White Rock Minerals Ltd (ASX:WRM) (OTCMKTS:WRMCF) has completed interpreting magnetic data from an airborne magnetics survey conducted in 2020 at Last Chance Gold Target in Alaska, identifying a distinct remnant signature associated with mapped Cretaceous granites, which will assist in further drill targeting during 2021.
The work aimed to identify structural positions related to potential intrusion sources driving the large gold mineral system identified at Last Chance and has indicated the likely presence of a roofed intrusive system extending east-west to the south of the main surface gold anomaly.
This could be a probable heat and metal source for Cretaceous age hydrothermal activity.
Inversion modelling in the area of the Last Chance gold anomaly indicates that the depths to the top of the interpreted intrusions range between 500 to 2,000 metres, with a number of possible intrusive apophyses and controlling structures with related alteration extending close to surface.
Additional work required
Additional work is required to distinguish between structures active during gold mineralisation and the more recent active neotectonic faults unrelated to mineralisation.
Drilling to date has uncovered brittle re-activated fault systems which were once pathways for hydrothermal fluids as well as more recent barren fault-gouge structures.
The magnetic interpretation provides the beginnings of a structural framework that can continue to be refined with additional data and will form the foundation for targeting structural hosted gold mineralisation.
Selection of the most favourable structural conduits above the interpreted granites will be aided by the alteration and geochemical data acquired from mapping, surface sampling, drilling and satellite spectral analysis completed during 2020.
White Rock expects to be able to drill test structural positions with the potential for high-grade gold mineralisation during the 2021 field season that is expected to begin in mid-June.
New VMS targets
Furthermore, the magnetics interpretation has provided improved understanding of the VMS potential that extends across the tenement package to the north of Last Chance.
Reconnaissance mapping and sampling identified six target areas with outcropping VMS mineralisation at Horseshoe, Bib, Bib West, Ringer, Peaches and Grapple in February as well as a clear stratigraphic domain that hosts these western VMS mineral occurrences.
The prospective Magnetic VMS Domain provides an area of focus for more intense prospecting in conjunction with more detailed surface sampling and geophysical surveys across the new target areas early during the 2021 field season.
It is expected that surface prospecting will define targets for drill testing during the second half of the 2021 field season.