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<p>This study analyzes the provenance and diagenesis of the Upper Jurassic–Lower Cretaceous sandstone deposits of the NW South-Iberian Basin (Teruel and Valencia provinces, SE Spain) in order to understand the controls on their field appearance (color and friability), which conditioned the definition of formal lithostratigraphic units. Specifically, analyzed sandstone belongs to the Kimmeridgian-Tithonian Villar del Arzobispo Fm, a mixed carbonate-siliciclastic unit deposited in coastal, fluvial, deltaic and aeolian sedimentary environments. This unit includes, at its uppermost part, the essentially siliciclastic, very friable and whitish deposits previously assigned to the El Collado Fm, a unit traditionally assigned to the Barremian and recently dated as Kimmeridgian-Tithonian. Compositional provenance study has included point-counting and K-feldspar and tourmaline microprobe analyzes. Sandstones are mainly arkoses, which have similar framework composition all along the studied sedimentary record. The absence of plagioclases in all samples indicates strong chemical weathering in source areas, which is characteristic of warm and wet climatic conditions. The source areas were mostly peraluminic granites, probably from the Central Iberian Zone (Iberian Massif), located more than 200 km away to the NW of the study area; Paleozoic metaquartzites, slates and schists from the Iberian Massif plus sedimentary rocks from nearby areas. The lower and middle-upper parts of the Villar del Arzobispo Fm have sedimentary carbonate rock fragments, which influenced pervasive carbonate precipitation during diagenesis, generating their competent field appearance. However, the uppermost part of this formation, traditionally assigned to the El Collado Fm, has very low carbonate rock fragments and large amount of kaolinite epimatrixes, which favored its whitish and friable appearance. Thus, the color and friability of the sandstone deposits were mainly controlled by diagenetic processes and not by changes in source areas, advising the consideration of diagenetic processes when defining sandstone stratigraphic units.</p>

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Sandstone provenance and diagenesis as tools for the definition of lithostratigraphic units

  • 期刊论文

  • 发表日期：

    2025年2月4日

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  • L. González-Acebrón,
  • S. Campos-Soto,
  • M. I. Benito,
  • I. E. Quijada,
  • P. Suarez-Gonzalez

摘要

This study analyzes the provenance and diagenesis of the Upper Jurassic–Lower Cretaceous sandstone deposits of the NW South-Iberian Basin (Teruel and Valencia provinces, SE Spain) in order to understand the controls on their field appearance (color and friability), which conditioned the definition of formal lithostratigraphic units. Specifically, analyzed sandstone belongs to the Kimmeridgian-Tithonian Villar del Arzobispo Fm, a mixed carbonate-siliciclastic unit deposited in coastal, fluvial, deltaic and aeolian sedimentary environments. This unit includes, at its uppermost part, the essentially siliciclastic, very friable and whitish deposits previously assigned to the El Collado Fm, a unit traditionally assigned to the Barremian and recently dated as Kimmeridgian-Tithonian. Compositional provenance study has included point-counting and K-feldspar and tourmaline microprobe analyzes. Sandstones are mainly arkoses, which have similar framework composition all along the studied sedimentary record. The absence of plagioclases in all samples indicates strong chemical weathering in source areas, which is characteristic of warm and wet climatic conditions. The source areas were mostly peraluminic granites, probably from the Central Iberian Zone (Iberian Massif), located more than 200 km away to the NW of the study area; Paleozoic metaquartzites, slates and schists from the Iberian Massif plus sedimentary rocks from nearby areas. The lower and middle-upper parts of the Villar del Arzobispo Fm have sedimentary carbonate rock fragments, which influenced pervasive carbonate precipitation during diagenesis, generating their competent field appearance. However, the uppermost part of this formation, traditionally assigned to the El Collado Fm, has very low carbonate rock fragments and large amount of kaolinite epimatrixes, which favored its whitish and friable appearance. Thus, the color and friability of the sandstone deposits were mainly controlled by diagenetic processes and not by changes in source areas, advising the consideration of diagenetic processes when defining sandstone stratigraphic units.