High—Resolution Dating of Stalagmites and Reconstruction of Paleo—Environments

The discovery of abrupt paleo-climate change events and the prediction of environmental changes in the future time have raised an urgent request for high-resolution paleo-environmental records.This paper reviews the progress made in hronology and paleo-environment of stalagmites from karst caves in China and presents some of the results of TIMS-U-series dating of stalagmites composed of secondary carbonates,taken from the Dongge,Longquan and Yamen karst caves in Libo County and the Qixing karst cave in Duyun,Guizhou Province,on a MAT-262 mass spectrometer.     

Minerogenetic Mechanism of the Songxi Silver—Antimony Deposit of Northeastern Guangdong—Ore—Controlling Role of Organic Matter

Organic geochemistry and comparisons of characteristics of the organic matter in wall rocks of the ore-controlling strata and ores of the Lower Jurassic Songling black shale formation and the related Songxi silver-antimony deposit of northeastern Guangdong have been studied in this paper.The results show that the Lower Jurassic Songling shale formation is a suite of biologic-rich and organic-rich ore-bearing marine sedimentary rocks.Micro-components of the organic matter in the Songling black shale formation consists primarily of algae,amorphous marine kerogen,solid bitument,and pyrobitument.The thermal evolution of organic matter is at the over-maturity stage.There is a general positive correlation between total organic carbon(CO)and metallogenetic elements such as Ag and Sb in the black shale formation.Organic matter in the host rocks in the Songxi ore deposit played a role in controlling the silver-antimony depositing environment during the forming process of the black shale ore-bearing formation.In the absence of vitrinite,the relative level of thermal maturity calculated by solid bitument reflectance indicates that the ore-forming temperatute of the Songxi silver-antimony deposit was about 150-170℃,which was considered as an epithermally reworked ore deposit.The roles of organic matter in the formation of the Sonxi ore deposit are a primitive accumulation of the metallogenetic elements(Ag,Sb) in the sea-water cycle system for ore source and a concentration of metals by ion exchange of chelation as well as reductionn of the oxidzed metals.     

Thermodynamic properties of hematite — ilmenite — geikielite solid solutions

A solution model is developed for rhombohedral oxide solid solutions having compositions within the ternary system ilmenite [(Fe ₂₊ ^s Ti ₄₊ ^1–s ) ^A (Fe ₂₊ ^1–s Ti ₄₊ ^s ) ^B O₃]-geikielite [(Mg ₂₊ ^t Ti ₄₊ ^1–t ) ^A (Mg ₂₊ ^1–t Ti ₄₊ ^t ) ^B O₃]-hematite [(Fe³⁺) ^A (Fe³⁺) ^B O₃]. The model incorporates an expression for the configurational entropy of solution, which accounts for varying degrees of structural long-range order (0s, t1) and utilizes simple regular solution theory to characterize the excess Gibbs free energy of mixing within the five-dimensional composition-ordering space. The 13 model parameters are calibrated from available data on: (1) the degree of long-range order and the composition-temperature dependence of the transition along the ilmenite-hematite binary join; (2) the compositions of coexisting olivine and rhombohedral oxide solid solutions close to the Mg–Fe²⁺ join; (3) the shape of the miscibility gap along the ilmenite-hematite join; (4) the compositions of coexisting spinel and rhombohedral oxide solid solutions along the Fe²⁺–Fe³⁺ join. In the course of calibration, estimates are obtained for the reference state enthalpy of formation of ulvöspinel and stoichiometric hematite (–1488.5 and –822.0 kJ/mol at 298 K and 1 bar, respectively). The model involves no excess entropies of mixing nor does it incorporate ternary interaction parameters. The formulation fits the available data and represents an internally consistent energetic model when used in conjuction with the standard state thermodynamic data set of Berman (1988) and the solution theory for orthopyroxenes, olivines and Fe–Mg titanomagnetite-aluminate-chromate spinels developed by Sack and Ghiorso (1989, 1990a, b). Calculated activity-composition relations for the end-members of the series, demonstrate the substantial degree of nonideality associated with interactions between the ordered and disordered structures and the dominant influence of the miscibility gap across much of the ternary system. The predicted shape of the miscibility gap, and the orientation of tie-lines relating the compositions of coexisting phases, display the effects of coupling between the excess enthalpy of solution and the degree of long-range order. One limb of the miscibility gap follows the composititiontemperature surface corresponding to the ternary second-order transition.     

The calculation of hydrocarbon-generating temperature——Theory and practice

How to quantitatively evaluate the maturity of crude oils is still an open question. Mango discovered a remarkable compositional invariance of four isoheptane ratios in crude oils, and proposed a steady-state catalytic model for the origin of light hydrocarbons. According to this model, 2,4/2,3 dimethylpentane ratio is a pure temperature parameter. Bement, Mango et al. established the functional equation between the two parameters-light hydrocarbon temperature and burial temperature and applied it to the calculation of hydrocarbon-generating temperature, which provided a new choice for the study of oil maturity. In this paper, the Mango's parameters for hydrocarbons from the Tazhong area were calculated, the average K1 value is 1.06, which is in good consistency with the Mango's proposal that the K1 value is relatively stable. Calculated with the functional formula of hydrocarbon-generating temperature, the hydrocarbon-generating temperatures are with the range of 120-129℃, and the converted vitrinite reflectance (Ro) varies from 0.88% to 0.90%. This is well consistent with the maturity characteristics of neohopanes. The results have verified the reliability of this method.     

Adsorption of radioelements on mixtures of minerals — experimental study

An experimental study has been undertaken concerning the adsorption of radioelements on mixtures of minerals. The question is whether the adsorption of trace elements by rocks and soils can be easily predicted from the properties of the constituent minerals. The goal of these experiments was the comparison between the measurements of distribution coefficients of some radioelements for pure minerals and for binary mixtures according to the Doehlert’s uniform shell designs and to test an additive law of combination of Kd. The results showed that when one of the constituents acts as a dilutant in the mixture, i.e. it presents a very low adsorption capacity with respect to some trace element, then the relations of additivity of Kd are fulfilled. Otherwise, these relations are not satisfied and this is probably caused, in the present cases, by interactions from solubilized species.     

Migration of Magnetotelluric Data in Two——Dimensional Model

Since the wave equation of magnetotelluric(MT)field is similar to the one of seis-mic,the migration techniques used in seismic can be applied to MT data.In thispaper we make use of the principle of reflector mapping(i.e.U/D imaging principle)to image MT data.That is,the MT wavefield observed on the surface of the earth canbe resolved into upgoing and downgoing waves,the waves are extrapolated downward bythe phase-shift method or the phase-shift plus interpolation(PSPI)method.Conductivi-ty interfaces of the medium could be found by using the time coincidence of the upgoingand downgoing waves.Theoretical calculations show that the migration technique of MTdata presented here is very effective.It can not only enhance the lateral resolution of MTdata,but also obtain the visual image of subsurface interfaces.As compared with theconventional 2-D inversion,this procedure is more simple in calculation and can be easi-ly put into practice on a personal computer and is able to obtain the MT depth section,which is     

A Correlation Analysis of Tourism Based on Gray Theory——A case of Xingwen County

Tourism industry has already become an important part of national economy,which not only played a positive role in the development of the economy,but promoted the adjustment and optimization of industrial structure.The paper analyzes the correlation between the tourism industry and the other industry through changes of the Xingwen County tourism industrial output value in the past seven years.With the Gray Model,the correlation degree among the tourism industry and agriculture,industry,transport,wholesale and retail trade,postal and telecommunications industries is measured.The analysis result indicates that the order of the corresponding correlation degree:catering accommodation is 0.691> wholesale and retail is 0.617 > agriculture is 0.616 > Postal and telecommunications industry is 0.610> Transport is 0.602> Industry is 0.537.In accordance with the actual conditions of the industry in Xingwen,the industrial development policies and measures are put forward,which help the tourism industry Xingwen their rapid,coordinated and highly efficient operation.     

List of Publication for Earth Science——Journal of China University of Geosciences （Chinese Version） in 2006

No. 1 Interaction between Crust and Weakening Lithospheric Mantle: Taking the Yanshan Orogenic Belt as an Example LU Feng-xiang , ZHENG Jian-ping , ZHANG Ruisheng , et al (001) Highly Chemical Heterogeneity of Subcontinental Lithosphere Mantle beneath North China and Its Major Transformation ZHOU Xinhua , ZHANG Hong- fu (008) Formation of the Taihangshan Gravity Lineament by the Diachronous Lithospheric Thinning of the North China Craton XUYi-g…     

List of Publication for Earth Science——Journal of China University of Geosciences （Chinese Version） in 2004

No .1StableIsotopeEquilibriumTestbetweenBenthicForaminiferCibicidoidesandUvigerinaatODPSite 114 3,SouthernSouthChinaSeaTIANJun ,WANGPin xian ,CHENGXin rong (0 0 1)…………Mid PleistoceneRevolutionRecordedbyPulleniatinaobliquiloculataintheSouthernSouthChinaSeaXUJian ,WANGPin xian ,HUANGBao qi ,etal (0 0 7)…………………………………………………PreliminaryStudyonAncientHumanDNAfromYangshaoCultureLAIXu long ,YANGShu juan ,TANGXian hua ,etal (0 15 )……………………………