气候变化领域集成服务门户(CCPortal): Mechanical anisotropies and mechanisms of mafic magma ascent in the middle continental crust: The Sondalo magmatic system (N Italy)

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DOI	10.1130/B31693.1
	Mechanical anisotropies and mechanisms of mafic magma ascent in the middle continental crust: The Sondalo magmatic system (N Italy)
	Petri B.; Skrzypek E.; Mohn G.; Mateeva T.; Robion P.; Schulmann K.; Manatschal G.; Müntener O.
发表日期	2018
ISSN	167606
起始页码	331
结束页码	352
卷号	130 期号:2021-01-02
英文摘要	Magma transfer between lower and upper continental crust is a fundamental process linking the dominantly mafic composition of the lower crust with the more felsic composition of the upper crust. We explored the mechanisms of mafic magma ascent and emplacement in the middle crust by studying a midcrustal gabbroic to dioritic magmatic system (Sondalo complex, eastern central Alps, northern Italy). We characterized the structure and anisotropy of magnetic susceptibility (AMS) fabric of concentric gabbroic to dioritic intrusions. The significance of AMS fabrics is discussed using anisotropy of anhysteretic remanent magnetization (AARM) and crystallographic preferred orientation (CPO) data acquired on different test sites. The magmatic and magnetic fabrics of the pluton were acquired during its emplacement in the Permian and were not subsequently tilted: The fabrics are essentially vertical, indicating vertical magma transfer through the crust with a two-phase intrusion history. (1) The concordant orientation between the magmatic foliation and the host-rock xenoliths in the center of the pluton suggests that the first magma ascent phase occurred along pathways subparallel to the vertical fabric of the host metasedi- mentary rocks. (2) The second magma ascent phase was controlled by a change in the rheology of the host rock and the mafic magma. Heat dissipation to the contact aureole induced partial melting, thereby lowering the mechanical strength of the host rocks, whereas the viscosity of the mafic magma increased due to cooling and associated fractional crystallization. This caused an en-masse rise of the pluton, resulting in the formation of a structural aureole, i.e., a vertical foliation in the contact aureole and a weaker but concordant magmatic foliation at the rim of the pluton. This ascent phase accounts for the pressure-temperature evolution recorded by metasedimentary rocks in the contact aureole of the pluton. © 2017 Geological Society of America.
语种	英语
来源期刊	Bulletin of the Geological Society of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/185106
作者单位	Ecole et Observatoire des Sciences de la Terre, Institut de Physique du Globe de Strasbourg-CNRS UMR7516, Université de Strasbourg, 1 rue Blessig, Strasbourg Cedex, F-67084, France; Institut des Sciences de la Terre, Université de Lausanne, Lausanne, 1015, Switzerland; Department of Geology and Mineralogy, Graduate School of Science, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan; Département Géosciences et Environnement, Université de Cergy-Pontoise 5, mail Gay Lussac, Neuville-sur-Oise, Cergy-Pontoise Cedex, 95031, France; Department of Earth and Ocean Sciences, University of Liverpool, Liverpool, L69 3BX, United Kingdom; Center for Lithospheric Research, Czech Geological Survey, Praha 1, 11821, Czech Republic
推荐引用方式 GB/T 7714	Petri B.,Skrzypek E.,Mohn G.,et al. Mechanical anisotropies and mechanisms of mafic magma ascent in the middle continental crust: The Sondalo magmatic system (N Italy)[J],2018,130(2021-01-02).
APA	Petri B..,Skrzypek E..,Mohn G..,Mateeva T..,Robion P..,...&Müntener O..(2018).Mechanical anisotropies and mechanisms of mafic magma ascent in the middle continental crust: The Sondalo magmatic system (N Italy).Bulletin of the Geological Society of America,130(2021-01-02).
MLA	Petri B.,et al."Mechanical anisotropies and mechanisms of mafic magma ascent in the middle continental crust: The Sondalo magmatic system (N Italy)".Bulletin of the Geological Society of America 130.2021-01-02(2018).