EARLY PLEISTOCENE AGE OF FLUVIAL SEDIMENT IN THE STARA GARDA CAVE REVEALED BY (26)AL/(BE)-B-10 BURIAL DATING: IMPLICATIONS FOR GEOMORPHIC EVOLUTION OF THE MALE KARPATY MTS. (WESTERN CARPATHIANS)

Autor: Aster Team G. Aumaître, D. Bourlès, K. Keddadouche, Peter Magdolen, Alexander Lačný, Régis Braucher, Michal Šujan
Přispěvatelé: Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Collège de France (CdF)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Institut National de la Recherche Agronomique (INRA), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)
Jazyk: angličtina
Rok vydání: 2017
Předmět:
Zdroj: Acta Carsologica
Acta Carsologica, 2017, 46 (2-3), pp.251-264. ⟨10.3986/ac.v46i2-3.5157⟩
Acta Carsologica, Scientific Research Centre Publishing, 2017, 46 (2-3), pp.251-264
HAL
CIÊNCIAVITAE
ISSN: 0583-6050
DOI: 10.3986/ac.v46i2-3.5157⟩
Popis: Assessment of vertical movements of tectonically bounded blocks is crucial for determination of geohazards in densely inhabited zones, such as the border zone of western Slovakia and eastern Austria. The morphostructure of the Male Karpaty Mts. divides the Vienna and Danube basins in the Western Carpathian – Eastern Alpine junction, and its neotectonic activity is of high importance. This study was focused on 26Al/10Be burial dating of fluvial sediment in the Stara Garda Cave, located in the central part of the mountains. The structural research revealed predisposition of forming of horizontal passages in low angle to subhorizontal bedrock stratification together with low-grade metamorphic foliation. Fluvial origin of the passages was inferred from mezoscale erosional features on the bedrock as well as from facies character of the well preserved sedimentary profile. Cave sediment was according to petrographic analysis derived from a watershed comparable to recent one of the Stupavský Potok Stream. Three analysed dating samples provided low values of isotopic concentrations, allowing us only to calculate the minimum burial age of the deposit of 1.72 Ma. Assuming the low position of the cave above recent surface streams, resulting maximum incision rate of 26 m/Ma indicates very low uplift of the mountains horst during the Quaternary. The slow incision of the river network is in good agreement with a widespread preservation of the planation surface called "Mid-mountain level". In contrast are relatively high values of palaeodenudation rates inferred from isotopic concentrations. Generally, our results indicate that the Male Karpaty Mts. horst underwent relatively intense but short uplift in the Early Pleistocene, followed by very moderate uplift up to the recent. Key words: Western Carpathians, Male Karpaty Mts., fluvial cave sediment, burial dating, Early Pleistocene, neotectonics. Zgodnja pleistocenska starost fluvialnih sedimentov v jami Stara Garda, ki jo je dala 26Al/10Be datacija: uporabnost za geomorfni razvoj Nizkih Karpatov (Zahodni Karpati) Ocena vertikalnih premikov tektonsko omejenih blokov je kljucna za dolocitev geohazardov v gosto naseljenih obmocjih. Morfostruktura Malih Karpatov deli Dunajski in Donavski bazen na sticiscu Zahodnih Karpatov – Vzhodnih Alp in njegova neotektonska aktivnost je zelo pomembna. Studija se je posvetila 26Al/10Be dataciji fluvialnih sedimentov v jami Stara Garda v osrednjem delu gorovja. Strukturna raziskava je razkrila predispozicijo oblikovanja vodoravnih jamskih rovov pod nizkim kotom v odvisnosti od subhorozontalne stratifikacije kamnine ter tudi z nizko stopnjo metamorfne foliacije. Na fluvialno poreklo rovov smo sklepali iz srednje velikih erozijskih oblik na njihovih stenah kot tudi iz lastnosti faciesov dobro ohranjenega sedimentnega profila. Glede na petrografske analize jamski sediment izhaja iz povodja, ki je primerljiv z recentnim povodjem potoka Stupavský. Trije analizirani vzorci so nam dali nizke vrednosti koncentracij izotopov, ki so nam omogocile le izracun najnižje pokopne starosti sedimenta, ki je znasala 1,72 Ma. Ce upostevamo, da leži jama nizko nad recentnimi vodnimi tokovi, dobimo maksimalno hitrost vrezovanja dolin samo 26 m/Ma, kar kaže na zelo majhen tektonski dvig v casu kvartarja. Pocasno vrezovanje recne mreže se dobro ujema s siroko ohranjenim uravnanim povrsjem, imenovanim »Srednjegorska uravnava«. V nasprotju pa so sorazmerno visoke vrednosti hitrosti paleodenudacije, ki izhajajo iz koncentracij izotopov. Na splosno nasi rezultati kažejo, da je bil horst Nizkih Karpatov podvržen relativno mocnemu, toda kratkemu dvigovanju v spodnjem pleistocenu, ki mu je sledil zmeren dvig do sedanjosti. Kljucne besede: Zahodni Karpati, Nizki Karpati, fluvialni jamski sedimenti, pokopna datacija, starejsi pleistocen, neotektonika.
Databáze: OpenAIRE
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