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The eastern sector of the epicontinental Iberian platform underwent restriction after the sedimentation of the lower Muschelkalk carbonates (Middle Triassic) under extensional regime. This resulted in the accumulation of the marine evaporites and the alluvial siliciclastics of the middle Muschelkalk facies in the Triassic Catalan basin, which varied between 100 and 120 m in thickness. This facies consists of three lithostratigraphic units sedimented at basin scale (Lower, Middle and Upper), each of which includes a distinct evaporite unit. In the Lower Unit, the evaporitic sedimentation started as a transgressive sulfate lagoon (Paüls Gypsum unit). During the Middle Unit time, a regressive evaporitic mudflat, made up of a mosaic of shallow gypsum salinas surrounded by anhydrite sabkhas (Arbolí Gypsum unit) developed; in the northeastern half of the basin, an alluvial plain was formed by siliciclastics (Guanta Sandstone unit) of a west and northwest provenance (Lleida High). During the Upper Unit time, a new transgressive sulfate lagoon occupied the southern half of the basin (Camposines Gypsum), whereas an evaporitic mudflat of red-to-variegated mudstones, marls, and lacustrine carbonates developed in the northern half. Cyclic sedimentation was mainly recorded in the evaporitic mudflat-alluvial plain complex of the Middle Unit. The sulfur isotopic values of gypsum in the three evaporite units show a decrease in δ 34 S with time and also a clear distinction from the values of the Keuper facies in the basin. A division of the lithostratigraphic succession into two third-order depositional sequences is proposed. The middle Muschelkalk succession in the Catalan basin is compared with the equivalent one in the subsurface of the adjacent Triassic Maestrat basin, which was filled with >600 m of marine evaporites.

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Two small, alluvial-lacustrine subbasins developed during the early restraining overstep stages of the Oligocene -Miocene As Pontes strike-slip Basin (NW Spain). Later, the basin evolved into a restraining bend stage and an alluvial-swamp-dominated depositional framework developed. The palaeobiological record demonstrates that the Oligocene -Miocene palaeoclimate in NW Spain was subtropical, warm and humid to subhumid. The metamorphic and igneous basin catchment yielded clay assemblages made up by kaolinite, illite and Al-smectite. Illite occurred as an original mineral in the source rock area, whereas kaolinite and Al-smectite resulted mainly from weathering of feldspar and clinochlore, respectively. This detrital primary clay assemblage remained preserved in the colluvial, alluvial fan and shallow lacustrine facies, whose early diagenesis was influenced by diluted, poorly evolved pore waters with neutral to slightly alkaline pH. The original clay assemblage was mildly to strongly transformed under early diagenetic conditions in the lacustrine and swampy environments where significant hydrochemical and Eh -pH changes took place. A fibrous magnesium-rich clay mineral-dominated assemblage (palygorskite and sepiolite) formed in shallow, saline lakes and palustrine zones under the influence of magnesium-rich, alkaline waters. Moreover, kaoliniteenriched assemblages formed in deep lacustrine, swamp and swamp-related alluvial zones under the influence of slightly to highly acidic pore waters. Pore water acidic conditions, characterising environments with organic matter accumulation, led to early diagenetic transformation of Al-smectite into kaolinite. This process was relatively limited in some environments such as organic matter-rich bottoms in meromictic lacustrine zones, whereas it was pervasive in peat-forming swamp zones.The stratigraphic relationships between the diverse clay mineral assemblages in the As Pontes Basin fill demonstrate the coeval development of rather diverse clay compositions. This clearly reflects the influence on clay assemblages of palaeoenvironmental changes forced by the morphological and tectonic evolution of the catchment -basin system. The interplay between climate and tectonic processes in the source areas did not result in major variations of the clay minerals fed into the basin. Conversely, this tectonic-sedimentation interplay influenced the evolution of the drainage and the water balance in the depositional zones, causing a complex environmental -hydrochemical evolution to occur. As a consequence, drastic early diagenetic changes affected the original clay mineral assemblages and resulted in a variety of early diagenetic assemblages. The As Pontes case study emphasises the major influence of palaeogeographical and tectonosedimentary evolution on the claymineral record in nonmarine depositional systems. The depositional record in As Pontes Basin demonstrates that morphological and tectonically forced environmental and hydrochemical changes can result in variations similar to...

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The larger change in force direction in pain patients implies redistribution of loads across the arm as an associated effect of pain.

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