Papers by RELU DUMITRU ROBAN
Terra Nova
Situated at the junction between the Eastern Carpathians Mountains, the Pannonian and the Transyl... more Situated at the junction between the Eastern Carpathians Mountains, the Pannonian and the Transylvanian basins, the Baia Mare region (Romania) has a complex geological history that witnessed the interaction among the three main tectonic provinces. Here, we report results from new seismic reflection measurements that provide modern information about the subsurface geological structure. The integrated analysis of the newly acquired and vintage seismic reflection data from the study area reveals details about the architecture of the Palaeogene and the Neogene deposits at the contact between the northeastern Pannonian and northwestern Transylvanian basins. In particular, it unveils a fault zone that most probably controlled the tectonic evolution of the eastern Pannonian and Transylvanian basins. A better understanding of the crustal structure and tectonic features in the study area is a first step into evaluating the geothermal potential of the region.
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Basin Research
We present new sedimentological, petrographical, palaeontological and detrital zircon U–Pb data o... more We present new sedimentological, petrographical, palaeontological and detrital zircon U–Pb data on late Oligocene–early Miocene sedimentary rocks of the thin‐skinned thrust belt of East Carpathians. These data were acquired to reconstruct the sedimentary routing system for two compositionally different turbidite fans made of the regionally extensive Kliwa and Fusaru formations. On the eastern margin of the Moldavides foreland basin, large low‐gradient river systems draining the East European Platform provided well‐sorted quartz‐rich sand forming deltas on wide shallow shelves and thick Kliwa submarine fans. Due to the westward subduction of a thinned continental plate, the western basin margin was characterized by short, steep‐gradient routing systems where sediment transport to deep water was mainly through hyperpycnal flows. The Getic and Bucovinian nappes of the East Carpathians and the exhumed Cretaceous–Early Palaeogene orogenic wedge fed Fusaru fans with poorly sorted lithic s...
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11th Congress of the Balkan Geophysical Society, 2021
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Geochemistry, 2020
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Earth and Planetary Science Letters, 2019
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The Journal of Geology, 2016
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Geochemistry, Geophysics, Geosystems, 2018
We performed a detrital zircon (DZ) U‐Pb geochronologic survey of the lower parts of the Danube R... more We performed a detrital zircon (DZ) U‐Pb geochronologic survey of the lower parts of the Danube River approaching its Danube delta, Black Sea sink, and a few large tributaries (Tisza, Jiu, Olt, and Siret) originating in the nearby Carpathian Mountains. Samples are modern sediments. DZ age spectra reflect the geology and specifically the crustal age formation of the source area, which in this case is primarily the Romanian Carpathians and their foreland with contributions from the Balkan Mountains to the south of Danube and the East European Craton. The zircon cargo of these rivers suggests a source area that formed during the latest Proterozoic and mostly into the Cambrian and Ordovician as island arcs and back‐arc basins in a Peri‐Gondwanan subduction setting (~600–440 Ma). The Inner Carpathian units are dominated by a U‐Pb DZ peak in the Ordovician (460–470 Ma) and little inheritance from the nearby continental masses, whereas the Outer Carpathian units and the foreland have two m...
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Specific post-depositional processes acted differently, spatially and temporally, and have been i... more Specific post-depositional processes acted differently, spatially and temporally, and have been identified, as follows: differential compaction and illuviation of matrix, syn-depositional bioturbation, micritization, vadoseand submarine-cementation, polymorphic transformations, recrystallization (by aggradation), authigenesis of calcite, dolomite and pyrite, pressure solutions, and joints/fractures. Recrystallization is the most frequent, is selective and affected the matrix, peloides, intraclasts and bioclasts. The process is never complete and not symmetrical. Microstylolites are the effect of pressure solution and cover the boundaries between the layers. Dolomitization was a recurrent process in telogenesis and mesogenesis stages. The effective and total porosity of the studied reservoirs are subject to these processes that specifically controlled modifications of "grain-support" and pore space, within three diagenetic stages: incipient burial (eogenesis), uplift (telogenesis) and, respectively, progressive burial (mesogenesis).
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Frontiers in Earth Science
Over the last thousands of years, human impact led to significant changes in the landscape, with ... more Over the last thousands of years, human impact led to significant changes in the landscape, with impacts on the environment and the functioning of the ecosystems. We assumed that even small human settlements developed around water bodies might have a substantial impact that surpasses the natural cycles of climate change in an area, especially linked to forest cutting. We have chosen a temporary lake in the Romanian Carpathians as temporary lakes are overlooked in paleoclimatic studies, although they have potential as hotspots for paleoenvironmental research studies. Zăton Lake has exposed riverbank sediments dated with radioactive lead and optical stimulated luminescence techniques, analyzed for sediments and paleomagnetism, and sampled for fossil Oribatida mites. The results show that for the last 2,200 years, natural cycles of warm and cold periods changed the oribatid communities around the lake, with warmer cycles of rich fauna alternating with poor fauna during colder periods. ...
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Proceedings, 2018
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Proceedings of the 33rd Romanian Geomorphology Symposium, 2017
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Biogeosciences Discussions, 2015
Fossil invertebrates from cave sediments have been recently described as a potential new proxy fo... more Fossil invertebrates from cave sediments have been recently described as a potential new proxy for paleoenvironment and used in cross-correlations with alternate proxy records from cave deposits. Here we present the results of a fossil invertebrates study in four caves from two climatically different regions of the Romanian Carpathians, to complement paleoenvironmental data previously reported. Oribatid mites and ostracods are the most common invertebrates in the studied cave sediments. Some of the identified taxa are new for science, and most of them are indicative for either warm/cold stages or dry/wetter oscillations. In two caves the fossil invertebrates records indicate rapid climate oscillations during times known for a relatively stable climate. By corroborating the fossil invertebrates' record with the information given by magnetic properties and sediment structures, complementary data on past vegetation, temperatures, and hydraulic regimes could be gathered. This paper ...
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Quaternary International, 2014
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Geomicrobiology Journal, 2013
ABSTRACT The bacterial and fungal assemblages of clastic sediments collected fromtwo caves locate... more ABSTRACT The bacterial and fungal assemblages of clastic sediments collected fromtwo caves located in north-westernRomaniawere investigated by assessing ITS and 16S rRNA gene diversity. Bacterial members belonging to Chloroflexi, Nitrospirae, Proteobacteria, Firmicutes, Acidobacteria, Gemmatimonadetes, and fungal members of Ascomycota were identified. Except for Bacillus sp., all bacteria were related to uncultured or unknown species and the majority (86%) of the bacterial sequences from one of the caves had no close GenBank relatives. The bacterial sequences obtained clustered with species found in extreme environments. Half of the bacterial operational taxonomic units were clustered with clones isolated from deep subsurface sediments of a radioactively contaminated site in the USA. The present study represents the first attempt to identify microorganisms in Quaternary cave sediments.
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International Geology Review, 2015
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Tectonics, 2020
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Tectonics, 2020
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Papers by RELU DUMITRU ROBAN