Sediment fill geometry and structural control of the Pampa del Tamarugal basin, northern Chile

2018 ◽  
Vol 131 (1-2) ◽  
pp. 155-174 ◽  
Author(s):  
N. Labbé ◽  
M. García ◽  
Y. Simicic ◽  
E. Contreras-Reyes ◽  
R. Charrier ◽  
...  
Keyword(s):  
Structural Control ◽  
Northern Chile ◽  
Pampa Del Tamarugal ◽  
Sediment Fill

Water table variations in the hyperarid Atacama Desert: Role of the increasing groundwater extraction in the pampa del tamarugal (Northern Chile)

2019 ◽  
Vol 168 ◽  
pp. 9-16 ◽  
Author(s):  
Benoît Viguier ◽  
Hervé Jourde ◽  
Véronique Leonardi ◽  
Linda Daniele ◽  
Christelle Batiot-Guilhe ◽  
...  
Keyword(s):  
Water Table ◽  
Atacama Desert ◽  
Northern Chile ◽  
Groundwater Extraction ◽  
Pampa Del Tamarugal

Insights on the structural control of a Neogene forearc basin in Northern Chile: A geophysical approach

2018 ◽  
Vol 736 ◽  
pp. 1-14 ◽  
Author(s):  
Tiaren García-Pérez ◽  
Carlos Marquardt ◽  
Gonzalo Yáñez ◽  
José Cembrano ◽  
Rodrigo Gomila ◽  
...  
Keyword(s):  
Structural Control ◽  
Northern Chile ◽  
Forearc Basin

scholarly journals The Productora Cu-Au-Mo Deposit, Chile: A Mesozoic Magmatic-Hydrothermal Breccia Complex with Both Porphyry and Iron Oxide Cu-Au Affinities

2020 ◽  
Vol 115 (3) ◽  
pp. 543-580
Author(s):  
Angela Escolme ◽  
David R. Cooke ◽  
Julie Hunt ◽  
Ron F. Berry ◽  
Roland Maas ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Structural Control ◽  
Genetic Model ◽  
Spatial Association ◽  
Sulfur Source ◽  
Main Stage ◽  
Northern Chile ◽  
Porphyry Deposit ◽  
Coastal Cordillera ◽  
Calcite Veins

Abstract The Productora Cu-Au-Mo deposit is hosted by a Cretaceous hydrothermal breccia complex in the Coastal Cordillera of northern Chile. The current resource, which includes the neighboring Alice Cu-Mo porphyry deposit, is estimated at 236.6 Mt grading 0.48% Cu, 0.10 g/t Au, and 135 ppm Mo. Local wall rocks consist of a thick sequence of broadly coeval rhyolite to rhyodacite lapilli tuffs (128.7 ± 1.3 Ma; U-Pbzircon) and two major intrusions: the Cachiyuyito tonalite and Ruta Cinco granodiorite batholith (92.0 ± 1.0 Ma; U-Pbzircon). Previous studies at Productora concluded the deposit had strong affinities with the iron oxide copper-gold (IOCG) clan and likened the deposit to Candelaria. Based on new information, we document the deposit geology in detail and propose a new genetic model and alternative classification as a magmatic-hydrothermal breccia complex with closer affinities to porphyry systems. Hydrothermal and tectonic breccias, veins, and alteration assemblages at Productora define five paragenetic stages: stage 1 quartz-pyrite–cemented breccias associated with muscovite alteration, stage 2 chaotic matrix-supported tectonic-hydrothermal breccia with kaolinite-muscovite-pyrite alteration, stage 3 tourmaline-pyrite-chalcopyrite ± magnetite ± biotite-cemented breccias and associated K-feldspar ± albite alteration, stage 4 chalcopyrite ± pyrite ± muscovite, illite, epidote, and chlorite veins, and stage 5 calcite veins. The Productora hydrothermal system crosscuts earlier-formed sodic-calcic alteration and magnetite-apatite mineralization associated with the Cachiyuyito stock. Main-stage mineralization at Productora was associated with formation of the stage 3 hydrothermal breccia. Chalcopyrite is the dominant hypogene Cu mineral and occurs predominantly as breccia cement and synbreccia veins with pyrite. The Alice Cu-Mo porphyry deposit is characterized by disseminated chalcopyrite and quartz-pyrite-chalcopyrite ± molybdenite vein stockworks hosted by a granodiorite porphyry stock. Alice is spatially associated with the Silica Ridge lithocap, which is characterized by massive, fine-grained, quartz-altered rock above domains of alunite, pyrophyllite, and dickite. Rhenium-Os dating of molybdenite indicates that main-stage mineralization at Productora occurred at 130.1 ± 0.6 Ma, and at 124.1 ± 0.6 Ma in the Alice porphyry. Chalcopyrite and pyrite from Productora have δ34Ssulfide values from –8.5 to +2.2‰, consistent with a magmatic sulfur source and fluids evolving under oxidizing conditions. No significant input from evaporite- or seawater-sourced fluids was detected. Stage 3 tourmalines have average initial Sr of 0.70397, consistent with an igneous-derived Sr source. The Productora magmatic-hydrothermal breccia complex formed as a result of explosive volatile fluid release from a hydrous intrusive complex. Metal-bearing fluids were of magmatic affinity and evolved under oxidizing conditions. Despite sharing many similarities with the Andean IOCG clan (strong structural control, regional sodic-calcic alteration, locally anomalous U), fluid evolution at the Productora Cu-Au-Mo deposit is more consistent with that of a porphyry-related magmatic hydrothermal breccia (sulfur-rich, acid alteration assemblages and relatively low magnetite contents, <5 vol %). The Productora camp is an excellent example of the close spatial association of Mesozoic magnetite-apatite, porphyry, and magmatic-hydrothermal breccia mineralization styles, a relationship seen throughout the Coastal Cordillera of northern Chile.

scholarly journals A new species of Ithome Chambers (Lepidoptera, Cosmopterigidae, Chrysopeleiinae) from the Atacama Desert revealed by morphology and DNA barcodes

ZooKeys ◽  
2020 ◽  
Vol 912 ◽  
pp. 125-138 ◽  
Author(s):  
Sebastián Espinoza-Donoso ◽  
Dante Bobadilla ◽  
Wilson Huanca-Mamani ◽  
Marcelo Vargas-Ortiz ◽  
Héctor A. Vargas
Keyword(s):  
Dna Barcode ◽  
Atacama Desert ◽  
Taxonomic Status ◽  
Northern Chile ◽  
Maximum Likelihood Analysis ◽  
Dna Barcodes ◽  
Likelihood Analysis ◽  
Pampa Del Tamarugal ◽  
Additional Support ◽  
A New Species

Morphology and DNA barcode sequences were used to assess the taxonomic status of a micro-moth of the genus Ithome Chambers, 1875 (Lepidoptera, Cosmopterigidae, Chrysopeleiinae), whose larvae feed on inflorescences of Prosopis tamarugo Phil. (Fabaceae), a tree native to the Pampa del Tamarugal, Atacama Desert, northern Chile. As a result, Ithome tamarugensis Vargas, sp. nov. is described and illustrated. Its genitalia are remarkably similar to those of Ithome tiaynai Vargas, 2004 from coastal valleys of the Atacama Desert. However, the two species can be recognized by the shape of the phallus in males and the shape of the antrum and ductus bursae in females. The genetic distance between DNA barcodes of I. tamarugensis and I. tiaynai was 3.0–3.3% (K2P), and a maximum likelihood analysis indicated that they are in reciprocally monophyletic clusters, providing additional support for the heterospecific status suggested by morphology.

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