نتایج جستجو برای: mineralogical changes
تعداد نتایج: 875965 فیلتر نتایج به سال:
The Arctic is melting at an unprecedented rate and key drivers are changes in snow and ice albedo. Here we show that red snow, a common algal habitat blooming after the onset of melting, plays a crucial role in decreasing albedo. Our data reveal that red pigmented snow algae are cosmopolitan as well as independent of location-specific geochemical and mineralogical factors. The patterns for snow...
Heap leaching accounts for a fifth of global copper production, sourced primarily from porphyry ores, yet metal recoveries are often not optimal. Gangue, and its interaction with acid, plays an important role in such processes. Thus, a proper understanding of gangue minerals present in the ore, their textural relationships relative to particle size distribution, reactivity with acid under diffe...
12 Hydrogenetic ferromanganese crusts are iron-manganese oxide chemical 13 precipitates on the seafloor that grow over periods of tens of millions of years. Their 14 secular records of chemical, mineralogical, and textural variations are archives of deep15 sea environmental changes. However, environmental reconstruction requires reliable 16 high-resolution age dating. Earlier chronological meth...
Using laboratory methods, we investigate the effect of the presence and mineralogic form of iron on measured proton nuclear magnetic resonance NMR relaxation rates. Five samples of quartz sand were coated with ferrihydrite, goethite, hematite, lepidocrocite, and magnetite. The relaxation rates for these iron-oxide-coated sands saturated with water were measured and compared to the relaxation ra...
Parametric waveform, monoand multiscale analyses methods are used to characterize the properties of the 410 discontinuity. The characterization involves the estimation of the sharpness, smoothness and extent of this transition from Pds converted phases. In our approach sharpness is no longer associated with the extent of the first-order discontinuity. Instead, the sharpness is related to the fr...
Mineralogical and chemical variations were studied in the upper half of a 1 m thick discontinuous bentonite bed interlaminated in the Lower Cenomanian sedimentary formations of the northern Aquitaine basin (France). X-ray diffraction patterns obtained from the <2 μm fraction in the Ca and K-saturated states were decomposed and compared to those calculated from decomposition parameters. They rev...
Age Determination 105038 Kawano, Y. & Yuhara, M. Chronological and isotope geological study of Cretaceous granitic rocks, upper reach of the Nakagawa river, Fukuoka Prefecture. J. Geol. Soc. Japan, 114, 218-230, 8 figs., 2 tables (in Japanese with English abstract), 2008. Cretaceous granitic rocks, consisting of Itoshima granodiorite and Sawara granite, are occurred at upper reach of the Nakaga...
due to their widespread availability, sandstones are commonly used as a natural stone for buildings, monuments and sculptures. in thecurrent study, nine sandstone samples from the upper red formation (specified by the letters a, b, c, cg, s, s1, sh, tr and min)were studied from a petrophysical point of view and their durability was evaluated. then, their suitability as building stones wasassess...
A heavy media column is used for the separation of the mineral fractions of a sample. Thus the directly weighed per cent of the mineral composition of the rock or ore sample is accomplished. ttre teihnique may be applied to the concentration of a particular species, e,ren i.r trace amounts, for further mineralogical studies or for practical commercial metallurgical mineral beneficiation purposes'
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید