Saved in:
| Main Author: | |
|---|---|
| Format: | Artículo científico |
| Language: | en |
| Published: |
Universitat de Barcelona
2005
|
| Subjects: | |
| Online Access: | https://www.redalyc.org/articulo.oa?id=50530206 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
Table of Contents:
- Chemostratigraphy of the Pliensbachian, Puesto Araya Formation (Neuquén Basin, Argentina) S.A. Valencio M.C. Cagnoni H.O. Panarello A.M. Ramos A.C. Riccardi Ciencias de la Tierra Pliensbachian Bivalve shells Chemostratigraphy Ammonite Zonation In a preliminary attempt to establish an isotope stratigraphy, strontium, carbon and oxygen isotope ratios weredetermined from marine biogenic carbonates of Pliensbachian age, in the context of scheme of local ammoniteZones correlatable to the European Standard Zonation. Two sections, río Atuel and arroyo Serrucho, of themainly siliciclastic Puesto Araya Formation, Neuquén Basin, south-western Mendoza, Argentina, were studied.Specimens of the bivalve genera Weyla Bhöm and Gryphaea Lamarck were selected for the isotopic determinationsbecause of their low-Mg calcite original mineralogy and widespread presence. Scanning electronmicroscopy, X-ray diffraction and X-ray fluorescence spectrometry techniques were used to control the gooddegree of preservation of most of the biogenic material, as evidenced by pristine fabrics, 100% calcite compositionand Sr, Mn and Fe concentrations. Although strontium isotope ratios are slightly scattered, it is possible tocompare them with those of the Early Jurassic seawater reference curve. Carbon isotope signals show two relativemaxima, correlatable with those recorded for the upper part of the Ibex Zone and the middle part of theMargaritatus Zone in various European sections, indicating the possible global significance of these events.18O values were found to be unreliable for isotope stratigraphy, as they are largely depleted in comparison tothose of coeval unaltered marine carbonates. 2005 artículo científico 1695-6133 https://www.redalyc.org/articulo.oa?id=50530206 en http://www.redalyc.org/revista.oa?id=505 Geologica Acta: an international earth science journal application/pdf Universitat de Barcelona Geologica Acta: an international earth science journal (España) Num.2 Vol.3