Abstract:REE, trace element and Sr, Nd and Pb isotopic data of the Hekanzi alkaline complex are presented in this paper, together with a discussion on its relationship with the regional tectonic regime and its geological implications. Rocks of this complex have high REE contents. In the chondrite-normalized REE diagram, these rocks show LREE enrichment and have weak or very indistinct negative Eu anomalies. The PM-normalized trace element diagram exhibits LREE and LILE (Rb, Ba, Th and Sr) enrichment with negative Nb, Ta, K, P, Ti and Y anomalies. Transitional element contents of the complex are very low compared with data of the primitive mantle. REE and trace element characteristics of the Hekanzi alkaline complex are very similar to those of the Fengcheng alkaline complex in eastern Liaoning Province. A five point whole rock_mineral Rb-Sr isochron for themain intrusive stage of the complex yields an age of 221.4±8.5(2σ) Ma, implying that the Hekanzi alkaline complex results from activity of Indosinian alkaline magma. All εSr(t) values of the Hekanzi alkaline complex are positive with an average of 7.23, and the initial 87Sr/86Sr value obtained from the Rb-Sr whole rock-mineral isochron is 0.704 77±0.000 15. However, all the εNd(t) values are negative. Trace element compositions and Nd, Sr, Pb isotopic geochemical characteristics of the Hekanzi alkaline complex show that its source has features similar to those of the EMⅠ end member These features suggests that the upper mantle of the eastern North edge of North China platform was fertile in Triassic period and, what is more, the upper mantle under the eastern part was more fertile than that under the western part of Liaoning Province. Variation diagrams of major and trace elements imply that the Hekanzi alkaline complex was formed in an intra-plate environment, and its major magmatic process is dominated by batch melting.

Abstract:Based on studies of petrology, geochemistry, mineralogical chemistry of biotites, the authors hold that the three composite granitic plutons in the mid-western Nanling Region display two petrogenic models. One is the evolutional model of magmas with different parents, which occurred in the Huashan composite granitic plutons, and the Meihua supplementary granite might have resulted from derivative liquids segregated from fractional crystallization of magmas equivalent to Huashan magmas. The other is the evolutional model of magmas with the same parent, which occurred in the Jinjiling and Dadongshan composite granitic plutons. Their supplementary bodies, namely Pangxiemu granite and Zhutishi granite, resulted from the condensation of the residual magmas, and the two residual magma bodies were generated by fractional crystallization of the parental magmas of the Jinjiling and Dadongshan main bodies respectively. Two kinds of evolutional models of the supplementary granites may suggest the different genetic mechanisms of magmas of their main bodies.

Abstract:A large number of microgranular dioritic enclaves occur in some post-collisional metaluminous-peraluminous granites, which include Yebushan and Miao'ergou occurring respectively in eastern and western Junggar of North Xinjiang. Petrological and geochemical researches reveal the cogenetic relationship between the enclaves and the host granites. The microgranular enclaves having similar geochemical composition to host biotite granite in Yebushan were generated by the fractional crystallization of mantle-derived basic magma. By contrast, the enclaves hosted in Miao'ergou monzogranite seem to be restites resulting from partial melting of highly evolved basic rocks underplated in the lower crust during earlier mantle-derived magmatism. The enclaves carried by ascending acidic magma were assimilated and finally emplaced in the upper crust. Consequently, these enclaves in common with Junggar peralkaline granite are products of post-collisional magmatic activity in late-Paleozoic. The formation and evolution of both enclaves and host granites in Junggar region prove that the process of vertical growth of continental crust resulted from the underplating of post-collisional mantle-derived magmas in late-Pale-ozoic.

Abstract:There occur Cenozoic continental acid volcanic rocks in Tianshui area, West Qinling Mountains. They are composed mainly of rhyolite and partly of rhyolitic breccia tuffaceous lava as well as rhyolitic ignimbrite (breccia) tuff, together with a small amount of breccia tuff and volcanic breccia. These volcanic rocks are geochemically characterized by Si-, alkali-enrichment and Al-, Ca-depletion and belong to nonorogenic alkaline rocks, similar to continental rift type alkaline rhyolite. New evidence shows that Cenozoic acid volcanic rocks were formed by partial melting of crustal rocks in a continental extension setting, related to sinistral strike-slip shearing of Weihe faulted zone in early Cenozoic.

Abstract:The eclogites in Southern Sulu ultrahigh pressure metamorphic (UHPM) terrene show very different retrograded microtextures from the corresponding rocks in Northern Sulu, implying different thermal processes. Scanning electron and optical microscope observations indicate that the primary peak assemblage is anhydrous, composed of Grt + OmpⅠ + Ky + Rt (+ Coe). These peak minerals were replaced by the second and third stage minerals, resulting in pseudomorphic symplectite or coronas through the process of OmpⅠ→OmpⅡ + Ab + Fe-oxide symplectite (type Ⅰ), Rt→Rt+Ilm, Ky→Pg; OmpⅡ (+Ab+Fe-oxide)→Hb (+Pl+Fe-oxide) (type Ⅱ), and Grt→Prg+Fe-oxide. In contrast, epidote and quartz were formed at a very late stage as a result of fluid activity along micro-fractures. Mineral chemistry and mass-balance estimation demonstrate that the pseudomorphic textures were developed by metasomatism involving dissolution and precipitation that were intensified by fluids along the grain boundary. The form ation of symplectite by replacing primary omphacite would evidently produce extra Fe, Mg and Na but consume Ca and Si. The extra Mg and Fe (diffused to garnet grains) triggered an interexchange of (Mg, Fe)-Ca of the garnet, resulting in compositional zonation with Ca decreasing towards the edge of garnet grains where the expelled Ca was consumed during symplectite formation. The replacement of kyanite by paragonite consumed the extra Na. At the later stage when more aqueous fluid intruded into the eclogite, fluid infiltration partially converted Symplectite Ⅰ to Symplectite Ⅱ, and a film of pargasite resorbed a garnet from its boundary. Mass balance estimation suggests that the transformation and resorption might have been coupled qualitatively. p-T conditions based on mineral reactions and THERMOCALC software suggest that the retrogression of the eclogite occurred under HP conditions. The difference in p-T path between the Southern and Northern Sulu eclogites suggests the existence of different exhumation historis within the Sulu terrene.

Abstract:The U-Pb isotopic age of Hanshan gabbro in North Qilian Mountains is 347.1±6.4 Ma, belonging to Hercynian. The Hanshan gabbro is located in the south of the deposit and is obviously related to the deposit. Theore-forming age of the deposit is 339±10 Ma, being of Hercynian too. The petrogenic age is earlier than the ore-forming age, possibly suggesting that the rockbody provided heat for the deposit. This conclusion is theoretically important and practically significant in the search for gold deposits in the study area, because there occur a lot of intermediate-acid rocks there.

Abstract:The neogenic soil body is of great significance in the study of regional environmental evolution, nutrition element release and secondary ore formation. Using such means as chemical analysis, X-ray diffraction pattern, polarizing microscopy and scanning electronic microscopy, this paper has discussed the features and formation processes of secondary calcites in calcium nodules within ustic vertisols in Yuanmou Basin, Yunnan Province. Secondary calcites dominate calcium nodules, and the crystallinity of calcites is high. Calcium nodules and secondary calcites are closely related to climate and micromorphology. The features and formation of calcites reveal that dry and hot climate has prevailed in Yuanmou Basin since Holocene.

Abstract:Mineralogical characteristics, formation environments and environmental mineralogical significance of uranium acyl arsenate minerals in China are discussed systematically in this paper. They are supergene minerals occurring in oxidized zones of uranium deposits and assuming green-yellow colors. This kind of minerals can be used as one of the mineral indicators in search for uranium deposits. They are mainly composed of ~(3-) and ~(2+), in which As and U are known as poisonous and harmful elements causing environmental pollution. These elements are very active and have strong capacity of decomposition and migration in different acid, alkaline and oxidation-reduction media. Decomposition, migration and diffusion of arsenic and uranium result in serious extensive environmental pollution in mines and their downstream areas. Relatively stable uranium acyl arsenate minerals can be formed under the condition of weak acid to neutral media through combining ~(3-) with ~(2+) and other metallic cations. This process can reduce transportation and diffusion of uranium and arsenic and relieve to some extent their harmful effect on environment.

Abstract:Electronic microprobe analysis (EMPA), X-ray diffraction (XRD), Raman spectrum, scan electronic microscope (SEM) and polarized optical microscope were used to study nephrite cat's eyes from Sichuan Province,Southwest China . The results indicate that the nephrite cat's eye mainly consists of aggregates of microcrystalline-cryptocrystalline tremolites. Fiber-shaped tremolites are parallel to each other in a certain direction. Fibroblastic texture is dominant, with which the nephrite can show good cat's eye effect, while tremolites with relatively thick fibers or bunchy and bundle fibers do not show satisfactory cat's eye effect. Fiber-shaped tremolites gear with each other tightly, which seems to be the major reason why the nephrite cat's eye displays high tenacity and break-resistant capability.

Abstract:The thermal dissociation of the potassium shale-potash system has been experimentally investigated. The orthogonal experiment shows that the optimum reaction temperature is 820～830℃, the mass ratio of potassium shale to potash is 1.00∶1.51, the optimum reaction time is 60min, and the particle size of the raw material is 60～80 mesh. The process was analyzed by thermal analys is of TG and DTA, and the baked materials were analyzed by X-ray diffraction. The mechanism of the reaction is proposed on the basis of the above thermal dynamic data.

Abstract:There occur Cenozoic continental acid volcanic rocks in Tianshui area, West Qinling Mountains. They are composed mainly of rhyolite and partly of rhyolitic breccia tuffaceous lava as well as rhyolitic ignimbrite (breccia) tuff, together with a small amount of breccia tuff and volcanic breccia. Thesevolcanic rocks are geochemically characterized by Si-, alkali-enrichment and Al-, Ca-depletion and belong to nonorogenic alkaline rocks, similar to continentalrift type alkaline rhyolite. New evidence shows that Cenozoic acid volcanic rocks were formed by partial melting of crustal rocks in a continental extension setting, related to sinistral strike-slip shearing of Weihe faulted zone in early Cenozoic.

Abstract:The experiment has been done for adsorption of Zn2+ on palygorskite based on purification of palygorskite clay, the result shows that the adsorption is mainly affected by such factors as vibrating rate, adsorption time, amount of adsorbent and aqueous pH, and the adsorption curve (30℃) of Zn2+ on palygorskite conforms with Langmuir equation or BET equation. In this study, the optimized technological conditions are vibrating rate 150 r/min, adsorption time 120 min, amount of adsorbent 0.120 g, and pH 6.2. The corresponding removal efficiency of Zn2+ is 95.5%.