{"id":13459,"date":"2017-08-10T21:53:07","date_gmt":"2017-08-10T19:53:07","guid":{"rendered":"http:\/\/karmaka.de\/?p=13459"},"modified":"2017-08-10T21:54:37","modified_gmt":"2017-08-10T19:54:37","slug":"long-lived-magnetism-on-chondrite-parent-bodies","status":"publish","type":"post","link":"https:\/\/karmaka.de\/?p=13459","title":{"rendered":"Long-lived magnetism on chondrite parent bodies<span class=\"badge-status\" style=\"background:#787878\">OPEN ACCESS<\/span>&nbsp;"},"content":{"rendered":"<p>Jay Shah, Helena C. Bates, Adrian R. Muxworthy, Dominik C. Hezel, Sara S. Russell, Matthew J. Genge<\/p>\n<p>Earth and Planetary Science Letters<br \/>\nVolume 475, 1 October 2017, Pages 106\u2013118<br \/>\n10. August 2017<\/p>\n<p><a href=\"http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0012821X17304193\" target=\"_blank\">LINK (OPEN ACCESS)<\/a><\/p>\n<p>&#8220;Highlights<br \/>\n\u2022    Sub-millimeter-scale method for the paleomagnetic conglomerate test using micro-CT.<br \/>\n\u2022    Bjurb\u00f6le chondrules&#8217; magnetization suggest L\/LL dynamo \u223c80\u2013140 Ma after accretion.<br \/>\n\u2022    Vigarano chondrules&#8217; magnetization suggest CV dynamo \u223c9 Ma after accretion.<br \/>\n\u2022    Chondrite parent bodies likely had a differentiated interior with primitive crust.<\/p>\n<p>&#8220;We present evidence for both early- and late-stage magnetic activity on the CV and L\/LL parent bodies respectively from chondrules in Vigarano and Bjurb\u00f6le. Using micro-CT scans to re-orientate chondrules to their in-situ positions, we present a new micron-scale protocol for the paleomagnetic conglomerate test. The paleomagnetic conglomerate test determines at 95% confidence, whether clasts within a conglomerate were magnetized before or after agglomeration, i.e., for a chondritic meteorite whether the chondrules carry a pre- or post-accretionary remanent magnetization. We found both meteorites passed the conglomerate test, i.e., the chondrules had randomly orientated magnetizations. Vigarano&#8217;s heterogeneous magnetization is likely of shock origin, due to the 10 to 20 GPa impacts that brecciated its precursor material on the parent body and transported it to re-accrete as the Vigarano breccia. The magnetization was likely acquired during the break-up of the original body, indicating a CV parent body dynamo was active \u223c9 Ma after Solar System formation. Bjurb\u00f6le&#8217;s magnetization is due to tetrataenite, which transformed from taenite as the parent body cooled to below 320\u2009\u00b0C, when an ambient magnetic field imparted a remanence. We argue either the high intrinsic anisotropy of tetrataenite or brecciation on the parent body manifests as a randomly orientated distribution, and a L\/LL parent body dynamo must have been active at least 80 to 140 Ma after peak metamorphism. Primitive chondrites did not originate from entirely primitive, never molten and\/or differentiated parent bodies. Primitive chondrite parent bodies consisted of a differentiated interior sustaining a long-lived magnetic dynamo, encrusted by a layer of incrementally accreted primitive meteoritic material. The different ages of carbonaceous and ordinary chondrite parent bodies might indicate a general difference between carbonaceous and ordinary chondrite parent bodies, and\/or formation location in the protoplanetary disk.&#8221;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Jay Shah, Helena C. Bates, Adrian R. Muxworthy, Dominik C. Hezel, Sara S. Russell, Matthew J. Genge Earth and Planetary Science Letters Volume 475, 1 October 2017, Pages 106\u2013118 10. August 2017 LINK (OPEN ACCESS)&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[23,7,219,137,337],"tags":[1622,2491,4145,482],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/13459"}],"collection":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=13459"}],"version-history":[{"count":3,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/13459\/revisions"}],"predecessor-version":[{"id":13462,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/13459\/revisions\/13462"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=13459"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=13459"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=13459"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}