Summary of results. Laser ablation ICP-MS in situ apatite geochronology of the Molyhil tungsten-molybdenum deposit and Prospect D nickel-copper prospect

Abstract

This Record presents isotope and chronologic data collected on apatite at the Australian Research Council Centre of Excellence in Ore Deposits at the University of Tasmania. Analyses were carried out in August of 2017 in support of Northern Territory Geological Survey's regional geoscientific investigations and mapping programs. Isotope data and interpretations for apatite from two samples taken from the Aileron Province in HUCKITTA and BARROW CREEK in the Northern Territory are presented herein. Apatite was analysed in order to constrain the timing of igneous activity and hydrothermal infiltration at the skarn-hosted Molyhil tungsten-molybdenum deposit, and the timing of alteration or metamorphism related to nickel-copper mineralisation at Prospect D.

A sample of brecciated and calcite-quartz-fluorite veined fine-grained K-feldspar-quartz granite of the Marshall Granite was collected at the Molyhil deposit and yielded a concordia age of 1732 ± 8 Ma. This age is interpreted to record crystallisation of the Marshall Granite prior to vein emplacement.

A sample of altered or metamorphosed gabbro from Prospect D yields a lower intercept age of 1776 ± 53 Ma; this age is interpreted to record the timing of alteration or metamorphism of this unit. Disseminated sulfides in the sample likely formed during magmatic emplacement, and were deformed during alteration or metamorphism at ca 1.78 Ga.