Por favor, use este identificador para citar o enlazar a este item:
http://hdl.handle.net/10261/233104
COMPARTIR / EXPORTAR:
SHARE CORE BASE | |
Visualizar otros formatos: MARC | Dublin Core | RDF | ORE | MODS | METS | DIDL | DATACITE | |
Título: | Multiple veining in a paleo–accretionary wedge: The metamorphic rock record of prograde dehydration and transient high porefluid pressures along the subduction interface (Western Series, central Chile) |
Autor: | Muñoz-Montecinos, Jesús; Angiboust, Samuel; Cambeses, Aitor; García-Casco, Antonio | Fecha de publicación: | 29-abr-2020 | Editor: | Geological Society of America | Citación: | Geosphere 16: 765-786 (2020) | Resumen: | High pressure–low temperature metamorphic rocks from the late Paleozoic accretionary wedge exposed in central Chile (Pichilemu region) are characterized by a greenschist-blueschist litholog-ical association with interbedded metasediments that reached peak burial conditions of ~400 °C and 0.8 GPa during late Carboniferous times. We herein combine new extensive field observations, structural measurements, and geochemical and petrological data on vein and matrix material from Pichilemu transitional greenschist-blueschist facies rocks. The studied veins were first filled by albite, fol-lowed by quartz and calcite as well as glaucophane and winchite. Field, structural, and microscopic zoning patterns show that these rocks underwent a protracted sequence of prograde vein-opening events, which have been largely transposed to the main foliation before and during underplating in the basal accretion site near 25–30 km depth. While some of the earliest albite-filled vein sets may have formed after prograde breakdown of sub–green-schist facies minerals (<250 °C), our thermodynamic modeling shows that relatively minor amounts of fluid are produced in the subducted pile by dehy-dration reactions between 250 and 400 °C along the estimated geothermal gradient. It also confirms that the formation of interlayered blueschist and greenschist layers in Pichilemu metavolcanics is a consequence of local bulk composition variations, and that greenschists are generally not formed due to selective exhumation-related retrogression of blueschists. The early vein sets are a consequence of prograde internal fluid production followed by sets of hydrofractures formed at near-peak burial that are interpreted as a record of external fluid influx. We postulate that such a fractured sequence represents a close analogue to the high-Vp/Vs regions documented by seismological studies within the base of the seismogenic zone in active subduction settings. | Versión del editor: | http://dx.doi.org/10.1130/GES02227.1 | URI: | http://hdl.handle.net/10261/233104 | DOI: | 10.1130/GES02227.1 | Identificadores: | doi: 10.1130/GES02227.1 issn: 1553-040X |
Aparece en las colecciones: | (IACT) Artículos |
Ficheros en este ítem:
Fichero | Descripción | Tamaño | Formato | |
---|---|---|---|---|
Garcia_Casco_A_2020_Geosphere16_765.pdf | 3 MB | Unknown | Visualizar/Abrir |
CORE Recommender
Page view(s)
90
checked on 23-abr-2024
Download(s)
136
checked on 23-abr-2024
Google ScholarTM
Check
Altmetric
Altmetric
Este item está licenciado bajo una Licencia Creative Commons