43 KB1514 KB39 KB195320252009Ogorelec, Bojan11 straništevilka:2letnik:52str. 193-203ISSN:0016-7789COBISSID:1715285URN:URN:NBN:SI:doc-NHV9NETAslGeološki zavod SlovenijeGeologijaapnenecdolomitjurakarbonatne kamninePreserjestratigrafijastratigraphySpodnje jurske plasti v Preserju pri Borovnici| Lower jurassic beds at Preserje near Borovnica (Central Slovenia)|Described is a 50 m thick cross-section, which includes 26 cyclothems. Beds ofbiomicritic, in some places oolitic, limestone are interrupted by dolomitized laminites, thinner beds of flat pebble conglomerate, and rarely stromatolites. The bedrock of the cross-section is sparitic dolomite. The contact between Triassic and Jurassic is not included in the cross-section. Lithological varieties indicate sedimentation in the subtidal zone in the protected part of a shallow shelf within the Adriatic Dinaric carbonate platform with occasional connection with the open sea. Dolomite in the laminites and flat pebble conglomerate is of early diagenetic origin. It developed through capillary concentration of pore solutions in intratidal and supratidal environment. The Lower Jurassic age of the limestone is determined by Palaeodasycladus mediterraneous Pia algae. Chemical analyses include Ca, Mg, as well as, Sr, Fe, Mn and Na. Beds containing dolomite of early diagenetic origin are rich with Fe and NaV 50 m debelem profilu je zajetih 26 ciklotem. Plasti biomikritnega in mestomaoolitnega apnenca prekinjajo dolomitizirani laminiti, tanjše plasti nadplimskega konglomerata in redkeje stromatoliti. V talnini profila je zrnat dolomit. Sam kontakt med triasom in juro s profilom ni zajet. Litološki različki kažejo na sedimentacijo v podplimskem okolju, v zatišnem delu plitvovodnega šelfa znotraj Jadransko-Dinarske karbonatne platforme, ki je imela občasno povezavo z odprtim morjem. Dolomit v laminitih in nadplimskem konglomeratu je zgodnjediagenetski, nastal s kapilarno koncentracijo pornih raztopin v med- in nadplimskem okolju. Spodnje jursko starost apnenca določa alga Palaeodasycladus mediterraneous Pia. Kemične raziskave zajemajo poleg Ca in Mg še elemente Sr, Fe, Mn in Na. Plasti z zgodnjediagenetskim dolomitom so obogatene z železom in natrijemTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaGeološki zavod Slovenije