Response of supergene processes to episodic Cenozoic uplift, pediment erosion, and ignimbrite eruption in the porphyry copper province of southern Peru

The landform chronology for the area surrounding the Cuajone, Quellaveco, and Toquepala deposits (ca. 17 degrees S) is revised and extended northwestward through field mapping to the Cerro Verde-Santa Rosa district (ca. 16 degrees 30' S). The 40Ar-39Ar incremental-heating dates of supergene alunite group minerals from the Angostura (38.1 and 38.8 Ma) and Posco (38.8 Ma) prospects and the Cerro Verde deposit (36.1-38.8 Ma) demonstrate that supergene processes were underway in the late Eocene beneath a subplanar topography resulting from uplift and erosion during the Incaic orogny, now represented by a regional unconformity in the Cenozoic volcanic-sedimentary rock succession. Broadly contemporaneous supergene processes were probably active in the Cuajone-Quellaveco-Toquepala district. Slow erosion and the accumulation of elastic sediments through the tectonically quiescent early to mid-Oligocene are envisaged to have caused a rise in the water table and the widespread preservation of the Incaic supergene profiles. Aymara uplift subsequently led to the incision of the 23.8 to 24 Ma Altos de Camilaca and the 18.8 to 19.1. Ma Pampa Lagunas pediplains and their regional correlatives. The ensuing water-table lowering was associated with intense leaching and sulfide enrichment from the late Oligocene (24.4-28 Ma natroalunite at Cerro Verde, 26-27 Ma natroalunite at Santa Rosa, and 28.6 Ma jarosite at La Llave) to the early Miocene (23 Ma alunite and 21 Ma natroalunite at Cerro Verde, and 19.2 Ma jarosite at La Llave) and was plausibly responsible for much of the upgrading of the Cuajone and Toquepala deposits and thr Quellaveco prospect, which are intersected by both the Altos de Camilaca pediplain and erosional features representing upslope extensions of the Pampa Lagunas pediplain. The younger supergene profiles were widely superimposed on the remnants of those generated during the Incaic orogeny. Middle Miocene (<= 14.2 Ma biotite age) Chuntacala Formation flows protected the Cuajone supergene profile from destruction by erosion, but at 13.0 Ma interrupted supergene processes at Quellaveco. Revision of volcano-stratigraphic relationships in the latter area reveals that subsequent erosion of the Chuntacala Formation ignimbrites and part of the supergene profile took place prior to the deposition of a 10.1 Ma ash-flow tuff of the Asana Formation. Elsewhere, supergene activity persisted at the Cachuyito prospect through 11.4 Ma, and minor jarosite development occurred at least Until 4.9 Ma both there and at Cerro Verde during and following the Multiple Pediment landform stage (ca. 7.9-1.5.0 Ma). The landform chronology for the area surrounding the Cuajone, Quellaveco, and Toquepala deposits (ca. 17 degrees S) is revised and extended northwestward through field mapping to the Cerro Verde-Santa Rosa district (ca. 16 degrees 30' S). The 40Ar-39Ar incremental-heating dates of supergene alunite group minerals from the Angostura (38.1 and 38.8 Ma) and Posco (38.8 Ma) prospects and the Cerro Verde deposit (36.1-38.8 Ma) demonstrate that supergene processes were underway in the late Eocene beneath a subplanar topography resulting from uplift and erosion during the Incaic orogny, now represented by a regional unconformity in the Cenozoic volcanic-sedimentary rock succession. Broadly contemporaneous supergene processes were probably active in the Cuajone-Quellaveco-Toquepala district. Slow erosion and the accumulation of elastic sediments through the tectonically quiescent early to mid-Oligocene are envisaged to have caused a rise in the water table and the widespread preservation of the Incaic supergene profiles. Aymara uplift subsequently led to the incision of the 23.8 to 24 Ma Altos de Camilaca and the 18.8 to 19.1. Ma Pampa Lagunas pediplains and their regional correlatives. The ensuing water-table lowering was associated with intense leaching and sulfide enrichment from the late Oligocene (24.4-28 Ma natroalunite at Cerro Verde, 26-27 Ma natroalunite at Santa Rosa, and 28.6 Ma jarosite at La Llave) to the early Miocene (23 Ma alunite and 21 Ma natroalunite at Cerro Verde, and 19.2 Ma jarosite at La Llave) and was plausibly responsible for much of the upgrading of the Cuajone and Toquepala deposits and thr Quellaveco prospect, which are intersected by both the Altos de Camilaca pediplain and erosional features representing upslope extensions of the Pampa Lagunas pediplain. The younger supergene profiles were widely superimposed on the remnants of those generated during the Incaic orogeny. Middle Miocene (<= 14.2 Ma biotite age) Chuntacala Formation flows protected the Cuajone supergene profile from destruction by erosion, but at 13.0 Ma interrupted supergene processes at Quellaveco. Revision of volcano-stratigraphic relationships in the latter area reveals that subsequent erosion of the Chuntacala Formation ignimbrites and part of the supergene profile took place prior to the deposition of a 10.1 Ma ash-flow tuff of the Asana Formation. Elsewhere, supergene activity persisted at the Cachuyito prospect through 11.4 Ma, and minor jarosite development occurred at least Until 4.9 Ma both there and at Cerro Verde during and following the Multiple Pediment landform stage (ca. 7.9-1.5.0 Ma). The landform chronology for the area surrounding the Cuajone, Quellaveco, and Toquepala deposits (ca. 17 degrees S) is revised and extended northwestward through field mapping to the Cerro Verde-Santa Rosa district (ca. 16 degrees 30' S). The 40Ar-39Ar incremental-heating dates of supergene alunite group minerals from the Angostura (38.1 and 38.8 Ma) and Posco (38.8 Ma) prospects and the Cerro Verde deposit (36.1-38.8 Ma) demonstrate that supergene processes were underway in the late Eocene beneath a subplanar topography resulting from uplift and erosion during the Incaic orogny, now represented by a regional unconformity in the Cenozoic volcanic-sedimentary rock succession. Broadly contemporaneous supergene processes were probably active in the Cuajone-Quellaveco-Toquepala district. Slow erosion and the accumulation of elastic sediments through the tectonically quiescent early to mid-Oligocene are envisaged to have caused a rise in the water table and the widespread preservation of the Incaic supergene profiles. Aymara uplift subsequently led to the incision of the 23.8 to 24 Ma Altos de Camilaca and the 18.8 to 19.1. Ma Pampa Lagunas pediplains and their regional correlatives. The ensuing water-table lowering was associated with intense leaching and sulfide enrichment from the late Oligocene (24.4-28 Ma natroalunite at Cerro Verde, 26-27 Ma natroalunite at Santa Rosa, and 28.6 Ma jarosite at La Llave) to the early Miocene (23 Ma alunite and 21 Ma natroalunite at Cerro Verde, and 19.2 Ma jarosite at La Llave) and was plausibly responsible for much of the upgrading of the Cuajone and Toquepala deposits and thr Quellaveco prospect, which are intersected by both the Altos de Camilaca pediplain and erosional features representing upslope extensions of the Pampa Lagunas pediplain. The younger supergene profiles were widely superimposed on the remnants of those generated during the Incaic orogeny. Middle Miocene (<= 14.2 Ma biotite age) Chuntacala Formation flows protected the Cuajone supergene profile from destruction by erosion, but at 13.0 Ma interrupted supergene processes at Quellaveco. Revision of volcano-stratigraphic relationships in the latter area reveals that subsequent erosion of the Chuntacala Formation ignimbrites and part of the supergene profile took place prior to the deposition of a 10.1 Ma ash-flow tuff of the Asana Formation. Elsewhere, supergene activity persisted at the Cachuyito prospect through 11.4 Ma, and minor jarosite development occurred at least Until 4.9 Ma both there and at Cerro Verde during and following the Multiple Pediment landform stage (ca. 7.9-1.5.0 Ma). The landform chronology for the area surrounding the Cuajone, Quellaveco, and Toquepala deposits (ca. 17 degrees S) is revised and extended northwestward through field mapping to the Cerro Verde-Santa Rosa district (ca. 16 degrees 30' S). The 40Ar-39Ar incremental-heating dates of supergene alunite group minerals from the Angostura (38.1 and 38.8 Ma) and Posco (38.8 Ma) prospects and the Cerro Verde deposit (36.1-38.8 Ma) demonstrate that supergene processes were underway in the late Eocene beneath a subplanar topography resulting from uplift and erosion during the Incaic orogny, now represented by a regional unconformity in the Cenozoic volcanic-sedimentary rock succession. Broadly contemporaneous supergene processes were probably active in the Cuajone-Quellaveco-Toquepala district. Slow erosion and the accumulation of elastic sediments through the tectonically quiescent early to mid-Oligocene are envisaged to have caused a rise in the water table and the widespread preservation of the Incaic supergene profiles. Aymara uplift subsequently led to the incision of the 23.8 to 24 Ma Altos de Camilaca and the 18.8 to 19.1. Ma Pampa Lagunas pediplains and their regional correlatives. The ensuing water-table lowering was associated with intense leaching and sulfide enrichment from the late Oligocene (24.4-28 Ma natroalunite at Cerro Verde, 26-27 Ma natroalunite at Santa Rosa, and 28.6 Ma jarosite at La Llave) to the early Miocene (23 Ma alunite and 21 Ma natroalunite at Cerro Verde, and 19.2 Ma jarosite at La Llave) and was plausibly responsible for much of the upgrading of the Cuajone and Toquepala deposits and thr Quellaveco prospect, which are intersected by both the Altos de Camilaca pediplain and erosional features representing upslope extensions of the Pampa Lagunas pediplain. The younger supergene profiles were widely superimposed on the remnants of those generated during the Incaic orogeny. Middle Miocene (<= 14.2 Ma biotite age) Chuntacala Formation flows protected the Cuajone supergene profile from destruction by erosion, but at 13.0 Ma interrupted supergene processes at Quellaveco. Revision of volcano-stratigraphic relationships in the latter area reveals that subsequent erosion of the Chuntacala Formation ignimbrites and part of the supergene profile took place prior to the deposition of a 10.1 Ma ash-flow tuff of the Asana Formation. Elsewhere, supergene activity persisted at the Cachuyito prospect through 11.4 Ma, and minor jarosite development occurred at least Until 4.9 Ma both there and at Cerro Verde during and following the Multiple Pediment landform stage (ca. 7.9-1.5.0 Ma).