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| Format: | Artículo científico |
| Language: | en |
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Universidad Nacional Autónoma de México
2016
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| Online Access: | https://www.redalyc.org/articulo.oa?id=57246037003 |
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Table of Contents:
- Paleoclimate, paleoweathering and paleoredox conditions of Lower Cretaceous shales from the Mural Limestone, Tuape section, northern Sonora, Mexico: Constraints from clay mineralogy and geochemistry Jayagopal Madhavaraju Erik Ramírez-Montoya Rogelio Monreal Carlos M. González–León Teresa Pi-Puig Inocente G. Espinoza-Maldonado Francisco J. Grijalva–Noriega Ciencias de la Tierra paleo Sonora Geochemistry paleoclimate clay mineralogy Clay mineral analysis and major, trace and rare earth elements (REE) data were used in this study to interpret the paleoclimatic changes, paleoweathering and paleo-redox conditions in shale beds of the Tuape section of the Mural Limestone of Sonora. The clay mineralogical assemblages (illite-chlorite-kaolinite-smectite) of this section have provided information on the climatic conditions and environment of deposition that prevailed during late Aptian-early Albian age. The chondrite-normalized REE patterns are characterized by enriched LREE, flat HREE with negative Eu anomaly. The chemical index of alteration (CIA) and plagioclase index of alteration (PIA) values for these shales and A-CN-K diagram indicate a moderate intensity of chemical weathering. The low contents of TOC, TN, Mo, U and V and low Ni/Co and U/Th ratios in the Cerro La Ceja, Los Coyotes and Mesa Quemada members suggest that they have been deposited under oxic conditions. However, the Tuape Shale and Cerro La Puerta members show relatively low to moderate contents of redox sensitive elements, and their ratios suggest that the depositional basin experienced oxic to anoxic depositional conditions. 2016 artículo científico 1026-8774 https://www.redalyc.org/articulo.oa?id=57246037003 en http://www.redalyc.org/revista.oa?id=572 Revista Mexicana de Ciencias Geológicas application/pdf Universidad Nacional Autónoma de México Revista Mexicana de Ciencias Geológicas (México) Num.1 Vol.33