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  • In the frame of the Continental Margin Study Program of the Federal Institute for Geosciences and Natural Resources (BGR, Hannover) marine geophysical measurements (48-channel reflection seismic, sono-buoy refraction, gravity and magnetic) were conducted over the Atlantic continental margin of Canada from 23th July to 7th August 1979 with S.V. EXPLORA (BGR79 leg 2). The survey on the Canadian continental margin was planned in cooperation between the Federal Institute for Geosciences and Natural Resources (BGR) and the Atlantic Geoscience Centre of the Geological Survey of Canada (Bedford Institute of Oceanography, Dartmonth, N.S.) on the base of existing Canadian multichannel seismic lines. A main target of the cruise was to acquire data which allow a comparison of the deep sedimentary basins offshore Nova Scotia with the already known basins offshore Morocco. The eastern part of the survey imaged complex structural deformation due to salt diapirs. The western seismic lines allowed to investigate the structural relationship between the Scotian Basin and the Georges Bank.

  • The results of the 1978 SONNE survey by the Federal Institute for Geosciences and Natural Resources (BGR), in the Coral Sea indicated the presence of narrow rift valleys beneath the outer margins of the Queensland and Papuan Plateaus. On the margins of these valleys, features were observed which were then interpreted to be large fossil reefs underlying an Eocene/Oligocene unconformity. These conclusions were important because they indicated that the Coral Sea Basin region is ideal for research into the fundamental problems concerning the development of continental margins. That is, the region offers similar problems to areas of the world where detailed studies are currently being conducted (e.g. West African margin) but with less complicated superimposed structure and a much thinner sediment cover. During the period from 29th November 1980 to 9th January 1981 a 'follow up' survey on the first and second leg of cruise SO-16 using the R/V SONNE was carried out in the northern Coral Sea, around the margins of the Coral Sea Basin, by the BGR in co-operation with the Bureau of Mineral Resources, Geology and Geophysics, Canberra (BMR) and the Geological Survey of Papua New Guinea, Port Moresby (GSPNG). The survey, which was divided into a geophysical cruise (first leg of SO-16) and a geological sampling cruise (second leg of SO-16), resulted in the recording of about 7,140 km of bathymetric and gravimetric data, of about 6,950 km of magnetic data, 3,150 km of digital multichannel seismic reflection profiles, 3,560 km of analogue single channel seismic reflection profiles, 10 sonobuoy refraction profiles and the sampling of 16 stations by dredging and 9 by coring. In the period from 9th January to 6th February 1981, geophysical investigations on the 3rd leg of SONNE cruise SO-16 were carried out in the Arafura Sea between Tanimbar, Aru and Kai Islands, and in the southern part of the Makassar Strait by BGR in co-operation with the Geological Research and Development Centre, Dept. Mines and Energy of Indonesia, Bandung and the Indonesian lnstitute of Sciences (LIPI), Bandung. 4,060 km of bathymetric and gravity lines, 3,080 km of magnetic lines, 1,415 km of reflection seismic lines (digital and analogue), and 9 sonobuoy profiles were recorded during this leg. Objectives of the Arafura Sea survey were determination of (a) thickness, seismic pattern, tectonic style and subsidence of the Cenozoic/Mesozoic depositional sequences at the transition from the Australian continental shelf to the Tanimbar outer arc ridge and (b) the configuration of the Precambrian rocks of the above mentioned transition zone. Objectives of the Makassar Strait survey were determination of (a) the nature and configuration of the acoustic basement underlying the South Makassar Basin, (b) the formation and nature of the sediments overlying the acoustic basement, (c) the regional distribution of a major unconformity of assumed Middle Miocene age as observed on profile VA16-24 of the VALDIVIA cruise VA-16 in 1977 in order to get a better understanding of the development of the South Makassar Basin.

  • From 15th September to 26th October 2007 BGR together with the German Alfred-Wegener Institute for Polar and Marine Research (AWI), Bremerhaven, the French Institutes from Brest Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER) and Institut Polaire Français Paul-Emile Victor (the French Polar Institute, IPEV) and the Portuguese Institute Laboratório de Tectonofísica e Tectónica Experimental (LATTEX) conducted a marine geophysical research cruise on the French research vessel R/V MARION DUFRESNE. The cruise BGR07 MoBaMaSis consisted of two legs MD163 off Central Mozambique and MD164 off Southern Mozambique. The main research objective was to contribute to a better understanding of the initial breakup and the early opening of the Eastern Gondwana.

  • The expedition PS155/1 started on August 5th, 2018 in Tromsø (Norway) and ended in Longyearbyen (Spitsbergen) on September 3rd, 2018. In the course of BGR’s GREENMATE project the geological development of the European North Atlantic and the northern and north eastern Greenland shelf was analyzed using various marine geophysical methods (seismics, magnetics, gravity, heatflow measurements) and geological sampling (gravity corer, box corer, multi-corer, dredge). Sampling of marine Shelf sediments was undertaken in close correspondence with co-users from Geomar (add-on project ECHONEG), aiming to reconstruct Holocene paleo environmental and climatic evolution. Using the ship’s helicopters, marine sampling was complemented by onshore sampling operations to extract geological material at selected near coastal locations. Other scientific project groups used the cruise PS115.1 as an opportunity to quantify marine mammals and sea birds and their statistical distribution in our research area as part of the long-term project (add-on project Birds& Mammals) and to gather additional meteorological data via radiosondes (add-on Project YOPP). Against all expectations, outstanding ice conditions along the northern coast of Greenland enabled us to carry out reflection seismic surveys north of 84°N at the southern tip of Morris Jesup Rise with a 3 km long streamer. Structural data of this particular region of North Greenland is of special importance for BGR’s project GREENMATE for reconstructing the continental margin evolution. A 100 km long refraction seismic profile was measured to complement the reflection seismic data. After completing this, scientific work was concentrated on the northeastern Greenland shelf area between 76°N and 82.5°N. Over the time of the cruise a total of 2500 km of reflection seismic profiles (2250 km measured with 3km streamer length) and 100 km of refraction seismic profile (using nine ocean bottom seismometers) were measured, accompanied by gravity and magnetic surveys and seven heat flow measurement stations. Along the shelf and deep-sea area 21 geological sampling sites were chosen, with all together one dredge (around 200 kg of sample), 16 gravity cores (total core length 65 m), 12 box corers and 6 multi-corer stations. Onshore sediment sampling was done at 11 sampling sites. Beside sediment sampling hard rock from near coastal outcrops was collected in a total amount of 250 kg that will be used for age dating. The entire science program was carried out under consideration of the highest ecological standards to protect marine mammals and to meet all environmental requirements of the permitting authorities. In addition to external marine mammal observers (MMO) various acoustic monitoring systems and AWI’s on board infrared detection system AIMMS monitored any activity of marine mammals in the ships perimeter, especially during seismic operations.

  • During RV SONNE cruise 137 from 21st November to 28th December 1998 Geoscientific Investigations on the active Convergence Zone between the east Eurasian and Indo-Australian Plate (GINCO I) were carried out along the Sunda Arc, off Sumatra, Java and the Sunda Strait. The studies were headed by the BGR in close cooperation with German and Indonesian research institutions. A total amount of 5,500 km of magnetic, gravity and swath bathymetric profiles were recorded of which multi-channel seismic data exceeded 4,100 km. The scientific objectives were: (1) investigation of the structure and age of the accretionary wedges, outer arc highs and fore-arc basins off Sumatra and Java with special emphasis on the evolution of the Sunda Strait and the Krakatau area (2) differences in tectonic deformation between oblique (Sumatra) versus frontal (Java) subduction (3) search for oceanic crustal splinters in the accretionary wedges (4) definition of seismic sequences, thicknesses and ages of the fore-arc basin sediments as a pre-requisite for later on hydrocarbon assessments (5) identification and regional occurrence of bottom simulating reflectors (BSR) indicating gas hydrates. From the GINCO I project there is evidence for the existence of two accretionary wedges along the Sunda Arc: wedge I is of assumed Paleogene age and wedge II of Neogene to Recent age. The first inner wedge I is composed of tectonic flakes which are correlated from SE Sumatra across the southern Sunda Strait to NW Java. This implies a very similar plate tectonic regime at the time of the flake development during the Upper Oligocene to Lower Miocene and without marked differences in plate convergence direction from Java to Sumatra. Wedge I shows backthrusting along the northern transition toward the fore-arc basin. Today, wedge I forms the outer arc high and the backstop for the younger, outer wedge II. Magnetic, gravity and seismic results show, that within both wedges, there are no indications for an oceanic crustal splinter as hitherto postulated. Both wedges are underlain by oceanic crust of the subducting Indo-Australian slab which could be correlated from the trench off Sumatra up to 135 km to the northeast and up to 65 km from the trench off Java. Since the top of the oceanic crust differs considerably in reflectivity and surface relief we distinguished two types in the seismic records. One type is characterized by strong top reflections and a smooth surface and underlies accretionary wedge II and the southwest part of the wedge I (outer arc high) off Sumatra and Java. The second type has a low reflectivity and a rougher relief and underlies the tectonic flakes of accretionary wedge I (outer arc high) between the southwestern tip of Sumatra, the SundaStrait and NW Java. The missing outer arc high off the southern entrance of the Sunda Strait is explained by Neogene transtension in combination with arc-parallel strike-slip movements. The NW-SE running, transpressional Mentawai strike-slip fault zone (MFZ) was correlated from the SE Sumatra fore-arc basin to the NW Java fore-arc basin. Off the Sunda Strait northward bending branches of the MFZ are connected with the Sumatra Fault zone (SFZ). It is speculated that the SFZ originally was attached to the Cimandiri-Pelabuhan-Ratu strike-slip faults and shifted from the volcanic arc position into the fore-arc basin area due to clockwise rotation of Sumatra with respect to Java as well as due to increasingly oblique plate convergence since the late Lower Miocene. We explain the transtension of the western Sunda Strait (Semangka graben) and the transpression with inversion of the eastern Sunda Strait, along the newly detected Krakatau Basin, by this rotation. Seismostratigraphic interpretation revealed 5 main sequences (A - E), tentatively dated as Paleogene to Recent in age. The oldest seismic sequence A of assumed Eocene to Oligocene age is bounded at the top by a major erosional unconformity that was identified on all GINCO seismic profiles. The seaward diverging seismic pattern of sequence A is interpreted as a correlative sequence to the prograding Paleogene deltaic sediments encountered by wells offshore central and northern Sumatra. This is opposed to previous interpretation which assumed seaward dipping reflector sequences of basaltic origin erupted along the former Mesozoic passive margin of Sumatra. According to constructed time structure maps, the main NW-SE running depocentres of the post-Paleogene sediments are arc-parallel off Sumatra and Java with thicknesses of 3 s (TWT) and 5 s (TWT), respectively. The main depocentres of the Semangka graben and of the Krakatau Basin of the Sunda Strait strike north-south and have infills of 2 s - 5 s (TWT). Bottom simulating reflectors (BSR) occur within the upper sequences C - D along the flanks of the fore-arc basins and along doming structures but could not be detected in basin centres. Empiric relations of heat flow values and depths of BSR were determined indicating that with increasing waterdepth and decreasing heat flow the depths of the BSR increase.

  • From 1st May to 25th May 2011 the French Institute from Brest Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER) together with BGR conducted a scientific cruise on the IFREMER research vessel L'ATALANTE, which constitutes the 1st leg of the MIRROR survey. In order to acquire supplementary marine geophysical research data to the MIRROR scientific survey a 2nd leg was performed from 2nd June to 11th June 2011. Both legs are spread over the shelf edge and slope of Morocco, the adjacent Essaouira Rise, and the easternmost abyssal plain, and are located between 33°30' N and 30°30' N. The region of MIRROR Leg 2 is situated south of Leg 1. The main research objectives were to image the deep structure of the crust, to test the origin of the magnetic anomaly S1, and to test rifting models in order to understand the nature of the continental margin of Morocco as well as the opening history of the Atlantic Ocean. Another objective was to realize a comprehensive sediment basin analysis for specifying the hydrocarbon potential of the region. In total multi-channel seismic lines with a length of 1,391 km and additional 271 km with the other geophysical methods (magnetic field measurements as well as bathymetry) were acquired. The seismic data acquired during Leg 2 were processed onboard and two of the lines were interpreted. Line BGR11-208 traverses from DSDP Site 415 to Site 416 and ties the MCS grids of both MIRROR legs as well as other former MSC surveys of BGR. Therefore, the line enables a reliable regional seismostratigraphic interpretation and a moderately well mapping of the Jurassic, Cretaceous, and Cenozoic sequences. Large compressional structures are present in the sedimentary cover along the seismic line pointing to transform faults or an activated fracture zone. Regarding the NWW-SEE trending line BGR11-202 the area of investigation can be subdivided into three structural units, a zone of rifted continental margin, a zone of initial seafloor spreading, and a zone of regular seafloor spreading as well as post-Cretaceous igneous activity. Huge rotated basement blocks are located under the shelf and uppermost slope and striking salt domes at the lowermost slope. The zone of initial seafloor spreading is characterized by a sub-basement reflector with overlying tilted basement blocks. The sub-basement reflector trends generally horizontal and appears to be a detachment fault. The magnetic slope anomaly S1 is located at foot of the slope near the western boundary of the zone of rifted continental margin.

  • In the time from 13th August to 13th September, 1989 a geophysical survey was carried out with S.V. PROSPEKTA in the Southeastern Newfoundland Basin and in the Sohm Abyssal Plain. Sixteen multichannel seismic lines with a total length of 3,568 km were surveyed. The general aim of the survey was to study the structure of the oceanic crust formed during the period from 150 to 80 m.y.B.P.. The results we found that the magmatic-volcanic activity at the Mesozoic Atlantic spreading center was episodic, and there was some form of magmatic-tectonic cycling in the Mid-Atlantic Ridge processes. Drastic changes of the oceanic crustal structure have been observed, and a volcanic basement unit characterized by an internally divergent pattern of reflection horizons having an eastward dip was found coinciding with magnetic anomalies M-4 to M-0. This body consists probably of basaltic flows and volcanic clastic rocks extruded near or above sea level, and it appears that this unit is continuous from the Eastern Newfoundland Basin to the New England Seamount Chain. A doubling of the oceanic crustal thickness occurs around M-10 and is present in the area of the young end of the series of magnetic M-anomalies. Doubling of the thickness of the oceanic crust is also present in the conjugate eastern central North Atlantic segment in the area of magnetic anomalies M-10 to about M-0.

  • The previous BGR-cruises with RV AURELIA in 2003 and 2004 were designed to collect a grid of seismic MCS-data which should enable us to get a high-resolution overview over the upper 1 s TWT of the sediments of the German North Sea sector. The data format is Society of Exploration Geophysicists SEG Y. Together with the previously acquired data these new data should help to extend our knowledge of the Late Tertiary and Quaternary evolution of the German North Sea Sector. For the current measurements under the scope of the DFG-funded project RE2424/1-1 ‚Nordsee’ the research vessel RV HEINCKE was made available by the ‘Senatskommission für Ozeanographie’ of the DFG. During the cruise a total ca. 1400 km of high quality MCS lines were surveyed and simultaneously measured by a sediment echosounder system that enabled additional profiles during transits with speeds > 5 kn. The BGR high-resolution multichannel seismic reflection system consisting of a GI-Gun (0.8 l) and a 300 m streamer with 24 channels and a sediment echosounder type SES 2000 standard by Innomar, Rostock. While the BGR-seismic system was used to observe the shallow subsurface down to 2 s TWT penetration depth, the sediment echosounder with a penetration depth of several meters was primarily intended to identify sampling positions for the deployment of the BGR vibration corer during the succeeding Leg 2. Additionally, the echosounder system enables the relationship to the highest-resolution multichannel seismic measurements of the group of the University of Bremen on FK SENCKENBERG. All seismic records were processed onboard for the quality control and for a first interpretation.

  • In the period from 22nd December, 1987 to 15th January, 1988 a geophysical reconnaissance survey has been carried out with S.V. EXPLORA on the Argentine Eastern continental margin. A total of 3,675 km of digital seismic reflection profiles in parallel with gravimetric and in part magnetic measurements, and 13 sonobuoy refraction profiles were recorded during this survey. The general aim of the survey was to search the Argentine eastern continental margin between 37°S and 47°S for evidence of continent-ocean boundary structures previously recognized by us off South Africa. The following preliminary results were obtained: (1) Five regional seismic markers/unconformities have been observed, named from bottom to top AR V to AR I. (2) Two units are recognizable on all reflection seismic records: A buried lower unit the top of which is marked by the distinct 'AR IV' unconformity of presumably Beriasian/Valangian age, and a tectonically undisturbed upper sedimentary unit. (3) The dominant feature of the lower unit is a 50 km to 100 km broad wedge-shaped body characterized by an internally divergent pattern of reflection horizons having seaward dip. The seismic characteristics and recent ODP drilling is consistent with the wedge being formed from extrusive basaltic rocks. (4) The more than 5000 m thick wedge is parallel with the shelf edge and can be traced continuously for 1200 km. Its landward pinchout coincides with the magnetic slope anomaly 'G'. (5) A giant contourite mound of Neogene age has been recognized in the southeastern part of the survey area. (6) Bottom simulating reflectors have been recognized. Their occurrence is associated with the contourite mound.

  • During METEOR-Westafrica cruise 46, leg 1, geophysical measurements were carried out off Morocco between 31°30'N and 32°30'N in the time period from the 8th October to the 5th November 1977. Altogether 1,855 km of 24-fold reflection seismic data were collected on lines ME46-02 to ME46-11 and on lines ME46-14 to ME46-19. For the purpose of planning the programme, the reflection seismic data were processed (12-fold stack) aboard. 3,465 km of magnetic, gravimetric and bathymetric data were collected on lines ME46-01 to ME46-26 using the new BGR digital recording system. Along lines ME46-101 and ME46-102 with a total length of 209 km refraction seismic measurements were carried out with 6 moored telemetric buoys. A total of 164 shots with charges of 5 kg up to 200 kg were fired along the two lines in distances of about 1.5 km. A distinct fault zone was discovered in the area of investigation which is associated with a positive magnetic anomaly. The fault zone strikes NNE-SSW and probably marks the ocean-continent boundary. Beside diapiric structures (salt) allochthonous structures - thrust structures - are widespread features east of the discovered fault zone and below the lower continental slope. The seismic data indicate that the evolution of the old continental margin of the East Atlantic was also controlled by large scale gravity tectonics.