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Alvaro Rodrigo Iriarte,Umberto Giuseppe Cordani,Kei Sato
Pág. 403 - 441
The Cordillera Real granitoids are a suite of Triassic and Oligocene plutons in the core of the Eastern Cordillera of the Central Andes of Bolivia. Their tectonic setting, chemical and ore compositions make them part of the so-called ?Inner Magmatic Arc?...
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Alan Santos Polo,Guo Weimin,Fernando Rivera,Colombo Tassinari,Luis Cerpa,Shoji Kojima
Pág. 445 - 470
Early Jurassic arc-related igneous rocks host porphyry copper prospects and gold-bearing quartz vein deposits in southern Peru. Ten new zircon U-Pb ages for wall rocks of gold-bearing quartz veins, Jurassic rocks and copper-mineralized porphyry bodies in...
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Francisco Herve,C. Mark Fanning
Pág. 91 - 104
Sensitive High Resolution Ion MicroProbe (SHRIMP) U-Pb age determinations of detrital zircons from metasandstones of the Chonos Metamorphic Complex reveal a significant population of Late Triassic ages. One of the samples is immediately underlying the co...
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Victor Maksaev,Javier Arancibia,Francisco Munizaga,Colombo Tassinari
Pág. 285 - 312
U-Pb detrital-zircon geochronology of two discrete outcrops of mica schists of the western border of the Domeyko Cordillera in the Region of Atacama, northern Chile, indicates that the maximum age of sedimentation of their protolith corresponds to the La...
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Victor Maksaev,Francisco Munizaga,Victor Valencia,Fernando Barra
Pág. 264 - 287
New U-Pb zircon dating of volcanic intercalations in the lower conglomeratic part of the Cerrillos Formation shows that its deposition extended in time at least from 110.7±1.7 to 99.7±1.6 Ma. The significantly younger U-Pb zircon age of 69.5±1.0 Ma obtai...
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Ricardo Varela,Ana M. Sato,Miguel A.S. Basei,Oswaldo Siga Jr.
Pág. 265 - 284
Igneous and metamorphic units formed mainly during the Middle Proterozoic and Early Paleozoic times have been distinguished in the Sierra de Umango crystalline basement. These include granitic orthogneisses, a sequence of schists and marbles, amphibolite...
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Augusto N. Varela,Daniel G. Poiré,Thomas Martin,Axel Gerdes,Francisco J. Goin,Javier N. Gelfo,Simone Hoffmann
Pág. 359 - 379
Despite the abundant fossil content of the Mata Amarilla Formation (Southern Patagonia, Santa Cruz Province, Argentina), its age has always generated a considerable number of questions and debates. The chronological data provided by invertebrates, dinosa...
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Robert J. Pankhurst,Ian L. Millar,Francisco Herve
Pág. 35 - 42
ABSTRACT. A U-Pb zircon age 0f 285.7+/-1.5 Ma is presented for granodiorite from the Chanchoquin pluton of the Guanta Unit, Elqui Superunit of the Elqui-Limari Batholith. This is the first U-Pb zircon age reported from this batholith and is interpreted a...
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Alejandro Sanchez,Polina Pavlishina,Estanislao Godoy,Francisco Herve,Mark Fanning
Pág. 413 - 432
On the west coast of Tierra del Fuego, south of Cabo Nariz, in Chile, Upper Cretaceous to Paleocene sedirnentary successions of the Magallanes foreland basin crop out. The presence of dinoflagellate cysts, as well as radiometric U-Pb SHRIMP dating of det...
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Paul Duhart,Alberto C. Adriasola
The Coastal Ranges in the western part of the Chiloé Archipelago represent an emerged forearc high at the subduction front of south-central Chile. Prior to the Cenozoic framework of the subducting Farallón and Nazca plates beneath the South American plat...
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Joshua P. Taylor, Laura E. Webb, Cari L. Johnson and Matthew J. Heumann
The Central Asian Orogenic Belt, or Altaids, is an amalgamation of volcanic arcs and microcontinent blocks that records a complex late Precambrian?Mesozoic accretionary history. Although microcontinents cored by Precambrian basement are proposed to play ...
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Carlos Oscar Limarino,Leonardo R. Scarlatta,Patricia L. Ciccioli,Sabrina Miyno,Fanny Bello,Silvia N. Césari
Pág. 127 - 149
The La Veteada Formation, in the Sierra de Famatina (west of Argentina), is one of the few records of Early Triassic age in South America verified by isotopic age and palynological assemblages. This unit is composed of sandstones, mudstones, shales, lime...
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Samanta Serra-Varela,Pablo D. González,Raúl E. Giacosa,Nemesio Heredia,David Pedreira,Fidel Martín-González,Ana María Sato
Pág. 102 - 130
In San Martín de los Andes area (Argentinian Patagonia) the Palaeozoic basement consists of metamorphic and plutonic rocks. The metamorphic rocks include strongly deformed schists, gneisses and migmatites. Their geochemical and petrographic characteristi...
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Stella Poma,Eduardo O. Zappettini,Sonia Quenardelle,Joao O. Santos,?Magdalena Koukharsky,Elena Belousova,Neal J. McNaughton
Pág. 267 - 292
We have carried out zircon U-Pb SHRIMP dating and Hf isotope determinations as well as geochemical analyses on three plutonic units of Gondwanan magmatism that crop out in NW Argentina. Two episodes of different age and genesis have been identified. The ...
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Francisco Hervé,Mauricio Calderón,Mark Fanning,Robert Pankhurst,Carlos W. Rapela,Paulo Quezada
Pág. 301 - 317
Previous work has shown that Devonian magmatism in the southern Andes occurred in two contemporaneous belts: one emplaced in the continental crust of the North Patagonian Massif and the other in an oceanic island arc terrane to the west, Chaitenia, which...
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Marian V. Lupulescu, Jeffrey R. Chiarenzelli, Mark E. Pecha, Jared W. Singer and Sean P. Regan
Columbite crystals from niobium-yttrium-fluorine (NYF) pegmatites lacking zircon or containing metamict cyrtolite were analyzed for major and minor elements (Electron Microprobe (EMP)), trace elements (Laser Ablation-Inductively Coupled Plasma-Mass Spect...
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Jeffrey R. Chiarenzelli, Marian V. Lupulescu, Sean P. Regan and Jared W. Singer
At the Cheever Mine, located in the eastern Adirondack Mountains of the Mesoproterozoic Grenville Province, iron oxide-apatite ore forms a narrow (<3 m) sheet cross-cutting metasomatically altered, magnetite-bearing, albite-rich leucogranitic host roc...
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Victor Maksaev,Francisco Munizaga,Colombo Tassinari
Pág. 447 - 506
U-Pb zircon geochronological data provide record of about 130 Ma of igneous activity in the Andes of northern Chile, which extended episodically from the latest Early Carboniferous to Early Jurassic (328-194 Ma). The overall U-Pb data show that volcanism...
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Stuart N. Thomson,Francisco Herve
Pág. 255 - 271
Fission-track (FT) analysis was performed on ten samples of detrital zircons from several pre-Late Jurassic metamorphic accretionary complexes at the ancestral Pacific margin of Gondwana in southern Chile (42-52°S) previously dated by U-Pb SHRIMP. Post-m...
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Estanislao Godoy,Werner Loske
Pág. 119 - 127
RESUMEN. Tres fracciones granulometricas de circones en una diorita de dos piroxenos (charnoquita 'precambrica' segun estudios anteriores), que aflora en Laguna Verde, y dos fracciones de su equivalente neisico de Punta Curaumilla, indicaron edades conco...
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