نتایج جستجو برای: mesozoic refractory sand

تعداد نتایج: 88414  

2013
Thomas L. Stubbs Stephanie E. Pierce Emily J. Rayfield Philip S. L. Anderson

Mesozoic crurotarsans exhibited diverse morphologies and feeding modes, representing considerable ecological diversity, yet macroevolutionary patterns remain unexplored. Here, we use a unique combination of morphological and biomechanical disparity metrics to quantify the ecological diversity and trophic radiations of Mesozoic crurotarsans, using the mandible as a morpho-functional proxy. We re...

2013
Marco Ligi Enrico Bonatti Marco Cuffaro Daniele Brunelli

The seawater Mg/Ca ratio increased significantly from ~ 80 Ma to present, as suggested by studies of carbonate veins in oceanic basalts and of fluid inclusions in halite. We show here that reactions of mantle-derived peridotites with seawater along slow spreading mid-ocean ridges contributed to the post-Cretaceous Mg/Ca increase. These reactions can release to modern seawater up to 20% of the y...

2008
N. DS. GANI M. G. ABDELSALAM S. GERA M. R. GANI

The Blue Nile Basin, situated in the Northwestern Ethiopian Plateau, contains 1400 m thick Mesozoic sedimentary section underlain by Neoproterozoic basement rocks and overlain by Early–Late Oligocene and Quaternary volcanic rocks. This study outlines the stratigraphic and structural evolution of the Blue Nile Basin based on field and remote sensing studies along the Gorge of the Nile. The Blue ...

Journal: :Ceramics 2022

This article analyzes the mechanism of protective layer formation under action alkali in a refractory castable when ground quartz sand (GQS) is used as an admixture to produce conventional castables (CC) and medium cement (MCC). It was found that, independently composition, addition GQS (2.5%) reduces degree K2CO3 dissolution at high temperature, released potassium reacts with silica forms visc...

Journal: :The American Naturalist 1891

Journal: :Geological Magazine 1886

2010
Raymond Wilson Michelle D. Bates Anna Dostalova Lucie Jecna Rod J. Dillon Petr Volf Paul A. Bates

BACKGROUND The binding of Leishmania promastigotes to the midgut epithelium is regarded as an essential part of the life-cycle in the sand fly vector, enabling the parasites to persist beyond the initial blood meal phase and establish the infection. However, the precise nature of the promastigote stage(s) that mediate binding is not fully understood. METHODOLOGY/PRINCIPAL FINDINGS To address ...

2012
Oliver W. M. Rauhut Alexander M. Heyng Adriana López-Arbarello Andreas Hecker

BACKGROUND Rhynchocephalians, the sister group of squamates (lizards and snakes), are only represented by the single genus Sphenodon today. This taxon is often considered to represent a very conservative lineage. However, rhynchocephalians were common during the late Triassic to latest Jurassic periods, but rapidly declined afterwards, which is generally attributed to their supposedly adaptive ...

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