{"id":33915,"date":"2023-06-26T14:33:07","date_gmt":"2023-06-26T12:33:07","guid":{"rendered":"https:\/\/karmaka.de\/?p=33915"},"modified":"2023-06-26T14:33:08","modified_gmt":"2023-06-26T12:33:08","slug":"summanen-structure-further-geological-and-geophysical-evidence-of-a-meteorite-impact-event-in-central-finland","status":"publish","type":"post","link":"https:\/\/karmaka.de\/?p=33915","title":{"rendered":"Summanen structure: Further geological and geophysical evidence of a meteorite impact event in Central Finland<span class=\"badge-status\" style=\"background:#787878\">OPEN ACCESS<\/span>&nbsp;"},"content":{"rendered":"\n<p>Satu Hietala, Jarkko Jokinen, Jouni Lerssi, Matti Niskanen, Lauri J. Pesonen, J\u00fcri Plado<\/p>\n\n\n\n<p>MAPS<br>Version of Record online: 26 June 2023<\/p>\n\n\n\n<p><a href=\"https:\/\/onlinelibrary.wiley.com\/doi\/10.1111\/maps.14033\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>LINK (OPEN ACCESS)<\/strong><\/a><br><a href=\"https:\/\/onlinelibrary.wiley.com\/doi\/epdf\/10.1111\/maps.14033\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>PDF (OPEN ACCESS)<\/strong><\/a><\/p>\n\n\n\n<p class=\"justify-text\">&#8220;The Summanen structure is located in Central Finland and is one of Finland&#8217;s 12 known meteorite impact structures. In 2017, the discovery of Summanen was based on numerous shatter cone boulders with planar deformation features (PDFs) and a circular electromagnetic anomaly, which is 2.6\u2009km in diameter. The site was revisited in 2020 and 2022, and shatter cone-bearing outcrops were discovered. PDFs and feather features were identified in samples from these outcrops. A total of 38 PDF sets in 27 quartz grains resulted in rational crystallographic orientations concentrating on {1014}, {1013}, {1012}, and {1122}, implying shock pressures of 2\u201320\u2009GPa. Gravity measurements were taken, and the electrical conductivity of the structure was studied. The gravimetric results revealed a circular negative anomaly of about 4\u2009km in diameter, with an amplitude of \u22123.5\u2009mGal. Excluding the gravitational effect of water and Quaternary sediments reduces the anomaly to \u22121.6\u2009mGal. A bowl-shaped conductive layer, likely containing relict saline water in the impact-fractured bedrock, was identified to a depth of 240\u2009m. Topographic and bathymetric data were combined to determine the impact&#8217;s effect and interpret the level of erosion. Cobbles of sedimentary sand- and siltstones were found on the coastline of Lake Summanen. Based on their similarity to those found in the S\u00f6derfj\u00e4rden impact crater with a Cambrian age, it is likely that these rocks and post-impact infill are also of a similar age.&#8221;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Satu Hietala, Jarkko Jokinen, Jouni Lerssi, Matti Niskanen, Lauri J. Pesonen, J\u00fcri Plado MAPSVersion of Record online: 26 June 2023 LINK (OPEN ACCESS)PDF (OPEN ACCESS) &#8220;The Summanen structure is located in Central Finland and is&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[90],"tags":[92,1266,4586],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/33915"}],"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=33915"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/33915\/revisions"}],"predecessor-version":[{"id":33916,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/33915\/revisions\/33916"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=33915"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=33915"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=33915"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}