Chronology and Sources of Mesozoic Intrusive Complexes in the Xuzhou-Huainan Region, Central China: Constraints from SHRIMP Zircon U-Pb Dating   总被引：11，自引：0，他引：11  

XU Wenliang  WANG Qinghai  LIU Xiaochun  WANG Dongyan  GUO Jinghui College of Earth Sciences  Jilin University  Changchun  Jilin  Institute of Geomechanics  Chinese Academy of Geological Sciences  Beijing Institute of Geology  Geophysics  Chinese Academy of Sciences  Beijing 《《地质学报》英文版》2004,78(1):96-106

SHRIMP zircon U-Pb dating in the Liguo and Jiagou intrusives indicates that they were formed at -130 Ma in the Early Cretaceous. Most inherited zircons in the Liguo intrusive were formed at 2509±43 Ma. Most inherited and detrital zircons in the Jiagou intrusive were formed at -2500 Ma, -2000 Ma and -1800 Ma. The SHRIMP zircon U-Pb dating in two gneiss xenoliths from the Jiagou intrusive yields the ages of 2461±22 Ma and 2508±15 Ma, respectively. The dating results from inherited and detrital zircons in the intrusives and the gneiss xenoliths imply that the magmas could be derived from the partial melting of the basement of the North China Block (NCB). The magmatism is strong and extensive in the periods from 115 to 132 Ma, which is of typical bimodal characteristics. It is suggested that the lithospheric thinning in the eastern North China Block reached its peak in 115-132 Ma.  相似文献   

伪随机脉冲参数对BDS卫星定轨精度的影响分析     

张睿  涂锐  卢晓春  黄观文  王乐  瞿伟 《大地测量与地球动力学》2018,38(3):282-286

采用附加伪随机脉冲参数的动力学定轨方法对BDS卫星进行定轨,分别给出不同时间间隔的伪随机脉冲参数估计方案对BDS卫星常规状态、姿态转换状态以及进入地影状态时定轨精度的影响。结果表明,常规状态下,伪随机脉冲参数对GEO卫星定轨精度改善显著,相对较优的伪随机脉冲参数估计间隔与各类卫星运行周期吻合;对于姿态转换状态以及进入地影状态,6 h的伪随机脉冲参数估计间隔有助于提高相应卫星的定轨精度。  相似文献   

相山火山岩盆地磁异常特征分析   总被引：2，自引：0，他引：2  

龚晓春 《铀矿地质》1999,15(4):229-234

本文对相山火山岩盆地磁异常特征及其形成机理、分布特征和控制因素进行了研究,为进一步认识相山火山岩盆地地质构造提供了物探依据。  相似文献   

垂向地电阻率观测装置系数的计算——以江宁地震台为例     

樊晓春  李伟  孙君嵩  丁烨  吴帆  袁慎杰 《震灾防御技术》2020,15(3):651-657

井下地电阻率观测装置系数与电流的空间分布及电极位置有关,应针对不同的观测装置进行计算。本文以江苏省江宁地震台垂向观测为例,利用传统垂直观测装置系数方法、全空间及不完全全空间方式计算装置系数,比较不同装置系数对垂向观测的影响。研究结果表明,采用不完全全空间并考虑井距的装置系数计算方法适合江宁地震台垂向观测。  相似文献   

江宁地电台地表与井下地电阻率观测数据分析     

樊晓春  吴帆  袁慎杰  刘孝峰 《地震地磁观测与研究》2019,40(5):63-69

地铁建设对江宁地电台地电阻率观测造成较大影响,通过分析观测数据,比较了地表、井下观测受地铁等因素的干扰情况,并探讨了用影响系数来研究地表、井下观测的地表浅层干扰抑制能力,得到以下初步结果:①地铁试运行期间的干扰影响大于正式运营;②井下观测对供电电流更加敏感;③井下观测能够减轻地铁等的干扰,其地表浅层干扰抑制能力优于地表观测,可作为地电观测的重点发展方向之一。  相似文献   

黄河龙门段商周转折时期的古洪水事件及气候背景     

石彬楠  黄春长  庞奖励  查小春  周亚利  张玉柱  刘雯瑾 《湖泊科学》2017,29(1):234-245

通过野外观察研究,在黄河中游晋陕峡谷龙门段乡宁-韩城大桥西端支沟内,发现了全新世古洪水滞流沉积物.通过野外观察和室内实验分析,证明它们是黄河特大洪水悬移质泥沙在高水位滞流环境下的沉积物,记录了黄河晋陕峡谷段一期4次特大古洪水事件.通过地层学对比分析和光释光测年,确定这4次洪水发生在全新世中期-晚期转折阶段,即我国历史上商代末期-西周初期的气候突变转型期.利用"古洪水滞流沉积物厚度含沙量法"恢复古洪水洪峰水位,运用HEC-RAS模型估算出4次古洪水事件洪峰流量介于46280~48800 m~3/s之间.这些成果为黄河中游地区的防洪减灾、水资源开发利用、流域生态环境综合治理等方面提供了可靠的超长尺度水文数据.这为深入理解黄河流域水文系统对于全球变化的响应规律提供了新的证据.  相似文献   

新丰江水库大坝贯穿裂缝及其稳定性分析     

宋晓春  姜慧  王立新  刘智  朱敏 《震灾防御技术》2017,12(2):298-305

1962年3月19日新丰江水库大坝附近发生M_S 6.1级强烈地震后,13-17#坝段在108.5m高程处出现了长达82m的贯穿裂缝,导致水库渗漏,其后虽进行了加固处理,但经过50多年的运营,贯穿裂缝的现状如何,备受各级政府及专家学者的关注。本文利用近些年大坝上的多次小震观测记录,通过对有无贯穿裂缝坝段的地震加速度时程傅氏谱及上下坝体传递函数的对比分析,对14#坝段的整体性和稳定性进行了系统研究。结果表明,到目前为止,大坝贯穿裂缝没有明显恶化,但整体性依然较差,仍然是大坝稳定性的最大隐患。  相似文献   

汉江上游安康东段全新世古洪水沉积学与水文学研究   总被引：1，自引：1，他引：0  

许洁  黄春长  庞奖励  查小春  周亚利  周亮 《湖泊科学》2013,25(3):445-454

通过沿汉江上游河谷深入的考察,在安康东段发现了典型的古洪水滞流沉积剖面.通过采集样品、实验分析,确定它们是古洪水在高水位滞流环境当中的悬移质沉积物.根据地层对比、OSL测年和相关文化层年代,确定它们分别记录了发生在BL+AL与YD事件转折阶段(12500 a B.P.)的古洪水事件和发生在1000-900 a B.P.(1000-1100AD),即北宋后期的洪水事件.根据古洪水SWD的高程恢复其洪峰水位,结合相关参数,利用面积比降法计算恢复流量.结果表明在万年尺度,汉江上游古洪水洪峰流量介于35970~47400 m³/s之间.同时,利用2010年大洪水洪痕恢复计算洪峰流量,对古洪水洪峰流量计算结果进行了验证.进而结合历史洪水和观测洪水数据,获得了汉江上游万年尺度洪水洪峰流量与频率关系.这为汉江上游的水利水电和交通工程建设以及沿岸城镇防洪减灾提供了基础性数据.  相似文献   

2018年2月台湾花莲震群热红外遥感亮温异常分析          下载免费PDF全文

魏从信  卢晓春  成芳  惠少兴 《地震工程学报》2020,42(3):665-670

应用中国静止气象卫星FY-2G的TBB产品为基础数据,针对2018年2月上旬台湾花莲附近海域震群前出现在震中及附近区域的显著热红外异常,运用小波变换和相对功率谱法进行异常提取和资料分析。结果表明：花莲震群热红外异常范围主要分布在震中SW区域,震前约8个月出现功率谱增强现象,随时间推移,异常范围延纵谷断裂带逐渐扩大,持续近2个月,最大异常幅度超过14。  相似文献   

Genesis of Strata-bound Sulfide Orebodies in the Tongling Polymetallic Mineralization Cluster, SE China: Evidence from Colloform Pyrite     

XU Liang  XIE Qiaoqin  CHEN Tianhu  XU Xiaochun  ZHOU Yuefei  SUN Shaohu  CHEN Ping 《《地质学报》英文版》2020,94(6):1849-1859

Colloform pyrite (CPy) is widely distributed in the Tongling mineralization cluster of the Middle–Lower Yangtze River Mineralization Belt (MLYRMB), China. There have many debates as to whether such CPy is associated with Late Mesozoic igneous or Carboniferous sedimentation. CPy from the Xinqiao deposit, a representative of the stratabound sulfide deposits in the MLYRMB, was studied by powder X-ray diffraction (XRD), field-emission scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (TEM). The results show that CPy mainly comprises pyrite, pyrrhotite, quartz, and illite. Pyrite in CPy shows cubic, globule, and xenomorphic morphologies. No octahedral or pyritohedron was observed. Most of the quartz crystals display xenomorphic morphology, where pyrite mold are popular on the surface. Organic matter (OM), which is usually bound to illite, is an important component in CPy. Morphological investigations which exhibit detrital features of quartz and clay minerals indicate that they were derived from continental weathering. Specially, some hexagonal pyrrhotite nanoparticles which show mackinawite morphology are coexisted with OM. The results indicate that the transformation process of sulfides possibly is mackinawite (the precursor)—hexagonal pyrrhotite—pyrite. Thus, compositional and micro-textural characteristics of CPy in Xinqiao deposit suggest it to be a sedimentary origin rather than a hydrothermal origin which is associated with Yanshanian magmatism. Moreover, the coexistence of CPy and stratabound sulfide orebodies in the MLYRMB suggests a causal link between the two. It is considered that CPy might have served as a Cu mineralization geochemical barrier for the Cu-bearing ore-forming fluids, which originated from the Mesozoic magma in the MLYRMB.  相似文献