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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
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We present the results of modelling the energy distribution of a power law reflected by a dusty cloud. We explore in a fully consistent manner the case in which the reflecting nebula is of considerable optical depth. We apply the model to the observations of the detached emission line cloud at 8 kpc from the nucleus of Pks 2152-69 for whichcontinuum flux measurements exist up to the far UV. Our results for the thick case qualitatively agree with the results of Fosburyet al. (1991) (who studied the optically thin case) in that we also need a population of grain sizes dominated by small grains (smaller on average than in models of the standard extinction curve) in order to reproduce the energy distribution of the detached continuum source. We model the high excitation emission line spectrum of the cloud using the code MAPPINGS. Photoionization calculations in which the ionized gas contains the reflecting dust can easily reproduce the high electronic temperature as well as theapparent case B Ly/H ratio observed in the detached cloud, confirming that dust is a workable hypothesis for explaining the Ly emission and the blue extended light detected around many high redhift radio galaxies. 相似文献
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