"2004-11-01+01:00"^^ . . "Brno" . "Brno" . . . "43410" . . "Mendelova zem\u011Bd\u011Blsk\u00E1 a lesnick\u00E1 univerzita v Brn\u011B" . "Podm\u00EDnky fosilizace zkamen\u011Bl\u00FDch les\u016F v pou\u0161ti Gobi, jihov\u00FDchodn\u00ED Mongolsko"@cs . . "Podm\u00EDnky fosilizace zkamen\u011Bl\u00FDch les\u016F v pou\u0161ti Gobi, jihov\u00FDchodn\u00ED Mongolsko"@cs . . "RIV/62156489:43410/04:00002692!RIV/2005/GA0/434105/N" . "Conditions of fossilization of petrified forests in the Gobi desert, southeastern Mongolia"@en . "P(GD526/03/H036)" . . "During the Cretaceous period, about 130 million years ago, the examined area was a complex of swamps, lakes and rivers. But nearby active volcano belt -- great rift system of east -- west orientation regularly showered the area with ash. The mud, sand and ash covered ancient forests and everything that lived there. In the mineralized tufs and sandstone, detrital grains consisting of quartz, feldspar, vulcanic rock fragments, carbonaceous trashes and other accessory minerals were deposited in this time. But not only this material survived to the present days...together with fossil wood remnants (which rode out a large fires) were cemented by clays and minor authigenic calcite and quartz. Varieties of cryptocrystaline quartz selectively replaced carbonatized fossil wood (filled fossil wood cells). So large replacement of organic debris by secondary chalcedon and jasper was caused by a high activity of SiO2 fluids- high postvolcanic activity of whole area of rifts during its relatively long fossilizat" . . . "80-7157-794-4" . "80;84" . "RIV/62156489:43410/04:00002692" . "Conditions of fossilization of petrified forests in the Gobi desert, southeastern Mongolia" . . "1"^^ . . "Conditions of fossilization of petrified forests in the Gobi desert, southeastern Mongolia"@en . . . "MendelNet 2004, Proceedings of International Postgraduate Students\u00B4 Conference" . "During the Cretaceous period, about 130 million years ago, the examined area was a complex of swamps, lakes and rivers. But nearby active volcano belt -- great rift system of east -- west orientation regularly showered the area with ash. The mud, sand and ash covered ancient forests and everything that lived there. In the mineralized tufs and sandstone, detrital grains consisting of quartz, feldspar, vulcanic rock fragments, carbonaceous trashes and other accessory minerals were deposited in this time. But not only this material survived to the present days...together with fossil wood remnants (which rode out a large fires) were cemented by clays and minor authigenic calcite and quartz. Varieties of cryptocrystaline quartz selectively replaced carbonatized fossil wood (filled fossil wood cells). So large replacement of organic debris by secondary chalcedon and jasper was caused by a high activity of SiO2 fluids- high postvolcanic activity of whole area of rifts during its relatively long fossilizat"@en . "Kynick\u00FD, Jind\u0159ich" . "Conditions of fossilization of petrified forests in the Gobi desert, southeastern Mongolia" . . "1"^^ . . . "5"^^ . "Gobi desert;Mongolia;fossilization;petrified forests;silicification"@en . . "558569" . "[F543C8716140]" . . "Ve svrchn\u00EDm mesozoiku (obdob\u00ED k\u0159\u00EDdy, cca 130 Ma) p\u0159edstavovala studovan\u00E1 oblast komplex ba\u017Ein, jezer a \u0159ek. Pro fosilizaci okoln\u00EDch les\u016F hrala hlavn\u00ED roli p\u0159\u00EDtomnost aktivn\u00EDho kontinent\u00E1ln\u00EDho riftu ve sm\u011Bru V-Z, kter\u00FD periodicky produkoval ohromn\u00E9 mno\u017Estv\u00ED pyrtoklastick\u00E9ho materi\u00E1lu a l\u00E1v. Je velmi pravd\u011Bpodobn\u00E9, \u017Ee ka\u017Ed\u00FD les byl prakticky zcela zasyp\u00E1n je\u0161t\u011B \u017Ehav\u00FDmi pyroklastiky. Pro studovan\u00E9 lokality je typick\u00E9, \u017Ee se vyskytuj\u00ED v tufech, kde se p\u0159i diagenezi projevil p\u0159edev\u0161\u00EDm proces rychl\u00E9 ho uvol\u0148ov\u00E1n\u00ED oxidu k\u0159emi\u010Dit\u00E9ho. Oxid k\u0159emi\u010Dit\u00FD postupn\u011B pronikal do rozpadaj\u00EDc\u00ED se d\u0159evn\u00ED hmoty. Touto cestou pravd\u011Bpodobn\u011B doch\u00E1zelo k extr\u00E9mn\u011B rychl\u00E9 silicifikaci a t\u00EDm bylo rovn\u011B\u017E br\u00E1n\u011Bno procesu hnit\u00ED \u010Di prouhel\u0148ov\u00E1n\u00ED. Velmi rychl\u00E1 silifikace d\u0159evn\u00ED hmoty je podm\u00EDn\u011Bna n\u00EDzkoteplotn\u00EDmi metasomatick\u00FDmi procesy, ke kter\u00FDm doch\u00E1zelo p\u0159i vysok\u00E9 aktivit\u011B SiO2 v cel\u00E9 oblasti i d\u00EDky zv\u00ED\u0161en\u00E9 postvulkanick\u00E9 \u010Dinosti. U cel\u00E9 \u0159ady vzork\u016F je zachov\u00E1na komplexn\u00ED stavba p\u016Fvodn\u00ED buni\u010Diny a ligninu s r\u016Fstov\u00FDmi letokruhy, kte"@cs .