The mineralogy of Paleozoic rocks from the Amanos region, Turkey [Amanoslar bölgesi Paleozoyik kayaçlari{dotless}ni{dotless}n mineralojisi]

Abstract

In the Amanos region, a Precambrian-Triassic sequence is formed by mainly clastic and carbonate rocks and their very low-grade metamorphic equivalents that contain calcite, dolomite, quartz, feldspar, goethite and phyllosilicate (illite, chlorite, kaolinite, paragonite, paragonite-muscovite, smectite, illite-chlorite (I-C), chlorite-vermiculite (I-V) and chlorite-smectite (C-S)) minerals. Of these, maximum quantities are reached for quartz and feldspar in Zabuk and Sadan, calcite in Hasanbeyli and Cudi, and dolomite in the Koruk formations. Illite is abundantly found in all units, whereas there are increases in the chlorite contents in the Sadan, Sosink and Hasanbeyli formations, a minor amount of kaolinite in the Zabuk, Koruk and Seydisehir formations, I-C in the Sadan, Seydişehir and Ki{dotless}zlaç Formations, C-V in the Seydişehir, Ki{dotless}zlaç and Akçadag formations, and C-S in the Sadan and Sosink formations. Paragonite and paragonite-muscovite are observed only in the Ki{dotless}zlaç and Akçada? formations. Illites and IIb chlorites have mostly anchimetamorphic and partly late diagenetic and epimetamorphic crystallinity degrees. The b0 parameters of the illites are distinctive for units, and higher values are measured for Seydisehir and older units, whereas lower values are found for the younger units (Ki{dotless}zlaç, Hasanbeyli and Cudi). 2M1 illites are observed in all units, but 1M in Precambrian-Ordovician units (Sadan, Zabuk, Koruk, Sosink and Seydişehir) and 1Md in Devonian (Hasanbeyli) and in Precambrian-Ordovician units, in smaller amounts. Feldspar also increases in the chlorite and chloriteinterlayered minerals-bearing levels that are related to volcanic feeding, and 1M polytype accompanies this association. The mineralogical properties have no regular distribution based on thickness and geological age, and sudden changes are observed between some of the formations, which is an indication related to mostly source rock, tectonic setting and geodynamic evolution rather than to degrees of diagenesis/metamorphism. In the sequences representing passive margin depositional environments, the Precambrian Sadan formation and Ordovician Bedinan and Devonian Akçada? formation have the mineralogical characteristics of convergent-and extensional basins, respectively. The lower Paleozoic parts of the sequence are similar to equivalents in the Eastern Taurus Autochthon (Geyikda?i Unit) with regard to mineralogic features, but its Devonian-Triassic part is different from equivalent parts of the units of the Tauride Belt and Southeastern Anatolian Autochthon in the Hazro region.