 |
| Titel |
Late Pleistocene deglaciation and paleo-environment in the Retezat Mountains, Southern Carpathians |
| VerfasserIn |
Zsófia Ruszkiczay-Rüdiger, Balázs Madarász, Zoltán Kern, Petru Urdea, Régis Braucher, Aster Team |
| Konferenz |
EGU General Assembly 2017
|
| Medientyp |
Artikel
|
| Sprache |
en
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250139501
|
| Publikation (Nr.) |
 EGU/EGU2017-2755.pdf |
|
|
|
|
|
| Zusammenfassung |
| This study aims to use in situ produced 10Be based Cosmic Ray Exposure (CRE) ages to
reconstruct glacier evolution in the Retezat Mts, the Southern Carpathians most glaciated area
with peak elevations up to 2509 m asl. In the study area currently devoid of glaciers, the
calculated theoretical ELA is at ∼2860 m asl. The paleo-Equilibrium Line Altitudes (ELAs)
were calculated over the ∼21 to ∼13 ka time period based on the reconstructed glacial
stillstands or re-advances geometries using the ssAAR method [1, 2]. Regarding the
Northern side of the Retezat Mts, new and re-evaluated 10Be CRE ages (n=34) [3]
were used while regarding the Southern side, they all result from a new sampling
(n=25).
According to the data, the most extended glaciation occurred during the LGM, down to
∼1050 m asl. on both sides of the Retezat Mts with most probable 10Be CRE ages of 21.0
−1.5+0.8 ka and 20.7 −1.0+0.9 ka. The reconstructed ELA depression in the North was ∼1010
m while it was ∼1190 m, in the South where the valleys glacial system (Lăpuşnicu – Judele)
was significantly larger with longer glacier tongues. At the beginning of the Lateglacial
(∼17-18 ka) the glaciers withdrew and the North-South difference between the ELA
depression was decreased (∼885 m and ∼945 m, respectively). The ELA differences
further reduced and vanished for the ∼15.3 ka glacial event – the last cold stage
before the abrupt Bölling/Alleröd warming – with ELA depressions of ∼728 m and
∼712 m, respectively. The last glacial phase in the area characterized by small
cirque glaciers occurred at 13.5 −0.6+0.6 ka in the North and 13.9 −0.4+0.9 ka in
the South. By this time, the ELA depression was reduced to ∼660-680 m. Due to
the small glacier size this value may have been influenced by local topoclimatic
factors. So far, no data support Younger Dryas or Holocene glaciation of the Retezat
Mts.
The elevation difference of the ELAs suggests more precipitation on the Southern side of
the Retezat Mts during the LGM. This may indicate a southerly wind regime at this part of
Europe, which subsequently gave place to the westerly winds during the warming climate of
the Lateglacial.
Using a Chironomidae-based summer temperature (T) reconstruction from the area [4], T
and mean annual precipitation (P) at the ELA were calculated for the ∼15.3 ka stage. Based
on Ohmura et al. [5] a ∼4.5-4.9 ˚ C decrease of T and a ∼10-15% increase of P compared to
the present values were calculated.
Thanks to OTKA PD83610, PD104899; NKM-96/2014, NKM-31/2015; OMAA 90öu17;
LP2012-27/2012, INSU/CNRS, the ANR through the program “EQUIPEX Investissement
d’Avenir”, IRD and CEA.
References:
[1] Pellitero et al. 2015 Computers & Gerosciences 82: 55-62
[2] Kern and László, 2010. Quat. Sci. Rev. 29, 2781–2787.
[3] Ruszkiczay-Rüdiger et al. 2016 Quat. Int. 415. 216-229.
[4] Tóth et al., 2012. Quat. Res. 77. 122-131.
[5] Ohmura et al. 1992. J. of Glaciology, 38. 397-411. |
|
|
|
|
|
|