LINK<\/strong><\/a><\/p>\n“Highlights
\n\u2022 NWA 7325 is an ungrouped achondrite from a differentiated planetesimal.
\n\u2022 The meteorite contains no detectable stable natural remanent magnetization.
\n\u2022 Dynamo, nebular, and solar wind fields at NWA 7325 were <\u223c1.7 \u03bcT at an estimated age of \u223c4563.09\u00b10.26\u223c4563.09\u00b10.26 Ma.\n\u2022 NWA 7325 serves as a control for studies of magnetized meteorites.\n\u2022 Early planetesimal dynamos were apparently common but not ubiquitous.\"\n\n\"Paleomagnetic studies of meteorites have shown that the solar nebula was likely magnetized and that many early planetary bodies generated dynamo magnetic fields in their advecting metallic cores. The surface fields on these bodies were recorded by a diversity of chondrites and achondrites, ranging in intensity from several \u03bcT to several hundred \u03bcT. In fact, an achondrite parent body without evidence for paleomagnetic fields has yet to be confidently identified, hinting that early solar system field generation and the dynamo process in particular may have been common. Here we present paleomagnetic measurements of the ungrouped achondrite NWA 7325 indicating that it last cooled in a near-zero field (<\u223c1.7 \u03bcT), estimated to have occurred at 4563.09\u00b10.264563.09\u00b10.26 million years ago (Ma) from Al\u2013Mg chronometry. Because NWA 7325 is highly depleted in siderophile elements, its parent body nevertheless underwent large-scale metal-silicate differentiation and likely formed a metallic core. This makes NWA 7325 the first recognized example of an essentially unmagnetized igneous rock from a differentiated early solar system body. These results indicate that all magnetic fields, including those from any core dynamo on the NWA 7325 parent body, the solar nebula, young Sun, and solar wind, were <1.7 \u03bcT at the location of NWA 7325 at 4563 Ma. This supports a recent conclusion that the solar nebula had dissipated by \u223c4 million years after solar system formation. NWA 7325 also serves as an experimental control that gives greater confidence in the positive identification of remanent magnetization in other achondrites.\"\n\n<\/p>\n","protected":false},"excerpt":{"rendered":"
Benjamin P. Weiss, Huapei Wang, Thomas G. Sharp, J\u00e9r\u00f4me Gattacceca, David L. Shuster, Brynna Downey, Jinping Hu, Roger R. Fu, Aaron T. Kuan, Cl\u00e9ment Suavet, Anthony J. Irving, Jun Wang, Jiajun Wang Earth and Planetary…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[139,219,137,507],"tags":[3514,1861,2285],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/12406"}],"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=12406"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/12406\/revisions"}],"predecessor-version":[{"id":12407,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/12406\/revisions\/12407"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=12406"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=12406"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=12406"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}