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| Titel |
Linking glacial deposits and lake sediments for paleoclimate studies in the Northern Romanian Carpathians |
| VerfasserIn |
Andrei Zamosteanu, Marcel Mindrescu, Flavio Anselmetti, Naki Akçar, Sally E. Lowick, Hendrik Vogel |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250112746
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| Publikation (Nr.) |
 EGU/EGU2015-12923.pdf |
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| Zusammenfassung |
| Timing and extent of glaciations in the Carpathian mountains are still controversely
discussed, mostly due to the lack of well dated geomorphological and geochronological
studies. We present the preliminary results of geomorphological and sedimentological
analyses of glacial and lacustrine deposits in Bistricioara Valley located in the Rodna
Mountains (Northern Romanian Carpathians). Most of the glacial deposits in the Romanian
Carpathians, such as moraines, typically occur above 1600 m a.s.l. marking the maximum
lowering of past glaciations. Most of the glacial lakes occur between 1800 and 2000
m a.s.l. Field surveys included mapping of moraines and erratic boulders using
detailed topographical maps and aerial photos. A Digital Elevation Model (DEM) was
derived using GIS (ArcMap 10.1) from 1:25000 topographic maps, which was further
completed by field survey data. The resulting geomorphological map shows a series
of moraines, which indicate the occurrence of several glacial phases in the study
area.
Sediment samples were collected from a peat bog (1630 m a.s.l.) dammed by a large
lateral moraine within Bistricioara Mare, one of the largest glacial cirques in the
Romanian Carpathians. A Russian corer was used to extract the sediment profile from
the peat bog (approx. 5 m long sediment core). A X-ray computed tomography
(CT) system was employed for the study of sedimentary and deformation structures
and X-ray fluorescence spectroscopy (XRF) for multi-element analysis at high
resolution. Glacial deposits from the lateral moraine in front of the peat bog were also
sampled, as well as from the frontal moraines, upstream and downstream of the
peat bog. This set of samples from multiple archives allows to link and merge the
chronologies and the paleoenvironmental records of glacial deposits and lake sediments.
Moreover, we employed cosmogenic nuclide dating for the reconstruction of glacial
stages and their paleoclimatic implications during deglaciation in this area of Rodna
Massif.
The lake sediment succession showed an evolution from a basal glacially-influenced
lacustrine environment to a shallow lake and eventually to a peat bog. The 5 m-long sediment
core allows a good temporal resolution to document environmental and palaeoclimatic
changes in the region since deglaciation. The lithostratigraphic profile exhibits several abrupt
changes. The transitions from the clastic-rich lowest 30 cm of the profile to the
overlying units reflects a change in the detritic input that is mostly related to initial
proximity to a glacial source. The overlying sections are mostly characterized by
differences in the amount of organic matter, which are in turn related to the climate
variability. Anthropogenic influences cannot be discarded and will be further investigated |
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