The major goal of this study is to define the paleoclimatic conditions in Ankara
region during Plio-Pleistocene period by evaluating the mineralogical and
geochemical proxies carried from the paleosols and their calcretes. The field
observations, mineralogical, micromorphological, geochemical and stable isotope
investigations were all conducted to achieve a paleoclimatic approach.
As pedogenic minerals in calcretes, presence of dolomite with palygorskite in the
Karahamzali section and calcite with palygorskite in the Bala section together
with high salinity and calcification values reveal the semi-arid and dry climatic
conditions.
The geochemical signatures of the paleosols are consistent with each other
indicating low clastic input during the dry seasons favouring the formation of
calcretes. The &delta / 13C and &delta / 18O values indicate the formation of calcretes from
percolating soil-water under predominantly C4 to C3:C4 association type
vegetation. Temperature calculations show that paleoclimatic conditions
favouring the formation of calcretes in the region are semi-arid and seasonally dry
with approximately 25° / C soil depositional temperature.
This study is the first to give both a radiometric age data to the calcretes of
Central Anatolia, Ankara and document their stable isotope compositions. Dated
calcretes having ESR ages of 419± / 69ka and 761 ± / 120ka point the formation
during Middle Pleistocene when Mid-Brunches Event (MBE) was happened and
the periodicity changed affecting the climatic control over the European continent.
Like the Mediterranean calcretes, this study suggests that calcretes in the study
area started to develop with MBE warmth between Marine Isotope Stages of 13-
11 and 19-17.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/12613876/index.pdf |
| Date | 01 September 2011 |
| Creators | Kucukuysal, Ceren |
| Contributors | Turkmenoglu, Asuman Gunal |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | Ph.D. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for METU campus |
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