{"id":28004,"date":"2021-06-08T15:32:41","date_gmt":"2021-06-08T13:32:41","guid":{"rendered":"https:\/\/karmaka.de\/?p=28004"},"modified":"2021-06-08T15:37:01","modified_gmt":"2021-06-08T13:37:01","slug":"asteroid-break-ups-and-meteorite-delivery-to-earth-the-past-500-million-years","status":"publish","type":"post","link":"https:\/\/karmaka.de\/?p=28004","title":{"rendered":"Asteroid break-ups and meteorite delivery to Earth the past 500 million years<span class=\"badge-status\" style=\"background:#787878\">OPEN ACCESS<\/span>&nbsp;"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">Fredrik Terfelt and Birger Schmitz<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">PNAS June 15, 2021 118 (24)<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/www.pnas.org\/content\/118\/24\/e2020977118\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>LINK (OPEN ACCESS)<\/strong><\/a><br><a href=\"https:\/\/www.pnas.org\/content\/pnas\/118\/24\/e2020977118.full.pdf\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>PDF (OPEN ACCESS)<\/strong><\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><a rel=\"noreferrer noopener\" href=\"https:\/\/www.pnas.org\/content\/pnas\/suppl\/2021\/06\/04\/2020977118.DCSupplemental\/pnas.2020977118.sapp.pdf\" target=\"_blank\"><strong>Supplementary Information<\/strong><\/a><\/p>\n\n\n\n<p class=\"justify-text wp-block-paragraph\">&#8220;The meteoritic material falling on Earth is believed to derive from large break-up or cratering events in the asteroid belt. The flux of extraterrestrial material would then vary in accordance with the timing of such asteroid family-forming events. In order to validate this, we investigated marine sediments representing 15 time-windows in the Phanerozoic for content of micrometeoritic relict chrome-spinel grains (&gt;32 \u03bcm). We compare these data with the timing of the 15 largest break-up events involving chrome-spinel\u2013bearing asteroids (S- and V-types). Unexpectedly, our Phanerozoic time windows show a stable flux dominated by ordinary chondrites similar to today\u2019s flux. Only in the mid-Ordovician, in connection with the break-up of the L-chondrite parent body, do we observe an anomalous micrometeorite regime with a two to three orders-of-magnitude increase in the flux of L-chondritic chrome-spinel grains to Earth. This corresponds to a one order-of-magnitude excess in the number of impact craters in the mid-Ordovician following the L-chondrite break-up, the only resolvable peak in Phanerozoic cratering rates indicative of an asteroid shower. We argue that meteorites and small (&lt;1-km-sized) asteroids impacting Earth mainly sample a very small region of orbital space in the asteroid belt. This selectiveness has been remarkably stable over the past 500 Ma.&#8221;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Fredrik Terfelt and Birger Schmitz PNAS June 15, 2021 118 (24) LINK (OPEN ACCESS)PDF (OPEN ACCESS) Supplementary Information &#8220;The meteoritic material falling on Earth is believed to derive from large break-up or cratering events in&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[77,23,8,3157,7,3035,3256],"tags":[945,1998,1403,3188,490,3548,5504,4634,327,2371,1807,1673,498],"class_list":["post-28004","post","type-post","status-publish","format-standard","hentry","category-asteroid","category-l","category-meteorite","category-micrometeorites","category-chondrite","category-s-type","category-v-type","tag-asteroid-belt","tag-asteroid-disruption","tag-asteroid-family","tag-l-chondrite","tag-l-chondrite-parent-body-lcpb-breakup","tag-meteorite-flux","tag-meteorite-record","tag-micrometeorite-flux","tag-micrometeorites","tag-mid-ordovician","tag-chondrite","tag-s-type-asteroid","tag-v-type-asteroid"],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/28004","targetHints":{"allow":["GET"]}}],"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=28004"}],"version-history":[{"count":2,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/28004\/revisions"}],"predecessor-version":[{"id":28006,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/28004\/revisions\/28006"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=28004"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=28004"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=28004"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}