar in most metapelitic samples point to upper