LINK<\/strong><\/a><\/p>\n\n\n\n“With no significant topographic expression and limited bedrock exposure, the ~10\u2009km diameter Karla impact structure (Tatarstan, Russia) is poorly known. The age of the impact is also poorly constrained stratigraphically to between 4 and 60\u2009Ma, even if an upper Miocene age is more likely. Targeted gravity and magnetic field surveys were conducted over Karla to explore its size and structure in 2019. Bouguer gravity anomaly data reveal a central positive (+2\u2009mGal) peak ~2\u2009km in diameter surrounded by a concentric negative (\u22121\u2009mGal) anomaly extending to ~3\u2009km radius; a more irregular, outward-decreasing (+1 to \u22121\u2009mGal) positive anomaly extends to 6\u20138\u2009km radius. A complex impact structure with diameter of 8\u201310\u2009km is consistent with the Bouguer anomalies. Magnetic field data show 1 to several km-wavelength anomalies with amplitude variation from +150 to \u2212150\u2009nT and little concentric structure, although the impact feature broadly corresponds to a magnetic low with a weak central high. A 2-D numerical model of the structure was built using these potential-field data and petrophysical properties measured on collected samples. It confirms a central uplift composed of Paleozoic sediments and Archean crystalline basement up to 1\u2009km of depth. A 500\u2009m deep collapsed disruption cavity filled by breccia and lacustrine deposits accounts for the Bouguer negative ring. The reversely polarized and weak central magnetic anomalies are controlled by the geometry of the crystalline basement associated with the deformation during the central uplift.”<\/p>\n","protected":false},"excerpt":{"rendered":"
Yoann Quesnel, Natalia S. Bezaeva, Dilyara M. Kuzina, Pierre Rochette, J\u00e9r\u00f4me Gattacceca, Minoru Uehara, Dmitry D. Badyukov, Bulat M. Nasyrtdinov, Dmitry A. Chareev, Cedric Champollion MAPSVersion of Record online: 21 March 2022 LINK “With no…<\/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],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/30371"}],"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=30371"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/30371\/revisions"}],"predecessor-version":[{"id":30372,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/30371\/revisions\/30372"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=30371"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=30371"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=30371"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}