气候变化领域集成服务门户(CCPortal): Sub-axial deformation in oceanic lower crust: Insights from seismic reflection profiles in the Enderby Basin and comparison with the Oman ophiolite

CCPortal

DOI	10.1016/j.epsl.2020.116698
	Sub-axial deformation in oceanic lower crust: Insights from seismic reflection profiles in the Enderby Basin and comparison with the Oman ophiolite
	Sauter D.; Werner P.; Ceuleneer G.; Manatschal G.; Rospabé M.; Tugend J.; Gillard M.; Autin J.; Ulrich M.
发表日期	2021
ISSN	0012821X
卷号	554
英文摘要	We analyzed high-quality seismic reflection profiles across the ocean-continent transition in the Enderby Basin between the Kerguelen Plateau and the Antarctic margin. There, we observe numerous high-amplitude dipping reflections in the lower oceanic crust which was accreted at a magmatic spreading center as testified by the almost uniform 6.4-7 km thick crust and its unfaulted, flat top basement. The deep reflections are rooting onto the Moho and are dipping both ridgeward and continentward. They occur in dense networks in mature oceanic crust as well as close to the continentward termination of oceanic crust and in the ocean-continent transition zone. The comparison with field observations in the Oman ophiolite suggests that these lower crustal dipping reflectors could correspond to syn-magmatic faults. In Oman, very high temperature (up to syn-magmatic), high temperature (sub-solidus plastic deformation) and low temperature (brittle) deformation coexist along the same fault over distances of a few hundred meters at Moho level. This very high temperature gradient may be explained by the sudden and intense interaction between crystallizing magmas and hydrothermal fluids induced by the episodic nucleation of faults in a context of continuous magmatic spreading. The igneous layering becomes extremely irregular compared to its monotonous sub-horizontal orientation away from the faults which, together with enhanced hydrothermal alteration restricted to the fault zones, might change the physical properties (velocity, density) and increase the reflectivity of syn-magmatic faults. We further speculate that these processes could explain the brightness of the lower crustal dipping reflectors observed in our seismic reflection data. Both the seismic reflection profiles of the Enderby Basin and the Oman ophiolite show evidence for syn-accretion tectonism at depth together with the systematic rotation of originally horizontal lava flows or originally vertical dikes, pre-dating cessation of magmatic activity. This indicates ubiquitous deformation processes within the axial zone of magmatic spreading centers. © 2020 Elsevier B.V.
关键词	dipping reflectors Enderby Basin lower oceanic crust ocean-continent transition oceanic accretionary processes Oman ophiolite
英文关键词	Clay alteration; Reflection; Seismic waves; Temperature; Crystallizing magma; Deformation process; Field observations; High temperature gradient; Hydrothermal alterations; Hydrothermal fluids; Seismic reflection data; Seismic reflection profiles; Seismology; accretionary prism; comparative study; deformation; deformation mechanism; hydrothermal alteration; low temperature; lower crust; magmatism; ocean-continent transition; oceanic crust; ophiolite; plastic deformation; plate tectonics; seismic reflection; spreading center; tectonic setting; transition zone; Enderby Basin; Indian Ocean; Kerguelen Plateau
语种	英语
来源期刊	Earth and Planetary Science Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/203284
作者单位	Institut de Physique du Globe de Strasbourg (IPGS), UMR7516 CNRS, Université de Strasbourg, 1 rue Blessig, Strasbourg Cedex, 67084, France; Géosciences Environnement Toulouse (GET), Observatoire Midi Pyrénées, Université de Toulouse, CNRS, IRD, 14 avenue E. Belin, Toulouse, 31400, France; Research Institute for Marine Geodynamics (IMG), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima, Yokosuka, Kanagawa, 237-0061, Japan; Institut des Sciences de la Terre Paris (ISTeP), UMR 7193, Sorbonne Université, CNRS, 4 Place Jussieu, Paris, 75005, France
推荐引用方式 GB/T 7714	Sauter D.,Werner P.,Ceuleneer G.,et al. Sub-axial deformation in oceanic lower crust: Insights from seismic reflection profiles in the Enderby Basin and comparison with the Oman ophiolite[J],2021,554.
APA	Sauter D..,Werner P..,Ceuleneer G..,Manatschal G..,Rospabé M..,...&Ulrich M..(2021).Sub-axial deformation in oceanic lower crust: Insights from seismic reflection profiles in the Enderby Basin and comparison with the Oman ophiolite.Earth and Planetary Science Letters,554.
MLA	Sauter D.,et al."Sub-axial deformation in oceanic lower crust: Insights from seismic reflection profiles in the Enderby Basin and comparison with the Oman ophiolite".Earth and Planetary Science Letters 554(2021).