Northern Mozambique: Crustal structure across a sheared margin

The rifting of Gondwana started some 180 million years ago. The continental drift created some of the oldest ocean basins along Eastern Africa, the Somali and the Mozambique basins. As a consequence of the relative movements between Africa and Antarctica-India-Madagascar a shear margin developed alo...

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Main Authors: Baetzel, Maren, Franke, Dieter, Heyde, Ingo, Schreckenberger, Bernd, Jokat, Wilfried
Format: Conference Object
Language:unknown
Published: 2015
Subjects:
Online Access:https://epic.awi.de/id/eprint/37136/
https://hdl.handle.net/10013/epic.44942
id ftawi:oai:epic.awi.de:37136
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spelling ftawi:oai:epic.awi.de:37136 2024-09-15T17:46:20+00:00 Northern Mozambique: Crustal structure across a sheared margin Baetzel, Maren Franke, Dieter Heyde, Ingo Schreckenberger, Bernd Jokat, Wilfried 2015-04 https://epic.awi.de/id/eprint/37136/ https://hdl.handle.net/10013/epic.44942 unknown Baetzel, M. , Franke, D. , Heyde, I. , Schreckenberger, B. and Jokat, W. orcid:0000-0002-7793-5854 (2015) Northern Mozambique: Crustal structure across a sheared margin , European Geosciences Union General Assembly 2015, Vienna, Austria, 12 April 2015 - 17 April 2015 . hdl:10013/epic.44942 EPIC3European Geosciences Union General Assembly 2015, Vienna, Austria, 2015-04-12-2015-04-17Vienna, Austria Conference notRev 2015 ftawi 2024-06-24T04:11:05Z The rifting of Gondwana started some 180 million years ago. The continental drift created some of the oldest ocean basins along Eastern Africa, the Somali and the Mozambique basins. As a consequence of the relative movements between Africa and Antarctica-India-Madagascar a shear margin developed along the present day coastline of northern Mozambique and Tanzania. In addition, the N-S oriented offshore Davie Ridge is believed to have formed during the shear movements between both parts of Gondwana. However, if the Davie Ridge is of continental origin or has been formed by magmatic processes during the continental drift is unknown, since any crustal information is missing so far. Previous studies in this area are rare and only few seismic reflection data sets from the 1970s and 1980s are available. In 2014 four seismic refraction data along east-west-orientated profiles as well as gravity and magnetic field data across the Davie Ridge with RV Sonne were collected to determine its crustal composition as well as the position of the continent-ocean-transition. Here, we present a first P-wave velocity model across the Mozambican sheared margin at 13º S. The profile is situated in a region, where the ridge topography vanishes. In total, 20 OBS/OBH systems were used on profile 20140130 over the Davie Ridge. Most of the instruments recorded data with a very good quality. In the best records, P-wave phases can be observed at a source-receiver offset of 130 km. The total thickness of the sediments is about 5 km in the Comores Basin and about 3 km offshore Mozambique. The sediments show at 3.5 and 5 km depth unusual high seismic velocities of 4.0-4.6 km/s. Our results indicate a shallow Moho close to the shelf break. Here, the crust thins to 4 km. This area is assumed to be the western part of the Davie-Ridge and might represent a sharp transition (50 km) from continental to oceanic crust, which is typical for a sheared margin. East of the Davie Ridge the data indicate a crustal thickness of 6 km, which is most likely of ... Conference Object Antarc* Antarctica Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center)
institution Open Polar
collection Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center)
op_collection_id ftawi
language unknown
description The rifting of Gondwana started some 180 million years ago. The continental drift created some of the oldest ocean basins along Eastern Africa, the Somali and the Mozambique basins. As a consequence of the relative movements between Africa and Antarctica-India-Madagascar a shear margin developed along the present day coastline of northern Mozambique and Tanzania. In addition, the N-S oriented offshore Davie Ridge is believed to have formed during the shear movements between both parts of Gondwana. However, if the Davie Ridge is of continental origin or has been formed by magmatic processes during the continental drift is unknown, since any crustal information is missing so far. Previous studies in this area are rare and only few seismic reflection data sets from the 1970s and 1980s are available. In 2014 four seismic refraction data along east-west-orientated profiles as well as gravity and magnetic field data across the Davie Ridge with RV Sonne were collected to determine its crustal composition as well as the position of the continent-ocean-transition. Here, we present a first P-wave velocity model across the Mozambican sheared margin at 13º S. The profile is situated in a region, where the ridge topography vanishes. In total, 20 OBS/OBH systems were used on profile 20140130 over the Davie Ridge. Most of the instruments recorded data with a very good quality. In the best records, P-wave phases can be observed at a source-receiver offset of 130 km. The total thickness of the sediments is about 5 km in the Comores Basin and about 3 km offshore Mozambique. The sediments show at 3.5 and 5 km depth unusual high seismic velocities of 4.0-4.6 km/s. Our results indicate a shallow Moho close to the shelf break. Here, the crust thins to 4 km. This area is assumed to be the western part of the Davie-Ridge and might represent a sharp transition (50 km) from continental to oceanic crust, which is typical for a sheared margin. East of the Davie Ridge the data indicate a crustal thickness of 6 km, which is most likely of ...
format Conference Object
author Baetzel, Maren
Franke, Dieter
Heyde, Ingo
Schreckenberger, Bernd
Jokat, Wilfried
spellingShingle Baetzel, Maren
Franke, Dieter
Heyde, Ingo
Schreckenberger, Bernd
Jokat, Wilfried
Northern Mozambique: Crustal structure across a sheared margin
author_facet Baetzel, Maren
Franke, Dieter
Heyde, Ingo
Schreckenberger, Bernd
Jokat, Wilfried
author_sort Baetzel, Maren
title Northern Mozambique: Crustal structure across a sheared margin
title_short Northern Mozambique: Crustal structure across a sheared margin
title_full Northern Mozambique: Crustal structure across a sheared margin
title_fullStr Northern Mozambique: Crustal structure across a sheared margin
title_full_unstemmed Northern Mozambique: Crustal structure across a sheared margin
title_sort northern mozambique: crustal structure across a sheared margin
publishDate 2015
url https://epic.awi.de/id/eprint/37136/
https://hdl.handle.net/10013/epic.44942
genre Antarc*
Antarctica
genre_facet Antarc*
Antarctica
op_source EPIC3European Geosciences Union General Assembly 2015, Vienna, Austria, 2015-04-12-2015-04-17Vienna, Austria
op_relation Baetzel, M. , Franke, D. , Heyde, I. , Schreckenberger, B. and Jokat, W. orcid:0000-0002-7793-5854 (2015) Northern Mozambique: Crustal structure across a sheared margin , European Geosciences Union General Assembly 2015, Vienna, Austria, 12 April 2015 - 17 April 2015 . hdl:10013/epic.44942
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