藏南错那洞穹隆高分异淡色花岗岩的矿物学特征

藏南特提斯喜马拉雅东部的错那洞淡色花岗岩产出有白云母、石榴子石、电气石等特征性矿物,显示具有高度分异岩浆岩的特征。从二云母花岗岩到电气石花岗岩到石榴子石花岗岩,碱性长石均为正长石,斜长石从更长石演变为钠长石,白云母Al₂O₃、Na₂O含量逐渐升高,反映花岗岩逐渐向富Al富Na演化的趋势。二云母花岗岩中黑云母X_Fe值、Al^Ⅵ逐渐升高,表明二云母花岗岩之间存在结晶分异演化。电气石X_vac值、Al、Mg和Fe含量之间的变化,反映电气石花岗岩到花岗伟晶岩岩浆结晶环境中Na含量的增加,表明花岗伟晶岩结晶分异演化程度高于电气石花岗岩。石榴子石高X_Fe、X_Mn值的特征,也是高分异花岗岩的标志。上述矿物学研究结果表明,错那洞二云母花岗岩是由岩浆早期结晶矿物与残余的母岩浆组成的糊状物经过长期结晶形成的,而电气石花岗岩和石榴子石花岗岩由从晶粥体中分离出来的衍生熔体形成。     

Wind tunnel experimental study on shed tunnels to prevent and control blowing snow on highways北大核心CSCD

There is a severe phenomenon of blowing snow by wind in winter in Mayitas area of Xinjiang. Road traffic interruptions and casualties caused by wind and snow disasters often occur. The existing engineering measures can alleviate the problems of low visibility and problems with accumulating snow on pavement caused by wind and snow to a certain extent, but cannot completely eliminate the impact. Aiming at the problem that the blowing snow disaster difficult to be completely cured under strong wind conditions, a shed tunnel engineering treatment scheme is proposed, and a wind tunnel simulation experiment is carried out on the shed tunnel form and snow prevention scheme at the entrance of the tunnel. The wind tunnel experimental section is 8 m long, 1. 3 m horizontally wide and 1 m high. The shed tunnel model is made by 1:60 scale 3D printing method, the snow barrier model is made of wooden strips, and the simulation medium is made of fine sand, refined salt and sawdust. Firstly, three kinds of shed structures, including fully enclosed, overhanging and ventilated, were simulated under the condition of 90° wind direction, and compared with the form of blowing snow stacking. Three parameters for similarity were used:density, particle size and stacking shape. The similarity is determined by weighted Euclidean distance between simulation medium and blowing snow, the similarity of the slump angle of the predecessors is verified, and the most suitable medium for simulating blowing snow is deduced. According to the experimental results, combined with the actual situation of wind blowing and snow disasters in Mayitas, flow field of the closed shed tunnel by a wind direction angle of 30° has been separately conducted with or without protective measures. The results show that when the wind tunnel stacking experiment is used to study the deposition state of blowing snow under non-low temperature conditions, the sawdust has good similarity with the blowing snow in the process of wind and snow movement. A large amount of medium was poured into the ventilated shed during the experiment, which proved that its anti-wind and snow performance was not ideal. By contrast, the closed shed and the overhanging shed have better wind and snow prevention effects. The snow barrier has a good blowing snow inhibition function at the entrance. From the stacking experiment, in the comparison with and without snow barrier, volume of the medium in the shed is very different, which proves that the snow barrier can effectively prevent the blowing snow from entering the shed. Among them, the difference in wind speed inside and outside the shed is obvious, which proves that snow barrier can significantly reduce the wind speed outside the shed and has the function of inhibiting the formation of weak wind areas inside the shed. The study has confirmed that the shed tunnel project with suitable snow barrier layout plan for tunnel entrance protection is an effective means to control wind and snow disasters. For highway traffic in Xinjiang, it is a feasible solution to use shed tunnel engineering to control blowing snow disasters. After dealing with the snow deposition at the entrance of shed tunnel, the shed tunnel engineering form of low-cost environment integration and the vehicle operation safety guarantee measures of long-distance shed tunnel are the problems that need to be solved in the future. © 2022 Tianjin Press of Chinese Herbal Medicines. All rights reserved.     

川南普格上二叠统玄武岩葡萄石-石英晶洞中矿物组合及热液演变特征北大核心CSCD

利用冷热台、激光拉曼光谱仪、电感耦合等离子体质谱仪等仪器设备,对川南普格跨山上二叠统玄武岩葡萄石—石英晶洞中的矿物进行系统的测试分析,揭示出晶洞中热液的来源与演变特征。晶洞中的主要矿物为葡萄石和石英,有少量的硅铁灰石、绿帘石、绿纤石以及赤铁矿等,葡萄石、石英以及硅铁灰石有不同的世代,它们生成的顺序依次为:第1世代浅紫色石英+赤铁矿→第2世代石英+第1世代葡萄石→第3世代石英+第2世代葡萄石+第1世代硅铁灰石→第4世代石英+第2世代硅铁灰石+绿帘石+绿纤石。除浅紫色石英外,其它各世代石英晶体内部均呈现出一定的环带,浅紫色石英中的流体包裹体含有一定量的二氧化硫,而其它三个世代石英中的流体包裹体中均含有二氧化硫和甲烷等气体。晶洞中的热液属于低盐度(8.28%~10.61%NaCl_(eqv))、低温(141.7~188.2℃)型热液,且热液的温度呈现出先升后降(140→190→158℃)的变化趋势。第1世代葡萄石晶体较小,浅黄绿色,单晶体呈板柱状,集合体为葡萄状;第2世代葡萄石呈蓝绿色,单晶体为板状,集合体呈灯笼状。不同世代葡萄石中微量元素含量的变化趋势一致,但第2世代葡萄石中Cr,Ni的含量(分别为301.09×10^(-6)和329.61×10^(-6))高于第1世代葡萄石中Cr,Ni的含量(分别为199.08×10^(-6)和247.57×10^(-6))。葡萄石—石英晶洞中的初始热液是在玄武岩结晶分异晚期,富含二氧化硫的挥发性组分进入玄武岩裂隙和气孔中形成。随着玄武岩浆的冷却,浅紫色石英以及赤铁矿从晶洞中富含二氧化硫和Fe(Ⅲ)的热液中结晶析出,后期深部岩浆热液将玄武岩下伏的碳酸盐岩中富含甲烷和二氧化硫等成分的流体带入到葡萄石—石英晶洞中,导致晶洞附近的玄武岩发生蚀变,岩石蚀变释放出的Cr,Ni等成分随流体进入晶洞,引起晶洞中的温度升高以及晶洞热液中甲烷、二氧化硫以及Cr,Ni等含量的变化。随着石英和葡萄石的大量晶出,晶洞环境逐渐由氧化向还原转变,从而形成了晶洞中不同的矿物。     

应用氩离子抛光-扫描电镜方法研究四川九老洞组页岩微观孔隙特征

微观孔隙结构是页岩储层研究的重点,而扫描电镜方法无法识别机械抛光中由于页岩硬度差异所造成的不规则形貌。本文利用氩离子抛光-扫描电镜方法对四川威远区块九老洞组页岩进行研究,发现了三种孔隙类型:1无机孔以粒间孔和黏土矿物层间孔为主,同时发育晶间孔和生物孔,孔径主体100~500 nm;2有机孔受控于热成熟度或有机黏土复合体,孔径范围数十纳米至数微米;3微裂缝包括成岩收缩裂缝、高压碎裂缝、构造裂缝和人为裂缝,缝宽数微米,缝长数微米至数十微米。研究表明无机孔和微裂缝是九老洞组页岩气的主要储集空间。     

柴北缘乌兰县二郎洞达肯大坂岩群中混合岩化黑云斜长片麻岩锆石SHRIMP测年及其意义

柴北缘乌兰县二郎洞地区的达肯大坂岩群主要由黑云斜长片麻岩、混合岩、黑云母石英片岩、斜长角闪岩和大理岩、花岗片麻岩等共同组成。本文首次对两件混合岩化黑云斜长片麻岩样品中的锆石进行了内部结构分析和SHRIMP测年, 黑云斜长片麻岩中的锆石大多具有核-边结构, 核部和边部分别表现为典型的岩浆和变质成因锆石特征。一件样品中锆石核部²⁰⁶ Pb/²³⁸ U加权平均年龄为503.8±5.1 Ma, 边部²⁰⁶ Pb/²³⁸ U加权平均年龄为449±9.9 Ma; 另一件样品核部²⁰⁶ Pb/²³⁸ U加权平均年龄为493.6±4.5 Ma。这些结果表明, 乌兰县二郎洞地区达肯大坂岩群中的混合岩化黑云斜长片麻岩原岩形成年龄为504~494 Ma, 属于晚寒武世岩浆活动的产物, 变质年龄为449 Ma, 分别与柴北缘岛弧岩浆作用和超高压变质作用的时限相一致。研究表明, 二郎洞地区达肯大坂岩群不仅有新太古代-古元古代基底岩石, 还包含早古生代的岩石组合, 为一套不同性质和不同时代的混杂岩。     

输水管道工程跨区域施工外部协调方法创新

结合阎良供水安全提升改造工程,阐述了输水管道施工中征地协调及穿越道路、桥梁、渠道等手续办理情况。论述通过工程建设外部协调重要性及其与工程施工组织设计的有机结合,促进工程建设步伐,节省成本,提高管道工程建设水平,避免恶性事件的发生。并探索管道施工协调工作创新模式和实践要点。     

某引水工程中长输水隧洞断面初选设计分析

断面比选设计是为了研究输水隧洞在复杂的地质条件中能够更好的施工,在运行期具有更好的过流能力,并且在建设中节省工程投资而进行的不同断面设计分析。以在建某长输水隧洞为例,选择城门洞型和马蹄形两种不同设计断面,从水力参数设计、施工方法、工程量及工程投资等各个方面进行对比分析计算,选择出易于施工,水利条件好并节省投资的设计断面,再进行输水隧洞正常水深、临界水深、临界底坡的水力计算,并分析了设计断面的水力特性。最后,提出了在输水隧洞断面设计上的几点建议,供水利设计和施工人员参考。     

织金洞扫尾豪猪灭迹之原因探讨

本文通过对织金洞内扫尾豪猪粪层观测、分析、研究,初步阐述了全新世中晚期（６７１０±１３０～１１６５±９０ａ）洞内扫尾豪猪的生态习性,提出了食物的减少、出入洞口的堵塞、洞穴环境的变异、自然灾害的发生是洞内扫尾豪猪灭迹之主要原因      

贵州盘县风洞藻席蓝藻群落生态初探

本文通过对盘县风洞蓝藻的实地考察和实验室研究,首次揭示洞穴藻席中蓝藻群集已经达到群落层次,即蓝藻群落表现为对微域生态位的广泛占据和普遍适应,其分布不仅具有高等植物群落具有的地段性分布,还具有高等植物群落所不具有的非地段性分布,而且以后一种占优势。一至若干蓝藻群落总以不同程度的嵌合、叠置、埋入和融合的方式组成群嵌,群嵌可视为蓝藻群落分类的基本单位。蓝藻的群嵌结构与洞穴岩溶藻席显著的生物岩溶作用密切相关,这种“相关”的形成是历史上一定蓝藻组合与环境相互选择演变而成的,是进化生态学作用的结果。      

湖北省恩施市三门洞坝址工程地质条件浅析

湖北省恩施市龙凤镇流经的带水河,是清江北部规模较大的一条支流,它多次引发洪水,曾数度危及恩施市的安全。