地震测氡仪野外校准的新方法     

赵影  黄仁桂  鲍志诚  查小惠  肖孟仁  胡旭东  王成楠 《中国地震》2021,37(1):140-147

为克服地震测氡仪野外校准氡气固体源监管严格等工作环境问题,引进东华理工大学新研制的豁免级微型氡室开展地震测氡仪野外校准实验,分析该微型氡室应用于地震测氡仪定期校准的可行性。根据《JJG 825-2013测氡仪检定规程》,分别使用微型氡室和标准氡室对2款在网观测测氡仪开展对比校准实验,分析认为采用微型氡室的校准方法基本可行。该微型氡室采用豁免级氡气源及自动化氡浓度控制系统,具备操作便捷、运输方便等特点,适用于地震台站测氡仪的现场定期校准。  相似文献   

由相对地热梯度推断的腾冲火山区现存岩浆囊   总被引：15，自引：6，他引：15  

赵慈平  冉华陈坤华 《岩石学报》2006,22(6):1517-1528

为利用温泉来研究和监测腾冲火山区的现今岩浆分布并探讨其活动性，提出相对地热梯度的概念：假设各热田或水热活动区的热储深度相等，则热储温度与地表温泉温度之差为该地相对地热梯度。通过对前人在该地区获得的温泉的基本要素和温泉水化学分析数据分析，选取了159个温泉计算相对地热梯度。用这159个数据，通过克里金插值方法获得了腾冲火山区的相对地热梯度平面分布。结果发现腾冲火山区有3个相对地热梯度在100℃以上的高值区域。结合其他资料，认为腾冲火山区现今存在3个岩浆囊，它们的几何尺度为19～28kin，深度为4～12km或更深，并且目前的活动性各不相同。  相似文献   

A new mixing equation for bed material composition in bed form dominant conditions     

Baozhen Jia  Deyu Zhong 《国际泥沙研究》2022,37(4):435-446

Vertical mixing beneath the bed surface and its effect on sediment composition has long been underestimated. This paper proposes a mixing equation to illustrate the temporal and spatial variations of bed material composition for bed form dominant rivers. A continuous mass conservation equation for elevation-specific nonuniform bed material composition is initially presented. A vertical mixing equation is finally derived as a diffusion-type partial differential equation with a source term charact...  相似文献   

废弃放射源贮存池的综合地球物理勘查     

曲赞  董浩斌  范志雄 《地质科技情报》2004,23(1):107-110

采用综合地球物理勘查技术,包括高精度磁测、高密度电法和地质雷达(GPR)对某处遗留于地下的铅封放射源进行了系统探查,对所获得的各类异常数据进行了分析处理,并指出了放射源所在的具体空间位置.开挖验证结果与解释结果完全吻合,显示了地球物理勘查技术在环境调查中具有快速、准确和非破坏性的优势.  相似文献   

流体的沸腾和混合在热液成矿中的意义   总被引：67，自引：0，他引：67  

张德会 《地球科学进展》1997,12(6):546-552

讨论了流体沸腾和混合在热液成矿中的重要作用及研究进展。成矿汉体的降温可能不是许多金属矿物沉淀的最有效机制；流体的沸腾作用对浅成热液帮床，斑岩铜钼等矿床中矿物的沉淀作用很大，造成的矿化具有强度大，品位富及垂向分带较发育的特征，同时因其影响范围小，作用时间短，限制了它的作用的发挥。  相似文献   

冰核观测中两种滤膜采样方法的比较     

周德平  张晋广  陈刚  李成龙  洪也  苏航  王扬锋 《气象与环境学报》2021,37(5):49-55

大气冰核观测是研究自然冷云降水和人工影响天气的一项基础性工作,滤膜—扩散云室法是观测冰核浓度的主要方法之一。为检测分析两种滤膜采集方法对冰核观测结果的影响,2011—2015年用自制的大气颗粒物采样器和FA-3型撞击式9级采样器开展了平行采样试验,采集的滤膜样本均在同一静力扩散云室中进行冰核活化显现分析。结果表明：自制采样器较9级采样器观测的冰核浓度高数倍甚至数十倍,但两者随季节和不同气象条件的变化表现出一致的起伏特征。自制采样器适用于对大气中总的冰核浓度分布及理化特征研究;9级采样器适用于对PM₁₀中不同粒径段大气冰核浓度和尺度分布以及理化特征的研究。滤膜法对冰核数量的低估与采样体积成正比,改变采样器气泵的抽气流量和控制采样体积对改进“体积效应”影响均有明显效果。  相似文献   

Diagenesis in salt dome roof strata: Barite - calcite assemblage in Jebel Madar,Oman     

《Marine and Petroleum Geology》2017

Halokinesis causes a dynamic structural evolution with the development of faults and fractures, which can act as either preferential fluid pathways or barriers. Reconstructing reactive fluid flow in salt dome settings remains a challenge. This contribution presents for the first time a spatial distribution map of diagenetic phases in a salt dome in northern Oman. Our study establishes a clear link between structural evolution and fluid flow leading to the formation of diagenetic products (barite and calcite) in the salt dome roof strata. Extensive formation of diagenetic products occurs along NNE-SSW to NE-SW faults and fractures, which initiated during the Santonian (Late Cretaceous) and were reactivated in the Miocene, but not along the E-W fault, which was generated during Early Paleocene time. We propose that the diagenetic products formed by mixing of a warm (100 °C) saline (17 wt% NaCl eq.) ⁸⁷Sr enriched (⁸⁷Sr/⁸⁶Sr: 0.71023) fluid with colder (35 °C) meteoric fluid during Miocene to Pleistocene. The stable sulphur and strontium isotope composition and fluid inclusion data indicate that a saline fluid, with sulphate source derived from the Ara Group evaporite and Haima Supergroup layers, is the source for barite formation at about 100 °C, predominantly at fault conjunctions and minor faults away from the main graben structure in the dome. In the Miocene, the saline fluid probably ascended along a halokinesis-related fault due to fluid overpressure (due to the rising salt and impermeable layers in the overlying stratigraphic sequence), and triggered the formation of barite due to mixing with barium-rich fluids, accompanied by a drop in temperature. Subsequently, evolving salt doming with associated fault activity and erosion of the Jebel allows progressively more input of colder meteoric fluids, which mix with the saline warmer fluid, as derived from stable isotope data measured in the progressively younger barite-associated calcite, fault zone calcite and macro-columnar calcite. The reconstructed mixing model indicates a 50/50 to 90/10 meteoric/saline fluid mixing ratio for the formation of fault zone calcite, and a 10 times higher concentration of carbon in the saline fluid end member compared to the meteoric fluid end member. The presented mixing model of salt-derived fluids with meteoric fluids is suggested to be a general model applicable to structural diagenetic evolution of salt domes world wide.  相似文献   

长白山天池火山岩浆系统分析   总被引：13，自引：1，他引：12       下载免费PDF全文

仇根根  裴发根  方慧  杜炳锐  张小博  张鹏辉  袁永真  何梅兴  白大为 《地球物理学报》2014,57(10):3466-3477

针对外媒报道长白山天池火山在近2年内有可能喷发的言论,在长白山天池火山区布测了一条长度约为103 km的二维大地电磁测深观测剖面,对火山区深部电性结构进行探测研究.由于研究区内不明来源的电磁干扰非常强,对数据采用了远参考处理、Robust处理、Rhoplus分析、张量阻抗分解和基于一维层状介质电阻率与相位互算方法等先进处理技术,获取到一批在强干扰区质量较为可靠的电磁数据,利用数据计算分析了长白山天池火山区二维构造走向和感应矢量特征,采用NLCG二维反演技术对资料进行了二维反演解释,并将反演结果与前人探测结果进行了对比分析.探测结果表明:在天池火山口下方存在明显的直立型岩浆通道,岩浆通道在下方约5~8 km位置形成关闭;在火山口下方往北方向附近,在埋深位置约7 km深处存在一个明显的低阻异常体,电阻率小于10 Ωm,且与岩浆通道对接,推测其可能是地表浅部发育的岩浆囊;在长白山山门附近C07-C09号测点之间和C04-C05号测点之间,在埋深约7~17 km深处发现近直立型低阻带,低阻带与下方低阻体直接相连,推测低阻带内赋存有活动的岩浆;随着埋深的增加,从天池火山口南部约20 km位置往北方向,在埋深13~30 km之间壳内广泛发育明显的低阻异常体,推测其可能是活动的岩浆囊.反演结果与前人探测结果整体电性特征相似,但又局部不同.  相似文献   

Numerical investigation of chaotic advection past a groyne based on laboratory flow experiment     

《Advances in water resources》2014

A laboratory flow past a groyne with complex hydrodynamics was investigated using surface Particle Tracking Velocimetry (PTV) technique for detecting chaotic features in fluvial mixing processes. In the reconstructed velocity field particles were deployed and tracked numerically in a Lagrangian way. Calculating some appropriate parameters (e.g. flushing times, finite-size Lyapunov exponent) originating from chaos theory, we are able to give a more detailed picture on surface mixing driven by aperiodic flows than traditional approaches, including the separation of sub-regions characterized by sharply different mixing efficiency.  相似文献   

沈阳春夏季大气冰核浓度的观测研究   总被引：2，自引：1，他引：1  

周德平  洪也  王扬锋  刘宁微  张云海  李丽光 《气候与环境研究》2012,17(6):719-726

为了解沈阳地区大气冰核浓度的时空分布状况,2010年起开始对沈阳地区的大气冰核浓度分布进行观测和研究.地面采用Bigg型混合云室法和滤膜法进行冰核气溶胶的采样测量,高空利用辽宁省人工影响天气办公室租用的人工增雨飞机进行滤膜法采样.采样滤膜的处理都是统一在活化温度-15℃及冰面过饱和度20％、水面过饱和度3％的湿度条件下进行的.根据取得的部分观测资料,给出了沈阳春夏季大气冰核的浓度及冰核温度谱分布参数,分析了冰核浓度在3～6月各月以及在不同天气状况下的分布特征,初步给出了大气冰核浓度的尺度谱分布及其随高度的变化.  相似文献