大兴安岭旁开门金银矿床赋矿围岩的锆石U——Pb 年龄及其地质意义   总被引：1，自引：0，他引：1  

唐臣  杨帆  孙景贵  王清海  陈行时  张斌  李怡欣  柴鹏  刘勇胜 《世界地质》2011,30(4):532-537

大兴安岭旁开门金银矿床赋存在上侏罗统甘河组基性岩和下白垩统富林组中酸性火山岩中,其赋矿围岩蚀变流纹岩中单颗粒锆石U-Pb 年龄测定表明,21 个成分点中有1 组不谐和年龄( 141 ± 2 Ma、129 ± 2 Ma) 和3 组谐和年龄,后者的加权平均值分别为116. 2 ± 3. 4 Ma、112. 5 ± 1. 1 Ma 和 108. 2 ± 4. 2 Ma。结合锆石晶形和CL 图像特征,进一步确定流纹岩的成岩时代为早白垩世晚期,岩浆房冷却到岩浆热液期经历约8 Ma,成矿作用与富林组火山作用有关,发生在108 Ma 之后,其成矿与中国东北部陆缘晚中生代浅成热液金矿大规模成矿时代相一致。  相似文献   

南岭地区锡多金属矿床空间数据库建设     

陈希清  程顺波  付建明  马丽艳 《华南地质与矿产》2011,27(2):174-178

南岭地区锡多金属矿床空间数据库建设是国家地质调查主管部门和南岭地区新一轮地质勘查、矿产开发的需要.数据库在Microsoft Access 2000和Mapgis软件中编辑制作,包括ACCESS(.mdb)和MAPGIS点文件(*.WT)两种格式的文件,由矿床基本情况与矿区地质情况两张基本表格和相应的表单、查询组成,矿...  相似文献   

Evidence for a seismic attenuation anomaly beneath the Hida Mountain Range, Central Honshu, Japan   总被引：2，自引：0，他引：2  

Kei Katsumata  Taku Urabe  Megumi Mizoue 《Geophysical Journal International》1995,120(2):237-246

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SLR资料的快速处理   总被引：3，自引：0，他引：3  

冯初刚  朱元兰  张飞鹏 《测绘学报》2001,30(3):226-232

详细地介绍了 SL R( Satellite L aser Range)资料的快速分析处理技术。SLR资料的分析处理方法、采用的力学模型和解参数的多少根据目标的不同而异。但是其关键是对 SLR卫星进行精密定轨。本文对此进行了详细分析、比较 ,得出了目前上海天文台已采用的解算模式。根据该解算模式 ,我们分析处理了 1 998年 1 2月 31日至 1 999年 6月 2 9日 ,每 3天一弧段的 ,L AGEOS卫星的 SLR资料。结果显示每 3天弧段的定轨的残差的 rms约为± 1 cm左右。  相似文献   

地震活动性参数的变尺度（Rem>/Sem>）分析   总被引：7，自引：0，他引：7       下载免费PDF全文

李娟  陈颙 《地震学报》2001,23(2):143-150

将改变时间标度的方法应用于地震活动性分析中，选择具有不同空间尺度范围、时间范围和地震活动背景的现代仪器地震目录作为研究对象，分析了几个地震活动性参数——地震频度和地震发生时间间隔与时间标度的关系．这些地震活动性参数的极差和均方差之比与时间标度呈现出幂指数变化方式，且幂指数都大于0.5，表明地震的发生并非无记忆的泊松过程，而是具有随机和规律的双重特性．犎指数偏离0.5的程度可以衡量随机与规律成分所占比重，偏离越大，该序列的规律性成分越多，反之则越少．通过时间标度变换，可以较短时间的观测为基础，对变量未来的发生情况做出保守的估计．   相似文献   

中国脆弱生态环境类型划分及其范围确定   总被引：9，自引：1，他引：9  

赵跃龙  刘燕华 《云南地理环境研究》1994,6(2):34-44

本文对中国脆弱生态环境进行了主要成因和结构的两级类型划分，得出七大类脆弱生态环境主要成因类型和６３类脆弱生态结构类型。并以脆弱生态环境主要成因为依据初步确定了中国脆弱生态环境的分布范围，绘出中国七大类脆弱生态环境主要成因类型大范围图。采用分步叠置的方法绘制了中国６３类脆弱生态环境结构类型分布图，确定了中国脆弱生态环境区域范围。  相似文献   

DERF2.0模式对贵州延伸期、月预测质量对比分析          下载免费PDF全文

白慧  黄晨然  李忠燕 《中低纬山地气象》2018,42(5):9-13

利用2014—2016年第二代月动力延伸预测模式业务系统(DERF2. 0)直接输出及预报员预报的贵州省气温和降水预报数据、贵州省84站观测数据,采用Ps、Cs和Zs 3种评分方法评估了DERF2. 0对贵州月气温、降水和月内强降水过程的预测性能,并与预报员业务值班发布的预报质量进行对比分析,系统性地对DERF2. 0产品在延伸期/月尺度的预测效果进行检验评估。结果表明:DERF2. 0月预测产品总体上对贵州气温的预测性能优于降水,气温偏高预测的可参考性高于其对气温偏低的预测。DERF2. 0预报月气温的Ps评分较预报员略高,月降水较预报员略低,总体来看DERF2. 0月预测效果较预报员综合预报略差且预报性能较不稳定。预报员预测数据的Zs和Cs评分总体高于DERF2. 0预测数据,但DERF2. 0预测数据的Zs和Cs评分较预报员逐年提高,尤其在整个雨季时段较为明显。DERF2. 0对主汛期(6—8月)的预报准确率较整个雨季期(4—10月)略高。  相似文献   

大兴安岭南段三叠纪基性火山岩时代与构造环境   总被引：15，自引：6，他引：9  

张连昌  英基丰  陈志广  吴华英  王非  周新华 《岩石学报》2008,24(4)

应用火山岩锆石U-Pb LA-ICPMAS法和基质Ar-Ar法定年,表明大兴安岭南段存在三叠纪玄武质岩石,其年龄为214～250Ma。主量和微量元素地球化学反映三叠纪火山岩为亚碱性和低K拉斑玄武岩系列,部分岩石具岛弧火山岩地球化学性质,但主要呈造山后伸展环境下的岩浆活动特征。Sr-Nd-Pb同位素组成说明三叠纪基性火山岩岩浆源区主要为岩石圈地幔,但局部地区有软流圈物质加入;岩浆演化过程受部分熔融和分离结晶作用控制,并有少量地壳物质的混染。综合研究表明三叠纪大兴安岭南段处于中亚造山带后造山伸展阶段,基性岩浆形成于软流圈上涌诱发岩石圈地幔的部分熔融,拉斑玄武岩和辉绿玢岩脉即为伸张条件下基性岩浆活动的产物。结合区域构造演化,本文推测西拉木伦河-长春-延吉缝合带可能具有西段造山和造山后伸张作用稍早于东段的特征。  相似文献   

Late Mesozoic Thermotectonic Evolution of the Jueluotage Range,Eastern Xinjiang, Northwest China: Evidence from Apatite Fission Track Data   总被引：1，自引：0，他引：1  

ZHU Wenbin  WAN Jinglin  SHU Liangshu  ZHANG Zhiyong  SU Jinbao  SUN Yan  GUO Jichun  ZHANG Xueyun 《《地质学报》英文版》2008,82(2):348-357

Although many authors have emphasized the Cenozoic history of deformation, exhumation and cooling in the Tiaushan area related to the India-Asia collision, very little is known about the Mesozoic history of compression and uplift within the Tianshan. In order to obtain information about the Mesozoic exhumation history and processes of cooling in eastern Tianshan, fission track methods on apatite were used. Sampling was made in the Jueluotage Range. Three samples （Z001-Z003） were taken from granite in borehole ZK6301 of Yandong pluton; the ages range from 97.0 to 87.6 Ma that are much younger than the pluton age which was dated by U-Pb zircon at 334±2 Ma. Two samples in northern piedmont of the Jueluotage Range were collected from Jurassic strata in Dikaner （DK001） and Dananhu （D001） whose ages are 91.5 and 93.4 Ma respectively. The average apparent exhumation rate is 0.039 nun/a calculated by extrapolation on the basis of Yandong samples, indicating an extremely slow exhumation in the Jueluotage Range since the Late Cretaceous. Two Jurassic samples reached the maximum depths after deposition and experienced the maximum temperatures of ca. 105 and 108℃ until the late Early Cretaceous before a period of cooling and exhumation occurred at 114 and 106 Ma.  相似文献   

Coarse sediment supply sets the slope of bedrock channels in rapidly uplifting terrain: Field and topographic evidence from eastern Taiwan     

Larry Syu-Heng Lai  Joshua J. Roering  Noah J. Finnegan  Rebecca J. Dorsey  Jiun-Yee Yen 《地球表面变化过程与地形》2021,46(13):2671-2689

The incision rate and steepness of bedrock channels depend on water discharge, uplift rate, substrate lithology, sediment flux, and bedload size. However, the relative role of these factors and the sensitivity of channel steepness to rapid (>1 mm yr⁻¹) uplift rates remain unclear. We conducted field and topographic analyses of fluvial bedrock channels with varying channel bed lithology and sediment source rock along the Coastal Range in eastern Taiwan, where uplift rates vary from 1.8 to 11.8 mm yr⁻¹ and precipitation is relatively consistent (1.5–2.7 m yr⁻¹), to evaluate the controls on bedrock channel steepness. We find that channel steepness is independent of rock uplift rate and annual precipitation but increases monotonically with sediment size and substrate strength. Furthermore, in reaches with uniform substrate lithology (mudstone and flysch), channel steepness systematically varies with sediment source rock but not with channel width. When applied to our data, a mechanistic incision model (saltation-abrasion model) suggests that the steepness of Coastal Range channels is set primarily by coarse-sediment supply. We also observe that larger particles are mainly composed of resistant lithologies derived from volcanic rocks and conglomerates. This result implies that hillslope bedrock properties in the source area exert a dominant control on the steepness of proximal channels through coarse-sediment production in this setting. We propose that channel steepness may be insensitive to uplift rate and flow discharge in fast-uplifting landscapes where incision processes are set by coarse sediment size and supply. Models assuming a proportionality between incision rate and basal shear stress (stream power) may not fully capture controls on fluvial channel profiles in landslide-dominated landscapes. Processes other than channel steepening, such as enhanced bedload impacts and debris-flow scour, may be required to balance rock uplift and incision in these transport-limited systems.  相似文献