DOI: 10.5880/gfz.dekorp.ktb8403.001
title: Deep seismic reflection profile KTB 1984 Line 3 in the Black Forest, Southwest Germany

description: The ca. 62 km long KTB Line 3 was recorded in 1984 as part of the DEKORP, the German Continental Seismic Reflection Program, in the context of presite investigations for the KTB, the German Continental Deep Drilling Project. KTB 8403 is one of the four KTB seismic reflection lines, which were performed in the Black Forest, one of the candidates for the KTB drilling site. The purpose of the investigations was to reveal a strongly differentiated crust beneath the Black Forest with high-fold near-vertical incidence vibroseis acquisition. The main focus was on the crustal structure of the Black Forest massif with respect to the role and extent of Variscan thrust and extension tectonics and the geometry of deep crustal reflection patterns. Details of the experiment, first results and interpretations were published by Lüschen et al. (1987) and KTB-Research Group Black Forest (1987). Results discussed together with the KTB surveys in the Upper Palatinate were presented in a number of works which can be found in Emmermann & Wohlenberg (1989). The Technical Report of KTB 8403 gives complete information about acquisition and processing parameters. The European Variscides, extending from the French Central Massif to the East European Platform, originated during the collision between Gondwana and Baltica in the Late Palaeozoic. Due to involvement of various crustal blocks in the orogenesis, the mountain belt is subdivided into distinct zones. The external fold-and-thrust belts of the Rhenohercynian and Saxothuringian as well as the predominantly crystalline body of the Moldanubian dominate the central European segment of the Variscides. Polyphase tectonic deformation, magmatism and metamorphic processes led to a complex interlinking between the units. The Black Forest is the uplifted eastern shoulder of the Upper Rhine Graben within the internal Moldanubian zone, where rocks of the Variscan basement complex of Central Europe are exposed. The crystalline basement of the Black Forest consists of high-grade gneisses and migmatites intruded by Variscan granites. It was uplifted during the Tertiary rift movements of the Rhine Graben. The E-W running profile 8403 extends through the Black Forest crystalline basement and the adjacent Triberg Granite Massif onto the Swabian Jura Platform. Near Haslach the profile crosses KTB 8402 and KTB 8401 farther to the east. The intersection of these three lines generates a triangle of 3-4 km side length with a focus on the proposed drilling area. To the west the profile is connected with the DEKORP 9S, which runs across the Rhine Graben and the northern tip of Vosges massif into the Lorraine Basin. To the east KTB 8403 is linked to the Urach profile U1, running through the geothermal anomaly at Urach.
description: The German Continental Seismic Reflection Program DEKORP (DEutsches KOntinentales Reflexionsseismisches Programm) was carried out between 1984 – 1999 as the German national reflection seismic program funded by the Federal Ministry of Research and Technology (BMFT), Bonn (now: the Federal Ministry of Education and Research (BMBF)). DEKORP was administrated by the former Geological Survey of Lower Saxony (NLfB), Hanover (now: the State Authority for Mining, Energy and Geology (LBEG)). In 1994 the DEKORP management was taken over by the Helmholtz Centre Potsdam GFZ German Research Centre for Geosciences. The aim of DEKORP was to investigate the deep crustal structure of Germany with high-resolution near-vertical incidence (mostly vibro)seismic acquisition, supplemented by wide-angle seismic and other target-oriented piggy-back experiments, all complemented by optimized methods of data processing and interpretation. The DEKORP project was closely linked with the KTB (German continental deep-drilling program) and was an equivalent to many other deep-seismic programs world-wide such as COCORP, BIRPS, LITHOPROBE, ECORS, CROP, BELCORP, IBERSEIS and many more. The DEKORP-Atlas (Meissner & Bortfeld, 1990) gives a detailed overview about most of the different campaigns and results. In sum, the resulting DEKORP database includes approximately 40 crustal-scale 2D-seismic reflection lines covering a total of ca. 4 700 km and one 3D-seismic reflection survey covering ca. 400 km². Each DEKORP survey is provided with all datasets that are necessary for either a re-processing (i.e. raw unstacked field records in SEGY) or a re-interpretation (i.e. finally processed sections in SEGY or PNG). The raw data are sorted by records or by CDPs. The final data are available as unmigrated or migrated stacks without or with coherency enhancement. Automatical line-drawings are also included. All data come with additional meta information for each domain (source, receiver, CDP) like coordinates, elevations, locations and static corrections combined in ASCII-tables for geometry assignment. Furthermore, all metadata originating from paper copies are made available as scanned files in PNG or PDF, e.g. field and observer reports, location maps in different scales, near-surface profile headers and others. The DEKORP datasets provide unique and deep insights into the subsurface below Germany covering the earth’s crust from the surface to the upper mantle and are increasingly requested by academic institutions and commercial companies. Fields of applications are geothermal development, hazard analysis, hydrocarbon/shale gas exploration, underground gas storage, tunnel construction and much more.