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Geochemical and tectonic characteristics of manganese mineralization in the Yozgat region, Turkey

Öksüz Nursel, Koçak İsmail, Temiz Uğur

Geological Quarterly

2021

Vol. 65, No. 2

art. no. 31

North of the Central Anatolian Crystalline Complex and bordered by the İzmir-Ankara-Erzincan Suture Zone, mineralization occurs within ophiolites known as Anatolian Ophiolite Complex. The mineralization is present within banded, laminated and lenticular radiolarites which are intensely fractured and folded. It is distributed around Derbent, Baltasarilar, Cihanpasa, Buyukmahal, Eymir and Kadisehri where pyrolusite, psilomelane, manganite and braunite comprise the main paragenesis and jacobsite, magnetite, limonite and goethite are minor phases. The negative Eu anomaly suggests that the hydrothermal source was distant from the mineralization area or was mixed with seawater. All samples from the Cihanpasa and Buyukmahal areas have a negative Ce anomaly and resemble low-temperature hydrothermal mineral deposits. Samples from other locations (Derbent, Baltasarilar, Cihanpasa, Eymir, Buyukmahal, Tarhana) are characterized by both negative and positive Ce anomalies. From this it can be inferred that both hydrothermal and hydrogenetic processes were active in mineralization. High Ba contents and a LREE-enriched pattern together with negative Ce anomalies and trace element distributions indicate that the mineralization in the area was derived from a primary hydrothermal source. In addition, diagenetic and epigenetic processes may also have played an important role in the manganese mineralization.

Geochemistry of the Igdekoy-Doganlar Na-Ca borate deposit, Emet Province (western Anatolia, Turkey)

Koçak İsmail

Geological Quarterly

2020

Vol. 64, No. 3

807--817

Borates at the Igdekoy-Doganlar locality were deposited in a Miocene lacustrine environment during periods of Paleogene to Early Quaternary volcanic activity. The mineral paragenesis consists of probertite – NaCaB5O7(OH)4 3H2O, ulexite - NaCa[B5O6(OH)6] · 5H2O, hydroboracite - CaMg[B3O4(OH)3]2 3H2O, colemanite - Ca[B3O4(OH)3] · H2O, halite, anhydrite, glauberite, smectite and illite. The major element, Ca, is higher in the lgdekoy-Doganlar deposits compared to the averages for andesite and the Earth's crust. Within the trace elements, notable enrichment is identified in Li, Se, As, Sb, Sr and Cs. Lithium and Se occur in sufficient concentrations to be considered as economically valuable by-products. B and Sr anomalies can be used as an important marker in the exploration for boron deposits. The Y/Ho ratio of the lgdekoy-Doganlar borates is close to chondritic values. The negative Ce anomaly in borates from the lgdekoy-Doganlar deposit suggests that deposition occurred under oxidative conditions. The Eu and Ce anomalies reflect a hydrothermal contribution of REE. Geochemical and geological data suggest that the lgdekoy-Doganlar borate deposits were formed in high-pH playa lakes that were discharged from volcanic and terrestrial environments under evaporative conditions due to the effect of arid-semi arid climate.