Commodity: gold - silver
Marillan Prospect is located at 42 Km to the NW of Los Menucos town, Rio Negro province, Argentine Republic. Central coordinates are 2.540.000 E and 5.491.000 N (Gauss Kruger, Campo Inchauspe). The interest area is covered by 3 mines with 8,825 hectares.
Was recognized an area of 10 Km2 with hydrothermal alteration. Mentioned alteration was characterized like advanced argillic by PIMA method. Main alteration minerals identified are kaolinite and dickite and occasionally pyrophyllite, halloysite, illite and smectite.
The andesitic rocks when are affected by the argillic alteration show all their minerals completely argillized and is possible to see veinlets of dickite - kaolinite with abundant hematite like product of mafic deferrization. When the alteration decreases in intensity the rock-forming minerals are partially argillized and dominates clays are smectite and halloysite registering occasionally veinlets of kaolinite - dickite, noting also hematite product of mafic deferrization.
Numerous outcrops of silicified structures (residual silica), which are replacements of the original rock by microcrystalline silica and occasionally pyrite and show like main orientation NE, NS and EW were recognized.
Genetically is considered this type of alteration like advanced argillic and are related to high sulphidation epithermal systems. Given the extension of the above-mentioned alteration is expected to be linked to a major in-depth epithermal system.
From three epithermal systems recognized on the LLIT belt, Marillan is where less works were done until today. Solely were done a couple of recognition campaigns, where 19 geochemical samples were taken. Likewise, 23 samples were taken in order to analyse by PIMA method to characterize different types of alteration. Precious metals were not detected although yes the presence of trace elements like mercury and barium.
Genéticamente se considera este tipo de alteración como argílica avanzada y se la relaciona con sistemas epitermales de alta sulfuración. Dada la extensión de la alteración mencionada es de esperarse que esté relacionada a un importante sistema epitermal en profundidad.