Skip to Main Content
Book Chapter

Provenance discrimination of Lower Cretaceous synrift sandstones (eastern Iberian Chain, Spain): Constraints from detrital modes, heavy minerals, and geochemistry

By
M.A. Caja
M.A. Caja
Departamento de Petrología y Geoquímica, Facultad CC. Geológicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
Search for other works by this author on:
R. Marfil
R. Marfil
Departamento de Petrología y Geoquímica, Facultad CC. Geológicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
Search for other works by this author on:
M. Lago
M. Lago
Departamento de Ciencias de la Tierra, Área de Petrología y Geoquímica, Facultad CC. Geológicas, Universidad de Zaragoza, 50009 Zaragoza, Spain
Search for other works by this author on:
R. Salas
R. Salas
Departamento de Geoquímica, Petrologia i Prospecció Geológica, Facultat de Geología, Universitat de Barcelona, 08028 Barcelona, Spain
Search for other works by this author on:
K. Ramseyer
K. Ramseyer
Institut für Geologie, Universität Bern, 3012 Bern, Switzerland
Search for other works by this author on:
Published:
January 01, 2007

Petrography, geochemical whole-rock composition, and chemical analyses of tourmaline were performed in order to determine the source areas of Lower Cretaceous Mora, El Castellar, and uppermost Camarillas Formation sandstones from the Iberian Chain, Spain. Sandstones were deposited in intraplate subbasins, which are bound by plutonic and volcanic rocks of Permian, Triassic, and Jurassic age, Paleozoic metamorphic rocks, and Triassic sedimentary rocks.

Modal analyses together with petrographic and cathodoluminescence observations allowed us to define three quartz-feldspathic petrofacies and recognize diagenetic processes that modified the original framework composition. Results from average restored petrofacies are: Mora petrofacies = P/F >1 and Q(r)70 F(r)22 R(r)9; El Castellar petrofacies = P/F >1 and Q(r)57 F(r)25 R(r)18; and Camarillas petrofacies = P/F ∼ zero and Q(r)64 F(r)28 R(r)7 (P—plagioclase; F—feldspar; Q—quartz; R—rock fragments; r—restored composition).

Trace-element and rare earth element abundances of whole-rock analyses discriminate well between the three petrofacies based on: (1) the Rb concentration, which is indicative of the K content and reflects the amount of K-feldspar modal abundance, and (2) the relative modal abundance of heavy minerals (tourmaline, zircon, titanite, and apatite), which is reproduced by the elements hosted in the observed heavy mineral assemblage (i.e., B and Li for tourmaline; Zr, Hf, and Ta for zircon; Ti, Ta, Nb, and their rare earth elements for titanite; and P, Y, and their rare earth elements for apatite). Tourmaline chemical composition for the three petrofacies ranges from Fe-tourmaline of granitic to Mg-tourmaline of metamorphic origin.

The three defined petrofacies suggest a mixed provenance from plutonic and metamorphic source rocks. However, a progressively major influence of granitic source rocks was detected from the lowermost Mora petrofacies toward the uppermost Camarillas petrofacies. This provenance trend is consistent with the uplift and erosion of the Iberian Massif, which coincided with the development of the latest Berriasian synrift regional unconformity and affected all of the Iberian intraplate basins. The uplifting stage of Iberian Massif pluton caused a significant dilution of Paleozoic metamorphic source areas, which were dominant during the sedimentation of the lowermost Mora and El Castellar petrofacies.

The association of petrographic data with whole-rock geochemical compositions and tourmaline chemical analysis has proved to be useful for determining source area characteristics, their predominance, and the evolution of source rock types during the deposition of quartz-feldspathic sandstones in intraplate basins. This approach ensures that provenance interpretation is consistent with the geological context.

You do not currently have access to this article.
Don't already have an account? Register

Figures & Tables

Contents

GSA Special Papers

Sedimentary Provenance and Petrogenesis: Perspectives from Petrography and Geochemistry

José Arribas
José Arribas
Search for other works by this author on:
Mark J. Johnsson
Mark J. Johnsson
Search for other works by this author on:
Salvatore Critelli
Salvatore Critelli
Search for other works by this author on:
Geological Society of America
Volume
420
ISBN print:
9780813724201
Publication date:
January 01, 2007

GeoRef

References

Related

A comprehensive resource of eBooks for researchers in the Earth Sciences

This Feature Is Available To Subscribers Only

Sign In or Create an Account

This PDF is available to Subscribers Only

View Article Abstract & Purchase Options

For full access to this pdf, sign in to an existing account, or purchase an annual subscription.

Subscribe Now