Abstract:The Cenoioic volcanic rocks in Changbai Mountains consistof basalts, trachytes and alkali rhyolites. A lotof enclaves named spinet lheriolite and pyroxenite derived from the mantle were fount In alkali basah.of Miocene Naitoushan period. The main minerals in mantle enclaves and volcanic rocks of different periods are olivine clinopyroxene, enstenite, spinel, plagioclase and alkali feldspar. the species and chemical compositions of minerals from different rocks are different, reflecting the trend of magmatic differentiation evolution. The geothermobaro-meter of minerals indicates that the basaltic mama derived from the mantle at the depth of more than 82 km formed the deep mama chamber in the upper mantle at the depth of SSkm to 65km. Laser Raman spectrum analysis of inclusions in minerals from different volcanic rocks show that magma in great depth comained a lotof volatiles, and that strong exsolution occurred during the upward migration of magma. Besides, mantle volatiles decreased and crust volatiles increased in upward direction and underground water might have played an important role in volcanic eruption.

Abstract:With the increasing deepening of the study on crystallization mechanism of the magmatic system the magmatic kinetic theory of volcanic and intrusive rocks has entered the stage of establishing a model. Through the study of the example of Shaxi porphyry body in Anhui Province the authors first figured out the storage time of plagioclase phenocrysts} then calcufated the nucleation rate and growth rate of the crystals and，on such a basis established the thermal model for cooling of the hypabyssal magmatic system.

Abstract:In the study area there exist two types of closely associated active epicontinental mantle-derived imrusive assemblages belonging to tholeiite series and calc - alkaline series respectively. Intrusive rocks of the two series show systematic chemical differences and generally experienced fractional crystallization of mafic minerals at the high magmatic chamber. Both the tholeiite series and the calc-alkaline series exhibit geochemical characteristics of mantle-derived magma along the margin of plate convergence, and are in different degrees enriched in large-ion lithophile elements and impoverished in high field strong elements, transitional elemenu and heavy rare earth elements. Geochemical studies show that magma of these two series originated from the same impoverished mantle source, with the source rock being spinet peridotite. The enrichmem of large-ion lithophile elements should be attributed to the devatering or melting of the subducting plate. The chemical differences between these two series resulted from the higher melting degree of the tholeiite series than that of the calc-alkaline series. They were both formed during the closing process of the Qinling paleooceanic basin in Dinning period.

Abstract:Lamprophyres in the Taoyuan-Xiaotongjiapuzi gold ore belt is of strong enrichment type of incompatible elements ,with obvious fractionation among incompatible elements. The rock is concentratedly enriched with rare earth elements，and ∑REE values are (359.8-669.5)X 10-6，suggesting a strongly right-inclined LREE enrichment type. Comparative studies show that during the alteration of lamprophyre, K20, TiO2 and P205 were rather stable ,whereas Si，Ca Mg and Fe were evidently taken out or brought in. Moderate alteration generally did not cause obvious addition or removal of elements, with Nb, Zr and Y being especially stable.Geological-geochemical characteristics of rocks demonstrate that the rock was formed in an extensional tectonic environmem.

Abstract:According to the study of PC 5794 columnar sample (147一695cm, early period of Early Miocene) from Fast Pacific Pasin in such aspects as oxygen isotopes , biogenic CaCO3，paleotemperature and ore-forming elements, the region had the following features in the early period of Early Miocene: δ180 values of sediments might be roughly divided into five groups;paleoclimate experienced cold-warm alternations composed at least of three warm periods and two cold(ice)periods; oxygen isotopes were in direct correlation with biogenic CaCO3;Nn、Fe、Co、Ni were in negative correlation with δ180 values but Cu in direct correlation with paleotemperature.

Abstract:The Namjabarwa area the core of the eastern Himalayan syntaxis, is the least-known part of the Himalayas. Recent research has revealed that this area consists of three tectonic units, viz. the Gangdise unit , the Yarlung Zangbo unit, and the Himalayan unit, separated from each other by faults. The Himalayan unit consists of amphibolite facies rocks in the south and granulite facies rocks in the north, with the latter rocks displaced south-ward over the former along the Namula thrust system. As an accessory minral in a carbonate vein that intruded the granulite facies rocks, astrophyllite is associated with dolomite , calcite, olivine, spinel,phlogopite, pargasite, apatite, garnet (Gr24.5Alm49.6 PYr18.6And6.7)，geikielite and three unknown minerals. One of these unknown minerals is composed of B, C,Mg, Ti，Fe and Al,being probably a new mineral.The unit cell parameters of astrophyllite are a0)=5.356 (1)Å，b0=11.607 (4)Å，c0=11.851 (6)Å ，a=64.57º(3),β=76.98º(4), γ=85.45º(3).Electron microprobe analysis (average of three samples)gave SiO2 35.22, TiO2 11 .47，Al2O31.18，Fe0 28.90，Mn0 5.15，MgO 1.51，Ca0 1.75，K20 5.90，and Na20 2.46, totally 93 .54%，corresponding to the formula of ( K，Na)3 (Fe, Mn, Mg, Ca)7 Ti2Si8O24(O,OH)7，which indicates that the astrophyllite is of a new mode of occurrence.

Abstract:In the present paper basin fluids refer to extremely complex aqueous solutions which are very active in all the diagenetic-epigenetic processes of sediments during the evolution of sedimentary basins. They mainly include fluids produced by compaction and phase change of sedimenu inside the basin as well as meteoric water driven downwards into the sedimentary basin by the gravitational potential along uplifting continental marlins adjoining the basin. Pasin fluids show typical features of low-temperature hydrothermal geochemistry, with temperatures mainly ranging 80-150℃. Isotope composition and dissolved compositions of basin fluids are controlled by sediment types decided by fluid-mineral interactions) and their spatial distribulion .The contribution of organic matters plays a very impotant role in such aspects as the fluidmineral interaction the change in physical-chemical parameters of basin fluids themselves and their environments the dissolution transport deposition and ore-forming process of metals and the formation of secondary porosity of sedimentary rocks. Pasin fluids make a very important contribution to dia}enetic-epigenetic processes of sediments, oil-has production and ore-formation in sedimentary basins. Spatial distribution of sediment systems together with syndepositional faulting systems uncompacted overpressure systerns and paleotopography of sedimentary basins controlled the migration and accumulation of basin fluids and the metals carried in the fluids. Ore deposits genetically related to basin fluids can be classified into four groups, viz. sedex type deposits MVT lead-zinc deposits continental sandstone type deposits and sediment-hosted micro-disseminated fold deposits. Two examples of deposits in China formed by basin fluids one belonging to sedex the other to sediment-hosted micro-disseminated fold deposit，are beiefly discussed in this paper.

Abstract:Hibonite, a rare mineral, was discovered for the first time in China from Mg Al skarn in Handan Xingtai Area, Hebei Province. It occurs as yellow semitransparent hexagonal flaky crystals associated with corundum, spinel, clintonite, grossular and vesuvianite. An analysis of the mineral paragenesis diagram suggests that hibonite was formed in an Al rich and Si poor as well as high temperature environment. The crystal parameters determined by four circle diffractometer and X-ray powder diffraction are space group P63/mmc, a0=0.56076(4)nm , c0=2.20227(5) nm. Electron microprobe analyses are CaO 8.10, Na2O 0.02, TiO2 4.27, SiO2 0.83, Al2O3 80.025, FeO 5.44, MgO 1.86, giving the chemical formula (Ca0.99 Na0.004)0.994 (Al10.79 Ti0.40 Si0.09 Mg0.32 Fe0.52)12.12 O19, theoretically as CaAl12O19. There exist 12 absorption bands in the infrared spectrum, showing the feature of complex oxides in hibonite.

Abstract:Crystal morphology and growth mechanism of sphalerite crystallites were studied by formulating the mathematical model and calculating the stability energy of the growth units on the basis of the theoretical model that the growth units are polyhedral structure of coordinative anions.

Abstract:Several primary dolomite samples of the Upper Sinian T)en}yin} Formation and replacement dolomite samples of Ordovician were selected in Yan}tie area for analysis. The high resolution TEM (Transmission Electron Microscope) was applied to make a microstructural correlalion between primary dolomite and replacement dolomite crystals. It has been revealed that microstructures (mainly dislocation and modulated structure)are quite common in fibrious and bladed dolomite cements, and crystal structures are heterogeneous. On the contrary, microstructures are relatively simple in micritic dolomite and coarse-gained dolomite cement and crystal structures are comparatively homogeneous. The main dislocation in primary dolomite crystals is screw dislocation. The interaction between dislocations results in the formation of dislocation wall or network which is relevant to extinction direction. The screw dislocation is formed by crystal face sliding during crystal growth at low-medium temperature rather than resulting from later deformation. In diffraction contrast, the modulated structure in primary dolomite appears locally and exhibits a somewhat regular alternating lamellae. The wavelength (modulated period width)is 10-30nm wide.The modulation is oriented with the long dimension always parallel to the growth normal.SAED (Selected Area Electron Diffraction) pattern exhibits ultra reflection ( Type c and Type d).The modulated structure in primery dolomite is of density-modulation (composition-modu-lation)，which is formed during crystal growth instrad of by later solid-state diffusion. The main growth of primary dolomite crystal is in orientation to (1014)，and the modulation is perpendicular to (1014). Microstructures are relatively rare in replacement dolomite crystals and mainly distributed in Ca-rich salt dolomite in which the modulated structure is perdominant. The main dislocaLion is blade dislocation which is formed as a result of later deformation. The modulation in replacement dolomite differs from that in primary dolomite in that it exhibits irregular lamellae and vermiform with poor continuity. Sometimes two modulated lamellae intersect each other.The wavelength varies considerably. The modulation is pervasive throughout a crystal. It is formed during the replacement of calcite by dolomite relevant to the corporation of excess Ca in Mg sites. According to EDS analyses , in primary dolomite, the Ca content in modulated area is slightly higher than that in unmodulated area. Mg contents in both areas are identical.In replacement dolomite Mg and Ca contents in modulated area are similar to those in primary dolomite, but the unmodulated area is almost full of Ca with merely a little Mg. Relict calcitecoexists with modulated dolomite. TEM has revealed that the microstructures in primary dolomite and replacement dolomite are different suggesting their different geneses.

Abstract:Manganese mineral phases in polymetallic nodules from Pacific Basin have been studied by means of TEM, XRD and FTIR. Six mineral phases viz. vernadite, todorokite, birnessite,buserite, buserite- asbolite mixed-layer mineral and woodruffite, have been identified. Their morphological and microstructural features have been described. In Central Pacific Ocean, nodules in CP zone are rich in vernadite and,next, todorokite,whereas in CC zone the sheet todorokite is dominant and vernadite comes second. Xodules from Fast Pacific basin are rich in lamellar todorokite and buserite, with minor vernadite. The IR spectroscopic study shows that condensed octahedral unite of MnO6 exist in the structure of vernadite, todorokite, birnessite,but the strength of Mn一O bond decreases gradually in order of todorokite, birnessite, vernadite. Relationships of the phase transformation among manganese minerals were inquired into.Phenomena of phase transformation between vernadite and todorokite and between layered buserite and vernadite were discovered .The result of heat treatment shows that up to 105 C buserite-I may be transformed into birnessite owing to dewatering, and there is no phase trans- formation between todorokite and birnessite; up to 400℃ layered buserite may be transformed into vernadite, but there exists no structural change for fibrous todorokite with tunnel structure.

Abstract:Microbeam analysis is a new technology applied in geology. Through microbeam analysis of minerals by means of electron microprobe the author obtained new evidence on the origin of ores which deepens the genetic theory on mineral deposits. Taking Au-Ag intergrowth compounds as an example this paper has reached the following conclusions. In the Au-Ag compounds of differem types of gold deposits as sequemially replaces Au, making up a continuous isomorphous series. The content of Au and Ag in native gold forms a regular pattern. The development of native gold and that of electrum have something to do with different types of gold deposits respectively. Abundances of trace elements in Au-Ag minerals are controlled by geological settings and geochemical fields. The above study provides new geological information and a new method for the study and exploration of gold deposits. 、