PROJECTS - Quispe
Introduction
Exeter has identified porphyry-style gold and copper mineralisation at the Quispe prospect in Catamarca Province. Exploration on the property has included geological mapping, Landsat interpretation, an airborne magnetic/radiometric geophysical survey, ground geophysical surveys (magnetics, gradient array and dipole-dipole IP), rock chip and trench geochemical sampling. This work has provided several well defined exploration targets.
Quipse was located by following up a prominent Landsat anomaly (centre)
Potential
Exploration has identified gold and copper mineralisation of probable porphyry affinity at the Quispe prospect. The high sulphide environment may contain evidence of leaching of surface geochemistry. Ground geophysics indicates that the strong IP anomalies associated with the known mineralisation and alteration extend over a minimum surface extent of one kilometre and remains open for an extension to the south. Drilling targets have been identified for both gold and gold-copper mineralisation. Potential also exists to locate additional centres of mineralisation as regional airborne geophysics has identified a number of anomalies within favourable structural settings that are possibly related to intrusive/alteration systems. A joint venture partner is being sought to undertake further exploration on the property including drilling.
Silica-pyrite & tourmaline altered sediments and breccias (foreground)
Location and Access
The Quispe project area is located in southwestern Catamarca province in NW Argentina. The main prospect is located approximately 70 kilometres west of the town of Fiambala at an altitude of 4800m. Altitudes within the project area range between 3800 - 5500m. A major provincial gravel road passes within 13km of the main prospect which can be accessed by a bulldozed dirt track off the main road.
Geology and Mineralisation
The project area is dominantly underlain by Permian and Carboniferous sediments that have been locally intruded by several phases of younger (Cretaceous?/Tertiary?) stocks and dykes of acid to intermediate composition
The main Quispe prospect comprises an early microdiorite intruding the older sedimentary sequence. This system has been subsequently intruded by felsic quartz-feldspar porphyry with associated silica-sericite-pyrite alteration and hornblende andesite porphyry dykes. The prospect is located on a major NW structure adjacent to a NE splay off an interpreted arc-parallel fault. Faulting appears to have played a significant role in emplacement of intrusives and localisation of alteration and mineralisation.
Structurally-controlled gold mineralisation is associated with strongly silica-pyrite + tourmaline altered sediments and breccias. Rockchip sampling has identified a number of zones of anomalous gold geochemistry with values between 0.5-14.5ppm Au. Bulldozer trenching of these zones has returned values of 39m @ 1.2g/t Au (T5), 39m @ 0.6g/t Au (T1A) and 11m @ 0.8g/t Au (T7)
Gold-copper porphyry target at Quispe
Copper (malachite-azurite) mineralisation occurs in association with quartz-stockworking within hornblende andesite porphyry approximately 500 metres south of the known gold mineralisation. Rockchip sampling of the stockwork zone has returned assay values up to 2.6% Cu, 0.1ppm Au. The exposed copper zone is up to 100 metres wide but colluvial cover obscures the true extent of the mineralisation. Trenching has returned assay results of 42m @ 0.33% Cu, 0.2g/t Au (T3).
IP showing copper & gold geochemical anomalies
Geophysics
Grid-based ground magnetics, gradient array IP and dipole-dipole IP was conducted over the main Quispe prospect. The gradient array data indicate a minimum one kilometre long zone of high to very high chargeability associated with phyllic alteration. The IP anomaly is open to the south. The copper zone is associated with a resistivity high reflecting silicification and a moderate magnetic high indicating the possibility of a zoned porphyry system. Dipole-dipole IP confirms the chargeability high-resistivity low anomalies in proximity to the copper mineralisation.
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