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  • 1
    ISSN: 1365-246X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences
    Notes: High-resolution reflection seismic data obtained around Gran Canaria allow a detailed and consistent correlation of seismic reflectors of the northern and southern Canary Basins with the lithology drilled by DSDP Leg 47A SSE of Gran Canaria, as well as with major phases of volcanic activity on Gran Canaria as mapped onshore. Two prominent reflectors were chosen as marker horizons and correlated with the drilled lithology. the results indicate that reflector R7 above the Miocene volcaniclastic debris flows V1-V3 reflects the shield-building phase of Gran Canaria. Reflector R3 is interpreted as corresponding with the Pliocene Roque Nublo formation.The top of the massive island flank of Gran Canaria, defined by seismically chaotic facies, extends 44 to 72 km off the coast of Gran Canaria. West of Gran Canaria the flank of Tenerife onlaps the steeper and older flank of Gran Canaria, which, in turn, is onlapping the older flank of Fuerteventura to the east in a similar way.Erosional channels, which can also be traced up to 50 km from the area between Gran Canaria and Fuerteventura into the deeper northern basin, have been identified in the bathymetry.The data presented provide new detailed information for modelling the submarine and subaerial evolution of the central Canary Islands of Gran Canaria and Tenerife, i.e. the timing of their shield-building phases and later stages of major volcanic activity, as reflected by the position of prominent seismic reflectors in the seismic stratigraphy.
    Type of Medium: Electronic Resource
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  • 2
    Publication Date: 2019-07-17
    Description: Davis Strait is a bathymetric high, located between Canada and Greenland. With a water depth of only 500 m, it acts as a gateway for the exchange of polar water from Baffin Bay in the north to the Labrador Sea and the Atlantic in the south. The Davis Strait region has undergone a complex tectonic evolution and the nature of crust is disputed. In a first stage the strait was characterized by extension due to the separation of the North American plate and Greenland. In a second stage transpression was the dominating force. The most prominent geologic feature is the Ungava Fault Complex, a major transform fault that cuts Davis Strait. To investigate the role of Davis Strait as a polar gateway during the opening of the Labrador Sea and Baffin Bay rift system, we analyse recent seismic reflection and refraction data in combination with potential field data. This information is incorporated into a plate tectonic model. On a 230-km-long east west line in central Davis Strait, a P-wave velocity and a density model were obtained by forward modelling. The models show several blocks of continental crust that are separated by major faults of the Ungava Fault Complex. High velocities in the lower crust indicate intense intrusions of mafic material, which we relate to the arrival of the Iceland mantle plume beneath Greenland in the Paleocene. Seismic reflection data were used to model the complex basement morphology and to develop a sediment stratigraphy. The tectonic modelling reveals that an overlap of 70 km of stretched continental crust needs to be compensated for in the transpressional stage of Davis Strait. We are now working on displaying the evolution of Davis Strait from the initial opening of the Labrador Sea to today and will present new results of this study.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
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