Rock and Mineral Analysis Vol.21,Content Index

ＲｅｓｅａｒｃｈＲｅｐｏｒｔｓａｎｄＳｈｏｒｔＰａｐｅｒｓＲｅｍａｇｎｅｔｉｚａｔｉｏｎＳｔｕｄｙｉｎＰａｌｅｏｍａｇｎｅｔｉｓｍｂｙＥＰＭＡＣＨＥＮＫｅ ｑｉａｏ ,ＸＵＨｅ ｌｉｎｇ ,ＭＡＸｉｎｇ ｈｕａ ,ＳＵＮＺｈｉ ｍｉｎｇ ( 1)…………………………………………………………………………………………………ＤｅｔｅｒｍｉｎａｔｉｏｎｏｆＰｌａｔｉｎｕｍＧｒｏｕｐＥｌｅｍｅｎｔｓａｎｄＧｏｌｄｉｎＧｅｏｃｈｅｍｉｃａｌＥｘｐｌｏｒａｔｉｏｎＳａｍｐｌｅｓｂｙＮｉｃｋｅｌＳｕｌｆｉｄｅＦｉｒｅＡｓｓａ…     

Garnet-bearing Granulite Facies Rock Xenoliths from Late Mesozoic Volcaniclastic Breccia, Xinyang, Henan Province

This paper presents the primary results of petrologic, mineralogical and petrochemical studies of garnet-bearing granulite facies rock xenoliths from Xinyang, Henan Province. These xenoliths, which are found in a pipe of late Mesozoic volcaniclastic breccia, are of high density (3.13-3.30 g/cm3) and high seismic velocity (Vp = 7.04-7.31 km/s), being products of underplating of basaltic magmas and had experienced granulite facies metamorphism. The underplating and metamorphism took place before the eruption of the host rock. Petrographical studies and equilibrium T-P calculations show that these xenoliths were captured at a 49 km depth and experienced at least a 16 km uplift before they were captured. The dynamics of the uplift could be related to the continent-continent collision between the North China plate and the Yangtze plate during the Triassic.     

Wall Rock Alteration Zoning Characteristics of the Shanggong Gold Deposit,Eastern Qinling Orogen, China

Please refer to the attachment(s) for more details     

Petrology and Geochemistry of Liujiang Formation Siliceous Rock in Dachang Ore District, Guangxi, China

Please refer to the attachment(s) for more details.     

Rock composition and origin of the Duwi Formation calcareous rocks, Upper Egypt

Upper Cretaceous phosphorite beds of the Duwi Formation, Upper Egypt, are intercalated with limestone, sandy limestone, marl, calcareous shales, and calcareous sandstone. Calcareous intercalations were subjected to field and detailed petrographic, mineralogical and geochemical investigations in order to constrain their rock composition and origin. Mineralogically, dolomite, calcite, quartz, francolite and feldspars are the non-clay minerals. Smectite, kaolinite and illite represent the clay minerals. Major and trace elements can be classified as the detrital and carbonate fractions based on their sources. The detrital fraction includes the elements that are derived from detrital sources, mainly clay minerals and quartz, such as Si, Al, Fe, Ti, K, Ba, V, Ni, Co, Cr, Zn, Cu, Zr, and Mo. The carbonate fraction includes the elements that are derived from carbonates, maily calcite and dolomite, such as Ca, Mg and Sr. Dolomite occurs as being dense, uniform, mosaic, very fine-to-fine, non-ferroan, and non-stoichiometrical, suggesting its early diagenetic formation in a near-shore oxidizing shallow marine environment. The close association and positive correlation between dolomite and smectite indicates the role of clay minerals in the formation of dolomite as a source of Mg^2＋ -rich solutions. Calcareous rocks were deposited in marine, oxidizing and weakly alkaline conditions, marking a semi-arid climatic period. The calcareous/argillaceous alternations are due to oscillations in clay/carbonate ratio.     

Rock slope stability and design in Arafat–Muzdalifa area,Saudi Arabia

The present contribution is a complete study extending before, during, and after the excavation of the mountain side that lying north of road 7. It includes slope stability analysis, rock cut design, and rockfall modeling for natural slope and rock cut face. Neoproterozoic granodiorite and biotite granite forming the slope body have medium to very high strengths. Mineral compositions and textures of these intact rocks control the strength values. These rocks are intensively dissected by fractures that are filled with montmorillonite and chlorite. The high plasticity and slippery nature of these filling materials represent the main problem that may face a rock cut designer because they damage the mechanical properties of these fractures. The problem begins with the selection of the rock mass classification that deals with the fracture fillings and extends during the stability analysis and the suggestion of mitigation and supporting measures. The rock masses building the natural slope are suffered by plane, wedge, and toppling failures. Therefore, two rock cut designs are suggested to avoid the hazards related to these failures and considering the construction cost as well. Rockfall modeling for the natural slope and rock cut designs was done to assess the hazards related to these falling of the blocks. The kinetic energy of falling blocks is represented on the roadway by the coverage distance and block rebound amplitude. Slope height has a positive effect on the values of these distance and amplitude, whereas the steepness of berm height has a negative effect on them. Coverage distance is a function to the location of rockfall barrier and to the width of road ditch, while the amplitude controls the barrier height.     

Shilin： The Formation of Stone Forests in Various Rock Types （Lunan, Yunnan, China）

Shilin is among the most interesting form of stone forest to occur in karst landscapes. They develop from karren subsoil, and their shapes, entire forests or just individual pillars and their rock relief, depend on the conditions under which they were formed, their location in the karst landscape, and above all on the characteristics of the rock： its composition, stratification, and fissuring. Because of the exceptional characteristics of this karst phenomenon in China, we propose that the term ＂shilin＂ be used in the professional literature for this type of stone forest.     

Insert and Buton Complex-Type Rock Driling Tools

ＩｎｓｅｒｔａｎｄＢｕｔｏｎＣｏｍｐｌｅｘ┐ＴｙｐｅＲｏｃｋＤｒｉｌｉｎｇＴｏｏｌｓ＊ＺｈａｎｇＧｕｏｊｕＺｈａｎｇＨａｎｂｉｎＩｎｓｔｉｔｕｔｅｏｆＥｘｃａｖａｔｉｎｇＥｎｇｉｎｅｒｉｎｇ，ＣｈｉｎａＵｎｉｖｅｒｓｉｔｙｏｆＧｅｏｓｃｉｅｎｃｅｓ，...     

The Igneous Rock Series and Tin Polymetailic Minerogenetic Series in the Tengchong Area, Yunnan

This paper discusses the late Yanshanian-Himalayan igneous rock series and minerogenetic series (Cheng et al., 1979, 1982) related to tin polymetallic deposits in the Tengchong area. The multi-stage differentiation and evolution of the igneous rock series led to the concentration of metal and ore-forming elements in a cupola of a granite body formed in the late stage. The minerogenetic series shows a zoning of Nb-Ta-W-Sn, Sn-Fe and Sn around the cupola in space and a multi-stage regularity in time. Finally a minerogenetic model and three key factors of tin minerogenesis are put forward for tin polymetallic deposits in the area.     

Hydrogeochemical Simulation of Water—Rock Interaction Under Water Flood Recovery in Renqiu Oilfield,Hebei Province,China

Hydrogeochemical simulation is an effective method to study water-rock interaction. In this paper, PHREEQM was used for the simulation of water-rock interaction under water flooding in the Renqiu Oilfield. Calculated results revealed that when fresh water was injected into the reservoir, Cl⁻ and Na⁺ would decrease without involvement in water-rock interaction. Erosion to dolomite will lead to an increase in Ca²⁺, Mg²⁺ and CaHCO ₃ ⁺ . Saturation index of calcite and aragonite decreased first and then increased. With fresh water accounting for up to 70%, mixed water has the strongest erosion ability. Deoiled water has erosion ability under high temperature and high partial pressure of CO₂. Pyrite and gypsum were sensitive to deoiled water, which can cause the dissolution of pyrite and the precipitation of gypsum. Micrographs revealed a great deal of information about water-rock interaction. The project was granted by the National Natural Science Foundation of China (No. 49672159).     

Identification of Composite Rock Body in Dongguashan Copper (Gold) Deposit, Anhui Province

Please?refer?to?the?attachment(s)?for?more?details.     

Rock Series and Genetic Types of Granitoids in the Western Kunlun Orogenic Belt, China

A systematic geological and geochemical study was conducted for the granitoids of different periods in the western Kunlun erogenic belt. The study indicates that the granitoids belong to tholeiitic, calc-alkaline, high-K calc-alkaline, alkaline and shoshonitic series, and that there are 5 genetic types, i.e., I-, S-, M-, A- and SH-type, of which SH-type is first put forward in this paper, which corresponds to shoshonitic granitoids.     

Rock—Forming and Ore—Forming Temperatures of Lianhuashan Tungsten Deposit,Guangdong Province

The Lianhuashan tungsten deposit occurs in the volcanic terrain in the coastal area of Southeast China,where rhyolite,quartz porphyry and granite consitute a complee magmatic series.The orebodies are located in the endo-and exo-contacts between the quartz porphyry and the metasandstone of the Xiaoping coal measues.Hongenization temperatures of melt inclusions in zircon and quartz are 1100℃and 1050℃ for rhyolite,1000℃ and 860℃for quartz porphyry,and 950-1000℃and 820℃ for granite,respectively,demonstrating that the rockforming temperatures dropped successively from the eruptive to the intrusive rocks and that the homogenization temperatures of melt inclusions in zircon are 50-180℃higher than those in quartz.Homogenization temperatures of gas-liquid inclusions in quartz are 230-520℃（mostly 230-270℃）for quartz porphyry,200-450℃（mostly 200-360℃）for ore-bearing quartz veins,150-210℃for granite 170-200℃ for the vein quartz in it.Quartz from the quartz porphyry and from the ore-earing quartz veins show similar characteristics in inclusion type and homogenization temperature,indicating that intergranular solutions must have been formed upon cooling of magma and that ore-forming solutions for the tungstem mineralization were evolved mainly from ore-bearing intergranular solutions in the quartz porphyry.     

Paleomagnetic Results of th Red Soil Volcanic Rock Series of Yingfengling Section,Southern Leizhou Peninsula

The Yingfengling scetion composed of red soil and volcanic rocks can be distinguished into 8 stratigraphic units and 4 red soil-volcanic rock cycles.64 paleomagnetic-orientated samples were collected from the bottom to the top of the section.Naturel remanent magnetization and magnetic susceptibility were firstly measured.All the samples were stepwisely treated with thermal or/and alternating fields.Four clear polarity segments were recorded in the section.Compared with the geo-magnetc polarity scale,the section was formed since the late Olduvai subchron,about 1.37Ma.B.P.