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Clay minerals as provenance indicators in continental lacustrine sequences: the Leza Formation, early Cretaceous, Cameros Basin, northern Spain

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Alonso Azcárate, Jacinto and Rodas, Magdalena and Fernández Barrenechea, José María and Mas Mayoral, José Ramón (2005) Clay minerals as provenance indicators in continental lacustrine sequences: the Leza Formation, early Cretaceous, Cameros Basin, northern Spain. Clay minerals, 40 . pp. 79-92. ISSN 0009-8558

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Official URL: http://www.minersoc.org/pages/e_journals/clay.html



Abstract

Variations in clay mineral assemblages, changes in KuÈbler index (KI), and the
chemical composition of chlorites are used to identify source areas in the lacustrine materials in the
Lower Cretaceous Leza Limestone Formation of the Cameros Basin, northern Spain. This formation
has fairly homogeneous lithological characteristics and facies associations which do not allow for
identification and characterization of local source areas. The Arnedillo lithosome of the Leza
Limestone Formation contains a clay mineral association (Mg-chlorite, illite and smectite) indicative
of its provenance. Chlorite composition and illite KI values indicate that these minerals were formed
at 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 Keuper
sediments of the area indicates that these materials acted as a local source area. This implies that
Triassic 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 altered
the Mg-chlorites in some samples.


Item Type:Article
Uncontrolled Keywords:Provenance, Lacustrine deposits, Inherited Mg-chlorite, Retrograde diagenesis
Subjects:Sciences > Geology > Stratigraphic geology
ID Code:17612
Deposited On:10 Jan 2013 10:26
Last Modified:11 Dec 2018 08:46

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