Universidad Complutense de Madrid
E-Prints Complutense

Isotope records (C-O-Sr) of late Pliensbachian-early Toarcian environmental perturbations in the westernmost Tethys (Majorca Island, Spain)

Impacto

Descargas

Último año

Rosales, Idoia y Barnolas Cortina, Antonio y Goy, Antonio y Sevillano, Ana y Armendáriz, Maider y López García, José María (2018) Isotope records (C-O-Sr) of late Pliensbachian-early Toarcian environmental perturbations in the westernmost Tethys (Majorca Island, Spain). Palaeogeography, Palaeoclimatology, Palaeoecology, 497 . pp. 168-185. ISSN 0031-0182

[img] PDF
Restringido a Sólo personal autorizado del repositorio

3MB

URL Oficial: https://www.sciencedirect.com/science/article/pii/S003101821730888X


URLTipo de URL
https://www.sciencedirect.com/Editorial


Resumen

The late Pliensbachian–early Toarcian (Early Jurassic) was a time of major environmental changes that culminated with the Early Toarcian Oceanic Anoxic Event (T-OAE, ca. ~183 Ma). This period is marked by significant disturbances in the carbon cycle and rapid climatic changes. To improve the understanding of the expression of these events in westernmost Tethyan domains, this study provides new belemnite and bulk carbonate C and O stable isotope records of a ~5 Myr upper Pliensbachian to middle Toarcian marine succession of the Balearic Basin (Es Cosconar section, Majorca). Time resolution has been improved by combination of biostratigraphic (ammonoids and brachiopods) and geochronologic (87Sr/86Sr) methods. Seawater paleotemperatures derived from δ18O belemnite records reveal cooler paleotemperatures in the upper part of the Spinatum Zone. The uppermost Spinatum Zone is characterized by the onset of a warming event that crosses the Pliensbachian-Toarcian boundary, culminating with the warmer temperatures (up to ~10 °C of warming) for the Serpentinum Zone of the lower Toarcian. This warming event has been detected contemporaneously in many other European and Tethyan basins and is interpreted to represent generalized raised seawater temperatures linked to the T-OAE. Four significant δ13C events have been recorded in belemnite and bulk carbonate records. The first is a negative carbon isotope excursion (CIE) around the Pliensbachian-Toarcian boundary, which is best represented in the belemnite record. Soon after, the bulk‑carbonate record shows a positive shift in the lower Tenuicostatum Zone concomitant with a return to background values in the belemnite record, suggesting strong water stratification or decoupling probably related with export of neritic carbonate to the basin. The third is a negative CIE represented in bulk carbonate across the Tenuicostatum-Serpentinum zonal transition, which could be correlated with the negative excursion characterizing the onset of the T-OAE in other sections. The position of this excursion corresponds with a gap in the belemnite record. Finally, in the lower Toarcian, both the bulk carbonate and belemnite carbon isotope records show pronounced positive CIEs in the lower-middle part of the Serpentinum Zone. These CIEs testify the impact of the T-OAE in the Balearic basin.


Tipo de documento:Artículo
Palabras clave:Stable isotopes, Strontium isotopes, Sea-level change, Hyperthermal event, Early Jurassic
Materias:Ciencias > Geología > Geología estratigráfica
Ciencias > Geología > Geoquímica
Ciencias > Geología > Paleontología
Código ID:47670
Depositado:21 May 2018 17:50
Última Modificación:11 Dic 2018 08:41

Descargas en el último año

Sólo personal del repositorio: página de control del artículo