影响塔里木盆地西部碎屑储集岩物性因素分析     

王琪  史基安  张晓宝 《新疆地质》2001,19(2):102-106

在塔里木盆地西部形成、演化的宏观背景控制下，碎屑储集岩本身的骨架颗粒成分、物理化学性质以及填隙物成分和含量等成为影响研究区碎屑储集岩物性的主要内在因素。通过统计不同时代碎屑岩中刚性、塑性和半塑性骨架颗粒含量，表明志留、泥盆系岩屑砂岩中较高的半塑性、塑性颗粒含量和机械压实作用是导致其物性变差的最主要原因。砂岩填隙物中泥质基含量增加与颗粒间接触强度之间存在良好的正相关性。而碳酸盐含量与砂岩孔隙度间的相关分析表明：该区砂岩孔隙间的碳酸盐矿物主要起堵塞孔隙的作用。将成岩作用划分为建设性成岩作用和破坏性成岩作用两大类，有利于从宏观上分析成岩作用对储集的影响。  相似文献   

秦岭造山带沉积物源地球化学研究及其构造意义   总被引：2，自引：2，他引：2  

欧阳建平  张本仁 《地球科学》1996,21(5):464-468

在秦岭造山带内，由前寒武纪基底岩层组成的隆起区和由显生宙地层构造的沉积盆地广泛共存，不同构造单元，不同地段的前寒武纪地层在Ｔｈ等微量元素和Ｓｍ／Ｎｄ比值特征上明显不同，通过对比不同时代的显生宙沉积地层与相关前寒武纪地层之间Ｔｈ含量和Ｓｍ／Ｎｄ比值，研究了各沉积小区碎屑沉积物随时代变化而发生的物源变化，由此讨论了南，北秦岭之间以及与扬子北缘之间前寒武纪基底抬升和块体聚会的时限。  相似文献   

Magnetic fabric and its significance in the Florianópolis dyke swarm, southern Brazil     

Maria Irene Bartolomeu Raposo 《Geophysical Journal International》1997,131(1):159-170

Magnetic fabric was determined by applying the anisotropy from the low-field magnetic susceptibility (AMS) technique in 62 mafic dykes from the Mesozoic Florianópolis (Santa Catarina Island) dyke swarm, southern Brazil. These dykes cut the crystalline basement rocks, which are mainly Proterozoic. They are vertical or subvertical in dip and trend mainly NE, although NW-trending dykes are also found. Dykes are tholeiitic in composition and are geochemically similar to those from the Ponta Grossa swarm. Thicknesses vary from 0.3 to 60 m. Polished sections show that titanomagnetites carry the AMS in these dykes. Hysteresis parameters show that the magnetic minerals fall in the PSD range. Two types of magnetic fabric are recognized. Type I is characterized by K ₁- K ₂ parallel to the dyke wall, representing magma flow within the dykes; type II, with K ₁- K ₃ parallel to the dyke wall, was found in four dykes. Type I is found in 94 per cent of the dykes, and approximately 20 per cent of these have K ₁ inclinations of less than 30°, suggesting horizontal or subhorizontal flow. About 80 per cent have K ₁ inclinations of greater than 30°, due to inclined to vertical flow. The comparison of AMS studies from both the Florianópolis and the Ponta Grossa dykes suggests a source position closer to Santa Catarina Island than the Ponta Grossa arch.  相似文献   

淮北煤田南部新生界底部松散沉积物沉积特征及古地理意义   总被引：1，自引：0，他引：1  

严家平  王祯伟 《沉积与特提斯地质》1997,17(2):47-52

通过对淮北煤田市部新生界底部松散沉积的沉积特征研究，初步得出结论，位于同一煤田的宿县矿区和临涣矿区的沉积物结构和矿物成份特征差别较大，导致这一差别的主要原因是物源区与岩性的不同，以及古地理条件的差别．在临涣矿区，以石英、长石和少量碳酸盐矿物组合以及以锆石、电气石为主的重矿物组合，反映了来自于矿区北部的中性闪长岩岩体的风化。而以含大量灰岩砾石，和以石英、燧石为辅的碎屑组成则说明了宿县矿区东部、北部奥陶系地层和煤系地层本身遭受了强烈风化。沉积物的复杂结构特征和矿物成份特征反映了基岩地貌南低北高，源区遭受的强烈物理风化作用以及在短距离内快速搬运和多源沉积特征。  相似文献   

海洋碎屑沉积物的分类   总被引：6，自引：0，他引：6  

何起祥  李绍全  刘健 《海洋地质与第四纪地质》2002,22(1):115-121

比较研究了以Shepard和Folk等为的海洋碎屑沉积物分类方案，提出沉积物的分类应兼具描述与解释两种功能。Shepard分类已经过时，Folk等的分类方案有显著的优点，但亦有不足之处，应予以改进。沉积物的成分分类受到忽视的现象应予以改变。为适应我国海洋地质测量的需要，作者提出了一套结构分类与成分分类相匹配的多重分类系统，解决了海洋碎屑沉积物分类中的矛盾和问题。  相似文献   

Application of Explosion Method to Soft Foundation Treatment of Great-West Dyke,Lianyungang Port     

Liu Huairen Engineer  Fifth Engineering Company  Third Navigational Engineering Bureau  The Ministry of Communications  Lianyungang 《中国海洋工程》1995,(2)

Explosion for the treatment of underwater soft foundation is a technique newly developed in China. This paper describes the application of the method of explosion to underwater soft foundation treatment of the Great-West Dyke, Lianyungang Port, including the technical characteristics and the effect, selection of explosion parameters, workmanship of construction, requirements of quality and inspection, and the like.  相似文献   

白云鄂博矿床碳酸岩墙/脉和赋矿白云岩中流体包裹体研究   总被引：2，自引：0，他引：2  

秦朝建裘愉卓  周国富王中刚张台荣  肖国望 《岩石学报》2007,23(1):161-168

Fluid inclusion study has been carried out for the carbonatite dykes/veins and the ore-hosted dolostone of the Bayan Obo superlarge REE-Fe-Nb deposit in order to provide the evidence and constraint for their origin.Based on the detailed geological observation and mineralogical investigation,the heating and cooling stage and laser Raman spectroscopy were mainly used for the laboratory work of this study.Following results have been obtained:(1)The discovery of melt and melt-fluid inclusions from carbonatite dykes/veins in the Dulahara and Jianshan Mountains,combined with the fine-grained(aplitic)texture of rocks,as well as the types and features of fluid inclusions such as CO_2 enrichment,higher homogenization temperature,provides a direct evidence for the magmatic origin of these dykes/veins.(2)The carbonatite dykes/veins distributed in two regions,nearby the axis of the Kuangou anticline and in the east to Bayan Obo town,mainly show coarse-grained texture.No melt inclusion was found,and the fluid inclusions possess features of less CO_2,lower homogenization temperature and higher salinity.They are tentatively identified as veins formed by some carbonate-rich hydrothermal solution.(3)Bedding carbonate layers/lens within the hanging wall and foot wall of ore-hosted dolostone,previously recognized as of magmatic origin,mainly composed by dolomite.The existence of single phase pure aqueous inclusions with very low homogenization temperature indicates their sedimentary origin.(4)The ore-hosted dolostone possesses apparent bedding and laminated structures.No melt inclusion was found,but,both single phase pure aqueous inclusions and CO_2 bearing multi-phase fluid inclusions coexisted in dolostones.In the direction towards ore-bodies,the homogenization temperature and CO_2 contents of fluid inclusion show an increasing tendency.It indicates the sedimentary origin of dolostone superimposed by late fluid metasomatism.  相似文献   

Interrelations between coeval mafic and A-type silicic magmas from composite dykes in a bimodal suite of southern Israel, northernmost Arabian–Nubian Shield: Geochemical and isotope constraints     

Y. Katzir  B.A. Litvinovsky  B.M. Jahn  M. Eyal  A.N. Zanvilevich  J.W. Valley  Ye. Vapnik  Y. Beeri  M.J. Spicuzza 《Lithos》2007,97(3-4):336-364

Late Neoproterozoic bimodal dyke suites are abundant in the Arabian–Nubian Shield. In southern Israel this suite includes dominant alkaline quartz porphyry dykes, rare mafic dykes, and numerous composite dykes with felsic interiors and mafic margins. The quartz porphyry chemically corresponds to A-type granite. Composite dykes with either abrupt or gradational contacts between the felsic and mafic rocks bear field, petrographic and chemical evidence for coexistence and mixing of basaltic and rhyolitic magmas. Mixing and formation of hybrid intermediate magmas commenced at depth and continued during emplacement of the dykes. Oxygen isotope ratios of alkali feldspar in quartz porphyry (13 to 15‰) and of plagioclase in trachydolerite (10–11‰) are much higher than their initial magmatic ratios predicted by equilibrium with unaltered quartz (8 to 9‰) and clinopyroxene (5.8‰). The elevation of δ¹⁸O in alkali feldspar and plagioclase, and extensive turbidization and sericitization call for post-magmatic low-temperature (≤ 100 °C) water–rock interaction. Hydrous alteration of alkali feldspar, the major carrier of Rb and Sr in the quartz–porphyry, also accounts for the highly variable and unusually high I(Sr) of 0.71253 to 0.73648.

The initial ¹⁴³Nd/¹⁴⁴Nd ratios, expressed by ε_Nd(T) values, are probably unaltered and show small variation in mafic and felsic rocks within a narrow range from + 1.4 to + 3.3. The Nd isotope signature suggests either a common mantle source for the mafic and silicic magmas or a juvenile crustal source for the felsic rocks (metamorphic rocks from the Elat area). However, oxygen isotope ratios of zircon in quartz porphyry [δ¹⁸O(Zrn) = 6.5 to 7.2‰] reveal significant crustal contribution to the rhyolite magma, suggesting that mafic and A-type silicic magmas are not co-genetic, although coeval. Comparison of ¹⁸O/¹⁶O ratios in zircon allows to distinguish two groups of A-type granites in the region: those with mantle-derived source, δ¹⁸O(Zrn) ranging from 5.5 to 5.8‰ (Timna and Katharina granitoids) and those with major contribution of the modified juvenile crustal component, δ¹⁸O(Zrn) varying from 6.5 to 7.2‰ (Elat quartz porphyry dykes and the Yehoshafat alkaline granite). This suggests that A-type silicic magmas in the northern ANS originated by alternative processes almost coevally.  相似文献   

北京西山南窖地区南东东110°～120°拉伸线理形成时间的年代学制约     

王瑜  李锦轶 《岩石学报》2007,23(3):617-624

本文简要报导位于北京西山房山岩体以西约15km左右的南窖闪长岩脉形成的锆石U-Pb年龄,以及区内变形岩层中同变形的白云母和绢云母矿物的40Ar/39Ar年龄.在野外构造研究、室内岩石及显微构造分析基础上,获得细粒闪长岩岩脉锆石U-Pb年龄为136±1Ma,并且该岩脉受到后期构造片理化的改造.区内变形岩层中所发育的南东东110°～120°矿物拉伸线理及相关的“褶叠层”中同变形的白云母、绢云母的^40Ar/^39Ar坪年龄为133±1～127±1Ma.显然这些变形并非形成于三叠纪或“印支期”,而是形成于大规模的向北西方向强烈的挤压变形之后,与相邻区域的岩浆热作用同期或稍晚.这些构造-热年代学证据对于区内构造格局的形成与演化是一个重要的约束.  相似文献   

冀东都山花岗岩基及相关花岗斑岩脉SHRIMP锆石U-Pb法定年及其意义   总被引：22，自引：1，他引：22  

罗镇宽  苗来成  关康  裘有守  Y.M.Qiu  N.J.McNaughton  D.I.Groves 《地球化学》2003,32(2):173-180

都山花岗岩体是冀东地区最大的花岗岩基,在其周边产有众多与其有关的“卫星”岩体和岩脉。采用先进的SHRIMP定年方法,测得都山花岗岩基的206Pb/238U年龄为(223±2)Ma,其东侧三家金矿区成矿前花岗斑岩脉的年龄为(222±4)Ma,二者在误差范围内一致,花岗岩基和花岗斑岩脉可视为同一次岩浆活动的产物。这种晚古生代末—早中生代印支期的花岗岩在华北克拉通北缘广泛分布,显示它是一次重要的构造-岩浆事件的产物。根据岩石化学和微量元素特征及有关判别图,都山等印支期花岗岩可能属中朝板块与西伯利亚板块碰撞造山作用的后碰撞花岗岩。花岗斑岩脉中发现有新太古代的继承锆石,表明花岗斑岩的部分源岩为区内新太古代八道河岩群变质岩。都山花岗岩与花岗斑岩脉同时、同源,推测其源岩也有部分为新太古代结晶基底的变质岩。花岗岩与区内金矿化有较大的时差,两者不存在直接的成因联系,仅表明成矿晚于早中生代印支期。  相似文献