Stratiform barite deposits hosted in metamorphic assemblages of Dinek and surrounding regions, Isparta, Turkey

The area of Dinek (Isparta, Turkey) hosts stratiform barite deposits that have been mined for sixty years. These deposits are extensive and contain over 90% BaSO4 in some places. Dinek deposits are thus economically significant, and represent a major portion of Turkey’s barite production. This paper describes the depositional, geochemical and origin characteristics of the Dinek and surrounding regions barite deposits. This information can help establish links with other barite deposits in Turkey, and help inform mining policy in Turkey. The 300 km2 study area was mapped in detail and some 300 samples were analyzed for petrography, bulk chemistry and sulfur and strontium isotopes. The most voluminous barite deposits occur in Lower Cambrian – Ordovician carbonate and pelitic rocks. Barites generally conform to host rock stratigraphy and display their own conformable stratiform morphology. Following deposition, host rock sections were deformed and rotated by regional metamorphism and tectonics. Barite deposits bear the signature of advanced diagenesis and show secondary veins, brecciation and fractured structure. Measured δ34S values for barite samples ranged from 3‰ to 31‰. Relatively high radiogenic Sr87/Sr86 values were observed for the northwestern (>0.71445) and southeastern sections (>0.71451) sections of the deposit, as well as for the host rocks (>0.71504). The relatively heavy sulfur isotopic ratios and radiogenic Sr signatures are inconsistent with a crustal magmatic or mantle derived source for the sulfate. These values instead indicate that barite sulfate derived from a primary marine source, while Ba cations may have been supplied by Ba-bearing host rocks. Numerous sedimentary structures, as well as the petrologic and geochemical character of the deposit indicate a dominantly sedimentary, diagenetic origin.

► The barite deposits occurred in the marine sedimentary basin.
► Barite deposits occur within Paleozoic sedimentary and low grade metamorphic rocks.
► Sulfate reduction processes leave seawater enriched in the heavier 34S isotope.
► Strontium isotopic values for barite samples were similar to those of host rocks.
► Barite was formed by mixing seawater sulfate and Ba rich pore fluids in the core.