Sub-recent volcanism in Northern Patagonia: A tectonomagmatic approach

MASSAFERRO, GABRIELA ISABEL

JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2006 vol. 155 p. 227 - 243

0377-0273

The Crater Basalt Volcanic Field (CBVF) in northern Patagonia (∼42°S, Chubut province) is located 400 km eastward of the current Peru–Chile Trench and to the southwest of the Meseta de Somuncura, in a back-arc position in the extra-Andean Patagonia. The CBVF lava flows cover glaciation related terraces and present stream valleys. The occurrence of CBVF is related with the Gastre Fault System (GFS), a very significant tectonic feature about 40 km wide. The CBVF volcanics cover a surface of ∼700 km2, occurring mainly as lava flows and scoria cones. CBVF volcanics have relatively high contents of MgO (6–9 wt.%), Cr (136–289 ppm) and Ni (25–198 ppm), and classify as alkali basalts, basanites and trachybasalts. Geothermometry indicates a crystallization temperature of ∼1140 °C and a ƒO2 of −1.0 1 to 0.0 (log FMQ units). The petrographic and geochemical characteristics of CBVF products suggest that the magma originated from a garnet-bearing lherzolite mantle source with asthenospheric characteristics, as a result of decompression, partial melting and ascent. These melts would have risen through a system of deep faults like the Gastre Fault System, following the last Quaternary glacial event. © 2006 Published by Elsevier B.V. The petrographic and geochemical characteristics of CBVF products suggest that the magma originated from a garnet-bearing lherzolite mantle source with asthenospheric characteristics, as a result of decompression, partial melting and ascent. These melts would have risen through a system of deep faults like the Gastre Fault System, following the last Quaternary glacial event. © 2006 Published by Elsevier B.V. trachybasalts. Geothermometry indicates a crystallization temperature of ∼1140 °C and a ƒO2 of −1.0 1 to 0.0 (log FMQ units). The petrographic and geochemical characteristics of CBVF products suggest that the magma originated from a garnet-bearing lherzolite mantle source with asthenospheric characteristics, as a result of decompression, partial melting and ascent. These melts would have risen through a system of deep faults like the Gastre Fault System, following the last Quaternary glacial event. © 2006 Published by Elsevier B.V. The petrographic and geochemical characteristics of CBVF products suggest that the magma originated from a garnet-bearing lherzolite mantle source with asthenospheric characteristics, as a result of decompression, partial melting and ascent. These melts would have risen through a system of deep faults like the Gastre Fault System, following the last Quaternary glacial event. © 2006 Published by Elsevier B.V. relatively high contents of MgO (6–9 wt.%), Cr (136–289 ppm) and Ni (25–198 ppm), and classify as alkali basalts, basanites and trachybasalts. Geothermometry indicates a crystallization temperature of ∼1140 °C and a ƒO2 of −1.0 1 to 0.0 (log FMQ units). The petrographic and geochemical characteristics of CBVF products suggest that the magma originated from a garnet-bearing lherzolite mantle source with asthenospheric characteristics, as a result of decompression, partial melting and ascent. These melts would have risen through a system of deep faults like the Gastre Fault System, following the last Quaternary glacial event. © 2006 Published by Elsevier B.V. The petrographic and geochemical characteristics of CBVF products suggest that the magma originated from a garnet-bearing lherzolite mantle source with asthenospheric characteristics, as a result of decompression, partial melting and ascent. These melts would have risen through a system of deep faults like the Gastre Fault System, following the last Quaternary glacial event. © 2006 Published by Elsevier B.V. trachybasalts. Geothermometry indicates a crystallization temperature of ∼1140 °C and a ƒO2 of −1.0 1 to 0.0 (log FMQ units). The petrographic and geochemical characteristics of CBVF products suggest that the magma originated from a garnet-bearing lherzolite mantle source with asthenospheric characteristics, as a result of decompression, partial melting and ascent. These melts would have risen through a system of deep faults like the Gastre Fault System, following the last Quaternary glacial event. © 2006 Published by Elsevier B.V. The petrographic and geochemical characteristics of CBVF products suggest that the magma originated from a garnet-bearing lherzolite mantle source with asthenospheric characteristics, as a result of decompression, partial melting and ascent. These melts would have risen through a system of deep faults like the Gastre Fault System, following the last Quaternary glacial event. © 2006 Published by Elsevier B.V. The CBVF lava flows cover glaciation related terraces and present stream valleys. The occurrence of CBVF is related with the Gastre Fault System (GFS), a very significant tectonic feature about 40 km wide. The CBVF volcanics cover a surface of ∼700 km2, occurring mainly as lava flows and scoria cones. CBVF volcanics have relatively high contents of MgO (6–9 wt.%), Cr (136–289 ppm) and Ni (25–198 ppm), and classify as alkali basalts, basanites and trachybasalts. Geothermometry indicates a crystallization temperature of ∼1140 °C and a ƒO2 of −1.0 1 to 0.0 (log FMQ units). The petrographic and geochemical characteristics of CBVF products suggest that the magma originated from a garnet-bearing lherzolite mantle source with asthenospheric characteristics, as a result of decompression, partial melting and ascent. These melts would have risen through a system of deep faults like the Gastre Fault System, following the last Quaternary glacial event. © 2006 Published by Elsevier B.V. The petrographic and geochemical characteristics of CBVF products suggest that the magma originated from a garnet-bearing lherzolite mantle source with asthenospheric characteristics, as a result of decompression, partial melting and ascent. These melts would have risen through a system of deep faults like the Gastre Fault System, following the last Quaternary glacial event. © 2006 Published by Elsevier B.V. trachybasalts. Geothermometry indicates a crystallization temperature of ∼1140 °C and a ƒO2 of −1.0 1 to 0.0 (log FMQ units). The petrographic and geochemical characteristics of CBVF products suggest that the magma originated from a garnet-bearing lherzolite mantle source with asthenospheric characteristics, as a result of decompression, partial melting and ascent. These melts would have risen through a system of deep faults like the Gastre Fault System, following the last Quaternary glacial event. © 2006 Published by Elsevier B.V. The petrographic and geochemical characteristics of CBVF products suggest that the magma originated from a garnet-bearing lherzolite mantle source with asthenospheric characteristics, as a result of decompression, partial melting and ascent. These melts would have risen through a system of deep faults like the Gastre Fault System, following the last Quaternary glacial event. © 2006 Published by Elsevier B.V. relatively high contents of MgO (6–9 wt.%), Cr (136–289 ppm) and Ni (25–198 ppm), and classify as alkali basalts, basanites and trachybasalts. Geothermometry indicates a crystallization temperature of ∼1140 °C and a ƒO2 of −1.0 1 to 0.0 (log FMQ units). The petrographic and geochemical characteristics of CBVF products suggest that the magma originated from a garnet-bearing lherzolite mantle source with asthenospheric characteristics, as a result of decompression, partial melting and ascent. These melts would have risen through a system of deep faults like the Gastre Fault System, following the last Quaternary glacial event. © 2006 Published by Elsevier B.V. The petrographic and geochemical characteristics of CBVF products suggest that the magma originated from a garnet-bearing lherzolite mantle source with asthenospheric characteristics, as a result of decompression, partial melting and ascent. These melts would have risen through a system of deep faults like the Gastre Fault System, following the last Quaternary glacial event. © 2006 Published by Elsevier B.V. trachybasalts. Geothermometry indicates a crystallization temperature of ∼1140 °C and a ƒO2 of −1.0 1 to 0.0 (log FMQ units). The petrographic and geochemical characteristics of CBVF products suggest that the magma originated from a garnet-bearing lherzolite mantle source with asthenospheric characteristics, as a result of decompression, partial melting and ascent. These melts would have risen through a system of deep faults like the Gastre Fault System, following the last Quaternary glacial event. © 2006 Published by Elsevier B.V. The petrographic and geochemical characteristics of CBVF products suggest that the magma originated from a garnet-bearing lherzolite mantle source with asthenospheric characteristics, as a result of decompression, partial melting and ascent. These melts would have risen through a system of deep faults like the Gastre Fault System, following the last Quaternary glacial event. © 2006 Published by Elsevier B.V. current Peru–Chile Trench and to the southwest of the Meseta de Somuncura, in a back-arc position in the extra-Andean Patagonia. The CBVF lava flows cover glaciation related terraces and present stream valleys. The occurrence of CBVF is related with the Gastre Fault System (GFS), a very significant tectonic feature about 40 km wide. The CBVF volcanics cover a surface of ∼700 km2, occurring mainly as lava flows and scoria cones. CBVF volcanics have relatively high contents of MgO (6–9 wt.%), Cr (136–289 ppm) and Ni (25–198 ppm), and classify as alkali basalts, basanites and trachybasalts. Geothermometry indicates a crystallization temperature of ∼1140 °C and a ƒO2 of −1.0 1 to 0.0 (log FMQ units). The petrographic and geochemical characteristics of CBVF products suggest that the magma originated from a garnet-bearing lherzolite mantle source with asthenospheric characteristics, as a result of decompression, partial melting and ascent. These melts would have risen through a system of deep faults like the Gastre Fault System, following the last Quaternary glacial event. © 2006 Published by Elsevier B.V. The petrographic and geochemical characteristics of CBVF products suggest that the magma originated from a garnet-bearing lherzolite mantle source with asthenospheric characteristics, as a result of decompression, partial melting and ascent. These melts would have risen through a system of deep faults like the Gastre Fault System, following the last Quaternary glacial event. © 2006 Published by Elsevier B.V. trachybasalts. Geothermometry indicates a crystallization temperature of ∼1140 °C and a ƒO2 of −1.0 1 to 0.0 (log FMQ units). The petrographic and geochemical characteristics of CBVF products suggest that the magma originated from a garnet-bearing lherzolite mantle source with asthenospheric characteristics, as a result of decompression, partial melting and ascent. These melts would have risen through a system of deep faults like the Gastre Fault System, following the last Quaternary glacial event. © 2006 Published by Elsevier B.V. The petrographic and geochemical characteristics of CBVF products suggest that the magma originated from a garnet-bearing lherzolite mantle source with asthenospheric characteristics, as a result of decompression, partial melting and ascent. These melts would have risen through a system of deep faults like the Gastre Fault System, following the last Quaternary glacial event. © 2006 Published by Elsevier B.V. relatively high contents of MgO (6–9 wt.%), Cr (136–289 ppm) and Ni (25–198 ppm), and classify as alkali basalts, basanites and trachybasalts. Geothermometry indicates a crystallization temperature of ∼1140 °C and a ƒO2 of −1.0 1 to 0.0 (log FMQ units). The petrographic and geochemical characteristics of CBVF products suggest that the magma originated from a garnet-bearing lherzolite mantle source with asthenospheric characteristics, as a result of decompression, partial melting and ascent. These melts would have risen through a system of deep faults like the Gastre Fault System, following the last Quaternary glacial event. © 2006 Published by Elsevier B.V. The petrographic and geochemical characteristics of CBVF products suggest that the magma originated from a garnet-bearing lherzolite mantle source with asthenospheric characteristics, as a result of decompression, partial melting and ascent. These melts would have risen through a system of deep faults like the Gastre Fault System, following the last Quaternary glacial event. © 2006 Published by Elsevier B.V. trachybasalts. Geothermometry indicates a crystallization temperature of ∼1140 °C and a ƒO2 of −1.0 1 to 0.0 (log FMQ units). The petrographic and geochemical characteristics of CBVF products suggest that the magma originated from a garnet-bearing lherzolite mantle source with asthenospheric characteristics, as a result of decompression, partial melting and ascent. These melts would have risen through a system of deep faults like the Gastre Fault System, following the last Quaternary glacial event. © 2006 Published by Elsevier B.V. The petrographic and geochemical characteristics of CBVF products suggest that the magma originated from a garnet-bearing lherzolite mantle source with asthenospheric characteristics, as a result of decompression, partial melting and ascent. These melts would have risen through a system of deep faults like the Gastre Fault System, following the last Quaternary glacial event. © 2006 Published by Elsevier B.V. The CBVF lava flows cover glaciation related terraces and present stream valleys. The occurrence of CBVF is related with the Gastre Fault System (GFS), a very significant tectonic feature about 40 km wide. The CBVF volcanics cover a surface of ∼700 km2, occurring mainly as lava flows and scoria cones. CBVF volcanics have relatively high contents of MgO (6–9 wt.%), Cr (136–289 ppm) and Ni (25–198 ppm), and classify as alkali basalts, basanites and trachybasalts. Geothermometry indicates a crystallization temperature of ∼1140 °C and a ƒO2 of −1.0 1 to 0.0 (log FMQ units). The petrographic and geochemical characteristics of CBVF products suggest that the magma originated from a garnet-bearing lherzolite mantle source with asthenospheric characteristics, as a result of decompression, partial melting and ascent. These melts would have risen through a system of deep faults like the Gastre Fault System, following the last Quaternary glacial event. © 2006 Published by Elsevier B.V. The petrographic and geochemical characteristics of CBVF products suggest that the magma originated from a garnet-bearing lherzolite mantle source with asthenospheric characteristics, as a result of decompression, partial melting and ascent. These melts would have risen through a system of deep faults like the Gastre Fault System, following the last Quaternary glacial event. © 2006 Published by Elsevier B.V. trachybasalts. Geothermometry indicates a crystallization temperature of ∼1140 °C and a ƒO2 of −1.0 1 to 0.0 (log FMQ units). The petrographic and geochemical characteristics of CBVF products suggest that the magma originated from a garnet-bearing lherzolite mantle source with asthenospheric characteristics, as a result of decompression, partial melting and ascent. These melts would have risen through a system of deep faults like the Gastre Fault System, following the last Quaternary glacial event. © 2006 Published by Elsevier B.V. The petrographic and geochemical characteristics of CBVF products suggest that the magma originated from a garnet-bearing lherzolite mantle source with asthenospheric characteristics, as a result of decompression, partial melting and ascent. These melts would have risen through a system of deep faults like the Gastre Fault System, following the last Quaternary glacial event. © 2006 Published by Elsevier B.V. relatively high contents of MgO (6–9 wt.%), Cr (136–289 ppm) and Ni (25–198 ppm), and classify as alkali basalts, basanites and trachybasalts. Geothermometry indicates a crystallization temperature of ∼1140 °C and a ƒO2 of −1.0 1 to 0.0 (log FMQ units). The petrographic and geochemical characteristics of CBVF products suggest that the magma originated from a garnet-bearing lherzolite mantle source with asthenospheric characteristics, as a result of decompression, partial melting and ascent. These melts would have risen through a system of deep faults like the Gastre Fault System, following the last Quaternary glacial event. © 2006 Published by Elsevier B.V. The petrographic and geochemical characteristics of CBVF products suggest that the magma originated from a garnet-bearing lherzolite mantle source with asthenospheric characteristics, as a result of decompression, partial melting and ascent. These melts would have risen through a system of deep faults like the Gastre Fault System, following the last Quaternary glacial event. © 2006 Published by Elsevier B.V. trachybasalts. Geothermometry indicates a crystallization temperature of ∼1140 °C and a ƒO2 of −1.0 1 to 0.0 (log FMQ units). The petrographic and geochemical characteristics of CBVF products suggest that the magma originated from a garnet-bearing lherzolite mantle source with asthenospheric characteristics, as a result of decompression, partial melting and ascent. These melts would have risen through a system of deep faults like the Gastre Fault System, following the last Quaternary glacial event. © 2006 Published by Elsevier B.V. The petrographic and geochemical characteristics of CBVF products suggest that the magma originated from a garnet-bearing lherzolite mantle source with asthenospheric characteristics, as a result of decompression, partial melting and ascent. These melts would have risen through a system of deep faults like the Gastre Fault System, following the last Quaternary glacial event. © 2006 Published by Elsevier B.V. ∼42°S, Chubut province) is located 400 km eastward of the current Peru–Chile Trench and to the southwest of the Meseta de Somuncura, in a back-arc position in the extra-Andean Patagonia. The CBVF lava flows cover glaciation related terraces and present stream valleys. The occurrence of CBVF is related with the Gastre Fault System (GFS), a very significant tectonic feature about 40 km wide. The CBVF volcanics cover a surface of ∼700 km2, occurring mainly as lava flows and scoria cones. CBVF volcanics have relatively high contents of MgO (6–9 wt.%), Cr (136–289 ppm) and Ni (25–198 ppm), and classify as alkali basalts, basanites and trachybasalts. Geothermometry indicates a crystallization temperature of ∼1140 °C and a ƒO2 of −1.0 1 to 0.0 (log FMQ units). The petrographic and geochemical characteristics of CBVF products suggest that the magma originated from a garnet-bearing lherzolite mantle source with asthenospheric characteristics, as a result of decompression, partial melting and ascent. These melts would have risen through a system of deep faults like the Gastre Fault System, following the last Quaternary glacial event. © 2006 Published by Elsevier B.V. The petrographic and geochemical characteristics of CBVF products suggest that the magma originated from a garnet-bearing lherzolite mantle source with asthenospheric characteristics, as a result of decompression, partial melting and ascent. These melts would have risen through a system of deep faults like the Gastre Fault System, following the last Quaternary glacial event. © 2006 Published by Elsevier B.V. trachybasalts. Geothermometry indicates a crystallization temperature of ∼1140 °C and a ƒO