Estratigrafía y sedimentología del Pérmico y Triásico del sector Deza-Castejón (Soria)

Resumo

We have studied here the Deza-Castejón área, in Soria province. A detailed mapping has been carried out in this área together with a stratigraphical and sedimentological study of the permian and triassic deposits. Six lithostratigraphic units have been distinguished. The Lutitas, Areniscas y Conglomerados del Arroyo Riduero is the oldest studied unit (Autunian, Early Permian). This unit appear only in sorne localized areas and consists of alluvial deposits with sorne volcanoclastic material. The overlying unit (Conglomerados y Lutitas del Araviana) mainly include nonmarine continental red beds resulting from an alluvial fan setting, in an arid to semiarid climate. Thickness and distribution is quite irregular in this área. lts age probably ranges between Permian and/or Early Triassic. The two overlying siliciclastic units (Areniscas de Tierga and Limos y Areniscas abigarrados de Torete), Early to Middle Triassic in age, were deposited all over the studied área. These units show an upwards evolution from sandy bed-load, low sinuosity braided streams into mixed carbonate-terrigenous marginal marine environments. The Triassic evolution in this área shows the presence of a carbonate platform (Dolomías de Tramacastilla and Limos y Areniscas abigarrados de Torete units) that are the result of the Tethys sea transgression over Iberia during the Middle Triassic. The uppermost Triassic sediments in this área consist of evaporitic sabkha deposits (Keuper facies).