共查询到20条相似文献，搜索用时 703 毫秒
1.
精细划分变质岩储层类型,并建立不同类型储层与产能间的关系,对变质岩油田高效勘探开发具有重要意义。基于岩心、薄片、物性、常规测井、成像测井以及生产测井资料,深入剖析了渤海海域JZ25-1S油田太古宇潜山储层类型及其测井响应特征,重点探讨了不同类型储层的产能差异。结果表明：研究区主要发育风化壳型储层、内幕碎裂带型储层和内幕裂缝型储层,分别以溶蚀孔缝、破碎砾间孔以及构造裂缝为主要的储集空间类型,不同的储层具有不同的测井响应特征;定义单位厚度油产能大于2 m3/d为高效渗流储层,风化壳型储层与内幕碎裂带型储层为主要的高效渗流储层,内幕裂缝型储层的渗流能力变化较大;储层类型、裂缝密度、裂缝走向与最大主应力夹角等因素共同控制了变质岩储层的产能差异。 相似文献
2.
Alexandra Guedes Fernando Noronha A. Carmelo Prieto 《International Journal of Coal Geology》2005,62(4):291
Dispersed organic matter (DOM) concentrates of C-rich rocks from areas with different metamorphic characteristics were studied by organic petrography, X-ray diffraction (XRD) and micro-Raman spectroscopy analysis. The concentrates contain several types of DOM with different morphologies, reflectance, X-ray diffraction and micro-Raman characteristics.Four different morphological types were identified in the two studied areas. The different types have different distributions and their reflectance is quite variable in the four types, with a dominance of the highest reflectance values in the DOM from the area with the highest metamorphic grade.XRD analyses of samples from the areas reveal the presence of fine graphite together with non-graphitised carbons.The Raman spectral profiles show the usual bands G (1582 cm−1) and D1 (1350 cm−1), on the first-order Raman spectrum, and S1 (2700 cm−1) on the second-order spectrum. Additional weaker bands, D2 (1620 cm−1), and more rarely D3 (1500 cm−1) and S2 (2900 cm−1), are present. These are characteristic for disordered carbons in the different types of DOM and in both studied areas. However, the Raman parameters (D1/G intensity area ratio and the frequency and width of G band) indicate variable degrees of organisation in all DOM types.The existence of different types of DOM with different degrees of ordering in the same lithologies and metamorphic grade seems to be related to different organic precursors, as they are graphitised to different extents under the same metamorphic conditions. However, in the same lithologies and metamorphic grade, the existence of various stages of graphitisation within the same type of DOM can only be explained though the interaction of DOM with the metamorphic fluids present in the rocks. The ordering graphitisation process may be due to the existence of metamorphic fluid circulation events with a variety of compositions. 相似文献
3.
The Portage Lake Lava Series of the Keweenaw Peninsula, northernMichigan, is composed of over 5000 m of tholeiitic lava flows.Chemical and petrologic study of thin undifferentiated flowsfrom this sequence shows that the bulk of the flows are olivinetholeiites; highly ironenriched tholeiites comprise up to 10per cent of the volume. In addition, a few small rhyolitic intrusives,exceedingly rich in alkalis, are exposed in the region. Duringburial the amygdular tops of each flow acted as channelwaysfor migrating fluids during a regional metamorphic event thatproduced a progressive sequence of secondary phases within theflow tops. In the upper part of the stratigraphic section, laumontite,analcime, albite, and chlorite dominate assemblages characteristicof the zeolite facies. Stratigraphically deeper. flow tops arecharacterized by metamorphic assemblages of the prehnite-pumpellyitefacies. Within the higher rank facies, rocks along fractureshave been transformed to calcium-rich monomineralic domains(metadomains) of epidote or pumpellyite. These metadomains gradeoutward through incompletely reconstituted rocks containingalbitized feldspars, and finally, in flow centers, to basaltdisplaying few signs of mineralogical readjustment. Extremechemical disparity exists within the altered flow tops, particularlywith respect to calcium and sodium content. Calculations revealthat bulk compositions of metamorphically adjusted flow topsare similar to unaltered basalts. Thus, the chemical variationdisplayed by the metamorphic rock types resulted from localizedmetamorphic differentiation. The Keweenawan sequence displays progressive dehydration fromthe top to the base of the stratigraphic section. At the topchlorite (H2O = 12 per cent) and pumpellyite (H2O = 6 per cent)metadomains formed by dehydration. The fact that most of theserocks were hydrated strongly suggests that fluid pressures wereless than total pressures during the metamorphic event. In rocksundergoing hydration in the uper part of the stratigraphic section,therefore, water pressures decreased away from channelways.As a result, the most hydrous rock types formed in these regions.Conversely, in rock undergoing dehydration water pressures increasedaway from channelwasys, so that the most dehydrated rocks formedin such regions. Water content of an individual rock is dependenton both position in the stratigraphic pile and position withrespect to fluid channelways. 相似文献
4.
大巩山金矿床在大地构造上处于中朝地块东南缘的蚌埠隆起东段,郯庐断裂带的两条次级断裂——朱顶-石门山断裂和五河-红心铺断裂所夹持的部位.矿区内出露五河群最下部的西堆组,并构成蚌埠复背斜的核部,断裂有北北东向、南北向、北西西向和北东向4组.南北向断裂在宏观上控制金矿体的产状和规模.向西缓倾的南北向断裂控制石英脉型金矿体的发育和产出,而向东陡倾的南北向断裂控制构造蚀变岩型金矿体的产出,这是与不同时期南北向断裂成生演化和岩浆活动作用密切相关的,也与该区及邻区成矿年代学研究成果相一致. 相似文献
5.
通过矿石中黄铁矿的ΔFe/ΔS值和Co/Ni值的分析,确定了内蒙古十八倾壕金矿床两种矿体-糜棱岩型矿体和石英脉型矿体中黄铁矿组分的不同特点：糜棱岩型矿体的黄铁矿属于贫铁贫硫型,Co/Ni值小于1;石英脉型矿体的黄铁矿属于贫铁富硫型,Co/Ni值大于1。这与该矿床两种矿石的S和Pb同位素的组成特征相呼应：前者反映同韧性剪切作用有关的变质热液成矿;后者反映岩浆热液成矿作用。这又一次在物质成分上证明了十八倾壕金矿床是两次成矿作用叠加的结果,同时也证明了前人提出的“不同层次叠加构造控矿”的观点。 相似文献
6.
E.M. Lazko V.P. Kiriluk V.I. Lashmanov A.M. Lyssak A.A. Sivoronov G.M. Jatsenko 《Precambrian Research》1978,6(2):223-233
Soviet geologists consider the Precambrian to be divided into two groups — Archaean and Proterozoic; but such a division is unsatisfactory. A major unconformity separates Proterozoic volcanic and sedimentary formations from an underlying sequence that contains two supergroups of supercrustal formations. The oldest of these is unanimously considered to be Archaean. Rocks of that supergroup play an essential part in the composition of the Baltic, Ukrainian, Aldan and Anabar Shields and of the ancient fold belts of the East-European and Siberian platforms.Distinctive features in the composition, tectonic structure, metamorphism and metallogeny of Archaean complexes lead to the conclusion that they were formed in specifically mobile areas, different from geosynclinal areas.The other supergroup of high-grade metamorphic rocks has no clear place in the accepted two-fold stratigraphic scheme of the Precambrian, and it is considered sometimes to be Archaean and sometimes to be Early Proterozoic. We propose restoring the forgotten name “Eozoic” for that supergroup. Eozoic complexes are characterized by peculiarities of composition and inner structure, which signify changes in the tectonic regime of the earth at the lower and upper boundaries of the Eozoic Supergroup. These peculiarities give grounds for distinguishing the Eozoic Supergroup as an independent stratigraphic division.The Stanovoy Complex of the southern part of the Aldan Shield is a stratotype for the Eozoic Supergroup. Many well-known stratigraphic subdivisions of the Siberian Platform (e.g., the Eniseiskaya, the Birusinskaya series and others), the Taratash Complex of the Urals, the Goranskaya and Shahdarinskaya series of the South-West Pamir, the Tikitch complex and Aulskaya series of the Ukrainian Shield, and in part the Belomorsky Complex of the Baltic Shield, as well as some others, are also Eozoic.The Eozoic complexes are characterized by the following specific features: only some supercrustal formations are typical for them; the small number of rock types which have a total thickness about 5–6 km; relatively monotonous mineral composition of the rocks; variable quantitative ratios of rocks; absence of contrasting marker beds; regional metamorphism and ultrametamorphism in the amphibolite facies; wide development of ultrametamorphic granitoids and migmatites; distinct tectonic differentiations of the basin of sedimentation.Dates determined by isotopic analyses, which mostly reflect the metamorphism of the deposits, fall predominantly in the range 2600–3100 Ma. 相似文献
7.
The rock types and mineral compositions of the Mt. Namjagbarwa region have been studied. Petro-chemical analyses and calculations
show that there are two types of metamorphic rock: ortho-and para-rocks in this region with the former being dominant. The
results of trace element and REE analyses indicate that the original rocks are of multiple source with the continental tholeiites
as the main source. 相似文献
8.
《地学前缘(英文版)》2016,7(1)
The formation of continents involves a combination of magmatic and metamorphic processes. These processes become indistinguishable at the crust-mantle interface, where the pressure-temperature(P-T)conditions of(ultra) high-temperature granulites and magmatic rocks are similar. Continents grow laterally, by magmatic activity above oceanic subduction zones(high-pressure metamorphic setting), and vertically by accumulation of mantle-derived magmas at the base of the crust(high-temperature metamorphic setting). Both events are separated from each other in time; the vertical accretion postdating lateral growth by several tens of millions of years. Fluid inclusion data indicate that during the high-temperature metamorphic episode the granulite lower crust is invaded by large amounts of low H_2O-activity fluids including high-density CO_2 and concentrated saline solutions(brines). These fluids are expelled from the lower crust to higher crustal levels at the end of the high-grade metamorphic event. The final amalgamation of supercontinents corresponds to episodes of ultra-high temperature metamorphism involving large-scale accumulation of these low-water activity fluids in the lower crust.This accumulation causes tectonic instability, which together with the heat input from the subcontinental lithospheric mantle, leads to the disruption of supercontinents. Thus, the fragmentation of a supercontinent is already programmed at the time of its amalgamation. 相似文献
9.
The method of earthquake-generated converted waves which is based on the simultaneous recording of longitudinal (P), transverse (S) and converted (PS and SP) waves has been used in the U.S.S.R. since 1956. Converted phases generated at crustal and upper-mantle discontinuities in the seismic focal area are carefully analyzed. In this paper some dynamic characteristics of transmitted PS- and SP-waves arising at different types of boundaries are described.
From a comparison of the properties of the recorded converted waves with the results of theoretical computations conclusions can be drawn with regard to the possible structure of the “exchange” (conversion) boundaries. Seismic cross-sections are presented which illustrate the high effectiveness of the method in regional investigations of crustal structure. Owing to its significance and the multitude of observations (over 22,000 km of observation lines) the method is one of the principal seismic techniques used in the U.S.S.R. which give quantitative information on crustal layering. 相似文献
10.
安徽大别山腹地中生代火山岩的发现及其地质意义 总被引：10，自引：0，他引：10
近期作者等在大别山腹地开展１∶５万区调过程时,于中深变质岩中发现一套中生代火山岩系;主要岩石类型为石英安山质晶屑凝灰熔岩、火山角砾岩及凝灰岩。通过详细观察、追索,其中查明火山岩系的空间分布及其与围岩的接触关系。对认识大别山的构造演化及热隆—顶蚀作用、超高压变质带的形成、折返机制等提供新的依据。 相似文献
11.
新疆西准噶尔地区两类蛇绿岩的地质特征及其成因研究 总被引：5，自引：0，他引：5
本文将西准噶尔地区蛇绿岩分为两类:一类是变质橄榄岩 橄长岩 辉长岩岩石组合(简称PTG系列);另一类则是变质橄榄岩 辉石岩 辉长岩岩石组合(简称PPG系列)。前者以达拉布特、和布克赛尔蛇绿岩带为代表,后者以唐巴勒、玛依勒山蛇绿岩带为代表。PTG系列遵循富Al的演化趋势,而PPG系列则遵循富Ca的演化趋势;从而造成两类蛇绿岩之间在岩石组合、矿物学、岩石化学、稀土元素等地球化学以及所含铬铁矿床的种属上均有明显的差异。 两类蛇绿岩中变质橄榄岩的成因机制是上地幔岩部分熔融,两者之间的差异则是由部分熔融程度决定的。而壳层岩石(指堆积杂岩、岩墙杂岩、熔岩)则是由岩浆结晶作用形成的;堆积杂岩中出现辉石岩 辉长岩和橄长岩 辉长岩的不同岩石组合则与堆积岩岩浆房出露的深度和氧化状态有关。 相似文献
12.
We review petrologic observations of reaction textures from high-grade rocks that suggest the passage of fluids with variable alkali activities. Development of these reaction textures is accompanied by regular compositional variations in plagioclase, pyroxenes, biotite, amphibole and garnet. The textures are interpreted in terms of exchange and net-transfer reactions controlled by the K and Na activities in the fluids. On the regional scale, these reactions operate in granitized, charnockitized, syenitized etc. shear zones within high-grade complexes. Thermodynamic calculations in simple chemical systems show that changes in mineral assemblages, including the transition from the hydrous to the anhydrous ones, may occur at constant pressure and temperature due only to variations in the H2O and the alkali activities. A simple procedure for estimating the activity of the two major alkali oxides, K2O and Na2O, is imple- mented in the TWQ software. Examples of calculations are presented for well-documented dehydration zones from South Africa, southern India, and Sri Lanka. The calculations have revealed two end-member regimes of alkalis during specific metamorphic processes： rock buffered, which is characteristic for the precursor rocks containing two feldspars, and fluid-buffered for the precursor rocks without K-feldspar. The observed reaction textures and the results of thermodynamic modeling are compared with the results of available experimental studies on the interaction of the alkali chloride and carbonate-bearing fluids with metamorphic rocks at mid-crustal conditions. The experiments show the complex effect of alkali activities in the fluid phase on the mineral assemblages. Both thermodynamic calculations and experiments closely reproduce paragenetic relations theoretically predicted by D.S. Korzhinskii in the 1940s. 相似文献
13.
The Semail ophiolite of Oman and the United Arab Emirates(UAE) provides the best preserved large slice of oceanic lithosphere exposed on the continental crust,and offers unique opportunities to study processes of ocean crust formation,subduction initiation and obduction.Metamorphic rocks exposed in the eastern UAE have traditionally been interpreted as a metamorphic sole to the Semail ophiolite.However,there has been some debate over the possibility that the exposures contain components of older Arabian continental crust.To help answer this question,presented here are new zircon and rutile U-Pb geochronological data from various units of the metamorphic rocks.Zircon was absent in most samples.Those that yielded zircon and rutile provide dominant single age populations that are 95-93 Ma,partially overlapping with the known age of oceanic crust formation(96.5-94.5 Ma),and partially overlapping with cooling ages of the metamorphic rocks(95-90 Ma).The data are interpreted as dating high-grade metamorphism during subduction burial of the sediments into hot mantle lithosphere,and rapid cooling during their subsequent exhumation.A few discordant zircon ages,interpreted as late Neoproterozoic and younger,represent minor detrital input from the continent.No evidence is found in favour of the existence of older Arabian continental crust within the metamorphic rocks of the UAE. 相似文献
14.
《地学前缘(英文版)》2016,7(5)
U-Pb analyses were carried out on detrital zircon grains from major river-mouth sediments draining South Korea to infer provenance characteristics and the crustal growth history of the southern Korean Peninsula, using a laser ablation inductively coupled plasma mass spectrometer(LA-ICP-MS). The Korean Peninsula is located in the East Asian continental margin and mainly comprises three Precambrian massifs and two metamorphic belts in between them. We obtained 515 concordant to slightly discordant zircon ages ranging from ca. 3566 to ca. 48 Ma. Regardless of river-mouth location, predominance of Mesozoic(249e79 Ma) and Paleoproterozoic(2491e1691 Ma) ages with subordinate Archean ages indicates that the zircon ages reflect present exposures of plutonic/metamorphic rocks in the drainage basins of the South Korean rivers and the crustal growth of the southern Korean Peninsula was focused in these two periods. Comparison of detrital zircon-age data between the North and South Korean river sediments reveals that the Paleoproterozoic zircon age distributions of both regions are nearly identical,while the Neoproterozoice Paleozoic ages exist and the Mesozoic ages are dominant in southern Korean Peninsula. This result suggests that Precambrian terrains in Korea record the similar pre-Mesozoic magmatic history and that the influence of Mesozoic magmatism was mainly focused in South Korea. 相似文献
15.
青藏高原东南缘"三江"地区变质杂岩带中的岩石类型十分复杂,斜长角闪岩和含角闪石斜长片麻岩是本区常见的变质岩石类型。斜长角闪岩可进一步划分为由石榴辉石岩退变而成的和基性原岩经角闪岩相-麻粒岩相变质形成的两种类型。斜长角闪岩的SiO2平均含量50.0%,具有高铝低钛的特点,轻稀土元素相对富集,铕无异常或略具负异常,Zr含量较低,Zr/Y比值较小,其原岩的主微量元素组成具有岛弧玄武岩的特点,反映其原岩形成于俯冲碰撞的构造环境。含角闪石斜长片麻岩的SiO2平均含量63.64%,MgO和TiO2含量低,轻、重稀土元素分馏,轻稀土元素明显富集而重稀土元素相对亏损,具有中等负Eu异常,大离子亲石元素K、Rb、Ba、Th强烈富集,高场强元素Ti、Zr、Hf、Nb和Ta含量较低,其原岩具有安山质岩石或安山质/玄武质岩石的特点,主要形成于板块聚敛边缘的构造环境。 相似文献
16.
http://www.sciencedirect.com/science/article/pii/S1674987112000564 总被引：10，自引：0，他引：10
High-pressure（HP） granulites widely occur as enclaves within tonalite-trondhjemitegranodiorite （TTG） gneisses of the Early Precambrian metamorphic basement in the Shandong Peninsula, southeast part of the North China Craton（NCC）.Based on cathodoluminescence（CL）,laser Raman spectroscopy and in-situ U-Pb dating,we characterize the zircons from the HP granulites and group them into three main types:inherited（magmatic） zircon,HP metamorphic zircon and retrograde zircon.The inherited zircons with clear or weakly defined magmatic zoning contain inclusions of apatites,and 207Pb/206Pb ages of 2915—2890 Ma and 2763—2510 Ma,correlating with two magmatic events in the Archaean basement. The homogeneous HP metamorphic zircons contain index minerals of high-pressure metamorphism including garnet,clinopyroxene.plagioclase,quartz,rutile and apatite,and yield 207Pb/206Pb ages between 1900 and 1850 Ma,marking the timing of peak HP granulite fades metamorphism.The retrograde zircons contain inclusions of orthopyroxene.plagioclase.quartz,apatite and amphibole.and yield the youngest 207Pb/206Pb ages of 1840—1820 Ma among the three groups,which we correlate to the medium to low-pressure granulite fades retrograde metamorphism.The data presented in this study suggest subduction of Meso- and Neoarchean magmatic protoliths to lower crust depths where they were subjected to HP granulite facies metamorphism during Palaeoproterozoic（1900—1850 Ma）.Subsequently, the HP granulites were exhumated to upper crust levels,and were overprinted by medium to low-pressure granulite and amphibolite facies retrograde event at ca.1840—820 Ma. 相似文献
17.
中国变质核杂岩的基本特征 总被引：3，自引：2，他引：3
基于前人的研究基础之上 ,确立了中国变质核杂岩的三层结构 ,即盖层 (上部脆性变形层 )、滑脱层 (固态流变中间韧性层 )、核部 (变质核、同构造侵入岩 ) ,分析并总结了各层的主要特征。中国变质核杂岩的形成时间以燕山期为主 ,喜山期次之 ,还有晋宁期、加里东期、海西期以及印支期。依据中国变质核杂岩出露的大地构造位置 ,可分为板缘变质核杂岩和板内变质核杂岩两类 ,它们均与热异常和岩浆活动有密切的联系 ,变质核杂岩核部基本上都发生一期以上的岩体侵入 ,是找矿探矿的理想构造区。 相似文献
18.
新疆阿尔泰阿祖拜地区发育两种类型区域变质作用,第一种为区域低温动力变质作用,第二种为区域动力热流变质作用.阿祖拜地区递增变质带是后者的典型代表之一,从花岗岩体外接触带依次发育矽线石-堇青带、红柱石-十字石带、黑云母-石榴石带,递增变质作用强度呈逐渐减弱趋势.结合变形变质作用特征和同位素年龄,可识别出3个变形变质阶段.早期阶段以区域低温动力变质作用为主,形成绿片岩相变质岩石组合;峰期阶段为区域动力热流变质作用,形成典型的递增变质带;晚期阶段则属退化变质作用.不同变质作用类型代表了不同大地构造环境,记录了造山带演化历史年和动力学过程. 相似文献
19.
斜方角闪石组合的变质压力类型 总被引：1，自引：0，他引：1
斜方角闪石组合是前寒武纪变质岩系中的一种特殊的岩石类型，以富Mg、Al，贫Ca、K为特征，矿物组成为堇青石、斜方角闪石和富铝矿物如Al2SiO5、十字石、石榴石、斜长石、云母类和单斜角闪石类。其分布遍及欧亚及大洋洲各地的古老岩系中，在许多产地与硫化物矿床有密切关系。按其变质条件可以分为低压和高压两种类型：低压型以堇青石-直闪石-镁铁闪石组合为特征；高压型以蓝晶石、铝直闪石组合为特征，有时有石榴石。堇青石、十字石构成围绕蓝晶石周围的冠状体，成为变质地体经历近绝热抬升的极好证据。本文论述其特征矿物组合、结构的演化、所涉及的变质反应及其形成的构造环境。 相似文献
20.
巴罗型中压变质带与巴肯型低压高温变质带的成因与大陆板块边缘的碰撞造山及陆内造山作用之间有着紧密的联系。根据变质带的空间时间配置关系、压力类型、变质作用pTt轨迹、伴生的岩浆岩等等,可以区分出3种类型的大陆造山模式:弧-陆拼贴型、陆-陆碰撞型(可进一步分为中高压型碰撞造山带和双变质型山带型(paired metamorphic mountain belt)陆-陆碰撞带)、陆内造山地壳加厚-伸展型。巴罗型中压变质带普遍出现于地壳加厚-热弛豫的构造环境,但巴肯型低压变质带形成的构造背景及物理化学条件在不同的造山带有不同的表现形式,其热源至少有:壳内岩浆侵入或岩浆板底垫托、沉降盆地放射性同位素的衰变热、构造热穹隆、变质核杂岩、地下热流体传热等。大陆边缘造山带中巴罗型变质带的倒转以及板内造山带中变质带问断等现象与造山动力学过程密切相关,记录了造山过程中的重要的地质事件,也是探讨造山历史的理想场所。由于四川丹巴地区松潘—甘孜造山带形成于很独特的3个板块双极性构造环境,表现出与世界上典型造山带诸多相似的地方,如巴罗型中压变质带、巴肯型低压高温带同时在一系列变质穹隆中发育,但又有其特殊性和复杂性,如通常只发育在大陆边缘的倒转的巴罗带和陆内造山过程中的变质相间断同时出现,显然这与本? 相似文献