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  • 2020-2024  (3)
  • 2015-2019  (5)
  • 1985-1989  (4)
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  • 1
    Schlagwort(e): Habilitationsschrift ; Hochschulschrift
    Materialart: Buch
    Seiten: Getr. Zählung , Ill., graph. Darst. , 30 cm
    Sprache: Deutsch , Englisch
    Anmerkung: Enth. Zeitschriftenaufsätze , Kiel, Univ., Habil.-Schr. : 1990
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  • 2
    Publikationsdatum: 2024-04-20
    Beschreibung: Multibeam bathymetry raw data was recorded in the North Pacific during cruise SO96/1 that took place between 1994-06-09 and 1994-06-27. The data was collected using the ship's own Atlas Hydrosweep DS echo sounder.
    Schlagwort(e): Binary Object; Binary Object (File Size); Binary Object (Media Type); Comment; DAM_Underway; DAM Underway Research Data; Data file recording distance; Data file recording duration; DATE/TIME; ELEVATION; Event label; File content; KODIAKSEIS; LATITUDE; LONGITUDE; Number of pings; Ship speed; SO96/1; SO96/1_0_Underway-1; Sonne; Start of data file, depth; Start of data file, heading; Start of data file recording, date/time; Start of data file recording, latitude; Start of data file recording, longitude; Stop of data file, depth; Stop of data file, heading; Stop of data file recording, date/time; Stop of data file recording, latitude; Stop of data file recording, longitude
    Materialart: Dataset
    Format: text/tab-separated-values, 493 data points
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  • 3
    Publikationsdatum: 2024-04-20
    Beschreibung: We provide seismic refraction and wide-angle data from two profile shot across the marine fore-arc of Nicaragua, Central Maerica. Profiles NIC20 and NIC50 were obtained aboard the US R/V Maurice Ewing cruise EW00–05 in 2000. All profile run across the condinantal margin and provide in total 26 digital record sections.
    Schlagwort(e): 1992 Nicaragua tsunami earthquake; Binary Object; Binary Object (File Size); Event label; EW0005; EW0005_NIC20; EW0005_NIC50; EW0005_OBH01; EW0005_OBH02; EW0005_OBH03; EW0005_OBH04; EW0005_OBH05; EW0005_OBH06; EW0005_OBH07; EW0005_OBH08; EW0005_OBH09; EW0005_OBH10; EW0005_OBH11; EW0005_OBH12; EW0005_OBH13; EW0005_OBH15; EW0005_OBH16; EW0005_OBH17; EW0005_OBH19; EW0005_OBH20; EW0005_OBH21; EW0005_OBH22; EW0005_OBH23; EW0005_OBH24; EW0005_OBH25; EW0005_OBH26; EW0005_OBH27; EW0005_OBH28; File content; Latitude of event; Longitude of event; Marine Fore-arc; Maurice Ewing; North Pacific Ocean; OBH; Ocean bottom hydrophone; SEIS; Seismic; seismic refraction; Seismic structure; Seismic tomography
    Materialart: Dataset
    Format: text/tab-separated-values, 30 data points
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  • 4
    facet.materialart.
    Unbekannt
    AGU (American Geophysical Union)
    In:  Journal of Geophysical Research: Solid Earth, 94 (B11). pp. 16023-16035.
    Publikationsdatum: 2018-03-06
    Beschreibung: A seismic refraction profile recorded along the geologic strike of the Chugach Mountains in southern Alaska shows three upper crustal high-velocity layers (6.9, 7.2, and 7.6 km/s) and a unique pattern of strongly focussed echelon arrivals to a distance of 225 km. The group velocity of the ensemble of echelon arrivals is 6.4 km/s. Modeling of this profile with the reflectivity method reveals that the echelon pattern is due to peg-leg multiples generated from with a low-velocity zone between the second and third upper crustal high-velocity layers. The third high-velocity layer (7.6 km/s) is underlain at 18 km depth by a pronounced low-velocity zone that produces a seismic shadow wherein zone peg-leg multiples are seen as echelon arrivals. The interpretation of these echelon arrivals as multiples supersedes an earlier interpretation which attributed them to successive primary reflections arising from alternating high- and low-velocity layers. Synthetic seismogram modeling indicates that a low-velocity zone with transitional upper and lower boundaries generates peg-leg multiples as effectively as one with sharp boundaries. No PmP or Pn arrivals from the subducting oceanic Moho at 30 km depth beneath the western part of the line are observed on the long-offset (90-225 km) data. This may be due to a lower crustal waveguide whose top is the high-velocity (7.6 km/s) layer and whose base is the Moho. A deep (~54 km) reflector is not affected by the waveguide and has been identified in the data. Although peg-leg multiples have been interpreted on some long-range refraction profiles that sound to upper mantle depths, the Chugach Mountains profile is one of the few crustal refraction profiles where peg-leg multiples are clearly observed. This study indicates that multiple and converted phases may be more important in seismic refraction/wide-angle reflection profiles than previously recognized.
    Materialart: Article , PeerReviewed
    Format: text
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  • 5
    Publikationsdatum: 2020-02-06
    Beschreibung: Highlights • The Lofoten/Vesterålen margin has less Early Cenozoic lava flows than believed. • Breakup of the L/V margin is delayed ∼1 m.y. from the Vøring Plateau to the south. • Late arrival of the Iceland Plume may explain delayed breakup and prolonged extension. The Early Eocene continental breakup was magma-rich and formed part of the North Atlantic Igneous Province. Extrusive and intrusive magmatism was abundant on the continental side, and a thick oceanic crust was produced up to a few m.y. after breakup. However, the extensive magmatism at the Vøring Plateau off mid-Norway died down rapidly northeastwards towards the Lofoten/Vesterålen Margin. In 2003 an Ocean Bottom Seismometer profile was collected from mainland Norway, across Lofoten, and into the deep ocean. Forward/inverse velocity modeling by raytracing reveals a continental margin transitional between magma-rich and magma-poor rifting. For the first time a distinct lower-crustal body typical for volcanic margins has been identified at this outer margin segment, up to 3.5. km thick and ∼50. km wide. On the other hand, expected extrusive magmatism could not be clearly identified here. Strong reflections earlier interpreted as the top of extensive lavas may at least partly represent high-velocity sediments derived from the shelf, and/or fault surfaces. Early post-breakup oceanic crust is moderately thickened (∼8. km), but is reduced to 6. km after 1. m.y. The adjacent continental crystalline crust is extended down to a minimum of 4.5. km thickness. Early plate spreading rates derived from the Norway Basin and the northern Vøring Plateau were used to calculate synthetic magnetic seafloor anomalies, and compared to our ship magnetic profile. It appears that continental breakup took place at ∼53.1. Ma, ∼1. m.y. later than on the Vøring Plateau, consistent with late strong crustal extension. The low interaction between extension and magmatism indicates that mantle plume material was not present at the Lofoten Margin during initial rifting, and that the observed excess magmatism was created by late lateral transport from a nearby pool of plume material into the lithospheric rift zone at breakup time.
    Materialart: Article , PeerReviewed
    Format: text
    Format: text
    Format: text
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  • 6
    Publikationsdatum: 2020-02-06
    Beschreibung: The continuation of the Caledonides into the Barents Sea has long been a subject of discussion, and two major orientations of the Caledonian deformation fronts have been suggested: NNW-SSE striking and NE-SW striking. A regional NW-SE oriented ocean bottom seismic profile across the western Barents Sea was acquired in 2014. In this paper we map the crust and upper mantle structure along this profile in order to discriminate between different interpretations of Caledonian structural trends and orientation of rift basins in the western Barents Sea. Modeling of P-wave travel times has been done using a ray-tracing method, and combined with gravity modeling. The results show high P-wave velocities (4 km/s) close to the seafloor, as well as localized sub-horizontal high velocity zones (6.0 km/s and 6.9 km/s) at shallow depths which are interpreted as magmatic sills. Refractions from the top of the crystalline basement together with reflections from the Moho give basement velocities from 6.0 km/s at the top to 6.7 km/s at the base of the crust. P-wave travel time modeling of the OBS profile indicate an eastwards increase in velocities from 6.4 km/s to 6.7 km/s at the base of the crystalline crust, and the western part of the profile is characterized by a higher seismic reflectivity than the eastern part. This change in seismic character is consistent with observations from vintage reflection seismic data and is interpreted as a Caledonian suture extending through the Barents Sea, separating Barentsia and Baltica. Local deepening of Moho (from 27 km to 33 km depth) creates “root structures” that can be linked to the Caledonian compressional deformation or a suture zone imprinted in the lower crust. Our model supports a separate NE-SW Caledonian trend extending into the central Barents Sea, branching off from the northerly trending Svalbard Caledonides, implying the existence of Barentsia as an independent microcontinent between Laurentia and Baltica.
    Materialart: Article , PeerReviewed
    Format: text
    Format: text
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  • 7
    facet.materialart.
    Unbekannt
    AGU (American Geophysical Union)
    In:  Journal of Geophysical Research - Solid Earth, 94 (B1). pp. 625-636.
    Publikationsdatum: 2018-03-06
    Beschreibung: During a seismic reflection survey conducted by the California Consortium for Crustal Studies in the Basin and Range Province west of the Whipple Mountains, SE California, a piggyback experiment was carried out to collect intermediate offset data (12–31 km). These data were obtained by recording the Vibroseis energy with a second, passive recording array, deployed twice at fixed positions at opposite ends of the reflection lines. The reflection midpoints fall into a 3-km-wide and 15-km-long region in Vidal Valley, roughly parallel to a segment of one of the near-vertical reflection profiles. This data set makes three unique contributions to the geophysical study of this region. (1) From forward modeling of the observed travel times using ray-tracing techniques, a shallow layer with velocities ranging from 6.0 to 6.5 km/s was found. This layer dips to the south from 2-km depth near the Whipple Mountains to a depth of 5-km in Rice Valley. These depths correspond closely to the westward projection of the Whipple detachment fault, which is exposed 1 km east of the near-vertical profiles in the Whipple Mountains. (2) On the near-vertical profile, the reflections from the mylonitically deformed lower plate at upper crustal and mid crustal depths are seen to cease underneath a sedimentary basin in Vidal Valley. However, the piggyback data, which undershoot this basin, show that these reflections are continuous beneath the basin. Thus near-surface energy transmission problems were responsible for the apparent lateral termination of the reflections on the near-vertical reflection profile. (3) The areal distribution of the midpoints allows us to construct a quasi-three-dimensional image on perpendicular profiles; at the cross points we determined the true strike and dip of reflecting horizons. This analysis shows that the reflections from the mylonitically deformed lower plate dip to the southwest westward of the Whipple Mountains and dip to the south southward of the Turtle Mountains. The results of this study support the interpretation of crustal reflectivity in the near-vertical reflection profiles to be related to the mid-Tertiary episode of extension which produced the Whipple metamorphic core complex. This association geometrically suggests a more regionally distributed mechanism for crustal thinning as compared with single detachment fault models.
    Materialart: Article , PeerReviewed
    Format: text
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  • 8
    facet.materialart.
    Unbekannt
    Oxford Univ. Press
    In:  Geophysical Journal International, 202 (1). pp. 454-463.
    Publikationsdatum: 2019-09-23
    Beschreibung: The Murray Ridge/Dalrymple Trough system forms the boundary between the Indian and Arabian plates in the northern Arabian Sea. Geodetic constraints from the surrounding con- tinents suggest that this plate boundary is undergoing oblique extension at a rate of a few millimetres per year. We present wide-angle seismic data that constrains the composition of the Ridge and of adjacent lithosphere beneath the Indus Fan. We infer that Murray Ridge, like the adjacent Dalrymple Trough, is underlain by continental crust, while a thin crustal section beneath the Indus Fan represents thinned continental crust or exhumed serpentinized mantle that forms part of a magma-poor rifted margin. Changes in crustal structure across the Murray Ridge and Dalrymple Trough can explain short-wavelength gravity anomalies, but a long-wavelength anomaly must be attributed to deeper density contrasts that may result from a large age contrast across the plate boundary. The origin of this fragment of continental crust remains enigmatic, but the presence of basement fabrics to the south that are roughly parallel to Murray Ridge suggests that it separated from the India/Seychelles/Madagascar block by extension during early breakup of Gondwana.
    Materialart: Article , PeerReviewed
    Format: text
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  • 9
    Publikationsdatum: 2019-09-24
    Beschreibung: Highlights • The basement at the mid-Norwegian Møre Margin is dominantly felsic in composition. • A lower crustal body is interpreted as a mixture of continental blocks and eclogite. • The thickness of the outer lower crustal body is twice as thick on the East Greenland Margin. • The thinning during this first phase of post-Caledonian extension was highest for proto Norway. Abstract The inner part of the volcanic, passive Møre Margin, mid-Norway, expresses an unusual abrupt thinning from high onshore topography with a thick crust to an offshore basin with thin crystalline crust. Previous P-wave modeling of wide-angle seismic data revealed the presence of a high-velocity (7.7–8.0 km/s) body in the lower crust in this transitional region. These velocities are too high to be readily interpreted as Early Cenozoic intrusions, a model often invoked to explain lower crustal high-velocity bodies in the region. We present a Vp/Vs model, derived from the modeling of wide-angle seismic data, acquired by use of Ocean Bottom Seismograph horizontal components. The modeling suggests dominantly felsic composition of the crust. An average Vp/Vs value for the lower crustal body is modeled at 1.77, which is compatible with a mixture of continental blocks and Caledonian eclogites. The results are compiled with earlier results into a transect extending from onshore Norway to onshore Greenland. Back-stripping of the transect to Early Cenozoic indicates asymmetric conjugate magmatism related to the continental break-up. Further back-stripping to the time when most of the Caledonian mountain range had collapsed indicates that the thinning during the first phase of extension was about 25% higher for proto Norway than proto Greenland.
    Materialart: Article , PeerReviewed
    Format: text
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  • 10
    facet.materialart.
    Unbekannt
    GSL (Geological Society London)
    In:  In: Tectonic Evolution of the Eastern Black Sea and Caucasus. , ed. by Sosson, M., Stephenson, R. A. and Adamia, S. A. Special Publications Geological Society London, 428 . GSL (Geological Society London), London, pp. 199-220.
    Publikationsdatum: 2021-05-10
    Beschreibung: The DOBRE-2 wide-angle reflection and refraction profile was acquired in June 2007 as a direct, southwestwards prolongation of the 1999 DOBREfraction’99 that crossed the Donbas Foldbelt in eastern Ukraine. It crosses the Azov Massif of the East European Craton, the Azov Sea, the Kerch Peninsula (the easternmost part of Crimea) and the northern East Black Sea Basin, thus traversing the entire Crimea–Caucasus compressional zone centred on the Kerch Peninsula. The DOBRE-2 profile recorded a mix of onshore explosive sources as well as airguns at sea. A variety of single-component recorders were used on land and ocean bottom instruments were deployed offshore and recovered by ship. The DOBRE-2 datasets were degraded by a lack of shot-point reversal at the southwestern terminus and by some poor signal registration elsewhere, in particular in the Black Sea. Nevertheless, they allowed a robust velocity model of the upper crust to be constructed along the entire profile as well as through the entire crust beneath the Azov Massif. A less well constrained model was constructed for much of the crust beneath the Azov Sea and the Kerch Peninsula. The results showed that there is a significant change in the upper crustal lithology in the northern Azov Sea, expressed in the near surface as the Main Azov Fault; this boundary can be taken as the boundary between the East European Craton and the Scythian Platform. The upper crustal rocks of the Scythian Platform in this area probably consist of metasedimentary rocks. A narrow unit as shallow as about 5 km and characterized by velocities typical of the crystalline basement bounds the metasedimentary succession on its southern margin and also marks the northern margin of the northern foredeep and the underlying successions of the Crimea–Caucasus compressional zone in the southern part of the Azov Sea. A broader and somewhat deeper basement unit (about 11 km) with an antiformal shape lies beneath the northern East Black Sea Basin and forms the southern margin of the Crimea–Caucasus compressional zone. The depth of the underlying Moho discontinuity increases from 40 km beneath the Azov Massif to 47 km beneath the Crimea–Caucasus compressional zone.
    Materialart: Book chapter , NonPeerReviewed
    Format: text
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