Geochemistry and Petrogenesis of Late Cretaceous–Paleocene Granites from the Tengchong Block, Western Yunnan: Implications for Angle-switching of Subducting Slab     

CHEN Xijie  MENG Yuanku  CAI Zhihui  LI Huaqi  LIU Xiaojia 《《地质学报》英文版》2022,96(5):1600-1614

The Cenozoic geological hallmark of Western Yunnan is the characteristic voluminous Late Cretaceous-Eocene granites; however, their geological background and petrogenesis have not been well constrained and elucidated. In this study, we present new zircon U-Pb dating, along with geochemical and Sr-Nd-Hf isotopic data for granites from the Tengchong–Lianghe granitoid belt (as abbreviated to Tengliang belt) and West Yingjiang batholiths from the Tengchong block. The mineralogical and geochemical features of the Tengliang granites and the West Yingjiang batholiths are ascribed to aluminous S-type granites and weak peraluminous I-type, respectively. Zircon U-Pb analyses yielded consistent ages ranging from 67.5 Ma, 68.4 Ma and 66.2 Ma from the Tengliang granitoid belt and 50.4 Ma to 60.8 Ma for three samples from the west Yingjiang batholiths. The Tengliang granites were emplaced during the Late Cretaceous (68?66 Ma) and demonstrate negative εHf(t) values (?24 to ?4) and initial?87Sr/86Sr ratios of 0.7101–0.7139 and significant negative εNd(t) values from ?8.91 to ?13.2, indicating a Proterozoic sedimentary source or enriched components. The hornblende-bearing I-type granites from West Yingjiang are characterized by lower initial?87Sr/86Sr ratios of 0.7076–0.7106, compared to Tengliang granite and negative whole-rock εNd(t) values from ?4.0 to ?11.9. The early Eocene west Yingjiang gneissic granites show wide ranges of εHf(t) values from +7.4 to ?8.5 and T2DM of 1.30–0.65 Ga, indicating partial melting of ancient crust with contributions of depleted mantle materials. In combination with the regional background and previous studies, we propose that such a spatio-temporal distribution of the Tengchong granitoid belt might be related to the rollback or angle-switching of the Neo-Tethyan subducting slab. This study sheds new light on the evolutionary history of the Tengchong block.  相似文献   

一种区域实时对流层内插模型及其在PPP中的应用     

宋佳  李敏  赵齐乐  戴志强 《测绘通报》2018,(4):1-5,15

利用反距离加权内插法,对基准站解算的天顶对流层延迟（ZTD）建立了区域实时ZTD模型,评估了该模型内插流动站对流层延迟对PPP定位精度和收敛时间的影响。试验表明：与传统ZTD采用参数估计的处理方法对比,二者解算得到的PPP精度在水平方向上效果相当,但在垂直方向上,模型内插对流层解算的定位精度提高约为5 cm,且能显著提高PPP收敛速度。说明应用本方法建立非气象参数的区域天顶对流层延迟模型能有效加快PPP的收敛速度,且提高定位精度。  相似文献   

几种常见矿物的油-水-矿物接触角测量及其讨论     

吴春正  薛海涛  卢双舫  田善思 《现代地质》2018,32(4):842

采用测量水中油滴在矿物表面接触角的方法,利用接触角测量仪测量了不同矿化度水中,不同单组分油和混合组分油在不同矿物表面的接触角,提出了一套合理的测量方法,保证了测量结果的准确性。经过测量润湿角的大小,对比发现水中矿物的亲油性由强到弱依次为：云母＞黄铁矿＞方解石＞白云石＞石英。矿物类型、油组分类型和水的矿化度都对接触角有较大影响：不同的矿物表面油水的润湿性不同;随着油滴中正十八烷含量的增多,油滴在云母表面的接触角变小,润湿性变好,在其它矿物表面的润湿性略有不同;随着水矿化度的提高,油滴在云母表面的接触角呈现出明显变大的趋势,润湿性逐渐变差,在其它矿物表面的润湿性略有不同。  相似文献   

The Dihedral Angle and Intersection Processes of a Conjugate Strike‐Slip Fault System in the Tarim Basin,NW China     

WU Guanghui  YUAN Yajuan  HUANG Shaoying  Thomas Matthew Vandyk  XIAO Yang  CAI Quan  LUO Bingxu 《《地质学报》英文版》2018,92(1):74-88

Recent studies, focused on dihedral angles and intersection processes, have increased understandings of conjugate fault mechanisms. We present new 3-D seismic data and microstructural core analysis in a case study of a large conjugate strike-slip fault system from the intracratonic Tarim Basin, NW China. Within our study area, "X" type NE and NW trending faults occur within CambrianOrdovician carbonates. The dihedral angles of these conjugate faults have narrow ranges, 19° to 62° in the Cambrian and 26° to 51° in the Ordovician, and their modes are 42° and 44° respectively. These data are significantly different from the ～60° predicted by the Coulomb fracture criterion. It is concluded that:(1) The dihedral angles of the conjugate faults were not controlled by confining pressure, which was low and associated with shallow burial;(2) As dihedral angles were not controlled by pressure they can be used to determine the shortening direction during faulting;(3) Sequential slip may have played an important role in forming conjugate fault intersections;(4) The conjugate fault system of the Tarim basin initiated as rhombic joints; these subsequently developed into sequentially active "X" type conjugate faults; followed by preferential development of the NW-trending faults; then reactivation of the NE trending faults. This intact rhombic conjugate fault system presents new insights into mechanisms of dihedral angle development, with particular relevance to intracratonic basins.  相似文献   

自适应抗差Kalman滤波在多天线原始观测值瞬时姿态确定中的应用     

甘雨  隋立芬  刘长建  董明 《测绘学报》2015,44(9):945-951

由载波相位观测值直接解算姿态能实现观测及姿态约束信息的最优利用。本文推导了基于失准角及乘性误差四元数的载波相位观测模型,分别建立了有外部角速度传感器和无外部传感器辅助下姿态参数估计的状态模型;利用自适应抗差滤波估计姿态误差,借鉴分类自适应因子的思想,分别确定模糊度和姿态误差参数的自适应因子,其中姿态自适应因子由Ratio值构造的三段函数确定。自适应抗差滤波能够充分利用约束信息和历史信息,将其融合在浮点解计算过程中,极大提高模糊度浮点解精度及其协方差的结构,在此基础上使用整数最小二乘模糊度降相关平差法(least-squares ambiguity decorrelation adjustment,LAMBDA)方法即能快速搜索出固定解,满足实时性需求。采用实测舰载GNSS 3天线测姿算例对方法进行了验证,结果表明,基于自适应抗差滤波的观测值直接定姿方法效率高、可靠性好。  相似文献   

车载测量系统几何标定的探讨     

薛武  张永生  张李军  于英  杨靖宇 《测绘科学》2015,40(1):68-71

文章针对移动车载测量系统的各项系统误差来源进行了分析,建立了相机畸变模型,以地面高精度三维控制场为依托对各项系统误差(相机畸变、GPS偏心矢量、IMU视准轴偏心角)进行了标定,并对标定后系统的直接定位绝对精度进行了评估。实验证明,系统几何标定之后具有较高的直接定位绝对精度,能够满足移动测量的需求。整个标定方案对于其他移动测量系统也具有一定的借鉴意义。  相似文献   

基于ASTER的蛇绿混杂岩带岩性识别     

马睿  张晓帆  陈川 《遥感学报》2015,19(2):195-208

本文运用ASTER遥感数据识别与提取新疆南天山铜花山地区蛇绿混杂岩带岩性信息。首先,利用比值法快速区别岩性,并比较了识别同一种岩性的不同指数的性能;然后,将对数残差算法应用在ASTER数据的短波红外波段上,在区域尺度上把蛇绿岩杂岩体同围岩区分开来;最后,运用标准光谱数据和光谱角填图法识别出多种蛇绿岩成分及其空间分布。现有地质图和野外验证反映出该方法有一定效果。利用混淆矩阵对光谱角填图法分类结果定量评价,结果表明,把ASTER的可见光-近红外、短波红外波段数据结合在一起进行岩性分类,可以达到比单独用短波红外数据分类更高的分类精度。  相似文献   

地基GPS水汽反演中区域大气加权平均温度模型     

李剑锋  王永前  胡伍生 《测绘科学技术学报》2015,(1):13-17

利用地基GPS反演可降水量,需要准确求得水汽转换参数。为了提高区域GPS大气水汽反演的精度,分析了大气加权平均温度的时空特性及其与地面温度之间的函数关系;利用江苏地区2003—2011年的气象探空数据建立了适用于江苏地区的局地大气加权平均温度计算模型。比较江苏模型、Bevis模型和李建国模型求得的大气加权平均温度值,江苏模型的精度较Bevis模型和李建国模型分别提高33.14%和9.28%。由江苏模型得到的可降水量内符合精度约为11.12 mm,较GAMIT软件结果精度提高约7.91%。  相似文献   

预测模型在对流层延迟计算中的应用研究     

李剑锋  王永前  郭俊元 《测绘科学技术学报》2015,(5):450-454

为了消弱对流层延迟影响,提高GPS定位的精度,探讨了利用预测模型计算对流层延迟的可行性。建立了计算对流层延迟的多元线性回归模型、组合预测模型、灰色模型和BP神经网络模型,并提出了一种基于可靠度的组合模型权系数确定方法。结合邳州、新沂两个CORS站的观测数据和地面气象数据,利用4种预测模型进行对流层延迟预测实验。实验结果表明:在48 h的预测时段内,4种模型预测对流层延迟的精度分别为10,15,25和30 mm。其中多元线性回归模型预测效果最佳,在已知学习样本真值的情况下,其预测精度达到1 cm,较传统对流层延迟改正模型精度提高约50%。  相似文献   

手持式超站仪配合实验形数法测定林分特征参数的原理与方法     

邱梓轩  冯仲科  祁曼  刘明艳 《地理信息世界》2015,(3):8-14

利用手持式超站仪配合实验形数法测定林分特征参数的原理与方法,可以迅速精确获得树木树干的胸径、树高、材积、角尺度、混交度、大小比数、林分胸高断面积、林分平均高、林分平均株数、蓄积量和生长量等数据。文章提出了观测五棵树构成样地的森林计测方法,通过实验研究表明,此方法比传统的森林调查技术更加精确和高效。  相似文献