Publication: Late Permian continental sediments in the SE Iberian Ranges,
eastern Spain: Petrological and mineralogical characteristics
and palaeoenvironmental significance
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Publication Date
2005
Authors
Horra del Barco, Raúl de la
López Gómez, José
Rodas, Magdalena
Alonso Azcárate, Jacinto
Arche, Alfredo
Luque del Villar, Francisco Javier
Advisors (or tutors)
Editors
Journal Title
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Publisher
Elsevier
Abstract
A detailed mineralogical and petrological study and the analysis of paleosol profiles in continental alluvial sediments of the
Late Permian in the SE Iberian Ranges (Spain) allow us to infer the significant environmental changes that occurred during this
time period. Three parts have been distinguished in the Late Permian sediments (Alcotas Formation). The lower part includes
abundant and well-preserved carbonate paleosol profiles and fine-grained sediments made up by quartz, feldspar, hematite and
illite, with scarce kaolinite. The preservation of dolomicrite in some paleosols suggests that they originally developed as
dolocretes in an arid to semi-arid climate with marked seasonality.
A change towards more humid and acid conditions can be deduced from the presence of siderite and goethite in paleosols in
the middle part of the Alcotas Formation. Moreover, the presence of plant remains, coal beds and/or carbonaceous shales at the
top of the middle part, and the lack of carbonate paleosols in the upper part of the formation would indicate a further step
towards acid conditions. These conditions would increase until the Early Triassic, as indicated by the lack of carbonates and the
presence of Sr-rich aluminium phosphate sulphates (APS minerals) at the base of the Triassic (Can˜ izar Formation), which
clearly indicates extreme acid conditions during the Permian–Triassic transition of the study area.