 |
 |
Dear all, Does crustal anatexis mainly occur in extensional settings? In the current Earth, large-scale anatexis appears to be occurring in the Tibetan crust, and also at the base of magmatic arcs. Martin Hand Department of Earth Sciences University of Adelaide Phone : +61 (0)8 831 36794 Phone : +61 (0)8 831 35324 Mobile: +61 (0)419 314 306 http://www.adelaide.edu.au/geothermal/ http://www.adelaide.edu.au/directory/martin.hand CRICOS Provider Number 00123M ----------------------------------------------------------- IMPORTANT: This message may contain confidential or legally privileged information. If you think it was sent to you by mistake, please delete all copies and advise the sender. For the purposes of the SPAM Act 2003, this email is authorised by The University [RAMONES] From: Metamorphic Studies Group <[log in to unmask]> On Behalf Of Yong-Fei?Zheng Sent: Friday, 22 June 2018 5:07 PM To: [log in to unmask] Subject: Re: [geo-metamorphism] Crustal anatexis Dear Mallickarjun, At supersolidus temperatures, crustal rocks undergo partial melting to produce a sizable volume of anatectic melts. This process is common during high-grade metamorphism at amphibolite- to granulite-facies conditions. Migmatites are its typical products in which anatectic melts were not escaped from the anatectic systems. Such a kind of crustal anatexis mainly occurs in extensional settings such as backarc and continental rifts, where the lithosphere is significantly thinned to cause upwelling of the asthenospheric mantle, transferring high heat flow into the lower crust for metamorphic dehydration and partial melting at crustal depths. While dehydrated and melt-extracted residues show HT to UHT granulitization, releassed fluids (aqueous solutions) result in amphibolitization of the overlying crustal rocks and escaped melts (hydrous, felsic) give rise to granitic intrusives in different sizes. Yong-Fei -- *********************************************************************** Dr. Yong-Fei Zheng Professor of Geochemistry School of Earth and Space Sciences University of Science and Technology of China Hefei 230026, China Tel & Fax: +86 551 63603554 Email: [log in to unmask]<mailto:[log in to unmask]> ********************************************************************** -----原始邮件----- 发件人:"Mallickarjun Joshi" <[log in to unmask]<mailto:[log in to unmask]>> 发送时间:2018-06-21 22:06:08 (星期四) 收件人: [log in to unmask]<mailto:[log in to unmask]> 抄送: 主题: Dear All, I wonder under what conditions a sizable volume of the anatectic melt formed as a consequence of high grade metamorphism in pelites would not be able to escape the system? Admittedly, metamorphism outlasting the deformation should be a likely precondition. Moreover, should it also shed some light on the tectonic set up other than that it is likely to have formed during the penultimate stages of the orogeny. I would much appreciate your opinion and any suggestions for references to understand the problem. Thanks and regards Mallickarjun Joshi Centre of Advanced Study in Geology Banaras Hindu University India ________________________________ To unsubscribe from the GEO-METAMORPHISM list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=GEO-METAMORPHISM&A=1 ________________________________ To unsubscribe from the GEO-METAMORPHISM list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=GEO-METAMORPHISM&A=1 ######################################################################## To unsubscribe from the GEO-METAMORPHISM list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=GEO-METAMORPHISM&A=1