补偿电流对核旋分量仪的影响及补偿稳流装置

着重讨论补偿电流对核旋分量磁力仪在观测地磁场垂直分量中的影响,介绍了补偿稳流装置和在大连地磁台应用的效果。     

郴桂地区中大比例尺成矿预测的方法与效果

郴桂地区是南岭多金属成矿带的重要地段，地质矿产工作研究程度较高，我院在此开展了大中比例尺成矿预测研究。本文扼要介绍了本区成矿预测的基本做法和预测方法，以及其主要成果和验证效果。     

An X-Ray Diffraction Study of an Inclusion in Diamond from the Luobusha Chromite Deposit in Tibet, China

Diamond was found in podiform chromitites of ophiolite and harzburgite from Luobusha, Tibet. There are silicate inclusions in some diamond grains from this area. In the present work, the CCD (charge coupled detector) technology of X-ray powder diffraction was applied to the study of the inclusion in diamond from the ophiolite of Tibet. Diffraction patterns are obtained even though the inclusion is only 20 μm in crystal size. The results show that the inclusion in diamond consists of talc and clinochrysotile. Therefore, it is clear that the diamond from the ophiolite of Luobusha, Tibet, is natural diamond rather than a synthetic one.     

Isotope Method for Confined Groundwater Recharge of the Lower Reaches of the Heihe River, Inner Mongolia, China

Environmental isotopes have been applied to analyze confined groundwater recharge in the lower reaches of the Heihe River,Inner Mongolia.CFC is regarded as a tracer that determines the date of groundwater,the date being less than 45 a.The confined groundwater within the Gurinai area and Ejin Basin other than the surface water of Heihe River might have originated from precipitation from Qilian Mountain or/and the Tibetan Plateau.The deep confined groundwater overflows into an upper aquifer and emerges into the ground,forming springs and lakes within the low-lying area.The recharge volume is estimated to be around 400 million-cubic meters.     

洞庭湖河湖疏浚对洪水位影响分析

洞庭湖是长江中游的重要调蓄湖泊，但由于接纳湘江、资水、沅江、澧水四水和长江三口洪水、泥沙，造成河道湖泊泥沙淤积，洪水位抬高，加重湖区的防洪负担，造成严重的洪涝灾害。根据洞庭湖河湖疏浚规划和典型河段疏挖竣工资料，运用水力学和水文学方法对疏浚前后洪水位的变化进行了分析。     

STUDY ON MIXED MODEL OF NEURAL NETWORK FOR FARMLAND FLOOD/DROUGHT PREDICTION

The paper concerns a flood/drought prediction model involving the continuation of time seriesof a predictand and the physical factors influencing the change of predictand.Attempt is made toconstruct the model by the neural network scheme for the nonlinear mapping relation based onmulti-input and single output.The model is found of steadily higher predictive accuracy by testingthe output from one and multiple stepwise predictions against observations and comparing theresults to those from a traditional statistical model.     

Neoproterozoic Molar-tooth Structure and Constraint of Depositional Facies and Environment in the North China Platform in Jiangsu, Anhui and Liaoning, Eastern China

Molar tooth structure （MTS） represented by complex ptygmatical shapes is widely distributed in the Proterozoic of the world. MTS filled by fine, equant sparry calcite （or dolomite） displays an abrupt contact with hosting rocks, which are mainly composed of carbonaceous micrites and fine-grained carbonates with local silts and stormdominated deposits with graded, cross or wave beddings, numerous erosional surfaces and truncated and fills or guttered bases. Occurrence of MTS suggests a result of the constraint of sedimentary facies, and the storm-base in ramp settings is the maximum depth for the formation of MTS. Vertical succession of MTS-bearing carbonates shows a deposition stacked by high-frequency shallow subtidal and peritidal cycles. An individual cyclic MTS-bearing sequence is characterized by thinning, shallowing and dynamic decreasing-upward, and peritidal caps of purple red iron and organic carbonaceous sediments with more complicated shapes of MTS are common on the top of individual MTS-bearing sequences.     

华北地台北缘某地区深断裂的特征及其与铀矿化关系的探讨

近年来随着航空磁测精度的提高,磁场信息量的增加,磁场规律性更为突出。航磁在研究区域深断裂构造的地质效果比较显著,特别是通过对航磁异常进行垂向导数、方向滤波等项数据处理,使航磁异常在断裂上显示更加清晰。本文通过航磁推测深断裂的研究,来探讨其与铀矿化的关系。     

Application of Grain Size Analysis to Study Sedimentary Environment of Sand Dune in the Vicinity of Tumen River

The dunes in estuary of Tumen River in China lie to the area between the Jiushaping and Fangchuan in the left bank of Tumen River (Fig.1). The dis-tance is about 15～20 km between the dunes and the coast. It ranges from China to D. P. R. Korea and Russia. The range of the height of dunes is about 15～20 m and the width is 100～200 m. By the re-connaissance, we protracted 9 section planes of the dunes and collected 40 sand samples of the dunes, and identified the sedimentary environment …     

三峡库区万州区山湾堰塘沉积物特征及演化历史

万州特有的阶梯状地貌特征是万州地区河流地貌演化及水平地层特殊地质环境共同作用的结果,通过系统的野外地质调查、勘探和资料收集,结合2008年堰塘的湖中钻探,对该堰塘沉积物进行系统取样与分析,并进行了沉积物年龄与成分的测定.结果表明山湾陡崖的崩塌与阶地抬升及区域构造运动一致.绘制了山湾滑坡崩塌堆积物各期次沉积剖面,共分为10个崩塌旋回.结合沉积物测年,研究了山湾滑坡体沉积物沉积速率,得出了山湾危岩陡崖后退速率为0.31~0.37 m/ka.