RT Journal Article
T1 Paleoecological and paleoenvironmental changes during the continental Middle–LatePermian transition at the SE Iberian Ranges, Spain
A1 Horra del Barco, Raúl de la
A1 Galán Abellán, Ana Belén
A1 López Gómez, José
A1 Sheldon, N.D.
A1 Fernández Barrenechea, José María
A1 Luque del Villar, Francisco Javier
A1 Arche, Alfredo
A1 Benito Moreno, María Isabel
AB 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.
PB Elsevier, B.V.
SN 0921-8181
YR 2012
FD 2012
LK https://hdl.handle.net/20.500.14352/42461
UL https://hdl.handle.net/20.500.14352/42461
LA eng
DS Docta Complutense
RD 6 may 2024