Geochemistry of the Jurassic and Upper Cretaceous shales from the Molango Region,Hidalgo, eastern Mexico: Implications for source-area weathering,provenance, and tectonic setting   总被引：3，自引：0，他引：3  

John S. Armstrong-Altrin  Ramasamy Nagarajan  Jayagopal Madhavaraju  Leticia Rosalez-Hoz  Yong Il Lee  Vysetti Balaram  Adriana Cruz-Martínez  Gladis Avila-Ramírez 《Comptes Rendus Geoscience》2013,345(4):185-202

This study focuses on the Jurassic (Huayacocotla and Pimienta Formations) and Upper Cretaceous (Méndez Formation) shales from the Molango Region, Hidalgo, Mexico. In this article, we discuss the mineralogy, major, and trace element geochemistry of the Mesozoic shales of Mexico. The goal of this study is to constrain the provenance of the shales, which belong to two different periods of the Mesozoic Era and to understand the weathering conditions and tectonic environments of the source region.  相似文献   

Carbon and Oxygen Isotopic Signatures in Albian-Danian Limestones of Cauvery Basin, Southeastern India     

J. Madhavaraju  I. Kolosov  D. Buhlak  J.S. Armstrong-Altrin  S. Ramasamy  S.P. Mohan 《Gondwana Research》2004,7(2):519-529

The Albian-Danian limestones of Cauvery Basin show a wide range of d¹³C and d¹⁸O values (–13.2 to +1.1% and –9.0 to –2.5%, respectively). The cement samples show negative carbon and oxygen isotope values (–18.9 to –3.9% and –9.0 to –4.3%, respectively). The petrographic study reveals the presence of algae, molluscs, bryozoans, foraminifers and ostracods as major framework constituents. The limestones have microspar and equant sparry calcite cements. The pore spaces and vugs are filled with sparry calcite cement. The bivariate plot of d¹³C and d¹⁸O suggests that most of the samples fall in the freshwater limestone and meteoric field, while few samples fall in the marine limestone and soil calcite fields. The presence of sparry calcite cement, together with negative carbon and oxygen isotope values, indicates that these limestones have undergone meteoric diagenesis.  相似文献   

Petrography and stable isotope geochemistry of the cretaceous El Abra Limestones (Actopan), Mexico: Implication on diagenesis     

John S. Armstrong-Altrin  J. Madhavaraju  Alcides N. Sial  Juan J. Kasper-Zubillaga  R. Nagarajan  K. Flores-Castro  Janet Luna Rodríguez 《Journal of the Geological Society of India》2011,77(4):349-359

Petrography and stable isotopes (carbon and oxygen) geochemistry of limestones from the El Abra Formation, Actopan, were studied to identify their digenetic environments. The major petrographic types identified are mudstone, wackestone, grainstone, and boundstone. Most of the studied samples show positive δ¹³C values, except two samples (2 and 28), which are slightly negative values (−0.27‰ and −0.02‰). The organic remains identified in foraminiferal wackestone type can be responsible for the negative δ¹³C values. The δ¹⁸O values range from −12.41‰ to −4.02‰ and indicate meteoric diagenesis.  相似文献