%0 Journal Article
%A Horra del Barco, Raúl de la
%A Galán Abellán, Ana Belén
%A López Gómez, José
%A Sheldon, N.D.
%A Fernández Barrenechea, José María
%A Luque del Villar, Francisco Javier
%A Arche, Alfredo
%A Benito Moreno, María Isabel
%T Paleoecological and paleoenvironmental changes during the continental Middle–LatePermian transition at the SE Iberian Ranges, Spain
%D 2012
%@ 0921-8181
%U https://hdl.handle.net/20.500.14352/42461
%X The Middle and Late Permian are characterized by a pair of mass-extinction events that are recorded in bothmarine and continental environments. Here, we present the first continental western peri-Tethyan record ofan extinction event located in the Middle–Late interval. In the SE Iberian Ranges, Central Spain, the transitionbetween the Lower and Middle subunits of the Middle Permian Alcotas Formation indicates a significant paleoclimaticchange from arid and semiarid conditions towards more humid conditions. Coincident with theonset of humid conditions there were changes in the sedimentology, mineralogy, and geochemistry that indicatesignificant environmental changes including a shift in weathering intensity and a change of fluvialstyle from braided to meandering systems. Near the top of the Middle Subunit, a local biotic crisis is recordedby palynomorph assemblages. Following this crisis, there is a total absence of coal beds, plant remains, andmicroflora that defines a barren zone in the uppermost part of the Alcotas Formation which is recordedthroughout the basin. The barren zone is accompanied by a shift back to braided stream systems, but notby a return to carbonate-bearing paleosols indicative of arid or semi-arid conditions. This combination of featuresis consistent with other Middle–Late continental basins related with mass extinctions, so the barrenzone is interpreted as the extinction interval. The regional character of the extinction interval and its proximitywith the Middle–Late Permian transition could be related with the global mid-Capitanian biotic turnoverdescribed in this period of time in other marine basins. However, the common difficulties of dating with precisionnon-marine rocks make this relationship difficult to probe in the Iberian Basin and in other Middle–Late Permian basins. Further work, including high resolution carbon-isotope analyses and complete studiesof the magnetostratigraphy, should be desirable in order to obtain a better age constraint and to producereliable comparisons with marine sections.
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