Hydrodynamic processes and depositional styles of glacierassociated deposits in the Moxi basin, Southwest China

This study aims to understand the particle size distribution and depositional styles of glacierassociated deposits in the Moxi basin in southwest China. Based on field surveys, 28 samples from glacier-associated deposits(including glacial till,fluvioglacial, debris flow, river and lake deposits)were collected and tested in the laboratory. The results showed that the glacier-associated deposits can be differentiated based on particle gradation,particle size distribution and accumulated percentages. We evaluated the evolution of a former dammed lake in the Moxi basin based on glacierassociated deposits. The results of this study also indicated that the Moxi Platform was not formed by a single depositional process but is composed of both fluvioglacial and debris flow deposits. This research shows that the depositional style analysis is useful in identifying different glacier-associated deposits in high mountain regions. Moreover, the evaluation of the differences in particle sizes of the glacierassociated deposits is useful in reconstructing geohazard events in periglacial regions, and this information can help in identifying and reducing the potential risks associated with geo-hazards.

Dynamic Magma Conduit System Related to the Jinchuan Ni-Cu Sulfide Deposit,NW China

The Jinchuan Ni-Cu sulfide deposits,NW China,are hosted in small ultramafic intrusions that were emplaced into Paleoproterozoic metamorphic rocks. The ultramafic intrusions were previously thought to be the segments of a single elongate intrusion that was dismembered by late faults into eastern and western portions,each of which have distinct stratigraphic sequences.

The Dynamic Mechanisms for the Formation of Primary Metal Zoning of Cassiterite-Sulfide Deposits in the Gejiu Metallogenic Province, Yunnan

Copper and tin in cassiterite-sulfide deposits of the Gejiu metallogenic province are intimately associatedand show peculiar primary metal zoning. The authors made use of computer techniques to simulatenumerically the zoning of these ore deposits. The study shows that the regular spatial zoning probably resultedfrom the succession of multiple, intermittent and pulsatory mineralizations, The successive transports with di-verse velocities along channelways of the ore-forming solutions, taking place under conditions of definite dif-ference between metal concentrations, in solutions and wallrocks, followed by differential deposition, consti-tute possible dynamic mechanisms for the primary metal zoning.

Coral community dynamics and shallow-water carbonate deposition of the reef-flat around Yongxing Island, the Xisha Islands

Microbes and microbial carbonates in reef-flat and coral community dynamics and submarine geomorphologic features in reef crest and fore reef of Yongxing Island,the Xisha Islands,South China Sea,were studied by means of scuba diving,underwater investigation,and line intercept transect survey.Studies indicate a very high coral mortality with few living corals in the reef flat of Yongxing Island.Moreover,macro algae,sea grass and cyanobacteria are common in reef flat.Microbes and microbially induced carbonates occur in reef flat.Living corals grow mainly in the reef crest and fore reef,but are also declined dramatically.From coast to off shore,the southeast reef flat of Yongxing Island can be divided into beach,inner reef flat,outer reef flat,reef flat front(reef crest and fore reef),and fore-reef slope settings.Sedimentary facies include coast,reef flat,reef crest and fore reef,and fore-reef slope.Reefal carbonate sediments are composed of coral skeletons and framework,coral fragments,bioclasts,and lime mud.With the deterioration of environment and water quality,the coral communities tend to be distributed in the reef crest and fore reef with clean sea water,well circulation and moderate water energy.Reef flat is occupied mainly by the macro algae and Heliopora coerulea communities.The coverage statistics on the reef crest demonstrate that the coverage of Acropora cytherea is more than 28% and represents a dominant species with wave-resistant ecological type.Sedimentary characteristics and geomorphologic features are different between the southeast and northwest reef-flat fronts(reef crest and fore reef) of Yongxing Island.The former shows discontinuously tidal channels in outer reef flat and different dimensional and deep reef ponds in reef crest and fore reef,and the latter presents a typical spur-and-groove system.Microbes(cyanobacteria Lyngbya sp.) occur generally in the inner reef flat and reef ponds of reef crest with restricted water circulation.Widely algae growth indicates a eutrophic environment,and the common microbes on the coral surface in the reef flat and reef ponds also demonstrate eutrophication in seawater and deteriorated water quality.

Experimental-computational study of fibrous particle transport and deposition in a bifurcating lung model

Experiments carried out using a lung model with a single horizontal bifurcation under different steady inhalation conditions explored the orientation of depositing carbon fibers, and particle deposition frac- tions. The orientations of deposited fibers were obtained from micrographs. Specifically, the effects of the sedimentation parameter （γ）, fiber length, and flow rate on orientations were analyzed. Our results indicate that gravitational effect on deposition cannot be neglected for 0.0228 〈 γ 〈 0.247. The absolute orientation angle of depositing fibers decreased linearly with increasing y for values 0.0228 〈 γ 〈 0.15. Correspondence between Stokes numbers and y suggests these characteristics can be used to estimate fiber deposition in the lower airways. Computer simulations with sphere-equivalent diameter models for the fibers explored deposition efficiency vs. Stokes number. Using the volume-equivalent diameter model, our experimental data for the horizontal bifurcation were replicated. Results for particle deposition using a lung model with a vertical bifurcation indicate that body position also affects deposition.