scholarly journals Reply to “Porphyry-related high-sulfidation mineralization early in Central American Arc development: Cerro Quema deposit, Azuero Peninsula, Panama” by Corral (2021)

2021 ◽  
Vol 73 (1) ◽  
pp. A101220
Author(s):  
José Perelló ◽  
Robert A. Creaser ◽  
Alfredo García

Dear Editor, we thank Corral (2020) for his anticipated interest in our paper on the timing of the porphyry-related high-sulfidation epithermal mineralization at Cerro Quema in the Azuero peninsula of southwestern Panama. Our study, based on three Re-Os ages for molybdenite intimately associated with Cu-bearing sulfide minerals from the hypogene roots of the La Pava center (Figure 1), shows that the main event of high-sulfidation Cu mineralization took place during the earliest Maastrichtian at ~71 Ma. The reported ages, together with the geologic relationships described in our paper (Perelló et al., 2020), plus a series of regional geologic, structural, petrochemical, and geotectonic considerations, not only precisely date the porphyry-related nature of the Cerro Quema high-sulfidation mineralization, but are also significant in that they confirm the rapid evolution of the earliest stages of the Central American Arc – from subduction initiation at 75-73 Ma to arc stability and maturation at 71 Ma (e.g., Buchs et al., 2011a and references therein) – and place the mineralization in a regional geodynamic setting. Irrespective of the regional geologic arguments reiterated by Corral (2020) in support of his previous genetic interpretation (e.g., Corral et al., 2016) and to invalidate our conclusions, Corral´s real concern is the reliability of our molybdenite ages, which are much older than his preferred age of mineralization for Cerro Quema. We believe that many of the points raised by Corral (2020), including the regional and local geologic backgrounds of the deposit and the dated samples, were properly addressed in Perelló et al. (2020), and that it would be redundant to repeat them here. Additional petrochemical evidence in support can be found in Whattam and Stern (2015, 2020) and Whatam (2018).

2021 ◽  
Vol 73 (1) ◽  
pp. A121220
Author(s):  
Isaac Corral

The Cerro Quema Au-Cu deposit is hosted by a dacite dome complex of the Río Quema Formation, a Late Campanian-Maastrichtian volcano-sedimentary sequence of the Panamanian magmatic arc. Its formational age is constrained at ~49 Ma by field evidences, crosscutting relationships and 40Ar/39Ar geochronology (Corral et al., 2016, Corral, 2021). The recent molybdenite Re-Os dates by Perelló et al. (2020) claim that ore is spatially and temporally related to the host volcanic domes at ~71 Ma. After a thorough review of the geologic, geochemical and geochronological data from the Cerro Quema area, it is concluded that the Re-Os dates of Perelló et al. (2020) are not representative of the Cerro Quema formational age. Their proposed formational age at ~71 Ma is significantly older than the age of the host rock (~67 Ma). Furthermore, they invoke a previously unrecognized regional-scale magmatic event solely based on their molybdenite Re-Os dates. Instead, the Cerro Quema genetic model discussed here, in which magmatic-hydrothermal fluids derived from porphyry copper-like intrusions associated with the Valle Rico batholith produced the Au-Cu mineralization at ~49 Ma, is consistent with the geology, geochemistry and geochronology of the Azuero Peninsula.


2020 ◽  
Vol 72 (3) ◽  
pp. A260719
Author(s):  
José Perelló ◽  
Alfredo García ◽  
Robert A. Creaser

The 70.74 to 70.66 Ma age range for three molybdenite samples accompanying pyrite- and enargite-bearing assemblages effectively constrains an earliest Maastrichtian age for the high-sulfidation Au-Cu mineralization at Cerro Quema, Panama. The epithermal system was contemporaneous with emplacement of a composite dacite dome complex in a geotectonic setting transitional from mafic, primitive intraoceanic (Azuero Protoarc) to more evolved island arc magmatism (Azuero Arc), during initial construction of the Central American land bridge at the trailing edge of the Caribbean Large Igneous Province (CLIP). The molybdenite ages confirm the rapid evolution of the earliest stages of the Central American Arc, from subduction initiation at 75–73 Ma to arc maturation at 71 Ma. A porphyry connection is apparent at Cerro Quema and characterized by highly contorted, banded, and planar quartz-veinlet stockworks and sheeted zones in pyrophyllite- and sericite-bearing patchy-textured rock. These are cut by ledges of quartz, alunite, and dickite, which implies overprinting of the advanced argillic lithocap onto the underlying porphyry environment. Hydrothermal telescoping resulted from synmineralization uplift congruent with an actively emerging volcanic arc, which the Re-Os molybdenite dates accurately constrain at 71 Ma, presumably as a far-field effect of collision between the leading edge of the CLIP with parts of North and South America.


2020 ◽  
Author(s):  
Isaac Corral

Abstract Cerro Quema is a high-sulfidation epithermal Au-Cu deposit located in the Azuero Peninsula, southwestern Panama. It is hosted by a dacite dome complex of the Río Quema Formation, a volcano-sedimentary sequence of the Panamanian Cretaceous-Paleogene magmatic arc. Cerro Quema has oxide resources of 24.60 Mt at 0.71 g/t Au and 0.04% Cu, and sulfide resources of 11.38 Mt at 0.41 g/t Au and 0.31% Cu. Alunite 40Ar/39Ar dating of a sample from Cerro Quema yielded a final age of 48.8 ± 2.2 Ma (weighted average of plateau age) and 49.2 ± 3.3 Ma (weighted average of total gas age). This age is interpreted to represent the formational age of the Cerro Quema deposit at ~49 Ma, linking it to the Valle Rico batholith intrusive event. Based on the new alunite 40Ar/39Ar data and a reexamination of published geochronological data, magmatic-hydrothermal deposits such as the Río Pito porphyry copper and the Cerro Quema high-sulfidation epithermal deposit formed during the early arc stage (68–40 Ma) in the Chagres-Bayano arc (eastern Panama) and the Soná-Azuero arc (western Panama), respectively. They formed in a similar geodynamic setting at ~49 Ma, when diorites and quartz-diorites intruded Cretaceous volcano-sedimentary sequences. Cerro Quema and Río Pito provide evidence for the exploration potential of Cretaceous-Paleogene arc segments. Exploration should focus on Cretaceous volcanic and volcano-sedimentary sequences intruded by Paleogene batholiths of intermediate to felsic composition.


Author(s):  
Anthony G. Coates ◽  
Marie-Pierre Aubry ◽  
William A. Berggren ◽  
Laurel S. Collins ◽  
Michael Kunk

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