نتایج جستجو برای: ferruginous composition
تعداد نتایج: 260148 فیلتر نتایج به سال:
The type section of the Lower Cenomanian Bahariya Formation at Gebel El-Dist (Bahariya Oasis, Western Desert), Egypt, comprises claystones, mudstones, siltstones and sandstones deposited in fluvial-deltaic coastal plain, lagoonal, estuarine and shallow marine environments. The formation is characterized by an abundance of ferruginous sandstones that locally weather to form prominent iron crusts...
The paper studies accessory Cr-spinels from deep drill holes crossing the Nude-Poaz massif, which is a part of Monchegorsk mafic-ultramafic layered complex (2.5 Ga, Kola Peninsula, Russia). occur as two morphological types that differ in their chemical composition, i.e., first type are more aluminous, while second ferruginous and titaniferous. massif characterized by Fe-Ti trend known for intru...
While exposure to fibers and particles has been proposed to be associated with several different lung malignancies including mesothelioma, the mechanism for the carcinogenesis is not fully understood. Along with mineralogical observation, we have analyzed forty-four major and trace elements in extracted asbestos bodies (fibers and proteins attached to them) with coexisting fiber-free ferruginou...
Incrustations and other biological growths in water mains and distribution pipes cause considerable difficulties in water engineering. The control of such obstructions in the pipes, in most cases, largely depends upon the character and composition of the water and the nature of the pipe material. A few years ago some studies were carried out at Bangalore on the tubercular incrustations in water...
Iron-rich (ferruginous) ocean chemistry prevailed throughout most of Earth's early history. Before the evolution and proliferation of oxygenic photosynthesis, biological production in the ferruginous oceans was likely driven by photoferrotrophic bacteria that oxidize ferrous iron {Fe(II)} to harness energy from sunlight, and fix inorganic carbon into biomass. Photoferrotrophs may thus have fuel...
Considerable discussion surrounds the potential role of anoxygenic phototrophic Fe(II)-oxidizing bacteria in both the genesis of Banded Iron Formations (BIFs) and early marine productivity. However, anoxygenic phototrophs have yet to be identified in modern environments with comparable chemistry and physical structure to the ancient Fe(II)-rich (ferruginous) oceans from which BIFs deposited. La...
Our health center evaluated an individual for suspected pneumoconiosis, which had resulted from exposures in a foundry/metal reclamation facility. Appropriate consent forms were obtained for the procedures. Historically, individuals who work in foundries have been exposed to various types of dusts. The clinical findings in this case were consistent with silicosis with a suspicion of asbestos-in...
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