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Detailed Reference Information |
Wagner, G.A., Coyle, D.A., Duyster, J., Henjes-Kunst, F., Peterek, A., Schröder, B., Stöckhert, B., Wemmer, K., Zulauf, G., Ahrendt, H., Bischoff, R., Hejl, E., Jacobs, J., Menzel, D., Lal, N., Van denHaute, P., Vercoutere, C. and Welzel, B. (1997). Post-Variscan thermal and tectonic evolution of the KTB site and its surroundings. Journal of Geophysical Research 102: doi: 10.1029/96JB02565. issn: 0148-0227. |
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The post-Carboniferous crustal evolution of the German Continental Deep Drilling Program (KTB) area, as summarized in this paper, could not be predicted from surface observations: deep drilling was essential for its revelation. The most conspicuous and unexpected feature discovered in the drill hole is the absence of marked gradients with respect to the pre-Carboniferous record. There are no depth-related differences in K-Ar cooling ages of hornblende and white mica, in petrology or in lithology. All metamorphic rocks encountered, both at the surface as well as in the drill hole down to 9100 m depth, were below 300 ¿C from the Carboniferous onward. The late to post-Carboniferous deformation is essentially confined to several fault zones. A major fault zone encountered in the drill hole at 7000 m depth is linked by a prominent seismic reflector to the Franconian Lineament, the surface boundary between Variscan basement and Mesozoic cover. This fault zone probably formed in the late Paleozoic and reactivated as a reverse fault in the Mesozoic. Two important episodes of NE-SW directed shortening by movements along reverse faults took place in the early Triassic and in the late Cretaceous, as indicated by the distribution of apatite and titanite fission-track ages, the sericite K-Ar ages of fault rocks, and the sedimentary record in the adjacent basins. Upper crustal slices were detached at a specific level, corresponding to the approximate position of the brittle-ductile transition in post-Variscan times, and form an antiformal stack that was penetrated by the KTB throughout its entire depth range.¿ 1997 American Geophysical Union |
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Abstract |
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Keywords
Tectonophysics, Continental tectonics—general |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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