长白山天池火山天文峰期黄色浮岩成因研究     

潘波  程滔  徐丹  刘松军 《岩石学报》2020,36(7):2067-2080

长白山天池火口北侧天文峰之上,一套醒目的黄色浮岩引起广泛的关注,其颜色成因问题更是讨论的热点。本文通过野外地质调查、显微形貌和地球化学分析等方法,探索了黄色浮岩的颜色成因问题,并对此次喷发活动(天文峰期喷发)有了更进一步的认识。黄色浮岩与其下部灰白色浮岩应为同一期喷发所形成,两者成分一致且特征相似。黄色浮岩初始颜色为灰白色,后期受所处环境(降水丰富)与本身气孔特征的影响,浮岩内发生了元素析出和元素沉淀的过程。首先,浮岩内Si与H2O结合形成弱硅酸(H2Si O3),而大气中CO2与H2O结合形成弱碳酸(H2CO3),在弱酸环境下火山玻璃逐渐析出Si、K、Al、Ca和Fe等阳离子,而析出的元素易溶于水的部分被流水带走,难溶于水的Fe与Al富集并粘附在火山玻璃壁上,同时由于Fe可与H2O络合形成黄色的Fe的水合物(Fe2O3·n H2O),而Al与H2O络合形成凝胶状白色水合物(Al2O3·n H2O),两者混合形成了黄色胶状物粘附在火山玻璃壁上,改变了浮岩原本的灰白色,形成了黄色浮岩。因此,天文峰期浮岩的黄色是由于后期风化淋滤作用所造成,属于次生色。本研究提高了对火山喷发堆积物风化淋滤作用过程的认识,也为其他地区相似颜色变化问题的讨论提供了借鉴。  相似文献   

利用接收函数方法研究中国东北东南部地区不同构造体的地壳特征   总被引：3，自引：0，他引：3       下载免费PDF全文

李天觉  陈棋福 《地球物理学报》2019,62(8):2899-2917

基于我们布设的探测深俯冲的中国东北地震台阵NECsaids台阵和固定地震台长时段的观测记录及NECESSArray流动台阵共计152个台站数据提取得到的33752条P波接收函数，采用H-κ叠加分析和共转换点（CCP）叠加成像等方法进行统一分析处理，并汇集他人接收函数研究结果得到中国东北东南部地区迄今为止最高分辨率的地壳厚度和平均波速比分布图像.对中国东北东南部地区不同构造体的地壳特征综合分析研究表明：研究区不同陆块的地壳属性存在明显差别，张广才岭地块中南部的地壳厚度和波速比与华北克拉通东北缘相当，地壳厚度同地表地形之间显示有明显的正相关关系；松辽地块东南缘地壳最薄、波速比最高，地壳厚度同壳内波速比之间显示出明显的负相关关系；兴凯地块西部地区的地壳结构表现为稍厚的地壳厚度和研究区内最低的壳内波速比，其地壳厚度同壳内波速比之间亦显示出明显的负相关关系；佳木斯地块西南缘在具有"正常"的壳内波速比同时地壳最厚.研究区内的郯庐断裂带北延段在切穿其下Moho面的同时表现出南北分段的特征：北段（44.4°N—47°N）两分支之下的Moho面整体下凹，而南段（41.5°N—43.3°N）两分支之下的Moho面则整体上隆.长白山天池火山下方表现为Moho面下凹沉落及高壳内波速比特征，推测其壳内岩浆囊很可能存在于火山口东北隅至少10 km的范围内.  相似文献   

我国火山地热流体地球化学研究新进展     

赵慈平 《矿物岩石地球化学通报》2011,30(4):382-389,422

本文综述了最近几年来中国研究者在地热流体地球化学研究领域取得的主要进展。在国际上关于地球内部流体及其作用研究取得重要进展的大背景下,我国学者在地热流体地球化学研究上也取得了一些重要成果,主要表现在火山地热区和非火山地热区两大方面,在火山学、地热学、环境学、大地构造学、地震学等五个学科领域都取得了一些重要进展。  相似文献   

泥火山的全球分布和研究进展   总被引：1，自引：0，他引：1  

黄华谷  邸鹏飞  陈多福 《矿物岩石地球化学通报》2011,30(2):189-197

本文系统介绍了泥火山的全球分布特征、分类、成矿、成因特征和机制、生物地球化学和地质灾害。泥火山是盆地地层深部含水的泥质物在高压作用下喷出地表形成的锥状沉积体,主要发育在沉积速率较快和有横向挤压构造作用的盆地中。全球陆地有超过40个泥火山发育区,海底有超过20个泥火山发育区,每个发育区有几座到200多座泥火山不等,陆地和浅海区共有2000多个泥火山。各地泥火山有不同的喷发周期,喷发物也各有不同的形态、成分、来源和年龄。尽管泥火山的成因机制尚颇有争议,但较快的沉积速率和活动大陆边缘横向构造挤压作用无疑是两个最为关键的因素。由于泥火山对大地构造属性、油气勘探、生物地球化学、地质灾害和全球气候变化等问题的研究有着重要的意义,已逐渐成为地球科学一个新的研究热点。  相似文献   

Mixing of magmatic CO₂ into volcano groundwater flow at Aso volcano assessed combining carbon and water stable isotopes     

Makoto Yamada  Shinji Ohsawa  Kohei Kazahaya  Masaya Yasuhara  Hiroshi Takahashi  Kazuhiro Amita  Hideo Mawatari  Shin Yoshikawa 《Journal of Geochemical Exploration》2011

To understand deep groundwater flow systems and their interaction with CO₂ emanated from magma at depth in a volcanic edifice, deep groundwater samples were collected from hot spring wells in the Aso volcanic area for hydrogen, oxygen and carbon isotope analyses and measurements of the stable carbon isotope ratios and concentrations of dissolved inorganic carbon (DIC). Relations between the stable carbon isotope ratio (δ¹³C_DIC) and DIC concentrations of the sampled waters show that magma-derived CO₂ mixed into the deep groundwater. Furthermore, groundwaters of deeper areas, except samples from fumarolic areas, show higher δ¹³C_DIC values. The waters' stable hydrogen and oxygen isotope ratios (δD and δ¹⁸O) reflect the meteoric-water origin of that region's deep groundwater. A negative correlation was found between the altitude of the well bottom and the altitude of groundwater recharge as calculated using the equation of the recharge-water line and δD value. This applies especially in the Aso-dani area, where deeper groundwater correlates with higher recharge. Groundwater recharged at high altitude has higher δ¹³C_DIC of than groundwater recharged at low altitude, strongly suggesting that magmatic CO₂ is present to a much greater degree in deeper groundwater. These results indicate that magmatic CO₂ mixes into deeper groundwater flowing nearer the magma conduit or chamber.  相似文献   

缅甸兰里岛泥火山灾害与成因机制探讨          下载免费PDF全文

万园  许建东  于红梅  赵波  潘波 《地震地质》2011,33(2):452-461

文中主要探讨缅甸兰里岛泥火山灾害与成因机制,结合兰里岛地质背景以及泥火山活动现状,对在兰里岛东北部、中部以及西部所取3个泥火山采样点的样品进行粒度分析以及显微形貌分析,发现样品粒度在1～100μm之间,均呈单峰正态分布,粒径中值相近,粒度分布集中,分选较差,粒度对称程度呈很正偏态;样品基质以泥质为主含有大量泥质碎屑、细...  相似文献   

新疆独山子泥火山沉积物及孔隙水的地球化学特征与流体来源     

黄华谷  李牛  王钦贤  陈多福 《大地构造与成矿学》2015,(2)

对陆地泥火山流体来源及其向地表渗漏过程中的改造作用开展研究,有利于加深理解泥火山释放甲烷的碳排放过程。新疆准噶尔盆地南缘独山子泥火山柱状沉积物和地表沉积物的矿物和元素组成,以及沉积物孔隙水离子组成等的分析结果显示,泥火山沉积物孔隙水Na+和Cl–间具有很好的正相关性,具有比海水高的Na+/Cl–和Li+/Cl–值、低的K+/Cl–和Mg2+/Cl–。泥火山沉积物与围岩相比,富集伊利石、绿泥石和方解石,缺少蒙脱石,富集Ca、亏损Si,这些变化主要与黏土矿物的脱水转变有关。表明泥火山流体主要来源于深部低盐度沉积物孔隙水,但经历了地表的蒸发作用,并混合了大气降水。  相似文献   

Was LUSI caused by drilling? – Authors reply to discussion     

Nurrochmat Sawolo  Edi SutrionoBambang P. Istadi  Agung B. Darmoyo 《Marine and Petroleum Geology》2010

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Thermoluminescence dating of the eruption at Mt Schank,South Australia     

B. W. Smith  J. R. Prescott 《Australian Journal of Earth Sciences》2013,60(3):335-342

Mount Schank, a young volcano in southeastern South Australia, has been dated by thermoluminescence. The dated material was quartz from a former beach dune overlain by the lava flow. Disequilibrium in the uranium decay series required a detailed analysis of the isotopic concentrations in the sand. The samples dated yielded an average age of 4930 ± 540 years BP which is consistent with palaeomagnetic measurements. Combined thermoluminescence, palaeomagnetic and radiocarbon evidence leave unresolved the relative chronologies of Mt Schank and nearby Mt Gambier.  相似文献   

Geophysical evidence of mud diapirism on the Mediterranean Ridge accretionary complex   总被引：2，自引：0，他引：2  

A. Camerlenghi  M. B. Cita  B. Della Vedova  N. Fusi  L. Mirabile  G. Pellis 《Marine Geophysical Researches》1995,17(2):115-141

Mud volcanoes, mud cones, and mud ridges have been identified on the inner portion of the crestal area, and possibly on the inner escarpment, of the Mediterranean Ridge accretionary complex. Four areas containing one or more mud diapirs have been investigated through bathymetric profiling, single channel seismic reflection profiling, heat flow measurements, and coring. A sequence of events is identified in the evolution of the mud diapirs: initially the expulsion on the seafloor of gasrich mud produces a seafloor depression outlined in the seismic record by downward dip of the host sediment reflectors towards the mud conduit; subsequent eruptions of fluid mud may create a flat topped mud volcano with step-like profile; finally, the intrusion of viscous mud produces a mud cone.The origin of the diapirs is deep within the Mediterranean Ridge. Although a minimum depth of about 400 m below the seafloor has been computed from the hydrostatic balance between the diapiric sediments and the host sediments, a maximum depth, suggested by geometric considerations, ranges between 5.3 and 7 km. The presence of thermogenic gas in the diapiric sediments suggests a better constrained origin depth of at least 2.2 km.The heat flow measured within the Olimpi mud diapir field and along a transect orthogonal to the diapiric field is low, ranging between 16 ± 5 and 41 ± 6 mW m^–2. Due to the presence of gas, the thermal conductivity of the diapiric sediments is lower than that of the host hemipelagic oozes (0.6–0.9 and 1.0–1.15 W m^–1 K^–1 respectively).We consider the distribution of mud diapirs to be controlled by the presence of tectonic features such as reverse faults or thrusts (inner escarpment) that develop where the thickness of the Late Miocene evaporites appears to be minimum. An upward migration through time of the position of the décollement within the stratigraphic column from the Upper Oligocene (diapiric sediments) to the Upper Miocene (present position) is identified.  相似文献