Characteristics and origins of primary fluids and noble gases in mantle-derived minerals from the Yishu area, Shandong Province, China

springerlink.com Studies of mantle fluids are currently one of the hot topics in the earth science, greatly contributing to re-vealing origins and evolutions of fluids. In general, the concept of mantle fluids refers to their active compo-nents, such as CO2, H2O, N2, etc., while the noble gases inert in chemical properties belong to another research system. Due to their marked differences in various fluid sources of the Earth[1], the isotopic sig-natures of He and Ar have been widely used a…     

On the geobiological evaluation of hydrocarbon source rocks

Hydrocarbon source rocks are characterized by the hydrocarbon discharge, and the alteration and variation in organic compositions and organic content due to the enhanced thermal maturation. These variations throw constraints on the application of the conventional inversion evaluation of hydrocarbon potential by assessing the residual organic matter left in source rocks. Geobiology, probing the interaction between the life system and the earth system, provides new principles in deciphering the whole dynamic processes related to the organic evolution history from living biomass to organic burial. Geobiological subdisciplines, including molecular geobiology, geomicrobiology, geoecology and biogeochemistry, offer new methodology and techniques to estimate the paleoproductivity, depositional organics and organic burial capacity and their components. Geobiofacies, newly proposed herein, is terminologized to define the geobiological dynamic processes through the combination of biofacies with organic facies and sedimentary facies, and expressed by the biohabitat types, paleoproductivity, depositional and preserved organics. Geobiofacies is identified as a useful means to create the geobiological evaluation system, which in turn rectifies the conventional evaluation system for the marine source rocks. __________ Translated from Earth Science—Journal of China University of Geosciences, 2007, 32(6): 727–740 [译自: 地球科学—中国地质大学学报]     

An attempt to quantitatively reconstruct the paleo-primary productivity by counting the radiolarian fossils in cherts from the latest Permian Dalong Formation in southwestern China

A quantitative reconstruction method of paleo-primary productivity is present on the basis of the investigation on the faunal record in cherts. By obtaining the accumulation rate of radiolarian shells in the cherts and considering all aspects of silica loss before burial, such as dissolution in the eutrophic zone or within the sediments, it is possible to reconstruct the production rate of radiolarian in the surface water, which would be used to estimate the paleo-primary productivity. This method is applied to the end Permian chert sequence from Dalong Formation in Dongpan area, southwestern China. The resulting paleo-primary productivity of the ocean in end Permian south China is about 477.9 g C/m²/a during the sedimentation of cherts, which, to some extent, agrees with the primary productivity reported for some modern oceans.     

青海省野马泉地区遥感找矿预测研究

以1/5万青海省野马泉地区图幅范围为研究区,利用TM遥感数据,针对研究区普遍存在的矿化蚀变现象,通过多种方法的对比分析后认为,“主成分分析＋比值”方法不仅能有效地抑制植被的干扰,而且还提取出与金属矿化有关的铁化蚀变异常。同时,结合地质矿产、物化探等资料的综合分析,圈定出了2处找矿靶区。经过野外实地查证,提取出的铁化蚀变异常与已知矿（床）化点十分吻合,而且还新发现了一处找矿线索。这为该区进一步的矿产勘查提供了有利的科学依据。     

A preliminary biogeochemistry-based quantification of primary productivity of end-Permian deep-water basin in Dongpan Section ,Guangxi ,South China

In this paper, the mean primary productivity of the Talung Formation in the deep-water basin (50–500 m depth) of Dongpan, Guangxi, South China, was calculated, roughly ranging from 0.1 to 0.6 g C·m⁻²·day⁻¹ on the basis of the content of the trace element Cu. Results showed that the primary productivity obtained was comparable with the previously-reported data for the black shale of the Phosphoria Formation, a Permian phosphate deposit in the northwest United States, and also similar to that of the modern deposit in the Cariaco basin, Venezuela. It was observed that the primary productivity increased with the enhanced abundance of algae and photosynthetic bacteria, and with the decrease in both the radiolarian individuals and the body size of brachiopods during the faunal mass extinction. This ecological coupling indicates that the changes of primary productivity are closely related to the propagation and the decline of producers (algae and bacteria), and that consumers (radiolarians and brachiopods) probably have little influence on the changes of primary productivity.     

储层沉积-成岩过程中孔隙度参数演化的定量分析——以鄂尔多斯盆地沿25区块、庄40区块为例

分别对鄂尔多斯盆地中南部沿25、西南部庄40两区块延长组长6段砂岩的成岩作用和孔隙演化进行分析。研究表明,两区块目的层砂岩目前均处于中成岩B期。受成岩环境酸碱性的控制,沿25区块普遍发育浊沸石和绿泥石,其浊沸石溶蚀孔隙为有利的储集空间;庄40区块高岭石较为发育,长石、岩屑溶孔为有利的储集空间。成岩过程中孔隙度演化的定量研究表明,相似的成岩演化阶段,孔隙度的演化不同。两区块初始孔隙度相近,沿25区块为34.91%,庄40区块为33.42%。机械压实过程中,沿25区块孔隙损失率为40.33%;庄40区块孔隙损失率为55.45%。胶结、交代过程孔隙损失率:沿25区块为46.86%;庄40区块为36.51%。后期溶蚀过程中,沿25区块次生孔隙空间主要为浊沸石溶孔,次生溶孔占比例为55.76%;庄40区块次生孔隙空间主要为长石、岩屑溶孔,次生孔隙占比例为73.51%。两区块沉积-成岩过程中孔隙度参数演化的定量分析为优质储层的筛选及相关砂岩油田的滚动勘探提供借鉴。     

On the relationship between the eddy covariance,the turbulent flux,and surface exchange for a trace gas such as CO<Subscript>2</Subscript>

In the context of CO₂ surface exchange estimation, an analysis combining the basic principles of diffusion and scalar conservation shows that the mixing ratio is the appropriate variable both for defining the (eddy covariance) turbulent flux and also for expressing the relationship between the turbulent flux and surface exchange in boundary-layer budget equations. Other scalar intensity variables sometimes chosen, both the CO₂ density and molar fraction, are susceptible to the influence of surface exchange of heat and water vapour. The application of a hypsometric analysis to the boundary-layer “control volume” below the tower measurement height reveals flaws in previously applied approaches: (a) incompressibility cannot be assumed to simplify mass conservation (the budget in terms of CO₂ density); (b) compressibility alone makes the analysis of mass conservation vulnerable to uncertainties associated with resultant non-zero vertical velocities too small to measure or model over real terrain; and (c) the WPL (Webb et al. (1980) Quart J Roy Meteorol Soc 106:85–100) “zero dry air flux” assumption is invalidated except at the surface boundary. Nevertheless, the definition and removal of the WPL terms do not hinge upon this last assumption, and so the turbulent CO₂ flux can be accurately determined by eddy covariance using gas analysers of either open- or closed-path design. An appendix discusses the necessary assumptions and appropriate interpretations for deriving the WPL terms.     

原生晕-因子分析地球化学异常识别——以内蒙古查干花地区1:5万水系沉积物Mo异常提取为例

近些年来我国的化探扫面工作积累了丰富的化探数据资料,如何有效利用这些化探数据,并结合已知的矿床（点）类型来针对性获得更加综合的找矿化探信息,是目前找矿过程中值得研究的课题。本文提出了原生晕-因子分析（PH-FA:primary halo-factor analysis）方法,通过利用原生晕的成矿元素的关联关系来刻画次生晕中的关联属性,使次生晕中成矿元素关联属性更接近成矿事件的元素数据结构。以内蒙古查干花地区为例,从原生晕矿石地球化学数据中分析得出Bi为Mo最相关的元素,通过对比背景的富集程度进行权重组合计算获得Mo、Bi的PH-FA权重系数分别为0.717607和0.282393,将Bi与Mo进行权重组合计算PH-FA得分,并提取化探异常。结果表明,该方法与传统的因子分析相比,所圈定的异常与控矿断层相交的重合率高13.05%,且构造线、岩体等控矿因素同样具有更强的空间分布相关性,表明该方法在识别控矿因素以及矿区外围找矿中有较高的可行性。     

Evaluation of potential crop productivity based on remote sensing and agro-ecological zones around the world

Human diets strongly rely on wheat, maize, rice and soybean; research on the potential crop productivity of these four main crops could provide the basis for increasing global crop yields. The evaluation model of realistic potential crop productivity based on remote sensing and agro-ecological zones was proposed in this study to provide reliable reference data for world food security. The statistical data on these four main crops yields were obtained from the FAO. The model was used to investigate the potential production of four staple crops in the world. The distributions of the realistic potential productivity of four staple crops (winter wheat, maize, rice and soybean) were produced. In the main producing countries of the four staple crops, statistical analysis was conducted on the realistic potential productivity (RPP) of the four staple crops, the highest productivity (HP) during the period 1983–2011 and the gap between RPP and HP.