{"id":4262,"date":"2025-07-27T00:25:49","date_gmt":"2025-07-26T22:25:49","guid":{"rendered":"https:\/\/www.zahadyazajimavosti.cz\/?p=4262"},"modified":"2025-08-02T03:30:38","modified_gmt":"2025-08-02T01:30:38","slug":"zahadne-zaledneni-zpusobil-meteorit-2","status":"publish","type":"post","link":"https:\/\/www.zahadyazajimavosti.cz\/index.php\/2025\/07\/27\/zahadne-zaledneni-zpusobil-meteorit-2\/","title":{"rendered":"Z\u00e1hadn\u00e9 zaledn\u011bn\u00ed zp\u016fsobil meteorit"},"content":{"rendered":"<p><strong>Asi p\u0159ed 12.900 lety sv\u011bt zachv\u00e1tilo ostr\u00e9 ochlazen\u00ed, co\u017e vedlo k masov\u00e9mu vym\u00edr\u00e1n\u00ed fauny na \u00fazem\u00ed dne\u0161n\u00ed Severn\u00ed Ameriky.<\/strong><!--more--><br \/>\nV\u011bdci James Kennett a Richard Firestone z Kalifornsk\u00e9 university v Santa Barba\u0159e (USA) zjistili, \u017ee p\u0159\u00ed\u010dinou ochlazen\u00ed byl p\u00e1d meteoritu nebo asteroidu. (1)<\/p>\n<p><strong>Kataklyzmata minulosti<\/strong><\/p>\n<p>P\u0159ed \u0161edes\u00e1ti p\u011bti miliony lety p\u00e1d meteoritu zp\u016fsobil vytvo\u0159en\u00ed kr\u00e1teru Chicxulub na poloostrov\u011b Yucat\u00e1n v Mexiku. \u0160lo tehdy o ob\u0159\u00ed meteorit o pr\u016fm\u011bru asi deset kilometr\u016f. P\u0159i n\u00e1razu do\u0161lo k uvoln\u011bn\u00ed energie rovnaj\u00edc\u00ed se 5 \u00d7 10 -23 joul\u016f, tj. 100 tis\u00edc gigatun TNT. Takov\u00fd v\u00fdbuch, podle odborn\u00edk\u016f, vyvolal vlnu tsunami o v\u00fd\u0161ce 50 &#8211; 100 metr\u016f, a zp\u016fsobil na Zemi katastrof\u00e1ln\u00ed zimu. Je mo\u017en\u00e9, \u017ee tato katastrofa zp\u016fsobila vyhynut\u00ed dinosaur\u016f na hranici mezozoikem a kenozoikem, v\u010detn\u011b aktivn\u00ed sope\u010dn\u00e9 \u010dinnosti na indick\u00e9m subkontinentu.<\/p>\n<p>Dal\u0161\u00ed glob\u00e1ln\u00ed katastrofa kosmogenn\u00edho charakteru, ke kter\u00e9 mohlo doj\u00edt asi p\u0159ed 12 900 roky, do\u0161lo na p\u0159elomu holoc\u00e9nu. Tehdy obdob\u00ed oteplov\u00e1n\u00ed, kter\u00e9 za\u010dalo s koncem posledn\u00ed doby ledov\u00e9, p\u0159eru\u0161ilo n\u00e1hl\u00e9 chladn\u00e9 po\u010das\u00ed, kter\u00e9 trvalo t\u00e9m\u011b\u0159 1100 let, co\u017e vedlo k vyhynut\u00ed takov\u00fdch druh\u016f, jako nap\u0159\u00edklad severoamerick\u00fdch mastodont\u016f, \u0161avlozub\u00fdch tygr\u016f a megatheria. V geologii toto obdob\u00ed dostalo n\u00e1zev <em>drias<\/em> (star\u0161\u00ed a mlad\u0161\u00ed drias). Obdob\u00ed zaledn\u011bn\u00ed st\u0159\u00edd\u00e1 obdob\u00ed oteplen\u00ed, kter\u00fdch jsou v prehistorick\u00e9 dob\u011b zn\u00e1m\u00e9 tak\u00e9 t\u0159i &#8211; Meyendorfsk\u00e9, Bellingsk\u00e9 a Alleredsk\u00e9.<\/p>\n<p><strong>N\u00e1v\u0161t\u011bvn\u00edk z vesm\u00edru<\/strong><\/p>\n<p>V roce 2006 vy\u0161la ve Spojen\u00fdch st\u00e1tech kniha<em> \u201eThe Cycle of Cosmic Catastrophes: How a Stone-Age Comet Changed the Course of World Culture\u201c<\/em> (2006), jej\u00ed\u017e auto\u0159i Richard Firestone a Allan West argumentovali, \u017ee tento jev byl zp\u016fsoben p\u00e1dem komety na 1,5 km siln\u00e9 ledov\u00e9 pokr\u00fdvky, kter\u00e1 v t\u00e9 dob\u011b zasahovala cel\u00e9 \u00fazem\u00ed Kanady a\u017e Velk\u00fdm jezer\u016fm. Do Atlantsk\u00e9ho oce\u00e1nu a Mexick\u00e9ho z\u00e1livu byly vr\u017eeny obrovsk\u00e9 masy sladk\u00e9 vody z ledovcov\u00fdch jezer. To vedlo ke zm\u011bn\u011b sm\u011bru Golfsk\u00e9ho proudu, a tedy je zm\u011bn\u011b podneb\u00ed v cel\u00e9 Eurasii.<\/p>\n<p>Prvn\u00ed stopy p\u00e1du kosmick\u00e9ho t\u011blesa ve form\u011b kovov\u00fdch \u00falomk\u016f a mikrosf\u00e9r byly nalezeny v roce 2007 v sediment\u00e1rn\u00edch hornin\u00e1ch a na dn\u011b jezera v Mexiku. K hlavn\u00edmu p\u00e1du do\u0161lo na \u00fazem\u00ed provincie Quebec.<\/p>\n<p>Ale dal\u0161\u00ed geologov\u00e9 nejsou p\u0159\u00edli\u0161 naklon\u011bni t\u00e9to verzi. Do\u0161li k z\u00e1v\u011bru, \u017ee tyto n\u00e1lezy jsou pozemsk\u00e9ho p\u016fvodu a jsou v\u00fdsledkem n\u011bkter\u00fdch m\u00edstn\u00edch geochemick\u00fdch proces\u016f. Jedin\u011b pokud by se tyto &#8222;stopy&#8220; na\u0161ly na v\u0161ech kontinentech, pak by se o tom dalo uva\u017eovat\u2026 (2)<\/p>\n<p>Kennett a Firestone se nehodlaj\u00ed vzd\u00e1t a \u0159\u00edd\u00ed v\u00fdkopy na \u00fazem\u00ed 12 st\u00e1t\u016f v Evrop\u011b, Asii, Africe, Ji\u017en\u00ed i Severn\u00ed Americe. Prakticky v\u0161ude se jim poda\u0159ilo objevit takzvanou &#8222;mezn\u00ed vrstvu&#8220;, jej\u00ed\u017e slo\u017een\u00ed bylo podobn\u00e9 vrstv\u011b v Mexiku. Podle v\u00fdzkumn\u00edk\u016f, pravd\u011bpodobnost, \u017ee v\u0161echny stopy poch\u00e1z\u00ed od stejn\u00e9 ud\u00e1losti, je 95 procent. Nejsp\u00ed\u0161e jde o katastrofu, ke kter\u00e9 do\u0161lo na Zemi asi p\u0159ed 12.835 lety. \u0160lo o p\u00e1d meteoritu, jeho\u017e stopy v podob\u011b platinov\u00fdch vm\u011bstk\u016f byly nalezeny v ledu na \u00fazem\u00ed Gr\u00f3nska.<\/p>\n<p><strong>Z\u00e1hada zaledn\u011bn\u00ed odhalena?<\/strong><\/p>\n<p><em>&#8222;P\u0159esn\u00e9 chronologick\u00e9 ur\u010den\u00ed t\u00e9to ud\u00e1losti je velmi d\u016fle\u017eit\u00e9, proto\u017ee se u\u017e dlouho sna\u017e\u00edme zjistit, co zp\u016fsobilo toto tajemn\u00e9 a anom\u00e1ln\u00ed ochlazen\u00ed,\u201c<\/em> p\u00ed\u0161e James Kennett v \u010dl\u00e1nku publikovan\u00e9m v \u010dasopisu <em>\u201eProceedings of the National Academy of Sciences.\u201c \u201eJsme p\u0159esv\u011bd\u010deni, \u017ee na\u0161e pr\u00e1ce d\u00e1v\u00e1 vy\u010derp\u00e1vaj\u00edc\u00ed odpov\u011b\u010f na tuto ot\u00e1zku, a douf\u00e1me, \u017ee to povzbud\u00ed na\u0161e kolegy, aby pou\u017eili statistick\u00e9 anal\u00fdzy v tomto v\u00fdzkumu.&#8220;<\/em> (3)<\/p>\n<p><em>&#8222;Hlavn\u00ed v\u011bc je, \u017ee v\u0161echny nep\u0159\u00edm\u00e9 ukazatele nazna\u010duj\u00ed existenci p\u0159\u00ed\u010dinn\u00e9 souvislosti mezi oteplen\u00edm a driasovym ochlazen\u00edm,\u201c<\/em> dod\u00e1v\u00e1 v\u011bdec.<em> \u201eJin\u00fdmi slovy, nyn\u00ed m\u016f\u017eeme \u0159\u00edci, \u017ee tato katastrofa zp\u016fsobila prudk\u00fd pokles teploty.&#8220;<\/em><\/p>\n<p><strong><em>Odkazy<\/em><\/strong><\/p>\n<p><em>(1) <a href=\"https:\/\/en.wikipedia.org\/wiki\/Younger_Dryas_impact_hypothesis\" target=\"_blank\" rel=\"noopener\">https:\/\/en.wikipedia.org\/wiki\/Younger_Dryas_impact_hypothesis<\/a> <\/em><br \/>\n<em>(2) <a href=\"http:\/\/www.csicop.org\/si\/show\/did_a_cosmic_impact_kill_the_mammoths\" target=\"_blank\" rel=\"noopener\">http:\/\/www.csicop.org\/si\/show\/did_a_cosmic_impact_kill_the_mammoths<\/a> <\/em><br \/>\n<em>(3) <a href=\"http:\/\/www.pnas.org\/content\/112\/15\/4684.abstract\" target=\"_blank\" rel=\"noopener\">http:\/\/www.pnas.org\/content\/112\/15\/4684.abstract<\/a><\/em><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Asi p\u0159ed 12.900 lety sv\u011bt zachv\u00e1tilo ostr\u00e9 ochlazen\u00ed, co\u017e vedlo k masov\u00e9mu vym\u00edr\u00e1n\u00ed fauny na \u00fazem\u00ed dne\u0161n\u00ed Severn\u00ed Ameriky.<\/p>\n","protected":false},"author":1,"featured_media":1155,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9,17,19],"tags":[41,42,25],"class_list":["post-4262","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-historie","category-veda","category-zahady","tag-archeologie","tag-geologie","tag-katastrofy"],"_links":{"self":[{"href":"https:\/\/www.zahadyazajimavosti.cz\/index.php\/wp-json\/wp\/v2\/posts\/4262","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.zahadyazajimavosti.cz\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.zahadyazajimavosti.cz\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.zahadyazajimavosti.cz\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.zahadyazajimavosti.cz\/index.php\/wp-json\/wp\/v2\/comments?post=4262"}],"version-history":[{"count":1,"href":"https:\/\/www.zahadyazajimavosti.cz\/index.php\/wp-json\/wp\/v2\/posts\/4262\/revisions"}],"predecessor-version":[{"id":4263,"href":"https:\/\/www.zahadyazajimavosti.cz\/index.php\/wp-json\/wp\/v2\/posts\/4262\/revisions\/4263"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.zahadyazajimavosti.cz\/index.php\/wp-json\/wp\/v2\/media\/1155"}],"wp:attachment":[{"href":"https:\/\/www.zahadyazajimavosti.cz\/index.php\/wp-json\/wp\/v2\/media?parent=4262"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.zahadyazajimavosti.cz\/index.php\/wp-json\/wp\/v2\/categories?post=4262"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.zahadyazajimavosti.cz\/index.php\/wp-json\/wp\/v2\/tags?post=4262"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}