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1.
江西冷水坑银铅锌矿田构造地球化学的若干问题 总被引：5，自引：0，他引：5
本文重点对冷水坑银铅锌矿田构造发育特征和构造地球化学的若干问题进行了初步探讨。运用裂隙统计、显微构造和组构分析方法对矿田NE向、NW向和近EW向断裂的力学性质和活动方式作了概略性论述。研究了银路岭矿床三个构造地球化学剖面的分析结果,其中主要成矿元素和伴生元素的分布和丰度变化与构造发育的关系,显示出本区构造地球化学场具有一定的分布规律。矿田F_1断裂是有一定区域意义的重要的成岩成矿和控岩控矿断裂,本次工作中选择了茶田剖面对F_1断裂带构造地球化学特征进行了初步探讨。 相似文献
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Martin Michálek Marián Putiš Christoph A. Hauzenberger 《Central European Journal of Geosciences》2011,3(2):197-206
This study focuses on metapelites of the Polinik complex in the Kreuzeck Mts. southeast of the Tauern Window, Eastern Alps, where kyanite — staurolite — garnet gneisses host eclogites and high pressure (HP) amphibolites of the Austroalpine basement. The stable mineral assemblage is garnet — staurolite — biotite — kyanite — quartz. Estimated metamorphic conditions from conventional geothermobarometry are 654±30 °C and 0.9±0.08 GPa, and Average P-T values calculated by THERMOCALC, are 665±15 °C at 0.77±0.09 GPa. Formation of the present mineral association in gneisses is related to the exhumation (D2) stage of hosted eclogites/HP amphibolites within a lateral strike-slip zone. 相似文献
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Petrology, Metamorphic Process and Genesis of The Dabie--Sulu Eclogite Belt, Eastern--Central China 总被引：10，自引：0，他引：10
Zhang Zeming You Zhendong Han Yujing Sang Longkang Department of Earth Sciences China University of Geosciences Wuhan Hubei 《《地质学报》英文版》1996,70(2):134-156
The Qinling-Dabie-Sulu high-pressure and ultra-high pressure metamorphic belt wasformed by subduction and collision between the North China and Yangtze plates. The study ofthe eclogite belt is very important in understanding the evolution of the Qinling Dabie orogen. Inthe present paper the geology, petrology, minerology and chronology of the eclogites in the Dabieand Sulu areas are described. The principal conclusions of this work are as follows: (1) Based up-on the field occurrence and the P-T conditions of the eclogites, two types of eclogite can be dis-tinguished: Type 1—the low-temperature and high-pressure eclogite in the mid-late Proterozoicmetamorphic series, and Type 2—the ultra-high pressure eclogite in the late Archaean to earlyProterozoic metamorphic complex. In the Dabie area, the ultra-high-pressure eclogite,high-pressure eclogite and epidote-blueschist units are nearly parallel to each other and stretchintermittently from north to south. (2) The P-T conditions of the high-pressure eclogites and ul-tra-high pressure eclogites have been estimated. The former are formed at 450-550℃ and1.4-1.6 GPa; while the latter at 650-870℃ and >2.7-2.9 GPa in the Dabie area and at820-1000℃ and >2.8-3.1 GPa in the Sulu area. The metamorphic temperatures of the eclogitesincrease progressively from west to east. (3) The ultra-high pressure eclogites were subjected to 5stages of metamorphism: pre-eclogite epidote amphibolite facies, peak coesite eclogite facies,post-eclogite amphibolite facies, epidote-blueschist facies or epidote amphibolite facies andgreenschist facies. The general features of the PTt path of the ultra-high pressure eclogite are:clockwise pattern, progressive metamorphism being a process of slow increasing temperature andrapid increasing pressure, and the retrogressive section with nearly isothermal decompression atthe early stage, isobaric cooling at the middle stage and nearly isothermal decompression at thelate stage. (4) At least two stages of high-pressure metamorphism occurred in the orogenic belt:the high-pressure eclogite and ultra-high pressure eclogite were formed by the subduction of theoceanic crust northward beneath the North China plate or the Dabie block during theCaledonian; while the epidote-blueschist belt came into being by subdution and collision be-tween the two continental plates during the Indosinian. (5) Due to the continuous sequentialsubduction of the cold plate, the ultra high-presssure metamorphic rocks were uplifted to thecrust by the underplating processes. They can be preserved just because of the "frozen effect" re-sulting from the continuous subduction of the cold plate. (6) The carbonates, such as magnesite,breunnerite, aragonite and dolomite, and the H_2O-bearing minerals, such as phengite, epidoteand zoisite, were stable during the high-pressure and/or ultra-high pressure metamorphism. 相似文献
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对四川稻城县海子山高原上的方枝柏进行树芯采集,经交叉定年后建立林线上限位置的方枝柏树轮宽度年表。标准化年表与气象资料的响应分析结果揭示了该地区树木生长主要受当年生长季前期温度条件的控制。轮宽指数与前一年9月到当年2月的平均气温呈显著正相关（R=0.56,P<0.01）。由此重建了该地区1850—2019年这170 a的前一年9月到当年2月平均气温的变化,转换函数方差解释量31.7%。重建结果与邻近地区树轮记录的温度变化具有较好的一致性。重建序列显示工业革命以来,研究区经历较冷的时期有：1870—1890年和1960—1980年;较暖的时期有：1884—1892年、1919—1925年、1940—1960年以及1980—2019年。1940—1960年是20世纪最暖的时期,20世纪60年代后温度呈现下降趋势,1980年开始气温保持持续升高,2010年之后气温有小幅下降。重建气温序列与太阳黑子数变化和北大西洋多年代际涛动AMO有较强的响应,揭示了太阳活动、海温等因子可能对该区温度变化产生重要影响。 相似文献
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沉积岩的微量、稀土元素对沉积环境的水介质变化有着较高的敏感度,对于研究古环境、沉积物源性质和构造背景方面具有重要的意义。前人对于东台坳陷元素地球化学方面的研究相对薄弱,利用元素地球化学资料解释古环境和源区性质方面的研究尚属空白。本文以苏北东台坳陷古新统阜宁组三段20件泥岩样品为研究对象,对其进行微量、稀土元素测定,并分析其地球化学特征及所揭示的地质意义。结果表明:(1)Sr含量、Sr/Cu、Rb/Sr、La_n/Yb_n比值指示干热气候;Li、Sr、Ni、Ga微量元素含量和Sr/Ba比值均指示淡水—半咸水的水体环境,整体以淡水环境为主,偶有咸水注入盆地,局部为半咸水环境;而V/(V+Ni)、V/Cr、Ni/Co、U/Th、δCe指示氧化—弱还原的水体环境。(2)Co/Th—La/Sc、La/Th—Hf判别图解和稀土元素配分模式,表明阜宁组三段沉积岩应来自于上地壳的长英质物质。(3)La—Th—Sc、Th—Co—Zr/10和Th—Sc—Zr/10构造背景判别图解反映了大陆岛弧与活动大陆边缘的构造背景,且与Bhatia不同构造背景杂砂岩的微量、稀土元素特征值的对比分析结果一致。 相似文献
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铜仁坝黄震旦系老堡组顶部晶屑凝灰岩SHRIMP锆石U Pb年龄及其地质意义 总被引：3，自引：0，他引：3
对于元古宙—显生宙的沉积—构造转换,前人做了大量研究工作,但一直以来未能获得较为一致的认识。野外调查发现,在处于上扬子东南缘台地与盆地相区的过渡带上的贵州铜仁坝黄长坪附近震旦系老堡组顶部硅质岩中,发育有一层10～20cm厚的凝灰岩夹层,岩石学研究也证实其为一层晶屑凝灰岩,并对其进行了SHRIMP锆石 UPb年龄测定,获得556±5Ma沉积年龄。结合前人生物地层学、沉积学等研究成果,显示处于深水陆棚相区的老堡组顶部硅质岩与页岩互层段为扬子克拉通元古宙—显生宙之交沉积—构造转换过程中的一次重要的沉积事件,该沉积事件始于556Ma左右,可与扬子克拉通上的广泛的火山事件相对应,且可能与约550Ma时Rodinia超大陆最后裂解和Iapetus洋的形成有关。 相似文献
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松辽盆地三肇凹陷葡萄花油层局部构造控油模式探讨 总被引：5，自引：0，他引：5
利用近4000口开发井初期产能资料,结合构造、测井解释、沉积微相和报废井类型等静态地质资料,对松辽盆地三肇凹陷葡萄花油层的油水分布规律进行了系统分析。研究表明,三级构造内单个的局部构造或单个的局部构造群控制油气的最终成藏,三级构造内油水分布受单个的局部（构造、岩性）圈闭控制,单个的局部（构造、岩性）圈闭内具有统一的油水分布规律,相邻的不同单个的局部（构造、岩性）圈闭具有不同的油水分布规律;储层的发育特征控制了油水的分布层位,断层与砂体的空间配置控制油水的分布边界。在相近的条件下,地垒型断块构造油藏〖FY〗反向正断层—鼻状构造油藏“人”字型反向正断层组合油藏断层—微幅度油藏断层—岩性油藏岩性油藏其它类型油藏,控油能力逐渐减弱。 相似文献
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Deformed and metamorphic ultramafic to mafic rocks emplaced into the Archaean Sargur supracrustal series (>3.0 Ga) in Karnataka, southern India, represent layered igneous bodies. The terrane has been affected by several episodes of deformation and metamorphism in the time span from 3.4 to 2.5 Ga ago.During the regional metamorphism about 2.5 Ga ago the igneous bodies re-equilibrated partly or completely at conditions of the upper amphibolite to granulite facies. The development of sagvandites with enstatite + magnesite and anthophyllite + magnesite-bearing assemblages, and of mafic garnet—pyroxene charnockites indicates the presence of CO2-rich intergranular fluids (XCO2 ? 0.5) in these rocks during metamorphism.The physical conditions of metamorphism have been estimated by applying methods of geothermobarometry to the recrystallized ultramafic assemblages with olivine, pyroxenes and spinel and to the charnockitic assemblages with garnet, pyroxenes, plagioclase and quartz. A best temperature estimate of 700 ± 30°C was derived with the geothermometers of Evans and Frost (Ol—Spi), Fabriès (Ol—Spi), Wells (Opx—Cpx), Powell (Opx—Cpx), Ellis and Green (Gra—Cpx), Lal and Raith (Gra—Opx), and Danckwerth and Newton (Al2O3-content in opx). A mean pressure estimate of 8.6 ± 0.8 kbar has been obtained with the models of Perkins and Newton (Gar—Opx/Cpx—Plag—Qtz). The P—T data indicate a minimum crustal thickness of about 35 km at c. 2.5 Ga in this part of the South Indian Archaean craton. 相似文献
10.
Thermodynamic equilibrium, kinetics, activation barriers, and reaction mechanisms for chemical reactions in Karst Terrains 总被引：2，自引：0，他引：2
W. B. White 《Environmental Geology》1997,30(1-2):46-58
Chemical reactions pertinent to karst systems divide broadly into (a) speciation reactions within aqueous solutions, (b) dissolution/precipitation and other acid/base reactions between aqueous solutions and solid minerals, and (c) redox reactions involving various carbon and sulfur-bearing species. As a backdrop against which other chemistry can be evaluated, selected phase diagrams and equilibrium speciation diagrams were calculated for the system Ca—Mg—O—H—C—S. The kinetics of reactions within this system span time scales from milliseconds for homogeneous reactions in solution through hundreds of hours for carbonate mineral dissolution reactions, to geologic time scales for reactions such as the aragonite/calcite inversion or the oxidation/reduction of native sulfur. In purely inorganic systems, kinetic barriers, typically on the order of tens of kJ/mole, are set by nucleation processes and by activated complex formation. Biological processes impact the purely inorganic chemistry by the following mechanisms: (a) Secretions and waste products from biological activity or consumption of CO2 by organisms changes the chemistry in the microenvironments of reaction surfaces. Oxidation potentials, pH, and ion activities may be modified, thus shifting equilibria. (b) Reaction rates may be increased due to modification of activated complexes and thus the activation barriers to reaction. (c) Organic compounds or microorganisms may act as substrates, thus lowering nucleation barriers. The preservation of microorganisms in cave deposits does not necessarily prove a cause and effect relationship. 相似文献
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内蒙古阿巴嘎旗奥陶纪岩体的发现及地质意义 总被引：4，自引：0，他引：4
阿巴嘎旗格日敖包岩体位于贺根山断裂带北侧,为一个复式岩体,由石英闪长岩、花岗闪长岩和黑云母二长花岗岩组成,主体为二长花岗岩。采用LA--MC--ICP--MS 锆石U--Pb 定年方法,获得黑云母二长花岗岩206Pb /238U 年龄为449 ± 3. 0 Ma,形成时代为晚奥陶世。岩石为高钾钙碱性系列,轻稀土富集,微量元素Ba、Sr、Nb、Ta 、P、Ti 亏损,Rb 、Th、U、K、Nd、Zr 等元素富集,表明其形成于活动大陆边缘环境。其形成可能与苏尼特左旗南侧俯冲事件有关。 相似文献
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内蒙古海拉尔盆地大磨拐河组孢粉组合 总被引：13，自引：1，他引：13
海拉尔盆地大磨拐河组自下而上可以划分出两个孢粉组合 :哈氏三角孢 -微细云杉粉 ( Deltoidospora hallii-Piceaepollenites exilioides)组合和澳洲无突肋纹孢 -卵形光面单缝孢 ( Cicatricosisporites australiensis- L aevigato-sporites ovatus)组合 ,分别分布于大磨拐河组一段和二段 ,组合特征明显 ,可以作为研究区内地层划分对比的生物地层学依据之一。两个孢粉组合中见有属种繁多的海金沙科孢子及其他繁盛于早白垩世的孢子花粉 ,结合在数以千计的岩心样品中没有发现可靠的早期被子植物花粉的情况分析 ,推测产这两个孢粉组合的大磨拐河组的地质时代为早白垩世凡兰吟期—欧特里沃期 ( Valanginian— Hauterivian) ,不排除部分进入巴列姆期 ( Barrem ian)的可能 相似文献
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V.Yu. Timofeev D.G. Ardyukov V.M. Solov'ev S.V. Shibaev A.F. Petrov P.Yu. Gornov N.V. Shestakov E.V. Boiko A.V. Timofeev 《Russian Geology and Geophysics》2012,53(4):376-391
The recent geodynamics of the Far East region of Russia is considered, where three large tectonic plates converge—Eurasian, North American, and Pacific, as well as several microplates—Okhotsk, Bering, and Amurian—have been hypothesized to exist. The available data on the position of the plate boundaries, the relative plate rotation poles, and the regional seismicity were analyzed, and parameters of plate motion models for northeastern Russia were determined in this study. The regional deep structure was investigated, using data obtained by different geophysical methods. The results of observations of the Magadan–Vrangel Island profile by deep seismic sounding (DSS), common-depth point (CDP) method, and correlation refraction method (CRM) are presented. 相似文献
15.
胶东海阳所堆积辉长岩的变质反应结构、石榴石形成及P—T演化 总被引：5，自引：0，他引：5
海阳所堆积辉长岩由橄长岩、橄榄辉长岩和辉长岩组成。在橄长岩和橄榄辉长岩中发育有典型的变质反应结构：主要为橄榄石与斜长石之间形成由斜方辉石、尖晶石、角闪石和石榴石等矿物组成的多期次次变边，并有三个不同世代变质矿物，早期Cpx＋Opx＋Spl，中期Amp，晚期Grt；期次是钛铁矿与斜长石之间形成石榴石次变边，相对比较简单，只有一个世代变质矿物，为Grt＋Amp＋Rut或Grt＋Rut岩中石榴石是通过斜长石与角闪石或斜长石与钛铁矿之间的变质反应形成的，虽为峰值变质作用的产物，但变质反应的期次及类型不同导致了所形成石榴石的温度和压力有所不同。堆积辉长岩形成演化的温压计算表明，堆积辉长岩在经过近等压降温的岩浆作用之后的变质作用早期，仍为近等压降温，而晚期则表现为近等温升压。这一特殊的P－T演化可能反映了堆积辉长冷侵位与深俯冲特征。 相似文献
16.
《《地质学报》英文版》1999,73(4):488-491
The Reservior Characteristics of Lower Ordovician Dolomites Below Pre-Mesozoic Unconformity in Yakela Fault-convex, Tarim Basin The Blueschist Belt in the Shuanghu Region, Central-Northern Tibet and Its Tectonic Implications Reef Palaeopool and Prediction of Buried Reefs in the Lower Permian Series from Shiwandashan Basin of Guangri Province Geochemistry of Rare Earth Elements in Late Paleozoic Coals in the North China Phase Transition and Composition Change of Minerals from Melting Experiment of Two Kinds of Metamorphics in Fuping Group, Pingshan, Hebei Province, China Palaeoecology and Palaeoenvironment of the Jehol Biota — A Palaeoecological and Palaeoenvironmental Reconstruction of Conchostracan Palaeocommunities in the Northern Hebei-Western Liaoning Area Research on Micro-FT.IR of Macerals of C-P Coals in the Bohal Bay Basin Self-similar Texture of the Mid—Longling—Ruili Strike-Slip System and the Location of Hydrothermal Deposits Metamorphism of the Eclogites from the ZK703 drillhole in Donghai, South Sulu (Jiangsu-Shandong) Ultrahigh-pressure Metamorphic Belt, Eastern China 相似文献
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《International Geology Review》2012,54(1):3-10
At the base of the sedimentary section of the Timan-Pechora basin are Late Precambrian rifts, which are filled by unmetamorphosed sedimentary rocks 10 km and more than 10 km thick. The upper parts of these rift deposits have potential for gas. Structurally the Phanerozoic sedimen tary fill of the basin is mildly deformed in the west and central parts into several broad depressions and more narrow intervening highs. The eastern part is strongly deformed by overthrusts that were emplaced in the Late Paleozoic in connection with development of the Ural fold belt. Eight oil-gas plays are recognized in the basin: 1—Ordovician-Lower Devonian, 2—Middle Devonian-lower Frasnian, 3—upper Frasnian-Tournaisian, 4—Lower Carboniferous, 5—upper Visean-Lower Permian, 6—Lower Permian, 7—Upper Permian, and 8—Triassic. The promising oil-gas basin is of great interest for global stratigraphy and tectonics as well as for petroleum exploration. 相似文献
18.
海拉尔盆地海参1井伊敏组孢粉组合的地层意义 总被引：3，自引：0，他引：3
海参1井伊敏组孢粉化石异常丰富,自下而上可以划分出3个孢粉组合:Impardecispora-Cyathidites-Clavatipollenites组合,Stereisporites-Deltoidospora-Asteropollis组合,Appendicisporites-Asteropollis-Tricolpites组合,分别分布于伊敏组一段、二段和三段,组合特征明显,是海拉尔盆地乌尔逊凹陷划分伊敏组与大磨拐河组的重要生物依据之一,更是伊敏组内三段划分和井间对比的生物依据之一。3个孢粉组合中见有属种繁多的海金沙科孢子及其他繁盛于早白垩世中晚期的孢子花粉,结合在绝大多数样品中发现的早期被子植物花粉的情况分析,推测含这3个孢粉组合的伊敏组地质时代为早白垩世巴列姆期—早阿尔必期(Barremian—Early Albian)。 相似文献
19.
早三叠世时期频繁的火山事件是导致全球性气候和海洋环境异常的主要原因,前人对早三叠世重要界线时期的火山事件地层开展了大量研究,但对典型界线时期以外的其他火山事件地层却鲜有报道。本文以上扬子西南普宜地区嘉陵江组两件沉凝灰岩为研究对象开展了岩石学、岩相学、锆石年代学及微量元素组合特征等方面的研究。沉凝灰岩样品具有典型岩浆锆石的内部结构和微量元素组合特征,两组沉凝灰岩锆石谐和年龄分别为250.6±0.6 Ma和249.1±0.8 Ma,代表了母岩岩浆中新生锆石的结晶年龄。沉凝灰岩母岩主要以酸性花岗岩类为主,次为中性正长岩类和少量基性岩类。嘉陵江组沉凝灰岩与二叠系—三叠系界线(PTB)凝灰岩及Olenekian—Anisian界线(OAB)绿豆岩具有同源性,形成于活动大陆边缘的碰撞造山环境,源区很可能位于中越边境地区长山构造岩浆带—十万大山火山带,且在陆壳碰撞过程中源区地壳处于持续的增厚阶段,下地壳增厚部位的部分熔融形成补给岩浆上涌并使早期结晶矿物发生了部分熔蚀。本文嘉陵江组沉凝灰岩样品250.6±0.6 Ma年龄对应着Smithian—Spathian界线时期的全球性降温及短期生物复苏事件;249.1±0.8 Ma年龄的样品对应Spathian亚阶中期极端高温气候和生物再次灭绝事件,再次证明了早三叠世时期频繁的火山活动是导致气候改变和生物周而复始新生和灭绝的重要因素。其原因可能是阳伞效应和温室效应等因素综合反馈的结果,但具体证据仍需要将来更多学科综合研究成果的约束。 相似文献
20.
Syed Hamidullah 《地学前缘》2000,(Z1)
GEOLOGY AND MINERAL CHEMISTRY OF THE DEOSAI VOLCANICS, BALTISTAN, N. PAKISTAN 相似文献