نتایج جستجو برای: element deposits
تعداد نتایج: 231488 فیلتر نتایج به سال:
Rare-element granites and pegmatites represent important sources of raw materials for “clean, green high technologies”, such as lithium tantalum, example. However, mechanisms rare-element pegmatite’s origin are still far from being fully understood. Several pegmatite fields a granite known in the Variscan realms located Iberia (Spain Portugal), enhancing interest this area studying formation th...
Silicic tuffs infilling an ancient submarine caldera, at Mineral King in California, show microscopic fabrics indicative of welding of glass shards and pumice at temperatures >500 degrees C. The occurrence indicates that subaqueous explosive eruption and emplacement of pyroclastic materials can occur without substantial admixture of the ambient water, which would cause chilling. Intracaldera pr...
This study reports the prevalence of immune deposits associated with the proximal and distal tubules in a series of routine renal biopsies received in our department during a single calendar year. From 87 cases, 65 (74%) were found to have glomerular immune deposits by immunofluorescence. Tubular immune deposits were found in 12 cases (18%), 3 of which had no glomerular deposits. By transmissio...
Copper, obtained from porphyry deposits formed in arc settings, is a critical resource, and primarily sourced magmas. However, the processes that shape copper contents of magmas are up for debate. Existing models place emphasis on different petrological agents explain large-scale trends systematics. Previous studies have noted ’Cu paradox,’ where with high Sr/Y ratios, indicative ore-forming po...
This study investigated the spatial variability characteristics of effective friction angle Crag deposits which are granular soils occur in east England. Cone Penetration Test data were obtained at 26 locations and interpreted statistically. The distribution characteristic was derived with mean value, standard deviation correlation length calibrated. Illustrations also shown on how factors such...
We present new observations of pyroclastic deposits on the surface of Mercury from data acquired during the orbital phase of the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission. The global analysis of pyroclastic deposits brings the total number of such identified features from 40 to 51. Some 90% of pyroclastic deposits are found within impact craters. The loca...
Deposition of β-amyloid (Aβ), a 'signature' pathological lesion of Alzheimer's disease (AD), is also characteristic of Down's syndrome (DS), and has been observed in dementia with Lewy bodies (DLB) and corticobasal degeneration (CBD). To determine whether the growth of Aβ deposits was similar in these disorders, the size frequency distributions of the diffuse ('pre-amyloid'), primitive ('neurit...
OBJECTIVE To evaluate whether otosclerosis is an underlying mechanism for the production of cupular deposits and to study the association between cupular deposits and dysequilibrium in otosclerosis. DESIGN Retrospective human temporal bone (TB) study. The incidence of cupular deposits in these 70 TBs was analyzed. Correlations between cupular deposits and vestibular symptoms, endosteal involv...
Spherule layers in the ~ 3.4 Ga Barberton Greenstone Belt, South Africa, have been interpreted as being the result of large asteroid or comet impacts on the early earth. This interpretation was based, among other arguments, on the enr ichment of siderophile elements, especially the platinum group elements. We made a detailed mineralogical, petrological and geochemical study of spherule bed samp...
Nonglacial deposits Artificial fill (Holocene)—Mud, sand, and gravel of varying proportions, possibly including foreign debris such as concrete, logs, timbers, or brick. Used for highway roadbeds and other construction. Thickness generally greater than 2 m. Mapped where fill substantially obscures or has altered original geologic deposit. Beach deposits (Holocene)—Soft sand, silt, and mud depos...
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