Cerro Quema (Azuero Peninsula, Panama): Geology, Alteration, Mineralization, and Geochronology of a Volcanic Dome-Hosted High-Sulfidation Au-Cu Deposit

Abstract

Cerro Quema (Azuero Peninsula, SW Panama) is a high sulfidation epithermal Au-Cu deposit hosted by a dacite dome complex of the Río Quema Formation (Late Campanian to Maastrichtian), a fore-arc basin sequence. Mineral resource estimate (Indicated + Inferred) are 30.86 Mt @ 0.73 g/t Au, containing 728,000 Oz Au (including 76.900 Oz AuEq of Cu ore). Hydrothermal alteration and mineralization are controlled by an E trending regional fault system. Hydrothermal alteration consists of an inner zone of vuggy quartz with locally developed advanced argillic alteration, enclosed by a well-developed zone of argillic alteration, grading to an external halo of propylitic alteration. Mineralization produced dissemination and microveinlets of pyrite and minor chalcopyrite, enargite and tennantite, with traces of sphalerite, crosscut by late stage base metal veins. New 40 Ar/ 39 Ar data of igneous rocks combined with biostratigraphic ages of the volcanic sequence indicate a maximum age of Lower Eocene (~55-49 Ma) for the Cerro Quema deposit. It was probably triggered by the emplacement of an underlying porphyry-like intrusion associated with the Valle Rico batholith. The geologic model suggests that in the Azuero Peninsula high sulfidation epithermal mineralization occur in the Cretaceous-Paleogene fore-arc. This consideration should be taken into account when exploring for this deposit type in similar geologic terranes.

Mineralogical Distribution of Germanium, Gallium and Indium at the Mt Carlton High-Sulfidation Epithermal Deposit, NE Australia, and Comparison with Similar Deposits Worldwide

“…We used two separate analytical protocols for sulfates/silicates and sulfides/sulfosalts, respectively. For alunite, barite and dickite, the collected analytes were 27 Al, 31 P, 44 Ca, 49 Ti, 53 Cr, 55 Mn, 57 Fe, 65 Cu, 66 Zn, 71 Ga, 72 Ge, 75 As, 77 Se, 85 Rb, 88 Sr, 98 Mo, 107 Ag, 115 In, 118 Sn, 121 Sb, 137 Ba, 139 La, 140 Ce, 197 Au, 208 Pb, 209 Bi, 232 Th and 238 U. The internal standard isotopes used for data reduction were 27 Al (alunite and dickite) and 137 Ba (barite), based on contents confirmed previously by WDS.…”

Exhumation of the Panama basement complex and basins: Implications for the closure of the Central American seaway

“…We present zircon U‐Pb ages, apatite (AHe) and zircon (ZHe) (U‐Th)/He thermochronologic data, and Lu‐Hf isotopic data from batholiths in the Azuero Peninsula, and from the oldest known sedimentary successions deposited in Central Panama (Gatuncillo Formation) and the Azuero Peninsula (Cobachón and Tonosí Formations) (Figure ). These data are combined with geochronologic and thermochronologic data compiled from recent studies [ Montes et al ., ; Whattam et al ., ; Farris et al ., ; Corral et al ., ; Lissinna , ; Villagomez and Spikings , ; Wegner et al ., ] (Table ) to constrain: (1) the low‐temperature cooling history of the batholiths of the Azuero Peninsula and Central Panama, (2) the cooling histories of the plutonic rocks currently exposed in drainage basins of the San Blas Range, (3) the provenance and source of the Eocene successions, (4) the timing of exhumation of the Eocene strata in the Gatuncillo, Tonosí and Cobachón basins, and (5) the variation on the exhumation patterns along the Isthmus. These results complement the previous studies about the paleogeographic evolution of the Isthmus of Panama, describing the history of uplift and exhumation of the Panamanian volcaniclastic basement in the Azuero Peninsula, Central Panama and associated basins.…”

Trace-metal content of the Cerro Quema Au-Cu deposit (Azuero Peninsula, Panama): Implications for exploration

“…The Cerro Quema high-sulfidation epithermal Au-Cu deposit covers an area of ~20 km 2 in the center of the Azuero Peninsula (Figure 1). The mineralization is hosted in the dacite dome complex of the Río Quema Formation (late Campanian to Maastrichtian; Corral et al, 2013Corral et al, , 2016. Peninsula and location of the Cerro Quema Au-Cu deposit (after Corral et al, 2013Corral et al, , 2016.…”

“…The Río Quema Formation is a volcanosedimentary sequence that represents the earliest calc-alkaline volcanism of the Azuero Arc Group. In the Cerro Quema area, this sequence is bounded to the north by the Valle Rico batholith, 552 GEOLOGIC SETTING a series of Eocene (55-49 Ma;Del Giudice and Recchi, 1969;Kesler et al, 1977;Lissinna, 2005;Montes et al, 2012;Corral et al, 2016) diorite and quartz diorite intrusions with calc-alkaline affinity. The Late Cretaceous Azuero Igneous Basement (Aptian to Santonian; Kolarsky et al, 1995;Kerr et al, 1997;Hoernle et al, 2002;Lissinna, 2005;Buchs et al, 2010) comprises tholeiitic basalts and pillow basalts with oceanic plateau affinity that bounds the Río Quema Formation to the south (Figure 1).…”

“…Additional orebodies have been discovered to the east of Cerro Quema; however, their resources have not yet been assessed. Although several studies have been performed on the geology of the deposit (Leach, 1992;Horlacher and Lehmann, 1993;Torrey and Keenan, 1994;Nelson, 1995;Corral et al, 2011), on its origin and evolution (Corral et al, 2016(Corral et al, , 2017, and on the metallogenic potential of the Azuero Peninsula (Del Giudice and Recchi, 1969;Ferenčić, 1970;Kesler et al, 1977;Corral et al, 2016), there is still a gap in the knowledge of the trace metal composition of the Cerro Quema Au-Cu ore. Lithocaps associated with high-sulfidation epithermal deposits can have large extensions of advanced argillic altered rocks (> 20 km 2 ). However, typically only a small portion of the lithocap is mineralized, and due to the lack of directional indicators, exploration in this environment can be difficult (Sillitoe, 1995;Corbett and Leach 1998;Chang et al, 2011).…”