After 80 years of industrial-scale mining, the Pasco Complex keeps revealing new styles of mineralization, new exploration targets, and ultimately, new resources and reserves. The complex is host to several types of mineralization formed during the intrusion of Oligocene porphyries into Late Triassic carbonated rocks (Chambará Formation, part of Pucará Group). Mineralization styles include Zn-Pb-Ag-Cu skarn, Pb-Zn-Ag breccias, Zn-Pb-Ag-Cu±Au intermediate sulfidation polymetallic veins, Pb-Zn-Ag stratabound in sandstones, and Cu-Au±Mo porphyry.
Recently, hyperspectral core imaging was performed on 3984.5 meters of drill cores from Pasco Complex, using imaging spectroscopy to collect continuous mineralogy. Two types of product were generated, images that preserve the textural context of minerals, and numerical data extracted from spectral features such as absorptions, in the visible-near infrared and short-wave infrared, and Reststrahlen peaks in the long-wave infrared.
This presentation shows the results of the hyperspectral imaging and its implications for the exploration of the district. One such result is the identification of intrusive pulses associated with early and late alteration of the Santa Barbara porphyry as a result of the characterization of micas using the shortwave infrared range. Another result is the use of the longwave infrared range for the differentiation of proximal and distal environments in the Atacocha skarn and its prograde and retrograde alteration domains.
Talk Title: Hyperspectral imaging in Pasco Complex and applications in exploration, Cerro Pasco district, Peru
Miguel Martínez, ALS
Aline dos Anjos, NEXA
Mervin Tapia, NEXA
Jonas Mota, NEXA
PDAC 2020, Room number: Room 711
Speaker presentation time: 10:50am
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