Mineralization Regularity Of Gold Deposits And Prospecting Potential Evaluation Of Two Mineral Properties In The Central Pine Creek Orogenic Belt,Northern Territory,Australia

The central part of the Pine Creek Orogen is one of the three major gold ore concentration areas in the northern part of Northern Territory,Australia,which nears the capital Darwin.The approximate latitude and longitude ranges are: 12°20?-14°20? south latitude and 130°35?-132°30? east longitude.This paper systematically collects regional data on geology and minerals,sorts out the database of gold deposits and occurrences,studies the geological characteristics of typical gold deposits,discusses and summarizes the metallogenic models and laws of various types of gold deposits,and on this basis,evaluates the prospecting potential of two mineral properties within the study area.The main results and understandings of this paper are as follows:The gold deposits(occurrences)in the study area are divided into four subtypes: a)quartz vein type gold ore;b)banded ferriferous rock-related gold ore;c)gold-polymetallic ore;and d)alluvial gold placer.The three types of primary gold deposits were mainly formed later than the contact metamorphic peak,with little difference in the ore-forming fluids,all being mixtures of contact-thermal metamorphic water and magmatic water.The major differences in the ore-forming models were the ore-controlling structures and the ways of gold precipitation from the fluids.The study summarizes the spatial distribution of various types of gold deposits in relation to strata,structures and magmatic rocks.The gold formation is remarkably strata-bound.The quartz vein type gold mineralization is mainly hosted in the Mount Bonnie Formation,Gerowie Tuff Formation and Burrell Creek Formation.Most of the banded ferriferous rock-related gold deposits occur in the middle of the Koolpin Formation.The ore bodies of the two gold-polymetallic deposits occur as bedded lens in the lower segment of the Mount Bonnie Formation.The gold mineralization is also structurally controlled and mostly takes place near basement fault.The quartz vein gold deposits are mainly controlled by the Pine Creek shear zone,secondary faults and fold structures on both sides of the basement faults.The banded ferriferous rock-related gold deposits are usually formed as stratoid ore bodies under the confinement of the NW-trending anticline.Two typical gold-polymetallic deposits are located in the west and east flank of the Margaret syncline,respectively,and the interlayer fracture zone and detachment space are favorable to ore formation.Most gold deposits(occurrences)are located in the external contact zone of the Paleoproterozoic granitoids.The gold mineralization shows obvious zonal distribution.Two mineral properties in the Pine Creek Orogen have been evaluated: EL25294 has superior metallogenic geological conditions,with favourable mineralization types being quartz vein type gold mineralization and hydrothermal vein type polymetallic mineralization,and the priority targets for prospecting in the future are the core of the anticline,and the intersections of the anticline with the northeast-and west-east-trending faults.EL24906 has relatively poor ore-forming geological conditions and is less explored.Its potential for gold prospecting is not quite good,not even for finding a small gold deposit.