Lateral and vertical variations in sedimentology and geochemistry of sub-horizontal laminated travertines (Çakmak quarry, Denizli Basin, Turkey)

Abstract

The laterally extensive sub-horizontal laminated travertine deposits outcropping in the Çakmak quarry (Denizli Basin, Turkey) allows reconstructing their three-dimensional geobody architecture. Based on field observations, detailed petrographic and geochemical analyses (stable carbon and oxygen isotopes, major and trace elements) the most important controlling porosity-permeability parameters in this lacustrine-dominated facies, in relation to microfacies and diagenetic modifications were constrained. Sedimentological analyses and the observed architectural geometries allowed to subdivide the sub-horizontal carbonate succession into three main depositional units. These units in turn, based on macro- and microscopic observations were subdivided into nine dominant lithotypes reflecting an overall shrub flat and a marsh pool depositional setting. The shrub flat facies mainly comprises dendritic shrub crusts boundstone, pustular grainstone and clotted micrite mudstone to boundstone. In contrast, the marsh pool environment is dominated by coated reed rudstone to boundstone, cryptalgal silty bioclast-rich bioturbated mudstone and peloidal packstones. The diagenetic study revealed that the sediments were affected by dissolution, cementation, sparmicritization, recrystallization, and local formation of Fe-oxi/hydroxides and chalcedony. Among the diagenetic products, in particular, the calcite cements were investigated, applying micro-analysis of stable carbon and oxygen isotopes. Accordingly, the co-variation between the obtained isotopic values and the elemental concentrations (Sr, Mg, Na, and S) point to a thermogene fluid system that likely circulated through the subsurface limestones, dolomites and evaporites of the Lycian Nappes. These findings ensure an in-depth understanding of continental carbonate deposition, i.e. sub-aqueous travertines, in the context of a lacustrine depositional system. © 2018