Provider: - Institution: - Data provided by Europeana Collections- Na području današnje Istre i kvarnerskih otoka kao sjeverozapadnog dijela nekadašnje Jadranske karbonatne platforme istraživane su ...relativne promjene morske razine zabilježene unutar gornjokrednih naslaga. Snimljeno je i uzorkovano ukupno petnaest geoloških stupova i profila (Dolina Mirne, Vodice–Jelovica, Vodice–Jelovica padina, Martinjak, Goli breg, Planik, Veprinac, Učka, Rabac, Barban, Medulin, Osor, Martinšćica A, Martinšćica B i Premuda). Pored mikrofacijesnih i biostratigrafskih analiza na pojedinim su uzorcima primijenjene i druge analitičke metode, poput rendgenske difrakcije, elektronske mikroskopije, analize stabilnih izotopa δ13C i δ18O i palinološke analize. Terenskim istraživanjem i analizama mikrofacijesa definirani su glavni litotipovi, značajke okoliša taloženja, te glavne dijagenetske promjene. Budući da su razmatrane i druge epizode potapanja SZ dijela Jadranske karbonatne platforme tijekom gornje krede pored najvažnijih neformalnih litostratigrafskih jedinica Milna (s članovima Rušnjak, Marušići, Vinkuran i Niska), Sv. Duh i Gornji Humac prikazane su i jedinice Crna, Sis, Belej (s članom Vrana), Veli Rat i Gornji Humac, a opisane su i pojave do sada neistraženih dubljemorskih naslaga stratigrafskog raspona konijak–santon na području vršnog dijela Učke i raspona turon–santon između Medulina i Marlere u južnoj Istri. Korelacijom izdvojenih litostratigrafskih jedinica i analizom drugih raspoloživih podataka izrađene su paleookolišne i paleogeografske rekonstrukcije istraživanog područja za razdoblja starijeg cenomana, srednjeg–mlađeg cenomana, cenomana–turona, turona–konijaka i starijeg santona. Na temelju rezultata istraživanja izdvojene su dvije stratigrafske razine s izrazitom facijesnom diferencijacijom i barem djelomičnim potapanjem platforme tijekom mlađe krede u istraživanom prostoru, međusobno odvojene kratkom epizodom isključivo plitkomorske sedimentacije tijekom mlađeg cenomana. Starija je epizoda uzrokovana sinsedimentacijskom tektonikom tijekom starijega cenomana, čime je u južnom dijelu Cresa i na Lošinju formirana karbonatna rampa s pučinskim utjecajem, a slabiji efekti sinsedimentacijske tektonike su zabilježeni i u područjima sjeverne i južne Istre – to je područje postupno zapunjavano tijekom starijeg, a mjestimice i srednjeg pa čak i starijeg dijela mlađeg cenomana. Mlađa je epizoda započela tijekom mlađeg cenomana potapanjem većeg dijela istraživanog područja zbog značajnog eustatskog porasta morske razine, pri čemu je u području današnje Ćićarije, istočne Istre i južnog Cresa plitkovodna sedimentacija ponovno uspostavljena tijekom turona. U isto su vrijeme pod djelovanjem sinsedimentacijske tektonike usprkos znatnom eustatskom porastu
Sažetak
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morske razine područja Savudrijske antiklinale u sjevernoj Istri, sjevernog dijela Cresa i većine Krka okopnjela, dok je jugoistočni dio istraživanog područja produbljen, tako da je u južnoj Istri, na Lošinju i Premudi taloženje produženo do konijaka i santona.- Relative sea-level changes have been studied in the area of Istria and Kvarner islands, the NW part of the Mesozoic Adriatic Carbonate Platform. A total of 15 geological columns and profiles was sampled (Mirna Valley, Vodice–Jelovica, Vodice–Jelovica Slope, Martinjak, Goli breg, Planik, Veprinac, Učka, Rabac, Barban, Medulin, Osor, Martinšćica A, Martinšćica B and Premuda). Besides standard microfacies and biostratigraphic analyses on some samples other analytical methods were performed, like X-Ray diffraction, electronic microscopy, δ13C and δ18O stable isotope analysis as well as palynological analyses. Based on the field data and microfacies analyses main lithotypes, environmental conditions and diagenetic changes have been defined. The study was focused on a very significant Cenomanian–Turonian eustatic sea-level rise, defined within deposits of the informal lithostratigraphic units Milna (including Rušnjak, Marušići, Vinkuran and Niska members), Sv. Duh and Gornji Humac. However, other drowning episodes and penecontemporaneous shallow-water successions have been studied too, so corresponding units Crna, Sis, Belej (with Vrana member), Veli Rat and Gornji Humac have also been described, as well as previously uninvestigated deeper-marine Coniacian–Santonian deposits in the apical part of the Učka Mt. and Turonian–Santonian deposits between Medulin and Marlera in southern Istria. Correlation of lithostratigraphic units and analysis of all available data enabled construction of palaeoenvironmental and palaeogeographic reconstructions of the study area during the Early Cenomanian, Middle–Late Cenomanian, Cenomanian–Turonian, Turonian–Coniacian and Early Santonian. Two episodes of significant facies differentiation and at least partial platform drowning have been delineated, separated by a short-lived epsiode of completely shallow-water deposition during Late Cenomanian. The first episode was caused by synsedimentary tectonics during the Early Cenomanian, resulting in formation of a carbonate ramp with pelagic influence in the present-day southern Cres and Lošinj.areas, as well as weaker deformation in northern and southern Istria areas – those deeper areas were gradually infilled during Early, Middle or even Late Cenomanian. The second, younger episode commenced in the Late Cenomanian by drowning of the major part of the study area due to the significant eustatic sea-level rise, followed by gradual recovery of shallow-marine deposition during the Turonian in the present-day Ćićarija, eastern Istria and southern Cres areas. Penecontemporaneously under the influence of the significant synsedimentary tectonics in spite of the eustatic sea-level rise Savudrija Anticline area in northern Istria, northern part of the island of Cres and most of the Krk island
Abstract
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were uplifted and emerged, while SE part of the study area was drowned, resulting in prolonged deposition of deeper-marine deposits until Coniacian and Santonian.- All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Provider: - Institution: - Data provided by Europeana Collections- All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain ...Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
