东昆仑万宝沟岩群基质地层中发现白垩纪孢粉组合

东昆仑造山带万宝沟岩群是一套混杂堆积地层,有外来岩块和基质地层之分,以往根据岩块中的化石将该套地层的时代划为前寒武纪的蓟县纪—青白口纪。根据野外调查和研究结果,曾于2005年首次报道了在昆仑桥南剖面该岩群基质地层中发现古近纪晚始新世至中—早渐新世的孢粉50属12种;同年还报道了在该岩群命名地点万宝沟剖面发现古近纪渐新世的孢粉22属15种。本次报道的是在昆仑桥北剖面该岩群基质地层中发现的早白垩世晚期—晚白垩世早期的孢粉化石43属19种(比较种)。白垩纪和古近纪孢粉化石的发现对进一步厘定该岩群的地质时代、分析其古环境及东昆仑造山带的形成演化具有重要意义。     

Fluid-assisted fracturing,cataclasis, and resulting plastic flow in mylonites from the Moresby Seamount detachment,Woodlark Basin

The Moresby Seamount detachment (MSD) in the Woodlark Basin (offshore Papua New Guinea) is a large active low-angle detachment excellently exposed at the seafloor, and cutting through mafic metamorphic rocks. Hydrothermal infiltration of quartz followed by that of calcite occurred during cataclastic deformation. Subsequent deformation of these a priori softer minerals leads to mylonite formation in the MSD. This study aims at a better understanding of the deformation mechanism switch from cataclastic to plastic flow. Deformation fabrics of the fault rocks were analyzed by light-optical microscopy. Rheologically critical phases were mapped to determine distributions and area proportions, and EBSD was used to measure crystallographic preferred orientation (CPO). Strong calcite CPOs indicate dominant dislocation creep. Quartz CPOs, however, are weak and more difficult to interpret, suggesting at least some strain accommodation by diffusion creep mechanisms. When quartz aggregates are intermixed with the polymineralic mylonite matrix diffusion creep grain boundary sliding may be dominant. The syntectonic conversion from mafic cataclasites to more siliceous and carbonaceous mylonites induced by hydrothermal processes is a critical weakening mechanism enabling the MSD to at least intermittently plastic flow at low shear stresses. This is probably a crucial process for the operation of low-angle detachments in hydrated and dominantly mafic crust.     

基于LDPC矩阵采样方法的三维地震数据重构

按照以往的测量矩阵进行实际勘察无法较好地实现地震数据的重构,大多数矩阵设计复杂且元素多样,不符合实际标准。笔者将LDPC矩阵应用到地震勘探采样中,用较少的地震数据来重构完整的地震记录。采用K-SVD字典对数据进行稀疏变换,FISTA算法进行重构。对比以往的随机采样、离散均匀采样和jitter采样,LDPC矩阵更适合三维环境且恢复重构效果更好。对比重构数据的信噪比,三维模拟数据和实际数据都证实了LDPC矩阵信噪比值最高,重构出的数据效果最好。     

计算层状介质中轴对称柱面瑞利面波频散函数的δ矩阵法

笔者将δ矩阵法应用于计算层状介质中轴对称柱面瑞利面波的频散函数,得到了六阶δ矩阵法、五阶δ矩阵法、快速δ矩阵法3种方法,很好地解决了高频数值精度丢失问题以及高频数值溢出问题,并提高了计算速度,数值计算及工程应用验证了上述方法的有效性,且表明了这些方法也完全适用于平面瑞利面波频散曲线的求取问题。     

New CGSP Carbonate Matrix Reference Materials for LA-ICP-MS Analysis

Four CGSP (Chinese Geological Standard Powders) carbonate matrix element reference materials were prepared by a coprecipitation method. The major and trace elements were dissolved from natural rare earth carbonate raw materials in strong acid and precipitated with ammonium bicarbonate or ammonia to form carbonate matrix phases. The carbonate reference materials were ground and pressed into tablets for microanalysis. The element homogeneity and stability in CGSP reference materials were tested by LA-ICP-MS using a calibration strategy without an internal standard element and evaluated mainly following ISO Guide 35: 2017 and JJF 1343-2012. Although the homogeneity of most of elements in the CGSP series were comparable to the repeatability obtained from homogeneous glasses, some elements (e.g., Mo, Se, Ga, Ge, Cd, Ni, Co, U) were found to have some degree of heterogeneity. All of elements passed the t-test evaluation in a 32-month stability examination except for Mo in CGSP-A, Na, Ge, Mo in CGSP-B, Ni, Cd, Sn in CGSP-C, and Al, P, Tb, Ho in CGSP-D. The certified element mass fraction values and uncertainties were determined with the characterisation of a non-operationally defined measurand using various bulk analysis methods in eight laboratories. GGSPs will provide a new carbonate calibration reference option for microanalysis.     

地下水系统对鄂尔多斯低阻油层成因的控制作用

鄂尔多斯西缘广泛发育低电阻率油层,其形成原因与地下水系统关系密切。地下水对电阻率的影响主要表现在以下几个方面:高束缚水饱和度、高地下水矿化度、岩石润湿性、钻井液侵入等。深入研究低电阻率油层,不仅在储层电性研究中具有很高价值,对油气勘探开发也有重大意义。     

小波包变换空间滤波法分离信号研究

利用小波包分析在时域和频域同时具有良好的局部化特性,对信号进行小波包变换后,用谱矩阵法计算质点的空间运动特性,构造相应的滤波函数,对分解后的信号进行滤波,将滤波结果用逆小波包变换进行重构,实现了滤除干扰、保留有用信号的目的,取得了非常满意的效果。     

基于浸润线矩阵的尾矿坝稳定性分析

由于尾矿坝的渗流边界条件极为复杂,采用的二维简化理论分析法的计算结果有可能与实测浸润线的结果相差较大,急需一种能较为准确预测尾矿坝浸润线位置的简易算法。在深入剖析尾矿坝浸润线影响因素的基础上,建立了浸润线叠加影响函数,归纳出与尾矿坝坝体特征相关的阶段影响因子,提出反映阶段影响因子的浸润线矩阵。运用多项式回归分析浸润线观测数据,拟合得出浸润线观测孔水位与库水位的函数曲线,求得尾矿坝浸润线矩阵。     

基于协调过程的地图政区自动着色

地图制图中行政区划通常用颜色来区分,本文以Heawood定理及其证明过程为基础,提出一个基于协调某些已着色区域,用限定色数对政区进行自动着色的方法。它在只要求区分相邻色块的情况下,用最多5种颜色就可完成着色过程。并且在此方法中,根据制图中图面颜色平衡的要求,引进颜色的权重及相应的着色步骤。通过分析地图行政单元的区划特点以及制图中表示行政单元的要求,指出对政区这一类地图着色,在存在分离区域的情况下,不能保证按给定色数完成自动着色过程。     

基于非均匀各向同性介质的黏弹性波正演数值模拟

本文基于广义线性黏弹性体,通过引入黏弹性拉梅常量,提出拉梅差异矩阵,给出了非均匀各向同性介质的黏弹性波简化方程.拉梅差异矩阵具有和物性矩阵相似的形式,与弹性、黏弹性物性矩阵之间具有特定的数量关系,体现了黏弹性与弹性物性参数之间的差异程度,可以大大简化方程.并利用该简化方程对SEG/EAGE二维盐丘模型进行了正演数值模拟,将模拟得到的单炮记录和声波、Carcione黏弹性波方程模拟得到的单炮记录进行了对比分析.结果表明该简化方程模拟得到的单炮记录不仅具有较好的效果,而且比Carcione黏弹性波方程计算效率高,与理论分析基本相符.