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Origin of Late Cretaceous dolomites at the southern margin of the Central System, Madrid Province, Spain

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dc.creator Benito, M. I.
dc.creator Mas, R.
dc.date 2008-07-01T09:30:48Z
dc.date 2008-07-01T09:30:48Z
dc.date 2007
dc.date.accessioned 2017-01-31T02:16:09Z
dc.date.available 2017-01-31T02:16:09Z
dc.identifier Journal of Iberian Geology 33 (1) 2007: 41-54
dc.identifier 1886-7995
dc.identifier http://hdl.handle.net/10261/5484
dc.identifier.uri http://dspace.mediu.edu.my:8181/xmlui/handle/10261/5484
dc.description [EN] This study focuses on the Late Cretaceous dolomitic units situated at the southern margin of the Central System in Spain. Dolomites were petrographically studied (transmited light, cathodoluminescence and scanning electron microscopy) and geochemically characterized (Mg/Ca ratio, ä13C, ä18O, 87Sr/86Sr) to interpret the diagenetic environment in which they precipitated and to infer the possible mechanisms for dolomitization. Our data suggest that units of the lower and middle part of the section (Caballar, Castrojimeno and Burgo de Osma Fms.), although deposited in different sedimentary environments, were simultaneously dolomitized during the initial stages of burial, via the refl ux of brines derived from the overlying Valle de Tabladillo Fm. This formation consists of interbedded evaporites and dolomicrites and/or collapsed breccias and was deposited in a coastal sabkha environment, where the unit was dolomitized during the initial stages of diagenesis.
dc.description [ES] Este trabajo ha consistido en la caracterizacion petrografi ca y geoquimica de las unidades dolomiticas del Cretacico Superior que se encuentran en el borde Sur del Sistema Central, en la interpretacion del ambiente diagenetico de precipitacion de las dolomias y en la defi nicion del modelo de dolomitizacion para cada una de las unidades. El estudio petrografi co, realizado mediante microscopia convencional, catodoluminiscencia y microscopia electronica, y el estudio geoquimico elemental (relacion Mg/Ca) e isotopico (ƒÂ13C, ƒÂ18O y 87Sr/86Sr) de las dolomias sugieren que las unidades que se encuentran en la parte inferior y media de la serie (formaciones Caballar, Castrojimeno y Burgo de Osma), aunque se depositaron en ambientes sedimentarios distintos, se dolomitizaron a la vez, durante las primeras etapas del enterramiento, mediante el refl ujo de salmueras procedentes de la unidad suprayacente, la Fm. Valle de Tabladillo. La Fm. Valle de Tabladillo, por su parte, esta formada una alternancia de evaporitas y dolomias o bien por brechas de colapso y su dolomitizacion tuvo lugar durante las etapas mas tempranas de la diagenesis de acuerdo con el modelo de "gsabkha".
dc.description Funds for this study were provided by a postdoctoral fellowship to the fi rst author by the Comunidad de Madrid and the European Union and by the Ministerio de Educación y Cultura of Spanish government (projects No. PB97-0298, BTE2001-026 and BTE2002-04453- C02-02). The authors would like to thank L. Wingate, G. Herrero, B. Moral, A. Fernández, and I. Sevillano for their technical support. We also thank Kyger C. Lohmann, Agustín Martín-Algarra and Alfonso Yébenes for their reviews, which have improved this paper.
dc.description Peer reviewed
dc.format 2588929 bytes
dc.format application/pdf
dc.language eng
dc.publisher Universidad Complutense de Madrid
dc.rights openAccess
dc.subject Dolomitization
dc.subject Petrography
dc.subject Geochemistry
dc.subject Stable isotope
dc.subject Strontium isotopes
dc.subject Late Cretaceous
dc.subject Central System
dc.subject Spain
dc.subject Dolomitización
dc.subject Geoquímica
dc.subject Isótopos estables
dc.subject Isótopos de estroncio
dc.subject Cretácico Superior
dc.subject Sistema Central
dc.subject España
dc.title Origin of Late Cretaceous dolomites at the southern margin of the Central System, Madrid Province, Spain
dc.title Origen de las dolomías del Cretácico Superior del borde sur del Sistema Central. Provincia de Madrid. España
dc.type Artículo


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