The KTB superdeep borehole: petrography and structure of a 9-km-deep crustal section

Journal article


Publication Details

Author(s): de Wall H
Journal: Geologische Rundschau
Publisher: Springer Verlag (Germany)
Publication year: 1997
Journal issue: 86
Pages range: 3-15
ISSN: 0016-7835


Abstract


The KTB boreholes that were drilled from 1989 to 1994 near Windischeschenbach, NE Bavaria, penetrated rocks of the Zone Erbendorf-Vohenstrauss (ZEV). The upper and lower sections of the 9101-m-deep profile are mainly composed of gneiss units and variegated units. Metabasic units constitute mainly the middle section. Geochemical data suggest their derivation from oceanic crust. All rocks are probably pre- to early Ordovician in protolith age. They underwent early Devonian MP metamorphism. Relics of preceding HP metamorphism are preserved in metagabbros. In contrast to the conditions of the Mesozoic (mainly Cretaceous/Tertiary) faulting the P-T conditions of MP metamorphism, the cooling ages and the late-Variscan graphite-bearing prehnite-actinolite facies mineralization show no significant depth-dependent gradients. This can be explained by Mesozoic supracrustal stacking.



FAU Authors / FAU Editors

de Wall, Helga Prof. Dr.
Professur für Geologie unter besonderer Berücksichtigung der Strukturgeologie [Tektonik] und Photogeologie

Last updated on 2018-11-08 at 00:59