Water circulation near the mixed - Water and microbiologic activity of the Mesozoic dolomite sequence, an example from the central Taurus, Turkey


Ayyildiz T., Tekin E., Satir M.

CARBONATES AND EVAPORITES, vol.19, no.2, pp.107-117, 2004 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 19 Issue: 2
  • Publication Date: 2004
  • Doi Number: 10.1007/bf03178474
  • Title of Journal : CARBONATES AND EVAPORITES
  • Page Numbers: pp.107-117

Abstract

Jurassic to Lower Cretaceous units, locating Central Taurus composed of thick dolomite with massive limestones beds and thinner dolomite beds with intercalated limestone are described. Various dolomite types include: Type 1) dolomite formed as dolomicrite as mimetic replacement, Type 11) dolosparite as a cloudy centre and clear rim in vugs, Type 111) The planar-e texture dolomites are scattered in a micrite matrix, Type IV) Mottled dolomite present as zones of light colored dolomite crystals in a darker groundmass, Type V) Fracture and void filling dolomite (zoned dolomite, overgrowth and saddle dolomite). The investigated dolomites exhibit 0.1 to -2.0parts per thousand PDB in delta(18)O values relative to their delta(13)C values (0.38 to 1.59parts per thousand PDB) in the Middle Jurassic dolomites. The petrographic and isotopic characteristics support that dolomitization fluids were variable mixtures of fresh and marine waters related to changes in sea level. The late dolomitization phase was followed by diagenesis in the presence of meteoric fluids. During this period, calcite cements were precipitated within fractures. These calcites have characteristically low delta(18)O and delta(13)C values (-3.0 to -4.9 and -0.8 to -5.7parts per thousand PDB, respectively).