青藏高原东北缘龙首山晚新生代多阶段构造隆升的盆地记录

龙首山地区位于青藏高原与阿拉善地块的结合部位,其盆山演化过程和断裂带扩展模式的恢复对揭示青藏高原新生代北东向生长具有重要意义。本文基于龙首山南北两麓3个新近系沉积剖面的构造特征和5个砂岩样品的碎屑锆石U-Pb同位素LA-ICP-MS年龄结果,重建了青藏高原东北缘龙首山地区晚新生代的盆山演化过程。研究结果显示,龙首山地区晚新生代沉积-构造演化经历了3个主要阶段：（1）~14Ma,龙首山南缘断裂带活化,阿拉善地块南缘沿此断裂逆冲于张掖盆地之上,张掖盆地开始接收阿拉善地块的物源;（2）~5Ma,龙首山南缘断裂带的次级断裂开始发育,使龙首山南侧山麓白垩系开始剥露并为张掖盆地提供物源,同时,龙首山北缘断裂带活化并导致潮水盆地发生挠曲沉降,接收龙首山的物源;（3）5~2.5Ma,龙首山北缘断裂带的次级断裂开始发育,导致龙首山北麓白垩系开始剥露并为潮水盆地提供物源。通过对龙首山周缘盆地沉积相和物源开展分析,本研究反演了龙首山地区中新世以来的断裂带活动和山体隆升过程,表明在14~2.5Ma,随着龙首山南缘断裂、北缘断裂的活化和次级断裂的发育,龙首山经历了3次强烈的隆升,这对揭示青藏高原北东向的扩展过程具有重要的指示意义。

     

地下资源开采与诱发地震：现状与进展

页岩气、地热等清洁能源正成为全球能源开发日益重要的组成部分,也是我国未来能源产量增长的主体,对保障能源资源安全、支撑双碳目标意义重大。然而随着页岩气、地热等地下工业开采活动规模的不断扩大,由此引发的地震灾害问题正日益受到人们的关注。强化工业活动与诱发地震关系研究、管控相关诱发地震灾害风险成为全球面临的重要课题和挑战。基于此,笔者等调研了工业活动诱发地震的全球典型案例,系统介绍了不同国家(美国、加拿大和韩国)工业活动诱发地震的现状及其差异,并对流体注入诱发地震的主要途径、物理机制、相关作业参数和诱发地震关系等做了全面的综述。发现诱发地震不仅与流体注入参数(体积、速率等)相关,还受控于特定的区域地质背景和断裂条件。合理管控地震灾害风险、促进相关能源的开采,应该统筹开采区地质地球物理的综合调查和开采过程的动态监测。     

河北高阳低凸起深部热储层回灌注水诱发断层失稳危险性探讨

近年来, 注水诱发断层活化引发地震已成为深部地热资源安全开采面临的突出地质安全问题。河北高阳低凸起深部岩溶热储丰富, 区内分布多条隐伏断层, 研究旨在探明未来大规模开发高阳低凸起深部地热资源是否会诱发区内隐伏断层失稳破坏。研究基于华北地区综合地应力场, 利用莫尔-库伦准则计算热储区及邻区主要隐伏断层的初始稳定状态; 选用Hsieh and Bredehoeft水文模型计算代表性地热井回灌注水10~40年产生的超孔隙水压力值; 在初始稳定状态的基础上叠加该孔隙水压扰动, 采用断层滑动失稳概率评价方法, 分析长期回灌注水对断层稳定性的影响; 讨论断层走向与最大水平主应力夹角变化对断层滑动失稳风险的作用规律。结果表明: 高阳低凸起及邻区代表性地热井在170 m3/h注水速率条件下, 持续注水40年产生的超孔隙水压力值最大不超过11 MPa, 该扰动以注水井为中心向四周呈幂函数规律递减, 其影响范围不超过8 km; 持续回灌注水对高阳低凸起代表性地热井附近2 km范围内隐伏断层的稳定性影响显著, 部分断层滑动失稳概率超过85%, 具有极高的活化风险; 距离注水井2 km范围内不同走向的断层, 在单井回灌注水50年的作用下, 滑动失稳概率随断层走向与最大水平主应力夹角的减小而迅速增加。文章研究方法及相关成果可为国内外深部地热资源安全开发利用提供地质科学支撑。     

蒋家沟流域泥石流形成条件活动特征及发展趋势

根据对蒋家沟泥石流形成条件、活动特征的调查,查明蒋家沟泥石流属暴雨型粘性泥石流,阐明该区泥石流的危害及发展趋势.     

牙形石微量元素对生物绝灭事件的响应: 以二叠-三叠系全球层型剖面第一幕绝灭事件为例

首次系统地利用浙江长兴煤山剖面牙形石化石, 依托中国地质大学(武汉) 地质过程与矿产资源国家重点实验室激光剥蚀等离子体质谱仪(LA-ICP-MS) 获取牙形石微区原位元素含量信息.结果显示, 牙形石的Ce异常和稀土总量出现快速的波动, 它们均反映出P/T之交环境(氧化-还原、生态条件等) 的不稳定性.这些微量元素特征可以很好地与古海洋环境和生物绝灭事件耦合.这一研究将为系统探索全球古生代末生物大灭绝及其后生物复苏的过程、时限与古海洋化学及古生态变化性质等问题的研究提供新的途径, 并有望对这些重要科学问题提供有效的制约.      

安徽省耿皇勘探区煤系地层沉积环境及成煤条件浅析

以耿皇勘探区钻孔资料为基础,对该区煤系地层沉积环境及成煤条件进行分析,简述了本区煤系地层是在海退基础上,以三角洲为主体的三角洲相与泻湖海湾潮坪相相互交替的沉积体系,通过对该特点的分析研究,为今后地质勘探和煤矿开采提供了借鉴和依据。     

Microseism Induced by Transient Release of In Situ Stress During Deep Rock Mass Excavation by Blasting

During deep rock mass excavation with the method of drill and blast, accompanying the secession of rock fragments and the formation of a new free surface, in situ stress on this boundary is suddenly released within several milliseconds, which is termed the transient release of in situ stress. In this process, enormous strain energy around the excavation face is instantly released in the form of kinetic energy and it inevitably induces microseismic events in surrounding rock masses. Thus, blasting excavation-induced microseismic vibrations in high-stress rock masses are attributed to the combined action of explosion and the transient release of in situ stress. The intensity of stress release-induced microseisms, which depends mainly on the magnitude of the in situ stress and the dimension of the excavation face, is comparable to that of explosion-induced vibrations. With the methods of time–energy density analysis, amplitude spectrum analysis, and finite impulse response (FIR) digital filter, microseismic vibrations induced by the transient release of in situ stress were identified and separated from recorded microseismic signals during a blast of deep rock masses in the Pubugou Hydropower Station. The results show that the low-frequency component in the microseismic records results mainly from the transient release of in situ stress, while the high-frequency component originates primarily from explosion. In addition, a numerical simulation was conducted to demonstrate the occurrence of microseismic events by the transient release of in situ stress, and the results seem to have confirmed fairly well the separated vibrations from microseismic records.     

Molecular biomarker evidence of origins and transport of organic matter in sediments of the Pearl River estuary and adjacent South China Sea

Surface sediments from the subtropical Pearl River estuary and adjacent South China Sea were investigated by molecular organic geochemical methods to determine the composition, distribution and origin of extractable lipids (n-alkanes, n-alkanols and sterols). The absolute and organic C normalized concentrations of total alkane, n-alkanol, and sterol ranged from 0.16 to 2.67 μg g⁻¹ and 0.9 to 12.3 μg g⁻¹ OC, 24.4 to 427.3 ng g⁻¹ and 63.2 to 1966.7 ng g⁻¹ OC, and 9.0 to 493.5 ng g⁻¹ and 58.4 to 1042.4 ng g⁻¹ OC, respectively. The spatial distributions of these biomarkers indicated that terrestrial-derived molecular biomarkers such as long-chain n-alkanes, n-alkanols and plant-derived sterols were higher at the river mouth and along the coastline, suggesting that a higher proportion of terrestrial particulate organic matter was deposited there. Relatively lower amounts of marine-derived biomarkers such as short-chain n-alkanes, algal sterols at the river mouth reflected the lower primary productivity due to high turbidity. The spatial patterns of these biomarkers were partially related to the estuarine processes and conditions, evidencing an increased terrestrial signal from the Pearl River mouth to the inner estuary, and enhanced marine conditions further offshore.     

不同尺寸煤颗粒分选机理的研究

针对不同用户对煤炭粒径有不同的要求,煤颗粒粒径在4mm以下,其中0.125mm粒径以下的颗粒不能超过10%的无烟煤精粉有大量的出口需求,而目前所用设备产品质量不能满足要求,而且效率低的状况,对煤颗粒粒级分选设备的工作原理进行了分析并提出改进方案。基于流体力学理论对改进的设备的工作原理进行了数学建模和算例分析,得出随粒径不同,沉降时间不同,因而在风流中沉降距离不同,从而可以利用风流达到对煤粒进行分选的目的。