Ayten Öztüfekçi Önal

Petrology of the İspendere (Malatya) ophiolite from the Southeast Anatolia: implications for the Late Mesozoic evolution of the southern Neotethyan Ocean

Abstract The İspendere ophiolite forms part of the Tauride active continental margin assemblage in SE Anatolia. The ophiolite exhibits an intact oceanic lithosphere section and is intruded by Late Cretaceous calc-alkaline granites. The ophiolite comprises mantle tectonites, ultramafic to mafic cumulates, isotropic gabbros, isolated diabase dykes, a sheeted dyke complex, plagiogranite and volcanic rocks. The volcanics and the sheeted dyke complex exhibit (1) similar rare earth element patterns, with flat to light rare earth element depletion (La–Yb)N=0.71–1.14 and 0.65–1.22, (2) negative Nb anomalies and (3) flat-lying high field strength element trends. These features differ from a typical Normal--Mid Ocean Ridge Basalt fractionation trend and could have resulted from c. 15% partial melting of a previously depleted mantle source. The whole-rock chemistry and the mineral chemistry of the ultramafic to mafic cumulates [high Ca plagioclases (An89–81), magnesian olivines (Fo88–81) and clinopyroxenes (Mg#90–83)] show that the primary magma of the plutonic suite is compositionally similar to modern island arc tholeiites. The available evidence suggests that the İspendere ophiolite formed at a northerly supra-subduction zone spreading centre of the Southern Neotethys, between the Taurides and the Bitlis–Pütürge metamorphic units, during the Late Cretaceous. Comparison with the adjacent Göksun, Kömürhan and Guleman ophiolites suggests that the İspendere ophiolite represents part of a single regional-scale sheet of oceanic lithosphere that was accreted to the base of Tauride active continental margin where it was cut by arc-type magmatic rocks.

Assessment of pollution potential of the Hasangazi chromite pit (Tunceli, Turkey): implications for the natural environment

AbstractThe Hasangazi chromite pit is an abandoned mine located to the east of the town of Pülümür (Tunceli, Turkey). The surface water that circulates in the pit flows into the Pülümür stream via the Turnadere creek. The quality of the surface water and soil from the region is important regarding the ecosystem in the Tunceli area. The open pit operations in the chromite deposits may be the cause of toxic element enrichments. To understand the effects of such pits, samples from the sediments, soil, waste material, and surface water were collected from the Hasangazi pit and its surrounding area. Samples were mineralogically and geochemically analyzed by XRD, ICP-OES, and ICP-MS methods. Mineralogical analyses showed the presence of chrysotile and plagioclase in the sediment and soil samples. These samples are also enriched in toxic elements, e.g., Cr, Ni, and Co. In particular, the Cr and Ni concentrations exceed the limits of soil pollution regulation of Turkey and the US Environmental Protection Agency. Overall the Cr, Ni, and chrysotile contents demonstrate the impact of the abandoned pit and the ultramafic rocks. Moreover, the surface water samples in the dry season have Zn concentrations above the toxic levels that may have been derived from the volcanic rocks. Environmental remediation precautions should immediately be taken around this inactive pit.

Identification of chrysotile in local soil at Beypinari village (Sivas-Turkey) regarding mine and health issue

Asbestos is dangerous for health and is forbidden to use in Turkey, but villagers who live in rural eastern part still use it especially for their home for insulation purposes and even as a substitute for baby powder. Therefore, geological and chemical properties of this type of soil, which is near the settlement, should be characterized and identified from the point of view of health. Beypinari asbestos deposits are located at Beypinari village, about 90 km southeast of Sivas, Turkey within Central Anatolian Ophiolites. Therefore, in the present study, the existence of chrysotile in Beypinari asbestos deposit were characterized and identified by mineralogical analysis and by major, trace, REE analysis. The results show that the samples contain different amount of calcite mineral, the main mineral being chrysotile.