RT Journal Article
T1 Geochemical markers of paleoenvironments, weathering, and provenance in Permian–Triassic terrestrial sediments
A1 Galán Abellán, Ana Belén
A1 Fernández Barrenechea, José María
A1 Horra Del Barco, Raúl De La
A1 Alonso Azcárate, Jacinto
A1 Luque Del Villar, Francisco Javier
A1 Borruel Abadía, Violeta
A1 López Gómez, José
AB This study compares several geochemical factors (major and minor rare earth elements, Ti/Al ratios, and chemical index of alteration, CIA, values) in the Early Triassic Cañizar Formation (Fm) (Buntsandtein facies) of E Iberia with those of adjacent Middle Permian and Middle Triassic units (Alcotas and Eslida fms, respectively). According to significant differences detected, it seems that most geochemical perturbation occurred during the Early Triassic. Variations in Ti/Al ratios suggest changes in source areas between the studied units and even within the Cañizar Fm. These provenance changes correlate with successive tectonic pulses during the opening and development of the Iberian Basin, as they can be linked to major sedimentary surfaces and unconformities, as well as major sedimentological variations. Ti enrichment in the lower and middle part of the Cañizar Fm, together with high Sr and P concentrations, may be indicative of environmental alterations related to acid meteoric waters. Moreover, this acid alteration took place under arid conditions as reflected by CIA values, indicating that during the deposition of the Cañizar Fm, variable but predominantly physical weathering prevailed in contrast to the chemical weathering that took place when the Alcotas and Eslida formations were deposited. Our data along with the known fossil record of the study area indicate that during the Middle–Late Permian and Early Triassic, conditions in this tectonically active area changed from humid to arid-acid, hampering biotic recovery. Then, during late Early–Middle Triassic times, the return of more humid and less acid environments promoted biotic development. Geochemical markers emerged as useful tools complementary to sedimentological, paleontological, and tectonic data for unveiling paleoenvironmental events, especially in a setting of significant regional change.
PB SEPM
SN 1527-1404
YR 2020
FD 2020
LK https://hdl.handle.net/20.500.14352/7585
UL https://hdl.handle.net/20.500.14352/7585
LA eng
NO Ministerio de Economía y Competitividad (MINECO)
NO Consejo Superior de Investigaciones Científicas (CSIC)
DS Docta Complutense
RD 8 abr 2025