Jörg Ebbing | Christian-Albrechts-Universität zu Kiel (original) (raw)

Papers by Jörg Ebbing

International Association of Geodesy Symposia, 2014

In order to better constrain the Cenozoic evolution of the Norwegian-Greenland Sea and contiguous... more In order to better constrain the Cenozoic evolution of the Norwegian-Greenland Sea and contiguous margins, a new aeromagnetic data (JAS-05 survey) was acquired in the Eastern part of the Jan Mayen Fracture Zone during autumn 2005. We present preliminary results and ...

Norsk Geologisk Tidsskrift

Analysis of the gravity anomalies associated with the Scandinavian mountain range (ie the Scandes... more Analysis of the gravity anomalies associated with the Scandinavian mountain range (ie the Scandes) suggests that the compensating loads are loca-ted at relatively shallow depths in the crust and/or in the mantle lithosphere. Potential crustal loads leading to positive buoyancy ...

At passive margins, the thinning of continental crust from a thickness of 30-40 to less than 10 k... more At passive margins, the thinning of continental crust from a thickness of 30-40 to less than 10 kilometres commonly results in a zone of taper that borders a wide zone of extremely attenuated continental crust, which, in turn, borders the continent-ocean transition. The taper area is thus a principal boundary that separates the proximal from the distal parts of the margin, and the evolution of this zone determines much of its later history. Along parts of the Mid Norway rifted margin, the taper area is well imaged by long-offset seismic reflection data. The North Atlantic passive margin is a type example of a magmatic margin, with breakup in the Eocene around 54 Ma. Breakup was, however, preceded by several magma-poor extensional phases that in the Mid Norway case include Devonian late/post-Caledonian extension, Permo-Triassic stretching and a phase of extreme Jurassic-Cretaceous crustal thinning. Along the SE borders of the rift, `top basement' detachment faults with heaves in the order of 15-40 kilometres evolved in at least two stages to become the boundaries between moderately thinned (20-30 km thick) crust and 100-200 km wide, highly extended areas with crustal thickness generally between 2 and 12 km. These areas evolved into the deep Møre and Vøring basins. In the footwalls of the basin-flank detachments, rocks from the lower and middle crust were exhumed in extensional domes that, in turn, became incised by a younger set of normal faults. In the Slørebotn Subbasin area, a warped-back detachment fault is overlain by an array of fault-blocks that underwent up to 50o of rotation in the Late Jurassic. This detachment was subsequently incised and deactivated by planar normal faults that incised the extensional culmination on the basin side. Under the most highly thinned areas, a more distal set of deep-seated (basin-floor) detachments incised and extended remnant crust and, probably, the upper mantle, leaving as little as <5 kilometres of continental crust to be preserved under thick syn- and post-rift deposits. We suggest that basin-flank detachments hold the potential to reduce the crustal thickness down to the critical value required for embrittlement. Offshore Mid Norway, this stage may have been reached in the Early Cretaceous. The large-magnitude Jurassic-Early Cretaceous faults show variable relationships to earlier structures and basins. Abrupt truncation of older faults and basins by Jurassic-Cretaceous basin-flank detachments can be observed along the margins of the Trøndelag platform. Gneiss-cored extensional culminations are well known from the onshore Palaeozoic extensional systems, and in the offshore, seismic and potential field data suggest the presence of such structures underneath Palaeozoic-Early Mesozoic basins in the Trøndelag Platform area as well as in the footwalls of Late Jurassic-Early Cretaceous detachment faults. A fundamental control on the margin geometry by late/post-Caledonian structures is indicated by the trends of the large-magnitude fault systems and, locally, by observations related to deep-seated extensional culminations. Variations in displacement magnitude and geometry of the basin-flank detachments controlled variations in the thinning gradient for the crystalline crust (crustal taper). An accumulating body of evidence indicates that this, in turn, controlled not only the location of deep post-rift basins, but also the behaviour of the onshore parts of the margin in the post-rift phase.

... 74-100, Haus N, Berlin, 12249 Germany ), AB(Institut für Geologie, Geophysik und Geoinformati... more ... 74-100, Haus N, Berlin, 12249 Germany ), AB(Institut für Geologie, Geophysik und Geoinformatik, FU Berlin, Malteserstr. ... Pleicherwall 1, Wuerzburg, 97070 Germany ), AH(Natural Resources Authority, PO Box 7, Ammann, 11118 Jordan ), AI(AN-NAJAH NATIONAL UNIVERSITY ...

When studying the structure of the crust and upper mantle, the geoid and gravity field are typica... more When studying the structure of the crust and upper mantle, the geoid and gravity field are typically used and integrated with seismological and electromagnetic studies. In addition to that, satellite gravity gradients are now available, which overcome some limitations of the vertical gravity component and geoid. The ongoing GOCE satellite mission measures gravity gradients at a perigee height of 255 km. These new data can provide a global gravity field with increased resolution of 80 km. Furthermore, GOCE provides gravity gradients in addition to the vertical gravity component. We will show that the use of gravity gradients increases the sensitivity to the shape and orientation of large-scale density structures. Especially the horizontal components are helpful to delineate different density domains and can be used to complement seismological imaging. Another beneficial attribute of the satellite gravity gradients is that they are very sensitive to the density structure from 150 km d...

Interpretation of long-offset seismic reflection data and potential field data from the Jurassic-... more Interpretation of long-offset seismic reflection data and potential field data from the Jurassic-Cretaceous rift offshore Mid Norway reveals the structural styles of the magmatic Mid-Norwegian margin The crustal structure of the Mid-Norwegian margin can be well correlated with detachments observed onshore Norway and their probable offshore continuation. These observations underlay the importance of inherited structures from the post-orogenic collapse of the Caledonides as a template for the later occurring extensional events. The integrated analysis shows that thinning of crystalline crust to a thickness of 10 km or less appears to have preceded breakup and associated Eocene magmatism with 50-100 million years. Low- to moderate-angle domain boundary faults that separate platform, terrace and subbasin areas from the deep Møre and Voering basins display geometries consistent with large magnitudes of extension (10-30 km) and denudation of high- density lower crust in dome-shaped culmin...

South African Journal of Geology

Here we present a comprehensive depth and thickness map of the main Karoo and Cape Basins using b... more Here we present a comprehensive depth and thickness map of the main Karoo and Cape Basins using borehole and reflection seismic data. The depth to the Whitehill Formation, which is the focus of current shale gas interest within the Karoo, is also mapped. Change: The deepest part of the basin is in the south, along the northern boundary of the Cape Fold Belt (~4000 m in the southwest Karoo and ~5000 m in the southeast; ~5500 to 6000 m sediment thickness). The Whitehill Formation along this boundary reaches a depth of ~3000 m in the southwest and ~4000 m in the southeast. Limited borehole data in the southeastern Karoo show a broad deepening of the basin here compared to the southwestern Karoo. In the southeast near East London faulting has resulted in deepening of the basin close to the coast, with the Whitehill Formation deepening to over ~5000 km. Seismic and borehole data show that the Cape Supergroup pinches out below the Karoo Basin around Beaufort West and Graaff-Reinet in the ...

GOCE gravity gradient data may improve modeling of the Earth's lithosphere and mantle composi... more GOCE gravity gradient data may improve modeling of the Earth's lithosphere and mantle composition and thereby contribute to a better understanding of the Earth's dynamic processes. We present a case study for the North-East Atlantic margin, where we analyze the use of satellite gravity gradients by comparison with a well-constrained 3D model. The model is based on a wealth of seismic profiles, commercial and scientific borehole data from the shelf and mainland Norway, petrophysical sampling and a dense coverage of gravity and aeromagnetic data. The 3D model provides a detailed picture from the upper mantle to the top basement (base of sediments). The latter horizon is well resolved from gravity and especially magnetic data. Sedimentary layers are constrained from seismic studies, but do in general not show a prominent effect in the gravity and magnetic field. In the North Atlantic, both gravity field and geoid are strongly affected by a regional component, which reflects the...

Topographic correction is commonly conducted with a standard radius of 167 km (~1.5 °) around eac... more Topographic correction is commonly conducted with a standard radius of 167 km (~1.5 °) around each station. It is a long standing question, whether this radius is appropriate in all cases. In areas of rugged topography the standard radius of 167 km can introduce long-wavelength artefacts from neglecting topography beyond this distance. Both very small (tens of km) and very large (up to global correction) radii have been used in past studies. New data derived from satellites missions (e.g. GOCE) - which also provide gravity gradients - introduce additional questions. First, it is unclear if the same radius can be used for observations which are above topography (e.g. 255 km for the GOCE satellite). Second, it is not investigated which radius is appropriate for correction of the full gravity gradient tensor. In our study, we analysed how the choice of correction radius affects gravity and gravity gradients systematically. We also account for isostatic effects and estimate how topograp...

Geophysical data provides an image of the deep sub-subsurface velocity, density or conductivity s... more Geophysical data provides an image of the deep sub-subsurface velocity, density or conductivity structure of mountain belts at the present day. However, that present day structure is the result of the evolution of the mountain belt over a period of time and hence the geophysical image represents the cumulative effects of the development of the mountain belt. The Scandinavian mountain belt has a protracted history. While it is best known from studies of the surface geology for preserving the core of the Scandinavian Caledonides, the crust forming the root of that orogen was involved in earlier Fennoscandian and Sveco-Norwegian mountain building and has subsequently been involved in epeirogenic uplift which has led to the present topographic expression. We present the results of 3 onshore geophysical profiles across the south, central and northern parts of the Scandinavian mountains approximately orthogonal to the strike of the Caledonian orogen. Acquired to look for along strike vari...

We first introduce new technology using a synthetic dipping prism model to support better inversi... more We first introduce new technology using a synthetic dipping prism model to support better inversion modelling method by implementing improvements in the prismatic approximation of surfaces using Cartesian Cut Cell method. Secondly, we demonstrate the use of iterative reweighting inversion to recover a more reasonable model in the absence of a-priori information. These technologies are then applied to Airborne Gravity Gradiometer (A.G.G.) data acquired by the Falcon System within the Karasjok Greenstone Belt, Norway. The A.G.G. density model is used in combination with magnetization vectors to co-model and interpret the greenstone belt in terms of its potential field properties.

Our study area in Northern Norway and Sweden lies at the transition between Archean and Proterozo... more Our study area in Northern Norway and Sweden lies at the transition between Archean and Proterozoic lithosphere and is bounded by the late Palaeoproterozoic Transscandinavian Igneous Belt. This region has been overthrusted by the Palaeozoic nappes of the Caledonian orogen and now forms the passive margin of the NE Atlantic. A prominent gravity and geoid low lies just south of the Lofoten peninsula, partly coinciding with the location of the Proterozoic granites and being slightly offset to the highest topography of northern Norway. We investigate this gravity anomaly performing combined 3D geophysical-petrological forward modelling of the lithosphere and sublithospheric upper mantle using the interactive modelling program LitMod3D. We compare two possible origins of the anomaly: a low-density upper crust, representing the northward extension of the Transscandinavian Igneous Belt and thick, depleted lithospheric mantle of possibly Archean origin. In oceanic domains and in the transit...

The Møre-Trøndelag Fault Complex (MTFC) is one of the most prominent fault complexes in Scandinav... more The Møre-Trøndelag Fault Complex (MTFC) is one of the most prominent fault complexes in Scandinavia and perhaps on Earth. The MTFC appears to have controlled the tectonic evolution of central Norway and its shelf for the past 400 Myr, at least, and has experienced repeated reactivation during Paleozoic (Devonian to Permian), Mesozoic (Jurassic) and Cenozoic times. Despite its pronounced signature in the landscape its deep structure has remained unresolved until now. We acquired multiple geophysical data sets across a segment of the MTFC composed of two main faults (i.e. the Tjellefjorden and Fannefjorden faults). The faults are partly exposed and their respective traces can be seen as prominent topographic escarpments. However their exact locations (i.e. below Quaternary sediments), extents and dips are less clear, and have not been studied systematically by geophysical methods. To detect the fault zones and their structural attributes, a series of magnetic, resistivity, shallow ref...

International Association of Geodesy Symposia, 2014

In order to better constrain the Cenozoic evolution of the Norwegian-Greenland Sea and contiguous... more In order to better constrain the Cenozoic evolution of the Norwegian-Greenland Sea and contiguous margins, a new aeromagnetic data (JAS-05 survey) was acquired in the Eastern part of the Jan Mayen Fracture Zone during autumn 2005. We present preliminary results and ...

Norsk Geologisk Tidsskrift

Analysis of the gravity anomalies associated with the Scandinavian mountain range (ie the Scandes... more Analysis of the gravity anomalies associated with the Scandinavian mountain range (ie the Scandes) suggests that the compensating loads are loca-ted at relatively shallow depths in the crust and/or in the mantle lithosphere. Potential crustal loads leading to positive buoyancy ...

At passive margins, the thinning of continental crust from a thickness of 30-40 to less than 10 k... more At passive margins, the thinning of continental crust from a thickness of 30-40 to less than 10 kilometres commonly results in a zone of taper that borders a wide zone of extremely attenuated continental crust, which, in turn, borders the continent-ocean transition. The taper area is thus a principal boundary that separates the proximal from the distal parts of the margin, and the evolution of this zone determines much of its later history. Along parts of the Mid Norway rifted margin, the taper area is well imaged by long-offset seismic reflection data. The North Atlantic passive margin is a type example of a magmatic margin, with breakup in the Eocene around 54 Ma. Breakup was, however, preceded by several magma-poor extensional phases that in the Mid Norway case include Devonian late/post-Caledonian extension, Permo-Triassic stretching and a phase of extreme Jurassic-Cretaceous crustal thinning. Along the SE borders of the rift, `top basement' detachment faults with heaves in the order of 15-40 kilometres evolved in at least two stages to become the boundaries between moderately thinned (20-30 km thick) crust and 100-200 km wide, highly extended areas with crustal thickness generally between 2 and 12 km. These areas evolved into the deep Møre and Vøring basins. In the footwalls of the basin-flank detachments, rocks from the lower and middle crust were exhumed in extensional domes that, in turn, became incised by a younger set of normal faults. In the Slørebotn Subbasin area, a warped-back detachment fault is overlain by an array of fault-blocks that underwent up to 50o of rotation in the Late Jurassic. This detachment was subsequently incised and deactivated by planar normal faults that incised the extensional culmination on the basin side. Under the most highly thinned areas, a more distal set of deep-seated (basin-floor) detachments incised and extended remnant crust and, probably, the upper mantle, leaving as little as <5 kilometres of continental crust to be preserved under thick syn- and post-rift deposits. We suggest that basin-flank detachments hold the potential to reduce the crustal thickness down to the critical value required for embrittlement. Offshore Mid Norway, this stage may have been reached in the Early Cretaceous. The large-magnitude Jurassic-Early Cretaceous faults show variable relationships to earlier structures and basins. Abrupt truncation of older faults and basins by Jurassic-Cretaceous basin-flank detachments can be observed along the margins of the Trøndelag platform. Gneiss-cored extensional culminations are well known from the onshore Palaeozoic extensional systems, and in the offshore, seismic and potential field data suggest the presence of such structures underneath Palaeozoic-Early Mesozoic basins in the Trøndelag Platform area as well as in the footwalls of Late Jurassic-Early Cretaceous detachment faults. A fundamental control on the margin geometry by late/post-Caledonian structures is indicated by the trends of the large-magnitude fault systems and, locally, by observations related to deep-seated extensional culminations. Variations in displacement magnitude and geometry of the basin-flank detachments controlled variations in the thinning gradient for the crystalline crust (crustal taper). An accumulating body of evidence indicates that this, in turn, controlled not only the location of deep post-rift basins, but also the behaviour of the onshore parts of the margin in the post-rift phase.

... 74-100, Haus N, Berlin, 12249 Germany ), AB(Institut für Geologie, Geophysik und Geoinformati... more ... 74-100, Haus N, Berlin, 12249 Germany ), AB(Institut für Geologie, Geophysik und Geoinformatik, FU Berlin, Malteserstr. ... Pleicherwall 1, Wuerzburg, 97070 Germany ), AH(Natural Resources Authority, PO Box 7, Ammann, 11118 Jordan ), AI(AN-NAJAH NATIONAL UNIVERSITY ...

When studying the structure of the crust and upper mantle, the geoid and gravity field are typica... more When studying the structure of the crust and upper mantle, the geoid and gravity field are typically used and integrated with seismological and electromagnetic studies. In addition to that, satellite gravity gradients are now available, which overcome some limitations of the vertical gravity component and geoid. The ongoing GOCE satellite mission measures gravity gradients at a perigee height of 255 km. These new data can provide a global gravity field with increased resolution of 80 km. Furthermore, GOCE provides gravity gradients in addition to the vertical gravity component. We will show that the use of gravity gradients increases the sensitivity to the shape and orientation of large-scale density structures. Especially the horizontal components are helpful to delineate different density domains and can be used to complement seismological imaging. Another beneficial attribute of the satellite gravity gradients is that they are very sensitive to the density structure from 150 km d...

Interpretation of long-offset seismic reflection data and potential field data from the Jurassic-... more Interpretation of long-offset seismic reflection data and potential field data from the Jurassic-Cretaceous rift offshore Mid Norway reveals the structural styles of the magmatic Mid-Norwegian margin The crustal structure of the Mid-Norwegian margin can be well correlated with detachments observed onshore Norway and their probable offshore continuation. These observations underlay the importance of inherited structures from the post-orogenic collapse of the Caledonides as a template for the later occurring extensional events. The integrated analysis shows that thinning of crystalline crust to a thickness of 10 km or less appears to have preceded breakup and associated Eocene magmatism with 50-100 million years. Low- to moderate-angle domain boundary faults that separate platform, terrace and subbasin areas from the deep Møre and Voering basins display geometries consistent with large magnitudes of extension (10-30 km) and denudation of high- density lower crust in dome-shaped culmin...

South African Journal of Geology

Here we present a comprehensive depth and thickness map of the main Karoo and Cape Basins using b... more Here we present a comprehensive depth and thickness map of the main Karoo and Cape Basins using borehole and reflection seismic data. The depth to the Whitehill Formation, which is the focus of current shale gas interest within the Karoo, is also mapped. Change: The deepest part of the basin is in the south, along the northern boundary of the Cape Fold Belt (~4000 m in the southwest Karoo and ~5000 m in the southeast; ~5500 to 6000 m sediment thickness). The Whitehill Formation along this boundary reaches a depth of ~3000 m in the southwest and ~4000 m in the southeast. Limited borehole data in the southeastern Karoo show a broad deepening of the basin here compared to the southwestern Karoo. In the southeast near East London faulting has resulted in deepening of the basin close to the coast, with the Whitehill Formation deepening to over ~5000 km. Seismic and borehole data show that the Cape Supergroup pinches out below the Karoo Basin around Beaufort West and Graaff-Reinet in the ...

GOCE gravity gradient data may improve modeling of the Earth's lithosphere and mantle composi... more GOCE gravity gradient data may improve modeling of the Earth's lithosphere and mantle composition and thereby contribute to a better understanding of the Earth's dynamic processes. We present a case study for the North-East Atlantic margin, where we analyze the use of satellite gravity gradients by comparison with a well-constrained 3D model. The model is based on a wealth of seismic profiles, commercial and scientific borehole data from the shelf and mainland Norway, petrophysical sampling and a dense coverage of gravity and aeromagnetic data. The 3D model provides a detailed picture from the upper mantle to the top basement (base of sediments). The latter horizon is well resolved from gravity and especially magnetic data. Sedimentary layers are constrained from seismic studies, but do in general not show a prominent effect in the gravity and magnetic field. In the North Atlantic, both gravity field and geoid are strongly affected by a regional component, which reflects the...

Topographic correction is commonly conducted with a standard radius of 167 km (~1.5 °) around eac... more Topographic correction is commonly conducted with a standard radius of 167 km (~1.5 °) around each station. It is a long standing question, whether this radius is appropriate in all cases. In areas of rugged topography the standard radius of 167 km can introduce long-wavelength artefacts from neglecting topography beyond this distance. Both very small (tens of km) and very large (up to global correction) radii have been used in past studies. New data derived from satellites missions (e.g. GOCE) - which also provide gravity gradients - introduce additional questions. First, it is unclear if the same radius can be used for observations which are above topography (e.g. 255 km for the GOCE satellite). Second, it is not investigated which radius is appropriate for correction of the full gravity gradient tensor. In our study, we analysed how the choice of correction radius affects gravity and gravity gradients systematically. We also account for isostatic effects and estimate how topograp...

Geophysical data provides an image of the deep sub-subsurface velocity, density or conductivity s... more Geophysical data provides an image of the deep sub-subsurface velocity, density or conductivity structure of mountain belts at the present day. However, that present day structure is the result of the evolution of the mountain belt over a period of time and hence the geophysical image represents the cumulative effects of the development of the mountain belt. The Scandinavian mountain belt has a protracted history. While it is best known from studies of the surface geology for preserving the core of the Scandinavian Caledonides, the crust forming the root of that orogen was involved in earlier Fennoscandian and Sveco-Norwegian mountain building and has subsequently been involved in epeirogenic uplift which has led to the present topographic expression. We present the results of 3 onshore geophysical profiles across the south, central and northern parts of the Scandinavian mountains approximately orthogonal to the strike of the Caledonian orogen. Acquired to look for along strike vari...

We first introduce new technology using a synthetic dipping prism model to support better inversi... more We first introduce new technology using a synthetic dipping prism model to support better inversion modelling method by implementing improvements in the prismatic approximation of surfaces using Cartesian Cut Cell method. Secondly, we demonstrate the use of iterative reweighting inversion to recover a more reasonable model in the absence of a-priori information. These technologies are then applied to Airborne Gravity Gradiometer (A.G.G.) data acquired by the Falcon System within the Karasjok Greenstone Belt, Norway. The A.G.G. density model is used in combination with magnetization vectors to co-model and interpret the greenstone belt in terms of its potential field properties.

Our study area in Northern Norway and Sweden lies at the transition between Archean and Proterozo... more Our study area in Northern Norway and Sweden lies at the transition between Archean and Proterozoic lithosphere and is bounded by the late Palaeoproterozoic Transscandinavian Igneous Belt. This region has been overthrusted by the Palaeozoic nappes of the Caledonian orogen and now forms the passive margin of the NE Atlantic. A prominent gravity and geoid low lies just south of the Lofoten peninsula, partly coinciding with the location of the Proterozoic granites and being slightly offset to the highest topography of northern Norway. We investigate this gravity anomaly performing combined 3D geophysical-petrological forward modelling of the lithosphere and sublithospheric upper mantle using the interactive modelling program LitMod3D. We compare two possible origins of the anomaly: a low-density upper crust, representing the northward extension of the Transscandinavian Igneous Belt and thick, depleted lithospheric mantle of possibly Archean origin. In oceanic domains and in the transit...

The Møre-Trøndelag Fault Complex (MTFC) is one of the most prominent fault complexes in Scandinav... more The Møre-Trøndelag Fault Complex (MTFC) is one of the most prominent fault complexes in Scandinavia and perhaps on Earth. The MTFC appears to have controlled the tectonic evolution of central Norway and its shelf for the past 400 Myr, at least, and has experienced repeated reactivation during Paleozoic (Devonian to Permian), Mesozoic (Jurassic) and Cenozoic times. Despite its pronounced signature in the landscape its deep structure has remained unresolved until now. We acquired multiple geophysical data sets across a segment of the MTFC composed of two main faults (i.e. the Tjellefjorden and Fannefjorden faults). The faults are partly exposed and their respective traces can be seen as prominent topographic escarpments. However their exact locations (i.e. below Quaternary sediments), extents and dips are less clear, and have not been studied systematically by geophysical methods. To detect the fault zones and their structural attributes, a series of magnetic, resistivity, shallow ref...