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华北地区太古宙和早元古宙的变质岩系,其出露面积占整个华北地台的44％。其中各类岩石所占的比例为:麻粒岩4.2％,片麻岩和混合岩48.4％,变质火山岩及其相伴的沉积变质岩8.7％,年龄老于20亿年的花岗岩和花岗闪长岩38.7％。太古宙由大面积分布的片麻岩和混合岩以及少量另星出露的麻粒岩组成,相当于片麻岩——麻粒岩区;早元古宙的早期以变质的火山岩系和变质沉积岩系为特征,可与浅变质的绿岩——片岩带相 相似文献
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龙岗古陆南缘光华岩群地质特征及时代探讨 总被引：5，自引：4，他引：1
吉林省通化市北部光华乡一带,发育有一套由变质基性席状岩墙、变质气孔状玄武岩、黑云变粒岩、大理岩、含榴二云片岩、变质流纹岩为组合的中-浅变质岩系.该套岩系岩石组合、变质程度均有别于龙岗古陆内的太古宙上壳岩.具有陆内裂谷环境下形成的双峰式火山岩建造特征.依据区域地层对比、岩石组合特征、同位素年龄资料,与周围侵入岩的相互关系,结合本地区地壳演化历史综合分析认为,其形成时代当属早元古宙,建立光华岩群. 相似文献
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吉林省通化市北部光华乡一带,发育有一套由变质基性席状岩墙、变质气孔状玄武岩、黑云变粒岩、大理岩、含榴二云片岩、变质流纹岩为组合的中一浅变质岩系。该套岩系岩石组合,变质程度均有别于龙岗古陆内的太古宙上壳岩。具有陆内裂谷环境下形成的双峰式火山岩建造特征。依据区域地层对比,岩石组合特征、同位素年龄资料,与周围侵入岩的相互关系,结合本地区地壳演化历史综合分析认为,其形成时代当属早元古宙,建立光华岩群。 相似文献
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甘肃敦煌地区太古宙孔兹岩系特征 总被引：10，自引：0，他引：10
本文根据甘肃敦煌地区广泛出露在太古宙ＴＴＧ杂岩中的一套副变质岩系的岩石组合、典型矿物组合、变质相特征和岩石化学特征的分析,认为它们是一套中深变质的碎屑岩－泥质岩－泥灰岩－碳酸盐建造,其中夹有少量的变质基性火山岩。原岩形成于具有基性火山作用的活动大陆边缘滨海－浅海环境。经过太古宙的区域高角闪岩相变质作用,形成孔兹岩系。 相似文献
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<正> 中国东部华北克拉通太古和早元古地壳以垂直增原为主,华北克拉通以外早元古地壳大范围地增生,其中、晚元古活动带则发生了地壳开会和水平增殖。它们分别具有各自的构造和地球化学的发展。 华北克拉通的太古宙地体主要由高级变质岩和花岗质岩石所构成。大部分地区仍可见到变质的上壳岩,如变质的双峰式火山岩及其火山碎屑岩、变粒岩、孔兹岩、大理岩和条带状铁建造等,形成了华北克拉通太古宙地体的自身岩石特征。已知太古宙的岩石时限为3.5—2.55Ga,其年代构造格架表现为大面积的晚太古岩石中包含了局部的3.5—2.9Ga的早 相似文献
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辽宁义县地区太古宙变质深成岩 总被引：1，自引：0，他引：1
地球化学特征研究表明,义县地区太古宙变质深成岩属于太古宙晚期富钾的正常钙碱性的花岗闪长岩－石英二长岩－花岗岩系列的岩石,属于壳源分异型花岗岩,形成环境为构造活动带。 相似文献
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吉林省板石沟—旺文川绿岩带岩石地球化学特征及成岩环境分析 总被引：1，自引：0，他引：1
吉林省南部晚太古宙绿岩带位于龙岗古陆核南部边缘,它包括板石沟、四方山和旺文川绿岩带,其岩石主要为变质镁铁质火山岩和变质长英质火山岩,反映出具双峰式火山岩的特征。另外,本区绿岩带岩石的岩石化学和地球化学特征与龙岗古陆核北部边缘的夹皮沟绿岩带具有明显的差异,表明两者成岩环境不同。本区绿岩带斜长角闪岩属板内玄武岩,其成岩环境与大陆裂谷环境相似。 相似文献
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采用地质调查和显微镜下观察方法,研究了辽南小黑山区太古宙岩石组成和构造变形特征。小黑山区太古宙岩石包括上壳岩、古老片麻岩和变基性岩脉,它们在小黑山变质岩体中呈包体出现。上壳岩由黑云变粒岩、条带状闪石磁铁石英岩组成;古老片麻岩为条带状角闪黑云斜长片麻岩、条带状角闪斜长片麻岩,原岩为英云闪长岩;变基性岩脉为斜长角闪岩和角闪石岩。上壳岩堆积之后有英云闪长岩侵位,基性脉侵位于上壳岩和英云闪长岩（古老片麻岩）。小黑山区太古宙岩石经历了2幕变形：D1幕变形主要表现为褶皱构造（DF1）、与褶皱轴面平行的面理（DS1）、矿物线理（DL1）;D2幕变形在叠加褶皱作用下形成斜歪倾伏褶皱（DF2）,面理和线理不发育。小黑山区太古宙变质岩中发育的变形序列、构造特征、变形特征、变质条件表明,这2幕构造形迹群属于中部构造相。D1幕变形形成逆冲推覆构造,D2幕变形形成第Ⅲ型叠加褶皱,它们都是在同方向的水平挤压应力作用下的产物。 相似文献
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This study integrated surface and subsurface stratigraphic data with geophysical logs and hydrogeologic data in order to
characterize the hydraulic properties of the Silurian dolomite in northeastern Wisconsin. Silurian stratigraphy consists of
predictable alternations of characteristic facies associations. A vertical profile of hydraulic conductivity, obtained from
short-interval packer tests in a core hole that penetrates a majority of the Silurian section, indicates that hydraulic conductivity
ranges over five orders of magnitude (10–1 to 10–6 cm/s). Matrix conductivity is generally low and varies with texture; the finer-grained restricted-marine and transitional
facies being less permeable than the coarser-grained open-marine facies. High-conductivity values are generally associated
with bedding-plane fractures, and fracture frequency is greater in the restricted-marine facies.
High-flow features in 16 wells were identified using fluid-temperature/resistivity and heat-pulse flowmeter logs. Natural-gamma
logs were used to identify the stratigraphic position of flow features in each well and to correlate flow features to specific
stratigraphic horizons. By combining stratigraphic, geophysical, and hydrogeologic data, 14 high-permeability zones within
the Silurian aquifer have been identified and correlated in wells more than 16 km apart. These zones parallel bedding, appear
most pronounced at contacts between contrasting lithologies, and are most abundant in restricted-marine lithologies.
Electronic Publication 相似文献
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Delineation of capture zones for municipal wells in fractured dolomite, Sturgeon Bay, Wisconsin, USA 总被引：1，自引：1，他引：1
A wellhead protection study for the city of Sturgeon Bay, Wisconsin, USA, demonstrates the necessity of combining detailed
hydrostratigraphic analysis with groundwater modeling to delineate zones of contribution for municipal wells in a fractured
dolomite aquifer. A numerical model (MODFLOW) was combined with a particle tracking code (MODPATH) to simulate the regional
groundwater system and to delineate capture zones for municipal wells. The hydrostratigraphic model included vertical and
horizontal fractures and high-permeability zones. Correlating stratigraphic interpretations with field data such as geophysical
logs, packer tests, and fracture mapping resulted in the construction of a numerical model with five high-permeability zones
related to bedding planes or facies changes. These zones serve as major conduits for horizontal groundwater flow. Dipping
fracture zones were simulated as thin high-permeability layers. The locations of exposed bedrock and surficial karst features
were used to identify areas of enhanced recharge. Model results show the vulnerability of the municipal wells to pollution.
Capture zones for the wells extend several kilometers north and south from the city. Travel times from recharge areas to all
wells were generally less than one year. The high seasonal variability of recharge in the study area made the use of a transient
model necessary.
Electronic Publication 相似文献
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前人在南羌塘达卓玛地区零星发现了一些地表油气显示并采集了少量的烃源岩进行分析,但勘查程度总体较低,未开展系统的生、储、盖研究。结合前人资料,通过野外石油地质调查、样品采集、室内分析、对比研究等手段,对南羌塘盆地达卓玛地区的烃源岩、储集岩、盖层等油气地质条件进行了分析,认为研究区阿堵拉组泥岩、页岩为好烃源岩,色哇组泥岩、粉砂质泥岩为差—中等烃源岩,布曲组、夏里组和索瓦组发育差烃源岩; 储集岩主要为阿堵拉组砂岩和布曲组白云岩; 盖层有泥质岩、灰岩和石膏,以Ⅰ、Ⅱ类盖层为主。野外调查中发现了大量地表油气显示,盆地经历了油气生成、运移、聚集和散失的过程,具有油气生成的物质基础和成藏的油气地质条件。建议在油气存储条件良好的达卓玛背斜布置钻井,进一步开展深部研究,力争实现该地区油气突破。 相似文献
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变质岩分类的三要素是:变质岩的物质成分(化学成分、矿物成分)、变质岩的组构(结构、构造)和变质岩的成因(变质作用类型和形成变质岩的物理化学条件).由于变质岩的化学成分、矿物成分、组构特征和形成变质岩的地质环境十分复杂,致使至今尚无以变质岩分类三要素为基础的、内容比较完善的分类方案.本文中主要变质岩的分类是以其分类三要素为基础编制的,首次将不同成因的变质岩类并列于同一表中、将鉴定变质岩的主要标志性矿物成分和组构特征列入同一分类表中.该分类对鉴定变质岩石具有可操作性和实用性,分类表中涵盖了自然界主要的变质岩石. 相似文献
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Previous researchers in Dazhuoma area of Southern Qiangtang Basin have found some sporadic oil and gas on the surface and collected a small amount of source rocks for analysis, but the exploration degree was generally low and they have not carried out systematic analysis of the generation, storage and cap of oil and gas. Based on the previous data, the authors in this paper have studied the characteristics of the source rocks, reservoir rocks and cap rocks in Dazhuoma area of Southern Qiangtang Basin by means of field petroleum geological survey, sample collection, indoor analysis and comparative research. The results suggest that the mudstone and shale of Adula Formation in the study area are considered as good source rocks, and the mudstone and silty mudstone of Sewa Formation are poor-medium source rocks, while Buqu Formation, Shari Formation and Suowa Formation are poor source rocks. The main reservoir rocks are the sandstone of Adula Formation and the dolomite of Buqu Formation. The cap rocks are argillaceous rocks, limestone and gypsum, and are mainly Ⅰ and Ⅱ cap rocks. Furthermore, the discovery of oil exposure shows that this basin has underwent the process of oil and gas generation, migration, gathering and losing, which builds the material foundation of oil and gas generation and the petroleum geological conditions of hydrocarbon accumulation. It is suggested that more drilling should be arranged in Darzhuoma anticline with good oil and gas storage conditions, and further deep research should be carried out to achieve oil and gas breakthrough in this area. 相似文献
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《地学前缘(英文版)》2018,9(6):1777-1794
Sedimentary rocks cover-73% of the Earth's surface and metamorphic rocks account for approximately91% of the crust by volume. Understanding the average behavior and variability of heat production for these rock types are vitally important for developing accurate models of lithospheric temperature. We analyze the heat production of ～204,000 whole rock geochemical data to quantify how heat production of these rocks varies with respect to chemistry and their evolution during metamorphism. The heat production of metaigneous and metasedimentary rocks are similar to their respective protoliths. Igneous and metaigneous samples increase in heat production with increasing SiO_2 and K_2 O, but decrease with increasing FeO, MgO and CaO. Sedimentary and metasedimentary rocks increase in heat production with increasing Al_2 O_3, FeO, TiO_2, and K_2 O but decrease with increasing CaO. For both igneous and sedimentary rocks, the heat production variations are largely correlated with processes that affect K_2 O concentration and covary with other major oxides as a consequence. Among sedimentary rocks,aluminous shales are the highest heat producing(2.9 μW~(-3)) whereas more common iron shales are lower heat producing(1.7 μW m~(-3)). Pure quartzites and carbonates are the lowest heat producing sedimentary rocks. Globally, there is little definitive evidence for a decrease in heat production with increasing metamorphic grade. However, there remains the need for high resolution studies of heat production variations within individual protoliths that vary in metamorphic grade. These results improve estimates of heat production and natural variability of rocks that will allow for more accurate temperature models of the lithosphere. 相似文献
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变质火山岩、火山碎屑岩的绿片岩相成岩格子可用阳起石—黑云母—方解石—绿泥石—绿帘石—白云母六相三元系和钠长石—阳起石—黑云母—方解石—绿泥石—绿帘石六相三元系成岩格子来表示,石英往往为过剩组分。在只讨论两个强度相同的变量前提下,每个六相三元系的成岩格子都只可能有一对成对的成岩格子,且这对成岩格子的非封闭双变区的分区相同、分区之间的边界斜率相同、相应的单变线的排列顺序也相同,因此,六相三元系的每个成岩格子中的不变点数、单变线数、和双变区数之间的关系可用数学式来表示。 相似文献
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本文主要基于对实验岩石学成果的简要评述,讨论与洋俯冲作用有关的两类典型的火成岩类:楔形地幔在含水条件下橄榄岩局部熔融产生的高镁安山岩/闪长岩类(HMA)和俯冲洋壳局部熔融岩浆与地幔楔相互作用产生的镁安山岩/闪长岩类(MA)。提出:(1)识别HMA和MA必须同时运用两套参数系统:SiO2-MgO系统和SiO2-FeO/MgO系统;(2)区别HMA和MA是在它们均符合LF-CA(低Fe钙碱趋势)特征条件下,再用SiO2-MgO系统进一步加以鉴别;(3)识别HMA和MA的方法,或用在给定SiO2时,MgO和FeO/MgO的具体数值,或用图解法。 相似文献