To protect the river bend intake safety,stable operation in the frozen period,the power plant water intake in the bend of Inner Mongolia section in the Yellow River as the research object,the model of river bend intake river ice dynamics were established and studied.The research is mainly divided into 3 steps,including the physical model test,the development and debugging,optimization mathematical model of ice scheme.The physical model experiment content is the motion characteristics of intake flow curve and its influence on river ice movement,movement analysis process of river ice in the corners and accumulation;The mathematical model includes model of unsteady flow in ice water and ice dynamics model,through the movement simulation of river ice under different working conditions to optimize and perfect the model;Through the guide of ice-rafted design run difference,we determine a reasonable design structure,optimize the ice scheme,finally put forward reasonable,effective ice model for different bend intake.
The scheelite with large size and euhedral shape from Xuebaoding, Sichuan Province is an ideal min- eral to study REE patterns and Sm-Nd dating of non-gold deposits. The scheelite has diameters of 1― 10 cm and colors of pale beige to deep orange. Most of these scheelites occur in association with beryl, cassiterite and muscovite. The rare earth elements indicate that scheelite samples from Xuebaoding W-Sn-Be deposits contain high concentrations of rare earth elements with total ΣREE+Y contents in the range of 369―1725 μg·g?1 and nearly all of these scheelite samples are enriched in LREE and depleted in HREE and have negative Eu anomalies. The REE patterns of the scheelites are similar to those of A-type granite with obvious tetrad effect, similar to that of type II scheelites. Based on reported fluid inclusion studies, the mineralizing-fluid of the Xuebaoding W-Sn-Be deposit indicates low Na activity. The REE patterns of the scheelite are probably controlled by partition coefficient in hydrothermal fluid. In the 147Sm/144Nd-143Nd/144Nd diagram, the scheelites show a linear array corresponding to an isochron age of 182.0±9.2 Ma (MSWD = 0.52). The Sm-Nd age represents the formation age of the scheelite and can indicate that the W, Sn and Be mineralization at Xuebaoding took place in the Early Yanshanian. The Sm-Nd dating result is important for the study of the multi-metal resources in western Sichuan Province.
Abstract The recently discovered B aizhangyan skarn‐porphyry type W – Mo deposit in southern A nhui Province in SE C hina occurs near the M iddle– L ower Y angtze V alley polymetallic metallogenic belt. The deposit is closely temporally‐spatially associated with the M esozoic Q ingyang granitic complex composed of g ranodiorite, monzonitic g ranite, and alkaline g ranite. Orebodies of the deposit occur as horizons, veins, and lenses within the limestones of S inian L antian F ormation contacting with buried fine‐grained granite, and diorite dykes. There are two types of W mineralization: major skarn W – Mo mineralization and minor granite‐hosted disseminated Mo mineralization. Among skarn mineralization, mineral assemblages and cross‐cutting relationships within both skarn ores and intrusions reveal two distinct periods of mineralization, i.e. the first W – Au period related to the intrusion of diorite dykes, and the subsequent W – Mo period related to the intrusion of the fine‐grained granite. In this paper, we report new zircon U – Pb and molybdenite Re – Os ages with the aim of constraining the relationships among the monzonitic granite, fine‐grained granite, diorite dykes, and W mineralization. Zircons of the monzonitic granite, the fine‐grained granite, and diorite dykes yield weighted mean U – Pb ages of 129.0 ± 1.2 Ma, 135.34 ± 0.92 Ma and 145.3 ± 1.7 Ma, respectively. Ten molybdenite Re – Os age determinations yield an isochron age of 136.9 ± 4.5 Ma and a weighted mean age of 135.0 ± 1.2 Ma. The molybdenites have δ 34 S values of 3.6‰–6.6‰ and their Re contents ranging from 7.23 ppm to 15.23 ppm. A second group of two molybdenite samples yield ages of 143.8 ± 2.1 and 146.3 ± 2.0 Ma, containing Re concentrations of 50.5–50.9 ppm, and with δ 34 S values of 1.6‰–4.8‰. The molybdenites from these two distinct groups of samples contain moderate concentrations of Re (7.23–50.48 ppm), suggesting that metals within the deposit have a mixed crust–mantle provenance. Field observation and new age and isotope data obtained in this study indicate that the first diorite dyke‐related skarn W – Au mineralization took place in the E arly C retaceous peaking at 143.0–146.3 Ma, and was associated with a mixed crust–mantle system. The second fine‐grained granite‐related skarn W – Mo mineralization took place a little later at 135.0–136.9 Ma, and was crust‐dominated. The fine‐grained granite was not formed by fractionation of the Q ingyang monzonitic granite. This finding suggests that the first period of skarn W – Au mineralization in the B aizhangyan deposit resulted from interaction between basaltic magmas derived from the upper lithospheric mantle and crustal material at 143.0–146.3 and the subsequent period of W – Mo mineralization derived from the crust at 135.0–136.9 Ma.
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