DOI: 10.1016/j.tecto.2020.228370
论文题名: The crustal structure of the southern Davie Ridge offshore northern Mozambique – A wide-angle seismic and potential field study
作者: Vormann M. ; Franke D. ; Jokat W.
刊名: Tectonophysics
ISSN: 00401951
出版年: 2020
卷: 778 语种: 英语
中文关键词: COT
; Davie Fracture Zone
; Davie Ridge
; Mozambique Channel
; Seismic refraction
; Somali Basin
英文关键词: Offshore oil well production
; Refraction
; Structural geology
; Topography
; Davie Ridge
; Fracture zone
; Mozambique channels
; Seismic refraction
; Somali Basin
; Seismology
; basin evolution
; continental crust
; crustal evolution
; crustal structure
; Gondwana
; potential field
; seismic refraction
; seismic source
; shear zone
; structural geology
; Indian Ocean
; Mozambique
; Somali Basin
英文摘要: Some of the oldest surviving oceanic basins in the world, the Mozambique and West Somali basins, were created during the breakup of Gondwana, starting around 180 Ma. Between the two basins, relative movements of West Gondwana and East Gondwana, including Madagascar, created a shear zone, the Davie Fracture Zone (DFZ) with a topographic elevation (Davie Ridge - DR) marking its centre. The crustal composition of the DFZ and DR is a subject of speculation and debate. In this study, we present seismic refraction data across the prominent topography of the southern DR. Ray tracing of the wide-angle data as well as additional seismic amplitude modelling and 2.5D density modelling constrain its crustal structure and architecture. The data indicate that in the Mozambique Channel the DR consists of fragments of continental crust with a thickness of 10 to 12 km. An oceanic crust indenter extends northward from the Mozambique Basin into the area between the DR and the East African margin at 16.5°S. Northeast of the DR, at 41.8°W/14.5°S, the Somali Basin is probably floored by 6 km thick oceanic crust. Hence, the continental DR separates oceanic crust of the Somali and Mozambique basins. The transitional crustal area at the central Mozambican margin is underlain by high velocity lower crust (HVLC). The HVLC has velocities up to 7.3 km/s and extents along the margin, vanishing northward between 16.5° and 14.5°S. At the Madagascan side of the DR, at 16.5°S, the highly intruded stretched continental crust is 9 km thick and possibly underlain with a smaller HVLC of 2.9 km thickness and an E-W extent of 120 km. The oceanic crust at 14.5°S represents the oldest part the Somali Basin, which formed after the initial NW-SE rifting between East and West Gondwana. © 2020 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/170725
Appears in Collections: 气候变化与战略
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作者单位: Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, Bremerhaven, 27570, Germany; Federal Institute for Geosciences and Natural Resources, Geozentrum Hannover, Stilleweg 2, Hanover, 30655, Germany; University of Bremen, Department of Geosciences, Klagenfurter Strasse 4, Bremen, 28359, Germany
Recommended Citation:
Vormann M.,Franke D.,Jokat W.. The crustal structure of the southern Davie Ridge offshore northern Mozambique – A wide-angle seismic and potential field study[J]. Tectonophysics,2020-01-01,778