Toculla Project
Catalina’s Toculla Gold Project (“Toculla”) comprises eight exploration concessions or “pedimentos mineros” covering 2,100 ha.
They are located approximately 140 km northeast of the city of Iquique in Chile’s Region I – the northernmost region of Chile. Toculla lies between 3,700 and 4,000 m above sea level.
Fig. 1 Location of the Toculla Gold Project.
The geological setting of the region around Toculla is relatively straightforward consisting of a series of Tertiary ignimbrites and andesitic–rhyolitic lavas (the “younger volcanics”) covering older volcano-sedimentary formations.
Catalina’s concessions at Toculla overlie the eastern part of an extensive area of the older volcano-sedimentary rocks exposed in a “window” where the otherwise ubiquitous cover of younger volcanics has been stripped away.
Fig. 2 The Toculla Concessions
The darker areas are underlain by fresh, unaltered younger volcanics; the older volcano-sedimentary rocks are lighter in colour due to extensive hydrothermal alteration.
Toculla lies on a large regional-scale, NW-SE-trending structure (the Toculla-Puchuldiza Fault) which hosts active hydrothermal systems at Uscana, Huancure, Tuja and Puchuldiza. The structure appears to exert a profound control on the geological setting of the Toculla concessions.
Fig. 3 Structural Control on Hydrothermal Systems near Toculla
The (Puchuldiza-Tuja) system lies some 30-40 km to the southeast and hosts a “non-JORC” resource of circa 1 million oz of gold and other precious metals in veins and stockworks developed in explosion breccias and silicified zones.
Northwest – southeast structural trends are significant in both Argentina and Chile where prominent sets of similar lineaments strike across the Cordillera from east of the Puna in Argentina to the Chilean coast. Research suggests that repeated reactivation of these left-lateral strike-slip systems can create sites for mineral deposition.
Fig. 4 Geological Features of the Toculla Concessions
At Toculla, there are two, possibly three, exploration targets; the tops of two high-sulphidation (“HS”) epithermal complexes are evident in the eastern and central part of the concession area.
Some 500 m to the north of these, an extensive east-west trending zone of silicification (Silica Ridge) is flanked by argillic alteration. It is over 1,100 m long and approximately 200 m wide. It lies on strike with several hot, hydrogen-sulphide emitting thermal springs and is intruded by a series of hydrothermal breccias.
The proximity of the HS systems and the hot spring–silicification zone raises the intriguing possibility of interaction between the two and the remobilisation and re-concentration of precious metal mineralisation – possibly associated with a series of younger hydrothermal breccias.
Samples from the hydrothermal breccias have returned low precious metal values consistent with those found in the upper levels of epithermal complexes. Arsenic and barium are anomalous; lead, antimony, tellurium, zinc and cadmium are elevated and molybdenum values are high. Mercury values are particularly high with a maximum value of 23 ppm.
Toculla presents a similar geological, stratigraphic and structural setting to that in which the gold-silver mineralisation has been developed at Puchuldiza-Tuja. Similar precious metal mineralisation may well have developed at Toculla.
Although some eight RC drillholes have been completed to unknown depths at some time in the past at Toculla, it is clear that no work has been undertaken locally for some years.
Toculla is the only section on the Toculla-Puchuldiza Fault which lies outside the Volcan Isluga National Park and thus represents an attractive exploration target with the potential for a multi-million ounce precious-metal deposit in veins and stockworks.
A joint-venture partner is being sought to assist in taking the Toculla Project forward.
