Quantification of both normal and right‐lateral late Quaternary activity along the Kongur Shan extensional system,Chinese Pamir

The Kongur Shan Extensional System (KES) is a ~250 km long normal fault system that bounds the Muji–Tashkorgan basin of the Chinese Pamir. It accommodates E–W extension due to the northward indentation of the Pamir salient, and its late Miocene activity has been the focus of tectonic studies. While the KES has a main normal component, ~WNW–ESE‐striking segments have an additional right‐lateral strike‐slip component. Here, we quantify late Quaternary horizontal and vertical slip rates at three locations along the KES, where active faults cut and offset abandoned geomorphic features. We find rates of >3–4 mm a^?1 (horizontal) along the western Muji fault in the north and of ~1.7 mm a^?1 (vertical) and ~1 mm a^?1 (horizontal) along the Kongur Shan fault in the south during the late Pleistocene. These rates are consistent with GPS and late Miocene rates, and imply that E–W extension in the Muji–Tashkorgan basin is faster in the north than in the south.     

不同类型矿床(点)空间关联关系定量研究-以中南半岛及临近地区为例北大核心CSCD

在具有较多已知矿床(点)的区域,从矿床(点)的空间分布模式中可以挖掘出成矿过程的重要信息,这些信息对于认识区域成矿规律、指导区域找矿具有重要意义。不同矿床类型之间的空间关联,通常都是通过结合地质和成矿规律定性分析来研究,缺少定量、精确的研究方法。针对这个问题,本文提出了一种定量分析不同矿床(点)类型之间空间关联的方法—基于ROC曲线的矿床空间关系挖掘方法。该方法采用数据分析中常用的ROC曲线,通过构建矿床空间点缓冲区,利用GIS软件计算得到ROC曲线和曲线下面积AUC以及Youden指数等相关参数,利用ROC曲线和AUC等参数定量探讨不同矿床类型之间的空间关联。通过网络分析对不同矿床类型之间的空间关系定量指标进行可视化,通过社团检测算法找出众多不同矿床类型中存在较强关联关系的矿床类型群组。以中南半岛矿床点的空间分布为实例进行研究,挖掘出了该研究区9种主要矿床类型之间的空间关联规律。结果表明,研究区的热液型Pb矿、热液型Cu矿、热液型Pb-Zn矿、砂矿型Au矿四种主要矿床类型之间存在较强空间关联(AUC值0.74~0.88),在空间上相互靠近,相伴产出。热液型Sn矿、砂矿型Sn两类之间关联关系强烈(AUC值0.62~0.79)。热液型Au矿、热液型Fe矿、热液型Sb矿的空间分布模式较为独立,与其他矿床类型之间关联较弱。利用本文提出的方法可以定量挖掘出区域上不同矿床类型之间的空间关联关系,为区域成矿研究和找矿实践提供重要信息。     

沉积微相控制下储层分类评价及预测

鄂尔多斯盆地环西—彭阳南段地区长8段沉积以辫状河三角洲平原为主,其储层品质明显受沉积微相控制。基于岩芯观察、薄片观察、压汞及常规测井等资料分析,将研究区长8段划分为5个小层,并对其辫状河三角洲平原沉积储层特征进行了精细研究。结果表明,研究区主要发育分流河道、越岸、分流间湾三种微相,其中分流河道构成了主要的砂体骨架,呈南西—北东向分布。分流河道砂体物性最好,越岸沉积物性次之,分流间湾物性最差。与之相对应,研究区储层可划分为I、II、III、IV四种类型,其中储层质量最好的I型主要位于河道中部,质量最差的IV型对应分流间湾。试油资料也进一步证实沉积微相控制研究区储层质量的差异,基于沉积微相的平面展布可实现储层平面分布规律预测。研究成果可为后续沉积储层精细评价乃至油气勘探开发综合研究奠定基础。     

基于相似性原理超固结土不排水扩张半解析解

在实际工程中,土体往往因卸载、再加载等复杂应力路径而处于超固结状态,而现有的圆孔扩张问题的计算模型往往不能反映超固结土中剪胀、软化等一些特殊性质。为了解决这一问题,基于相似性原理和统一硬化（UH）模型,结合相关联的流动法则和大变形理论,采用相似求解技术求解了超固结土不排水扩张问题的半解析解答。通过理想化算例分析了圆孔扩张挤土产生的应力和孔压响应,并通过分析不同超固结比OCR的土体应力路径的变化规律,讨论了UH模型的适用性。结果表明：对于轻超固结土,空腔周围土体孔压在塑性区沿径向单调递减,随着OCR增大,塑性区内孔压分布呈现出“S”形的趋势,孔壁附近的孔压逐渐减小,孔壁周围甚至出现负孔压。随着OCR增大,压力?扩张曲线收敛变慢。在扩孔过程中正常固结土一直处于剪缩硬化阶段。而对于超固结土,土体则经历了临界状态→剪胀硬化阶段→临界（特征）状态→剪缩硬化阶段。该研究成果不仅丰富了相似求解技术的应用,而且为超固结土中桩基承载力、隧道围岩变形预测和原位测试参数等岩土工程问题的计算提供了理论依据。     

Types, Petrophysical Properties and Pore Evolution of Late Ediacaran Microbial Carbonates, Tarim Basin, NW China

The Upper Ediacaran microbial carbonates of the Tarim Basin are potential reservoir geobodies for future hydrocarbon exploration with rising interest in exploration for deeply-buried reserves. However, little knowledge has been acquired on the types of microbial carbonates that are present, the properties of the reservoir and the pore evolution, hampering predictions of high-quality reservoirs in these carbonates. Integrated with petrography and in-situ U-Pb dating geochronology analyses, this study aims to clarify the types of microbial carbonates present and to reconstruct the pore evolution processes of the potential reservoir rocks. The Upper Ediacaran microbial carbonates of the Tarim Basin can be divided into four types, based on their features in terms of different scales (macro- to micro-): microbial laminite, stromatolite, spongiomicrobialite and microbial-peloidal wackestone/mudstone. Petrophysical properties show that all these microbial carbonates have low porosity and very low permeability with poor connectivity. These carbonates were subject to long-term and complex diagenetic processes, mainly consisting of dissolution, compaction, pervasive dolomitization, cementation and fracturing. The most important reservoir spaces are contributed by vugs and dissolution-enlarged pores, which are likely to have been associated with the widespread uplift of the Aksu area in the terminal Ediacaran. In contrast, the cementation of the fine-to-medium crystalline dolomite greatly reduced the pre-existing pores. Pore types are closely related to different microbial fabrics, which played an important role in the pore evolution of the microbial carbonates.     

内蒙古图古日格金矿床绢云母40Ar-39Ar定年及其地质意义

图古日格金矿床是位于兴蒙造山带西端的一个大型金矿床, 矿床的矿石主要有石英脉型和蚀变岩型两种, 矿床的成矿年龄尚存在争议。本文对矿床蚀变岩型矿石中热液成矿阶段的绢云母进行了40Ar-39Ar同位素定年研究, 获得坪年龄为(258.9±1.6) Ma(MSWD=0.69), 等时线年龄为(259.2±2.9) Ma(MSWD=5.4), 与前人获得的黄铁矿Re-Os等时线年龄((268±15) Ma)在误差范围内完全一致。结合矿区地质事实及前人研究结果, 认为该矿床的成矿年龄可以限定在268~259 Ma。图古日格金矿床与矿区内的似斑状花岗岩(265 Ma)具有紧密的成因关系, 属于与花岗质岩浆活动有关的石英脉型金矿床。兴蒙造山带乃至整个中亚造山带, 可能在二叠纪时期发育有一次与伸展背景下花岗质岩浆活动有关的金成矿事件, 找矿潜力巨大。     

Monitoring tilting angle of the slope surface to predict loess fall landslide: an on-site evidence from Heifangtai loess fall landslide in Gansu Province,China

Landslides - Due to the huge losses caused by landslides, landslide deformation monitoring has become essential. The change of the tilting angle of the slope surface can reflect the instability...     

Groundwater contamination source estimation based on a refined particle filter associated with a deep residual neural network surrogate

Hydrogeology Journal - Groundwater contamination source estimation (GCSE) involves an inverse process to match time-series monitoring data in sparse observation wells. It is commonly accompanied by...     

安哥拉东北部地区Inkisi组碎屑锆石U- Pb年龄、地球化学特征及其地质意义

Inkisi组是刚果盆地西南缘最古老的沉积地层之一,岩性主要为一套紫红色、红褐色细粒、细中粒长石砂岩、杂砂岩。通过对安哥拉东北部Inkisi组长石砂岩开展碎屑锆石测年、岩石地球化学研究,探讨其沉积时代、物质来源、沉积环境和大地构造背景,为研究刚果盆地演化提供科学依据。结果表明,碎屑锆石206Pb/238U年龄主要集中于3个年龄峰值区间2350~1900 Ma、1150~850 Ma、850~500 Ma,最年轻的锆石峰值年龄为531±9 Ma,据此,本文认为Inkisi组的沉积时代上限应厘定为早寒武世。Inkisi组砂岩地球化学特征显示,物源具有长英质物源近源搬运特征,沉积时期的水体为陆相开阔的淡水环境。通过碎屑锆石年龄谱特征、主微量元素物源判别及构造判别图解,本文认为,West Congo构造带为安哥拉东北部地区Inkisi组主要物源区,Lufilian构造带、Angola 地盾等是其次要物质来源,物源区构造环境主要为活动大陆边缘和被动大陆边缘构造环境背景。