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El metamorfismo en la Cuenca de los Cameros. Geocronología e implicaciones tectónicas

Casquet, César and Galindo Francisco, Mª del Carmen and González Casado, José Manuel and Alonso Millán, Ángela (1992) El metamorfismo en la Cuenca de los Cameros. Geocronología e implicaciones tectónicas. Geogaceta, 11 . pp. 22-25. ISSN 0213-683X

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Abstract

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.


Item Type:Article
Uncontrolled Keywords:Cameros Basin, Very Low grade metamorphism, Geochronology, K/Ar dating
Subjects:Sciences > Geology > Petrology
ID Code:11454
Deposited On:03 Nov 2010 11:46
Last Modified:03 Nov 2010 11:46

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