U-Pb and Ar-40-Ar-39 Geochronology and Isotopic Constraints on the Genesis of Copper-Gold-Bearing Iron Oxide Deposits in the Hasancelebi District, Eastern Turkey


KUŞCU İ., Yilmazer E., Gulec N., Bayir S., Demirela G., Kuscu G. G. , et al.

ECONOMIC GEOLOGY, cilt.106, ss.261-288, 2011 (SCI İndekslerine Giren Dergi)

  • Cilt numarası: 106 Konu: 2
  • Basım Tarihi: 2011
  • Dergi Adı: ECONOMIC GEOLOGY
  • Sayfa Sayısı: ss.261-288

Özet

The Hasancelebi deposit in eastern Turkey, with proven reserves of 95 million metric tons, is a copper-gold-bearing iron oxide deposit. It is chiefly hosted by rocks that underwent widespread sodic-calcic and potassic styles of alteration. In the Hasancelebi district, pervasive Na-Ca and K-Fe alteration types are overprinted by sericitization and by late alteration that occur in multiple, overprinting systems. The age of hydrothermal alteration and mineralization (ca. between 74-68 Ma) overlaps with the age of alkaline magmatism in the Hasancelebi district. Crystallization and cooling of alkaline magmatism is associated with hydrothermal features that spanned the duration of the district's igneous history. The Ar-40/Ar-39 and U-Pb geochronology of magmatism indicate that the hydrothermal system was synchronous with diabase and syenite and/or microsyenite porphyry intrusions and consisted of several discrete phases of Na-Ca and K-Fe alteration. The oldest alteration (phase 1) formed at ca 74.4 to 74.3 Ma; it is spatially and temporally associated with the emplacement of diabase dikes and contains scapolite and phlogopite. The next younger alteration (phase 2) formed at about 71.3 Ma and is spatially and temporally associated with syenite porphyry and microsyenite porphyry intrusions. It consists of scapolite, garnet, pyroxene, and actinolite that are superimposed on the first alteration phase. The next alteration assemblage (phase 3) formed at about 68.6 Ma and consists of phlogopite 2 and magnetite mineralization. Still later alteration (phase 4) overprints phases 1, 2, and 3 and consists of sericite-quartz, char copyrite, hematite, calcite, fluorite, and barite.