U-Series Dating and Origin of Yaprakhisar (Güzelyurt-Aksaray) Travertines.


Koçak İ., Temiz U. , Öksüz N. , Akbay S.

8. Geochemistry Symposium, Antalya, Turkey, 2 - 05 May 2018, pp.293-294

  • Publication Type: Conference Paper / Summary Text
  • City: Antalya
  • Country: Turkey
  • Page Numbers: pp.293-294

Abstract

Travertines occur along fractures in the crust and are formed by the deposition of calcium and bicarbonate from cold to hot mineral-rich waters. The fluid/rock interaction is an important process in the formation of calcitic or aragonitic travertines and tufa (CATT). In most situations the formation of CATT is related to dissolution of limestone from any location along the hydrogeological pathway. The formation of the travertines outcropping in Yaprakhisar village (Güzelyurt-Aksaray) which are the topic of the study is controversial. Geochemistry and dating studies with the 230Th/234,238U imbalance method were performed to determine the source of the travertines.

It is known that the link between base and the CATT (epigean and hypogean systems) can be revealed with evaluation of potential geochemical tracers such as Ba and Sr, which are used in geochemical evaluations and trace elements. In addition, CATT deposited from hypogenous sources with high Be content indicates granitic source, while high Cr values show the source may be fed from Cr-rich ultramafic rocks in the basement. According to the Ba-Sr diagram, travertines are sourced in hypogenous fluids from limestone-evaporite-dolomite, while the Be and Cr content were determined to present variations depending on the different travertine masses. When the NTE content of samples is noted, there were low values for total NTE and clear negative Ce and Eu anomalies in nearly all samples. Additionally, though not very clear, a positive Ho anomaly was determined.

Investigation and dating of travertines is very important in terms of determining the activity of faults and crustal deformation in tectonically active regions. With the U-series dating method, the Yaprakhisar travertines were identified to have ages ranging from 3500 to 146,000 years.

In conclusion, when all data are assessed, the travertines are concluded to have been deposited under oxic conditions from relatively low temperature water, with low acidity and hypogenous source in limestone-evaporite-dolomite. Additionally, considering the morphologies/ages of the Yaprakhisar travertines located in the region between the Tuzgölü Fault Zone Keçiboyunduran-Melendiz Fault, it may be considered that these travertines are related to these faults or formed in paleodiscontinuities occurring due to the interaction of these faults.