The first Precambrian gold deposit in North Xinjiang, NW China: Geochronology, metallogenic character, and ore genesis of the Dajingou gold deposit

The Dajingou gold deposit is one of the typical gold deposits in the Quruqtagh metamorphic terrane, north of the Tarim Craton. The deposit mainly comprises gold-bearing quartz veins hosted in Precambrian metamorphic rocks and structurally controlled by the subsidiary faults and ductile shear zone. To determine the age of gold mineralization in the Dajingou deposit, a single sericite 40Ar/39Ar age of 829.4 +/- 4.8 Ma (MSWD=0.57) and hydrothermal zircon weighted average U-Pb ages (812 +/- 15 Ma, MSWD=3.2) from auriferous quartz veins were obtained in this study, indicating that mineralization occurred in the mid-Neoproterozoic (ca. 0.83 Ga), corresponding to regional metamorphism of the Tarim Craton, termed the Tarim orogeny. The Dajingou deposit is the first Precambrian gold deposit identified in North Xinjiang, NW China. The delta O-18 and dD of quartz ranges from 14.7 parts per thousand to 15.9 parts per thousand and -104 parts per thousand to -75 parts per thousand, respectively; the calculated delta(OH2O)-O-18 of the fluids ranges from 0.9 parts per thousand to 5.0 parts per thousand. This suggests that the ore-forming fluids in the Dajingou gold deposit were derived from dehydration of metamorphic rocks during regional metamorphism, with a subsequent input of meteoric water. Based on its similarities with typical orogenic gold deposits, the Dajingou deposit is proposed to be an orogenic gold deposit formed during the mid-Neoproterozoic Tarim orogeny in the Tarim Craton.