气候变化领域集成服务门户(CCPortal): Wide-Angle Seismic Imaging of Two Modes of Crustal Accretion in Mature Atlantic Ocean Crust

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DOI	10.1029/2019JB019100
	Wide-Angle Seismic Imaging of Two Modes of Crustal Accretion in Mature Atlantic Ocean Crust
	Davy R.G.; Collier J.S.; Henstock T.J.; Rietbrock A.; Goes S.; Blundy J.; Harmon N.; Rychert C.; Macpherson C.G.; Van Hunen J.; Kendall M.; Wilkinson J.; Davidson J.; Wilson M.; Cooper G.; Maunder B.; Bie L.; Hicks S.; Allen R.; Chichester B.; Tait S.; Robertson R.; Latchman J.; Krüger F.; Collier J.; Henstock T.; Allen R.; Butcher S.; Castiello G.; Chen C.; Harkin C.; Posse D.; Roche B.; Bird A.; Clegg A.; Pitcairn B.; Weeks M.; Kirk H.; Labahn E.
发表日期	2020
ISSN	21699313
卷号	125 期号:6
英文摘要	We present a high-resolution 2-D P-wave velocity model from a 225-km-long active seismic profile, collected over ~60–75 Ma central Atlantic crust. The profile crosses five ridge segments separated by a transform and three nontransform offsets. All ridge discontinuities share similar primary characteristics, independent of the offset. We identify two types of crustal segment. The first displays a classic two-layer velocity structure with a high gradient Layer 2 (~0.9 s−1) above a lower gradient Layer 3 (0.2 s−1). Here, PmP coincides with the 7.5 km s−1 contour, and velocity increases to >7.8 km s−1 within 1 km below. We interpret these segments as magmatically robust, with PmP representing a petrological boundary between crust and mantle. The second has a reduced contrast in velocity gradient between the upper and lower crust and PmP shallower than the 7.5 km s−1 contour. We interpret these segments as tectonically dominated, with PmP representing a serpentinized (alteration) front. While velocity-depth profiles fit within previous envelopes for slow-spreading crust, our results suggest that such generalizations give a misleading impression of uniformity. We estimate that the two crustal styles are present in equal proportions on the floor of the Atlantic. Within two tectonically dominated segments, we make the first wide-angle seismic identifications of buried oceanic core complexes in mature (>20 Ma) Atlantic Ocean crust. They have a ~20-km-wide “domal” morphology with shallow basement and increased upper crustal velocities. We interpret their midcrustal seismic velocity inversions as alteration and rock-type assemblage contrasts across crustal-scale detachment faults. ©2020. The Authors.
英文关键词	active-source seismic; fracture zone; nontransform offset; oceanic core complexes; slow-spread oceanic crust; tomography
语种	英语
来源期刊	Journal of Geophysical Research: Solid Earth
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/187831
作者单位	Department of Earth Sciences and Engineering, Imperial College London, London, United Kingdom; Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton, Southampton, United Kingdom; Geophysical Institute, Karlsruhe Institute of Technology, Karlsruhe, 76131, Germany; Department of Earth Ocean & Ecological Sciences, University of Liverpool, Liverpool, L69 3GP, United Kingdom; Department of Earth Sciences and Engineering, Imperial College London, London, SW7 2AZ, United Kingdom; School of Earth Sciences, University of Bristol, Bristol, BS8 1RJ, United Kingdom; Ocean and Earth Science, National Oceanography Centre Southampton, Southampton, SO14 3ZH, United Kingdom; Department of Earth Sciences, Durham University, Durham, DH1 3LE, United Kingdom; Department of Earth Sciences, University of Oxford, South Parks Road, Oxford, OX1 3AN, United Kingdom; Department of Earth Sciences, Natural History Museum, London, SW7 5BD, United Kingdom; School of Earth and Environment, Universit...
推荐引用方式 GB/T 7714	Davy R.G.,Collier J.S.,Henstock T.J.,et al. Wide-Angle Seismic Imaging of Two Modes of Crustal Accretion in Mature Atlantic Ocean Crust[J],2020,125(6).
APA	Davy R.G..,Collier J.S..,Henstock T.J..,Rietbrock A..,Goes S..,...&Labahn E..(2020).Wide-Angle Seismic Imaging of Two Modes of Crustal Accretion in Mature Atlantic Ocean Crust.Journal of Geophysical Research: Solid Earth,125(6).
MLA	Davy R.G.,et al."Wide-Angle Seismic Imaging of Two Modes of Crustal Accretion in Mature Atlantic Ocean Crust".Journal of Geophysical Research: Solid Earth 125.6(2020).