The Maricunga belt hosts numerous alteration zones which are associated with appreciable precious metal mineralization. Marte, Lobo, and Aldebaran, is dominated by gold-rich porphyry deposits and prospects (>0.3 ppm Au) associated with eroded andesitic stratovolcanoes.
Marte and Lobo are rich in gold (1.43 and 1.6 ppm) and poor in copper (0.05 and 0.12%) and molydenum (46 and -'• 10 ppm), and may be designated as porphyry gold deposits. However, gold contents are lower (0.6-1 ppm) and hypogene copper contents probably higher at Refugio and Casale Hill.
In the Maricunga belt, nine examples of well-developed porphyry-type mineralization carrying gold and variable amounts of copper have been recognized to date: Marte, Lobo, Valy, Escondido, A1- Aldebaran (Casale Hill sector), La Pepa, Refugio, Amalia, and Santa Cecilia. Weakly developed quartz stockworking similar in style to that constituting the porphyry-type mineralization, and anomalous in gold, was observed within the alteration zones at Esperanza, La Coipa, and Pantanillos. As described above, porphyry-type mineralization is present in both the western--early Miocene--and eastern-middle Miocene--metallogenic subbelt.
Intrusive complexes
Subvolcanic porphyritic intrusive complexes are recognized locally in the Maricunga belt and appear to be located principally in the nuclei of eroded compound volcanoes, exclusively in association with areas of hydrothermal alteration. Some petr ........
