Cretaceous deformation history of the middle Tan-Lu fault zone in Shandong Province, eastern China

Based on field analysis of fault-slip data from different rock units of the Cretaceous basins along the middle part of the Tan-Lu fault zone (Shandong Province, eastern China), we document polyphase tectonic stress fields and address the changes in sense of motion of the Tan-Lu fault zone during the Cretaceous. The Cretaceous deformation history of the Tan-Lu fault zone can be divided into four main stages. The first stage, during the earliest Cretaceous, was dominated by N-S extension responsible for the formation of the Jiaolai basin. We interpret this extension to be related to dextral strike-slip pull-apart opening guided by the Tan-Lu fault zone. The second stage, during the middle Early Cretaceous, was overwhelmingly rift-dominated and characterized by widespread silicic to intermediate volcanism, normal faulting and basin subsidence. It was at this stage that the Tan-Lu-parallel Yi-Shu Rift was initiated by E-W to WNW-ESE extension. The tectonic regime then changed during the late Early Cretaceous to NW-SE-oriented transpression, causing inversion of the Early Cretaceous rift basin and sinistral slip along the Tan-Lu fault zone. During the Late Cretaceous, dextral activation of the Tan-Lu fault zone resulted in pull-apart opening of the Zhucheng basin, which was subsequently deformed by NE-SW compression. This deformation chronology of the Tan-Lu fault zone and the associated Cretaceous basins allow us to constrain the regional kinematic models as related to subduction along the eastern margin of Asia, or related to collision in the Tibet region.     

岩体边坡工程中的位移监测及分析

边坡工程的监测取决于监测人员对岩(土)体介质的认识程度和选择相应的方法和手段。通过对江西德兴铜矿大山村选矿厂东部边坡和北部楔形地质结构体稳定状况的监测,阐述了在边坡工程中位移监测的应用及有关分析。     

打桩挤土的现场试验研究及土体位移的计算公式

打桩挤土使周围土体发生位移,对周围其他桩及附近原有建筑物和基础设施产生破坏。本文通过典型工程打桩过程中的监测数据,运用小孔扩张理论结合回归分析方法导出了计算土体位移量的经验公式。运用该公式可定量预估挤土程度,防止意外事故的发生。     

Regional Fault Systems of Qaidam Basin and Adjacent Orogenic Belts

The purpose of this paper is to analyze the regional fault systems of Qaidam basin and ad-jacent orogenic belts. Field investigation and seismic interpretation indicate that five regional fault sys-tans occurred in the Qaidam and adjacent nment.qin belts, controlling the development and evolution of the Qaidam basin. These fault systems are: (1)north Qaidam-Qilian Mountain fault system; (2) south Qaidam-East Kunhm Mountain fault system;（3）Altun strike-slip fault system; (4) Elashan strike-slip fault system, and (5) Gansen-Xiaochaidan fault system. It is indicated that the fault systems controlled the orientation of the Qaidam basin, the formation and distribution of secondary faults within the basin,the migration of depocenters and the distribution of hydrocarbon accmnulation belt.     

Theoretical Study on Stochastic Modeling of Combined Gravity-Magnetic-Electric-Seismic Inversion and Its Application

As gravity field,magnetic field,electric field and seismic wave field are all physical fields,their object function,reverse function and compound function are certainly infinite contiuously differentiable func-tions which can be expanded into Taylor (Fourier) series within domain of definition and be further reduced in-to solving stochastic distribution function of series and statistic inference of optimal approximation,This is the basis of combined gravity-magnetic-electric-seismic inversion built on the basis of separation of field and source gravity-magnetic difference-value(D-value)trend surface,taking distribution-independent fault sys-tem as its unit,depths of seismic and electric interfaces of interests as its corresponding bivariate compound re-verse function of gravity-magnetic anomalies and using high order polynomial(high order trigonometric func-tion)approximating to its series distribution,The difference from current dominant inversion techniques is that,first,it does not respectively create gravity-seismic,magnetic-seismic deterministic inversion model from theoretical model,but combines gravity-magnetic-electric-seismic stochastic inversion model from stochastic model;second,after the concept of equivalent geological body being introduced,using feature of independent variable of gravity-magnetic field functions,taking density and susceptibility related to gravity-magnetic func-tion as default parameters of model,the deterministic model is established owing to better solution to the con-tradictioc of difficulty in identifying strata and less test analytical data for density and susceptibility in newly explored area;third,under assumption of independent parent distribution,a real modeling by strata,the prob-lem of difficult plane closure arising in profile modeling is avoided,This technology has richer and more detailed fault and strata information than sparse pattern seismic data in newly explored area,successfully inverses and plots structural map of Indosinian discontinuty in Hefei basin with combined gravity-magnetic-electric-seismic inversion,With development of high precision gravity-magnetic and overall geophysical technology,it is certain for introducing new methods of stochastic modeling and computational intelligence and promoting the develop-ment of combined gravity-magnetic-electric-seismic inversion to open a new substantial and promoting the develop-ment of combined gravity-magnetic-electric-seismic inversion to open a new substantial path.     

Application of Weights of Evidence to Mineral Potential Mapping of Yujiacun Ore Field in Northwest Yunnan Province, China

The multivariate information conprehensive processing technique is especially important at present to the digital mineral prospecting. However, the GIS-based weights of evidence have provided us with powerful tool for the quantitative assessment of mineral resource potential. In this paper, the mineralization model is established, based on the achievements made by previous researchers, to mend such deficiencies ad few references on ore fields in Yujiacun, Yunnan Province and the shortage of quantitative prediction and assessment of mineral resources. In addition, the weights of evidence are used to make a systematic quantitative prediction and assessment of mineral resources there, so that 2 mineral prospecting target areas of grade Ⅰ and 8 mineral prospecting target areas of grade Ⅱ are delineated, providing the further mineral resource exploration with the basis for the selection of mineral deposits.     

Deconvolving the δO seawater component from subseasonal coral δO and Sr/Ca at Rarotonga in the southwestern subtropical Pacific for the period 1726 to 1997

To reconstruct oceanographic variations in the subtropical South Pacific, 271-year long subseasonal time series of Sr/Ca and δ¹⁸O were generated from a coral growing at Rarotonga (21.5°S, 159.5°W). In this case, coral Sr/Ca appears to be an excellent proxy for sea surface temperature (SST) and coral δ¹⁸O is a function of both SST and seawater δ¹⁸O composition (δ¹⁸O_sw). Here, we focus on extracting the δ¹⁸O_sw signal from these proxy records. A method is presented assuming that coral Sr/Ca is solely a function of SST and that coral δ¹⁸O is a function of both SST and δ¹⁸O_sw. This method separates the effects of δ¹⁸O_sw from SST by breaking the instantaneous changes of coral δ¹⁸O into separate contributions by instantaneous SST and δ¹⁸O_sw changes, respectively. The results show that on average δ¹⁸O_sw at Rarotonga explains ∼39% of the variance in δ¹⁸O and that variations in SST explains the remaining ∼61% of δ¹⁸O variance. Reconstructed δ¹⁸O_sw shows systematic increases in summer months (December-February) consistent with the regional pattern of variations in precipitation and evaporation. The δ¹⁸O_sw also shows a positive linear correlation with satellite-derived estimated salinity for the period 1980 to 1997 (r = 0.72). This linear correlation between reconstructed δ¹⁸O_sw and salinity makes it possible to use the reconstructed δ¹⁸O_sw to estimate the past interannual and decadal salinity changes in this region. Comparisons of coral δ¹⁸O and δ¹⁸O_sw at Rarotonga with the Pacific decadal oscillation index suggest that the decadal and interdecadal salinity and SST variability at Rarotonga appears to be related to basin-scale decadal variability in the Pacific.     

GMS卫星遥感中国地区气溶胶光学厚度

讨论了利用GMS卫星遥感湖面上空气溶胶光学厚度的方法,根据在5个湖面附近与多波段光度计遥感结果的比较,对卫星遥感的方法和结果进行了检验,然后利用该方法遥感了中国大陆25个湖面上空气溶胶光学厚度.结果显示,利用卫星反演湖面光学厚度可以提供大陆上空气溶胶的信息,是研究大陆上空气溶胶光学厚度一个可行的方法.     

ENSO动力学与预测

发生在热带太平洋地区的ENSO现象是海气相互作用的集中表现,是年际气候变化中的最强信号.由于它的发生会在全球许多地区引起严重的气候异常,极大地影响着这些地区的工农业生产和人民生活,因此,对ENSO的机理及其预测的研究一直是大气海洋界的一个热点研究课题.中国科学院大气物理研究所在ENSO的机理及其预测等方面进行了大量的研究,取得了许多研究成果.作者将对中国科学院大气物理研究所在这方面的一些研究成果进行回顾和介绍.     

水稻低温冷害遥感监测技术与方法进展

根据国内外水稻低温冷害遥感监测和遥感灾损评估研究进展情况，分析了水稻低温冷害遥感监测的可行性和各种方法的优缺点，提出了低温冷害遥感监测方面需要开展的相关研究领域和需要解决的几个问题。