%0 Journal Article
%A Alonso Azcárate, Jacinto
%A Rodas González, Magdalena
%A Fernández Barrenechea, José María
%A Mas Mayoral, José Ramón
%T Clay minerals as provenance indicators incontinental lacustrine sequences: the LezaFormation, early Cretaceous, CamerosBasin, northern Spain
%D 2005
%@ 0009-8558
%U https://hdl.handle.net/20.500.14352/50266
%X Variations in clay mineral assemblages, changes in KuÈbler index (KI), and thechemical composition of chlorites are used to identify source areas in the lacustrine materials in theLower Cretaceous Leza Limestone Formation of the Cameros Basin, northern Spain. This formationhas fairly homogeneous lithological characteristics and facies associations which do not allow foridentification and characterization of local source areas. The Arnedillo lithosome of the LezaLimestone Formation contains a clay mineral association (Mg-chlorite, illite and smectite) indicativeof its provenance. Chlorite composition and illite KI values indicate that these minerals were formedat temperatures higher than those reached by the Leza Formation which indicates its detrital origin.The similarity in the Mg-chlorite composition between the Arnedillo lithosome and the Keupersediments of the area indicates that these materials acted as a local source area. This implies thatTriassic sediments were exposed, at least locally, at the time of deposition of the Leza Formation.The presence of smectite in the Leza Formation is related to a retrograde diagenesis event that alteredthe Mg-chlorites in some samples.
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