THE LEON PROPERTY: MOLYBDENUM-COPPER-SILVER-GOLD MINERALIZATION IN DECAPITATED ROOT ZONE OF THE EL CRESTON MINERAL DEPOSIT, SONORA, MEXICO
Mineralization on the Leon Property probably occurred in two pulses spatially associated with quartz veins in hydrothermally altered country rock. Host rocks commonly altered to hematite, limonite, sericite and kaolinite include Proterozoic gneiss and granite, Late Cretaceous granodiorite, Late Cretaceous(?) diorite, early(?) Tertiary rhyodacite porphyry, and mid(?) Tertiary leucocratic biotite monzogranite. Two sub-parallel detachment faults separate these mineralized footwall rocks from a hanging wall composed of Paleoproterozoic granite overlain by Neoproterozoic(?) quartz sandstone. These faults may represent up-dip extensions of the El Creston and Gemini faults (Leon and Miller, 1981), down dropped to the southwest along a N30W striking normal fault.
Colibri Corporation has collected and assayed hundreds of rock chip and soil samples. These samples delineate strong molybdenum, copper and zinc mineralization within the footwall block adjacent to the detachment fault. Soil assays exceed 200 ppm molybdenum and 1000 ppm copper over an area greater than 2 km2; chip samples from quartz veins and altered granodiorite host rock average 580 ppm molybdenum. Diamond core drilling demonstrates comparable assays, including a 72 m intercept averaging 0.195% (1950 ppm)