A Statistical Model for Investigating Climatic Trend Turning Points

A two-phase trend model is presented to investigate the turning-point signals of evolution trend in long-term series of a climatic element. Based on nonlinear fitting, the revised model brings out more evident improvement of the linear model proposed by Solow et al. (1987). Both theoretical deduction and case calculation show that our version can search the turning point and period accurately and objectively. In particular it is fit for computer exploring the turning points in long-range records from stations covering a large area, thus avoiding subjective judgement by a usual drawing method.     

<Emphasis Type="Italic">In-situ</Emphasis> trace element analyses and Pb-Pb dating of zircons in granulite from Huangtuling,Dabieshan by LAM-ICP-MS

It is revealed by CL images that there are multi-stage growth internal structures of zircons in the Huangtuling granulite, including the inherited zircons, protolith zircons, sector and planar zone zircons and retrograde zircons. In-situ trace element compositions and Pb-Pb ages have been analyzed by LAM-ICP-MS. The sector and the planar zone domains show typical trace element characteristics of granulite zircon (low Th, U, Th/U, total REEs, clear negative Eu anomalies, relatively depleted HREE and small differential degree between MREE and HREE, etc.), indicating that they formed during granulite-facies metamorphism. The protolith zircons have trace element characteristics of crustal zircon (high Th, U, Th/U, total REEs and enriched HREEs, etc.). 12 analyzed spots on granulite-facies domains give a weighted mean ²⁰⁷Pb/²⁰⁶Pb age of (2154±26) Ma (MSWD = 3.8), which is the best estimated age of granulite-facies metamorphism of this sample. The weighted mean ²⁰⁷Pb/²⁰⁶Pb age of 5 analyzed spots on protolith zircon domains is (2714 ± 22) Ma (MSWD = 1.4), which represents the protolith forming time. The discovery of ca. 3.4 Ga inherited zircon indicates that there are Palaeoarchean continental materials in this area. The interpretation of formation conditions and the ages of zircons can be constrained by simultaneous in-situ analysis of trace elements and ages.     

山西义兴寨金矿床金矿物颗粒的产出及其成矿动力学意义

山西义兴寨金矿床的金主要呈包体金和裂隙金两种产出状态.文章根据成矿地球化学动力学理论,论证了金元素在含矿断裂发生脆性破裂和脆-韧性扩张活动中析出的化学反应类型,以及受反应动力学条件的制约,形成矿石中金不同产出状态的规律.指出热液矿床中普遍存在的包体金为热液成矿早期阶段断裂发生脆性破裂和成矿流体沸腾,导致快速反应结晶的产物;而裂隙金和晶隙金为成矿晚期金等矿质在流体中残余富集,同时成矿断裂再次发生脉动破裂,即成矿热力学演化与有利的构造动力学因素耦合作用的结果.得出金矿物颗粒的产出状态具有成矿动力学意义的结论.     

一种四维绘图软件Vis5d使用要点简述

Vis5D是美国威士康星-麦迪逊大学空间科学与工程中心(SSEC)研制的可视化系统,主要有Bill Hibbard 和Johan Kellum 完成.Vis5D能够直观而清晰地显示3维立体图形,适用于中尺度研究结果,尤其是云物理结构研究.本文介绍了Vis5D的安装过程以及数据文件转换为v5d格式的方法,并以GRAPES数值模式输出产品为例进行了初步的可视化试验.     

Applications of interannual-resolution stable isotope records of speleothem: Climatic changes in Beijing and Tianjin, China during the past 500 years—the δ 18O record

δ¹⁸O of a stalagmite collected from Shihua Cave, 50 km southwest of Beijing is analyzed. The uppermost 2 cm was sampled at about 3-year intervals by a computer-controlled microsampling device. A total of 133 samples were analyzed, covering the last 480 years. A comparison of the δ¹⁸O record with the instrumentally recorded precipitation in Beijing and Tianjin back to 1840 AD shows that high precipitation correlates with negative δ¹⁸O peaks. The long-term δ¹⁸O trend records temperature changes. Between 1620 and 1900 AD, the temperature was cooler than the average value for the 480-year record, corresponding to the Little Ice Age. Temperatures warmer than the average prevailed during 1520–1620 and 1900—present. Superimposed on the long-term trend are about 14 δ¹⁸O cycles of 30–40-year periodicity, with wet periods centered around 1985, 1955, 1910, 1880, 1840, 1800, 1760, 1730, 1690, 1660, 1630, 1600, 1560 and 1530 AD. Project supported by the National Natural Science Foundation of China (Grant No. 9615875).     

The unique nature in ore composition,geological backgroudd and metallogenic mechanism of non-conventional superlarge ore deposits: A preliminary discussion

The new plants documented here, including a representative of the trimerophytesPsilophyton primitiuum sp. nov., a questionable rhyniophyte or trimerophyteHedeia sinica sp. nov., a prelycopodBragwanathia sp. and two species of zosterophyllophytes,Zosterophyllum australianum Lang and Cookson 1930 and2. sp. 1, from the Posongchong Formation of southeastern Yunnan, China, add to the known floral diversity of the Early Devonian of this region. Two sections of the Posongchong Formation, Changputang section of Wenshan district and Gegu section of Mengzi district also are introduced. After comparing the plants with those of the coeval flora of Australia and considering the data of recent paleocontinental reconstructions, the authors suggest that there is a northeastern Gondwana phytogeographic unit during the early Devonian comprising Australia, South China Block and perhaps Shan-Thai Block. The similarity of the floral component between Australia and South China is discussed. Because both Australia and South China also have dominant or endemic taxa, each might be recognized as a subunit, separately characterized byHedeia for Australia andEophyllophyton for South China. Project supported by the National Natural Science Foundation of China (Grant Nos. 49372075 and 49742004)     

Displacement of points determined by spatial intersection

Summary A procprocedure is presented for the direct determination of the components of the vector of spatial displacement of a point by spatial intersection. The horizontal, vertical and slope distances are determined by integrated surveying systems (electronic tacheometers), and the first survey is adjusted using conditional observations. The vector of displacement on the individual intervals of observation is determined by means of the matrix equation (33) into which it is only necessary to substitute the appropriate vectors of the observational differences.