SolGold provides exploration update for its Cascabel copper‐gold porphyry project in Ecuador.
The Aguinaga prospect lies along a prominent topographic high south of Rocafuerte and 1.3km to the north-east of Alpala. The interpreted porphyry centre at Aguinaga occurs at the confluence of a deep seated regional north-west trending structure with a major north-east trending lineament. This is the same structural regime that hosts porphyry centres at Alpala.
The Aguinaga prospect is characterised by a 500m x 500m magnetic high surrounded by an annular magnetic-low. This geometry is consistent with a porphyry system characterized by a central magnetic high related to an intrusive centre and a magnetite-destructive halo caused by pyritic phyllic / argillic alteration, such as indicated by large porphyry deposits elsewhere, including Alumbrera, Chile and Batu Hijau, Indonesia.
The presence of a contiguous and very strong chargeability high with a central tapering root at Aguinaga is consistent with sulphide-bearing, disseminated and/or stock work style mineralisation peripheral to and above a porphyry stock.
SolGold executive director Nicholas Mather said of Aguinaga: "It looks a lot like an Alumbrera magnetic signature. Porphyries often tend to cluster, like at Chuquicamata in Chile, so seeing four or five of them within the broader Cascabel project area is very encouraging."
Completion of a 100m x 100m soil grid over the prospect shows that the Aguinaga target area is also characterised by a central soil copper anomaly, which is defined at the 300ppm level with dimensions of 350m x 400m and contains a high of 1145 ppm or 0.11% copper. The presence of coincident molybdenum, gold and copper / zinc ratio in soil anomalies supports an inferred porphyry centre characterised by higher temperatures of mineralisation.
The low manganese in soil that flanks the central copper zone to the north and south is inferred to be related to intense late-stage hydrothermal alteration. The presence of elevated zinc surrounding this area of low manganese is a geochemical signature that is typical of the metal zonation around porphyry copper-gold deposits.
Reconnaissance field work has located mineralised porphyritic diorite along the northern slope of Aguinaga Hill, which returned assay results of 0.41% copper, and 0.29 g/t gold.
The diorite outcrop lies above the chargeability high that flanks the Aguinaga Hill and is described as "a porphyritic diorite containing quartz-pyrite-chalcopyrite quartz veins within a groundmass containing hornblende phenocrysts altered to a magnetite-biotite-chlorite alteration assemblage." This style of hydrothermal alteration is consistent with proximity to a porphyry centre.
Detailed, 1:500 scale, "Anaconda" style geological and structural mapping, trenching, infill soilsampling and spectral analysis of soil to determine hydrothermal alteration assemblages are planned in the near future to bring the prospect to a drill-ready status.