624 research outputs found
Timing of the magmatism of the paleo-Pacific border of Gondwana: U-Pb geochronology of Late Paleozoic to Early Mesozoic igneous rocks of the north Chilean Andes between 20° and 31°S
Indexación: Web of Science; ScieloABSTRACT. 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 and plutonism were essentially synchronous and major episodes of igneous activity developed during the Late Carboniferous to Mid-Permian (310 to 260 Ma) and from Late Permian to Late Triassic (255-205 Ma), with less prominent episodes in the mid-Carboniferous (330 to 320 Ma), and Early Jurassic (200-190 Ma). Thus, from the Carboniferous to the Early Triassic dominantly silicic magmatism developed along the Chilean segment of the southwestern border of Gondwana supercontinent. Further magmatism developed during the Mid-Late Triassic (250-194 Ma) was bimodal and synchronous with rift-related, continental and/or marine sedimentary strata related to the early stages of break-up of Gondwana. Most of the silicic volcanic rocks of the Precordillera and Domeyko Cordillera of northern Chile (21°30' to 25°30'S) are older than the silicic rocks assigned to the Choiyoi succession in Argentina, being instead equivalent in age to Carboniferous to Early Permian marine sedimentary sequences present in the eastern Argentinean foreland. On the other hand, silicic volcanic successions exposed in the easternmost part of northern Chile are equivalent in age to the Choiyoi succession of the San Rafael Block of Argentina. An eastward expansion or migration of the volcanism during the Mid-Permian to Early Triassic is inferred, interpretation that is consistent with expansion of the volcanism at that time in Argentina. The timing of the Late Paleozoic to Early Jurassic magmatism is coincident with that of the Andes of Perú and of western Argentina according to the available U-Pb data, revealing a rather consistent evolution in time of the magmatism along the southwestern, paleo-Pacific border of Gondwana.
Keywords: Geochronology, U-Pb, Andes, Gondwana, Choiyoi, Paleozoic, Carboniferous, Triassic.
RESUMEN. Los datos de U-Pb en circón registran aproximadamente 130 Ma de actividad Ãgnea en los Andes del norte de Chile, la que se extendió episódicamente desde el CarbonÃfero temprano hasta el Jurásico temprano (328-194 Ma). Los datos globales de U-Pb indican que el volcanismo y plutonismo fueron esencialmente sincrónicos con episodios mayores desde el CarbonÃfero tardÃo al Pérmico Medio (310-260 Ma) y durante el Pérmico TardÃo a Triásico TardÃo (255-205 Ma) y episodios menos prominentes durante el CarbonÃfero medio (330-320 Ma) y el Jurásico Temprano (200-190 Ma). Desde el CarbonÃfero hasta el Triásico Temprano se desarrolló magmatismo predominantemente félsico a lo largo del borde suroccidental del supercontinente de Gondwana, mientras que durante el Triásico medio a tardÃo (250-194 Ma) se desarrolló magmatismo bimodal sincrónico con estratos sedimentarios continentales y/o marinos relacionados con extensión (rift), durante las etapas tempranas de la desintegración de Gondwana. La mayor parte de las rocas volcánicas silÃceas de la precordillera y la cordillera de Domeyko en el norte de Chile (21°30' a 25°30'S) son más antiguas que las rocas silÃceas asignadas a la sucesión Choiyoi en Argentina, y son, en cambio, equivalentes en edad con las secuencias sedimentarias marinas del CarbonÃfero al Pérmico temprano presentes en el antepaÃs argentino al oriente. Por otra parte, las sucesiones volcánicas félsicas expuestas en la parte más oriental del norte de Chile, de la cordillera de Domeyko y de la cordillera Frontal al sur de 25°S son equivalentes en edad a la sucesión Choiyoi de Argentina. Se infiere una migración o expansión del volcanismo hacia el este durante el Pérmico Medio a Triásico Temprano, interpretación que es consistente con la expansión del volcanismo en Argentina durante ese perÃodo. La temporalidad del magmatismo del Paleozoico tardÃo a Mesozoico temprano es coincidente con la de los Andes de Perú y del oeste de Argentina, de acuerdo a los datos U-Pb disponibles, lo que revela una evolución temporal del magmatismo concordante a lo largo del borde suroeste del Gondwana.
Palabras clave: GeocronologÃa, U-Pb, Andes, Gondwana, Choiyoi, Paleozoico, CarbonÃfero, Triásico
Diferencias culturales para interpretar algunos fracasos del tratamiento de TBC pulmonar en Chile
The Making of a Spanish Orchestra of Language Based on Robson\u27s The Orchestra of Language
A monograph presented to the faculty of the Department of English at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Arts by Denise Munizaga Lagos in August of 1971
Automation of a Distillation Column of Packed Bed for an Alcohol Solution using Arduino
This study demonstrates the use of Arduino to automate the operation of a distillation column binary ethanol - water as learning material used by students in the career of Chemical Engineering at the Escuela Superior Politecnica del Litoral. The main objective was to build an automated computer with the technology of arduino, in which thermocouples were used to offer students the convenience of taking temperature readings on a LCD display and in turn it allowed us to observe the level of the solution to control ignition resistance. So they were able to identify the processes that occur during the distillation unit operation automatically and manually in the Unit Operations Laboratory
- …