Geochemical markers of paleoenvironments, weathering, and provenance in Permian–Triassic terrestrial sediments

Downloads

Downloads per month over past year

63291

Impacto

Downloads

Downloads per month over past year

Galán Abellán, Ana Belén and Fernández Barrenechea, José María and Horra del Barco, Raúl de la and Alonso Azcárate, Jacinto and Luque del Villar, Francisco Javier and Borruel Abadía, Violeta and López Gómez, José (2020) Geochemical markers of paleoenvironments, weathering, and provenance in Permian–Triassic terrestrial sediments. Journal of Sedimentary Research, 90 (8). pp. 906-920. ISSN 1527-1404

[thumbnail of Geochemical markers of paleoenvironments, weathering, and provenance in Permian–Triassic terrestrial sediments.pdf] PDF
Restringido a Repository staff only

2MB

Official URL: https://pubs.geoscienceworld.org/sepm/jsedres/article/90/8/906/590871/Geochemical-markers-of-paleoenvironments



Abstract

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.


Item Type:Article
Subjects:Sciences > Geology > Stratigraphic geology
Sciences > Geology > Geochemistry
Sciences > Geology > Petrology
ID Code:63291
Deposited On:04 Dec 2020 16:45
Last Modified:09 Dec 2020 11:13

Origin of downloads

Repository Staff Only: item control page