El metamorfismo en la Cuenca de los Cameros. Geocronología e implicaciones tectónicas
A case of hydrothermal metamorphism is described from the Cameros Basin along the rio Cidacos transect. The highest grade is reached at the base of the Urbión Group, a fluvial sequence Upper Jurassic to Lower Cretaceous in age (Weald facies). Physical conditions at the thermal peak are estimated at...
| Authors: | , , , |
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| Format: | article |
| Publication Date: | 1992 |
| Country: | España |
| Institution: | Universidad Complutense de Madrid (UCM) |
| Repository: | Docta Complutense |
| Language: | Spanish |
| OAI Identifier: | oai:docta.ucm.es:20.500.14352/56924 |
| Online Access: | https://hdl.handle.net/20.500.14352/56924 |
| Access Level: | Open access |
| Keyword: | 552.4(234.1) Cameros Basin Very Low grade metamorphism Geochronology K/Ar dating Petrología |
| Summary: | A case of hydrothermal metamorphism is described from the Cameros Basin along the rio Cidacos transect. The highest grade is reached at the base of the Urbión Group, a fluvial sequence Upper Jurassic to Lower Cretaceous in age (Weald facies). Physical conditions at the thermal peak are estimated at abo 1 Kb (PL) and 326± 13°C (i.e. very low grade metamorphism). Fluids were largely water brines with minor amounts of gases, CO2 and CH4• f02 and f52 were close to the graphite and Po-Py buffers respectively. This metamorphism is spatially associated with a deformation band (5-6 km. ín wídth) wíth schístosíty ín the pelitíc beds and promínent tensíonal, quartz ínfílled veíns in the more samítíc ones. K-Ar dating on authígeníc illites has gíven ages from 108 to 86 M.a., i.e. Míddle Cretaceous, and thus younger than the basín fílling (Urbíón Group+Enciso F.+Olívan F.). Metamorphism migth be related wíth the circulatíon of hot mígratory fluíds (i.e. tectoníc brínes), along the deformation bando The tectonic sígníficance of this deformation band is slill uncertain. |
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