The Tafak manganese deposit (Dursunbey-Balikesir, NW Turkey): Implications for the submarine hydrothermal origin of Izmir-Ankara-Erzincan Neotethyan Ocean

Abstract

In Turkey, radiolarian chert-hosted Mn-oxide deposits are exposed commonly within the deep-sea pelagic sediments belonging to the ophiolitic melange units along northern branch of the Neotethys (Izmir-Ankara-Erzincan Suture Zone) in northern Turkey. In the Tafak region (Dursunbey, Balikesir), Mn-deposit is currently mined from large- to medium- scale lenses (ca. 10 x 100 m) and interlayers with the mudstone and silicious pelagic sediments. This deposit comprises dominantly mineral assemblages of braunite, pyrolusite, and ganque minerals are quartz and rarely calcite. High Mn/Fe (437), Co/Zn (1.36), Co/Ni (2.04) ratios, low contents of sigma REE (27.7 ppm), Cu+Ni+Co (303 ppm), and also negative Ce anomaly (Ce/Ce*(PAAS) = 0.46), positive Y anomaly (Y-SN/Ho-SN = 1.33) with Y/Ho ratio (36.09) suggest that Tafak Mn deposit formed in a submarine hydrothermal system. Redox-sensitive element ratios (Ni/Co = 0.23-1.45, V/Mo = 2.63-20.81), positive Mn*(SN) (3.03-5.04), low Sr concentrations (82.2 ppm) and Ce-anom. (- 0.52) values indicate that the Tafak Mn deposit was formed in low-salinity and oxygenated marine environment. Meanwhile, the presence of weakly negative Eu anomaly (0.94), Ce anomaly (0.46), and sigma REE/Fe ratio (127.8 x10(-4)) suggests that low-temperature hydrothermal fluids (< 200 degrees C) in pelagic depositional site of the Izmir-Ankara-Erzincan Neotethyan Ocean were effective in formation of the Tafak manganese deposit.