{"id":4032,"date":"2021-04-16T09:28:16","date_gmt":"2021-04-16T08:28:16","guid":{"rendered":"https:\/\/research.kent.ac.uk\/astrophysics-and-planetary-science\/?p=4032"},"modified":"2021-07-28T00:21:42","modified_gmt":"2021-07-27T23:21:42","slug":"a-large-meteoritic-event-over-antarctica-ca-430-ka-ago-inferred-from-chondritic-spherules-from-the-sor-rondane-mountains-dr-van-ginneken","status":"publish","type":"post","link":"https:\/\/research.kent.ac.uk\/astrophysics-and-planetary-science\/2021\/04\/16\/a-large-meteoritic-event-over-antarctica-ca-430-ka-ago-inferred-from-chondritic-spherules-from-the-sor-rondane-mountains-dr-van-ginneken\/","title":{"rendered":"A large meteoritic event over Antarctica ca. 430 ka ago inferred from chondritic spherules from the S\u00f8r Rondane Mountains (Dr Matthias van Ginneken)"},"content":{"rendered":"<p>This paper reports the discovery of extra-terrestrial particles resulting from a large airburst on the flat glacially eroded top of nunatak Walnumfjellet in the S\u00f8r Rondane Mountains, Queen Maud Land, Antarctica. Furthermore, their unusual isotopic signatures suggest interaction with Antarctic ice during their formation in a dense and hot plume resulting from a touchdown impact, intermediate between an airburst and a crater-forming impact.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/research.kent.ac.uk\/astrophysics-and-planetary-science\/wp-content\/uploads\/sites\/1967\/2021\/04\/screenshot-300x186.png\" alt=\"\" width=\"300\" height=\"186\" class=\"alignnone size-medium wp-image-4038\" srcset=\"https:\/\/research.kent.ac.uk\/astrophysics-and-planetary-science\/wp-content\/uploads\/sites\/1967\/2021\/04\/screenshot-300x186.png 300w, https:\/\/research.kent.ac.uk\/astrophysics-and-planetary-science\/wp-content\/uploads\/sites\/1967\/2021\/04\/screenshot-1024x635.png 1024w, https:\/\/research.kent.ac.uk\/astrophysics-and-planetary-science\/wp-content\/uploads\/sites\/1967\/2021\/04\/screenshot-768x476.png 768w, https:\/\/research.kent.ac.uk\/astrophysics-and-planetary-science\/wp-content\/uploads\/sites\/1967\/2021\/04\/screenshot-1536x952.png 1536w, https:\/\/research.kent.ac.uk\/astrophysics-and-planetary-science\/wp-content\/uploads\/sites\/1967\/2021\/04\/screenshot-2048x1270.png 2048w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/p>\n<p>The main science highlights are:<\/p>\n<ul>\n<li>The discovery of unusual impact particles of chondritic composition on top of an old glacially eroded nunatak in the S\u00f8r Rondane Mountains, Antarctica.<\/li>\n<li>The impact particles are depleted in 18O with respect to bulk chondritic values, suggesting that they interacted with 18O-poor Antarctic ice upon condensation in a hot and dense impact plume.<\/li>\n<li>The unusual morphology, textures and oxygen isotopic signatures suggest that they are paired with ca. 430 ka old impact particles forming a discrete layer in the EPICA Dome C and Dome Fuji ice cores; this impact is one of two large meteoritic impacts over Antarctica over the last 800 ka recorded in these ice cores.<\/li>\n<li>Numerical models support a touchdown scenario, intermediate between an airburst and a crater-forming impact, during which the high-velocity vapor jet produced by the total disruption of an asteroid reached the Antarctic ice sheet.<\/li>\n<li>This study will serve as a guide to identify such unusual impacts in the geological records and help reassess the threat posed by medium-sized asteroids.<\/li>\n<\/ul>\n<div id=\"attachment_4020\" style=\"width: 610px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-4020\" src=\"https:\/\/research.kent.ac.uk\/astrophysics-and-planetary-science\/wp-content\/uploads\/sites\/1967\/2021\/04\/Touchdown-Impact-Photo-Cred-Mark-A.-Garlick-e1617210004115-1918x1280-1-300x200.jpg\" alt=\"Mocked up illustration of touchdown impact on Antarctica by Mark A. Garlick\" width=\"600\" height=\"400\" class=\"size-medium wp-image-4020\" srcset=\"https:\/\/research.kent.ac.uk\/astrophysics-and-planetary-science\/wp-content\/uploads\/sites\/1967\/2021\/04\/Touchdown-Impact-Photo-Cred-Mark-A.-Garlick-e1617210004115-1918x1280-1-300x200.jpg 300w, https:\/\/research.kent.ac.uk\/astrophysics-and-planetary-science\/wp-content\/uploads\/sites\/1967\/2021\/04\/Touchdown-Impact-Photo-Cred-Mark-A.-Garlick-e1617210004115-1918x1280-1-1024x683.jpg 1024w, https:\/\/research.kent.ac.uk\/astrophysics-and-planetary-science\/wp-content\/uploads\/sites\/1967\/2021\/04\/Touchdown-Impact-Photo-Cred-Mark-A.-Garlick-e1617210004115-1918x1280-1-768x513.jpg 768w, https:\/\/research.kent.ac.uk\/astrophysics-and-planetary-science\/wp-content\/uploads\/sites\/1967\/2021\/04\/Touchdown-Impact-Photo-Cred-Mark-A.-Garlick-e1617210004115-1918x1280-1-1536x1025.jpg 1536w, https:\/\/research.kent.ac.uk\/astrophysics-and-planetary-science\/wp-content\/uploads\/sites\/1967\/2021\/04\/Touchdown-Impact-Photo-Cred-Mark-A.-Garlick-e1617210004115-1918x1280-1.jpg 1918w\" sizes=\"auto, (max-width: 600px) 100vw, 600px\" \/><p id=\"caption-attachment-4020\" class=\"wp-caption-text\">Mocked up illustration of touchdown impact on Antarctica by Mark A. Garlick<\/p><\/div>\n<div id=\"attachment_4047\" style=\"width: 610px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-4047\" src=\"https:\/\/research.kent.ac.uk\/astrophysics-and-planetary-science\/wp-content\/uploads\/sites\/1967\/2021\/04\/VanGinneken_ScienceAdvances_Figure-1-219x300.png\" alt=\"\" width=\"219\" height=\"300\" class=\"size-medium wp-image-4047\" srcset=\"https:\/\/research.kent.ac.uk\/astrophysics-and-planetary-science\/wp-content\/uploads\/sites\/1967\/2021\/04\/VanGinneken_ScienceAdvances_Figure-1-219x300.png 219w, https:\/\/research.kent.ac.uk\/astrophysics-and-planetary-science\/wp-content\/uploads\/sites\/1967\/2021\/04\/VanGinneken_ScienceAdvances_Figure-1.png 501w\" sizes=\"auto, (max-width: 219px) 100vw, 219px\" \/><p id=\"caption-attachment-4047\" class=\"wp-caption-text\">Figure 1 of the paper, mainly good to show the sampling site and its geographical location in Antarctica: Location of the sampling site in WN, S\u00f8r Rondane Mountains, Queen Maud Land, Antarctica. (A) Landsat image of the sampling site on the summit of WN, where the particles studied here were recovered, along with the Princess Elisabeth Antarctica (PEA). Inset shows the locations of Dome Fuji (DF), Dome Concordia (DC), and BIT-58 for comparison (8, 9, 24). The ages of the various horizons can be found in Table 1. (B) The flat glacially eroded summit of WN on the border of the Antarctic plateau. 10Be exposure age of glacially eroded surfaces of WN range from 870 to 1740 ka (25). (C) The 30 \u00d7 30 \u00d7 10 cm sampling site on top of WN. Landsat 7 image courtesy of the Landsat Image Mosaic of Antarctica (LIMA) project. Photo credit: Matthias van Ginneken, University of Kent.<\/p><\/div>\n","protected":false},"excerpt":{"rendered":"<p>This paper reports the discovery of extra-terrestrial particles resulting from a large airburst on the flat glacially eroded top of nunatak Walnumfjellet in the S\u00f8r Rondane Mountains, Queen Maud Land, Antarctica. Furthermore, their unusual isotopic signatures suggest interaction with Antarctic ice during their formation in a dense and hot plume resulting from a touchdown impact, [&hellip;]<\/p>\n","protected":false},"author":351,"featured_media":4020,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[648],"tags":[],"class_list":["post-4032","post","type-post","status-publish","format-standard","hentry","category-caps-highlights"],"acf":[],"_links":{"self":[{"href":"https:\/\/research.kent.ac.uk\/astrophysics-and-planetary-science\/wp-json\/wp\/v2\/posts\/4032","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/research.kent.ac.uk\/astrophysics-and-planetary-science\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/research.kent.ac.uk\/astrophysics-and-planetary-science\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/research.kent.ac.uk\/astrophysics-and-planetary-science\/wp-json\/wp\/v2\/users\/351"}],"replies":[{"embeddable":true,"href":"https:\/\/research.kent.ac.uk\/astrophysics-and-planetary-science\/wp-json\/wp\/v2\/comments?post=4032"}],"version-history":[{"count":5,"href":"https:\/\/research.kent.ac.uk\/astrophysics-and-planetary-science\/wp-json\/wp\/v2\/posts\/4032\/revisions"}],"predecessor-version":[{"id":4380,"href":"https:\/\/research.kent.ac.uk\/astrophysics-and-planetary-science\/wp-json\/wp\/v2\/posts\/4032\/revisions\/4380"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/research.kent.ac.uk\/astrophysics-and-planetary-science\/wp-json\/wp\/v2\/media\/4020"}],"wp:attachment":[{"href":"https:\/\/research.kent.ac.uk\/astrophysics-and-planetary-science\/wp-json\/wp\/v2\/media?parent=4032"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/research.kent.ac.uk\/astrophysics-and-planetary-science\/wp-json\/wp\/v2\/categories?post=4032"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/research.kent.ac.uk\/astrophysics-and-planetary-science\/wp-json\/wp\/v2\/tags?post=4032"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}