从原岩建造角度探讨辽河群的形成环境          下载免费PDF全文

翟富荣  梁帅  郭洪方 《地质找矿论丛》2016,31(4):550-554

文章通过对辽河群上百条实测剖面中岩石类型进行了加权平均统计,得出了辽河群中各种岩石类型的百分含量;对辽河群中已有的上千组岩石化学数据进行了筛选,选取具有代表性的94组数据,用以对辽河群原岩建造恢复和形成构造环境的讨论。认为辽河群的原岩建造为巨厚的陆源沉积碎屑岩—内源沉积碳酸盐岩(夹少量火山岩)建造,具有典型的大陆架沉积特征;这在威尔逊旋回中属于成年期洋盆(大西洋)阶段所独具的沉积特征,这个洋盆暂且称之为辽吉古元古洋。  相似文献   

北阿尔金早古生代构造体制转换的时限:来自花岗岩的证据   总被引：3，自引：0，他引：3  

孟令通  陈柏林  王永  孙岳  吴玉  张文高  何江涛 《大地构造与成矿学》2016,(2):295-307

北阿尔金造山带中的阿北花岗岩体出露于喀腊大湾与阿尔金北缘断裂交叉部位的东南侧,主要由黑云母二长花岗岩和似斑状二长花岗岩组成,二者岩石地球化学特征较为相似。锆石SHRIMP U-Pb定年结果表明黑云母二长花岗岩结晶年龄为427.3±5.7 Ma。阿北花岗岩体具有以下地球化学特征:1高SiO_2(68.68%~72.83%)、高碱(Na_2O+K_2O=6.52%~7.91%,Na2OK_2O)、准铝质(A/CNK≈1);2高Sr和LREE,低Y(10μg/g)和Yb(1μg/g);3高Sr/Y值(40);4非常弱甚至没有Eu负异常。这些特征表明阿北花岗岩体形成于加厚的镁铁质下地壳部分熔融,其源区残留了大量的石榴子石而不含斜长石;同时,岩浆在上升的过程中经历了分离结晶作用。结合前人研究成果,在440~420 Ma北阿尔金造山带中残留有加厚的镁铁质下地壳,而在420 Ma之后发生了广泛的下地壳拆离与减薄。也就是说,北阿尔金造山带构造体制转换的时限为440~420 Ma,伴随着阿北花岗岩体的侵位。  相似文献   

A Review of the Bentong-Raub Suture vis-à-vis New Insight of the Tectonic Evolution of Malay Peninsula,South East Asia     

Aftab Alam KHAN  Mustaffa Kamal SHUIB 《《地质学报》英文版》2016,90(5):1865-1886

Genesis of the so‐called Bentong‐Raub Suture of Malay Peninsula does not fit to the model of subduction‐related collision. It has evolved from transpression tectonics resulting closure and exhumation of the inland basin which underwent extensive back‐arc extension during Triassic. Crust having similar thickness (average ～35 km) below entire Malay Peninsula nagate collision of two separate continental blocks rather supports single continental block that collided with South China continental block during Permo‐Triassic. Westward subduction of intervening sea (Proto South China Sea) below Malay Peninsula resulted in widespread I‐ and S‐Type granitization and volcanism in the back‐arc basins during Triassic. Extensive occurrence of Permo‐Triassic Pahang volcanics of predominantly rhyolitic tuff suggest its derivation from back‐arc extension. Back‐arc extension, basin development and sedimentation of the central belt of the peninsula continued until Cretaceous. A‐Type granite of metaluminous to peraluminous character indicates their emplacement in an intraplate tectonic setting. Malay Peninsula suffered an anticlockwise rotation due to the rifting of Luconia–Dangerous Grounds from the east Asia in the Late Cretaceous–Early Tertiary. Extensive ductile and brittle deformation including crustal segmentation, pull‐apart fracturing and faulting occurred during the closure and exhumation of the basins developed in the peninsula during Late Cretaceous–Early Tertiary. Crustal shortening in the central belt of the peninsula has been accomodated through strike‐slip displacement, shearing and uplift.  相似文献   

A model to assess fundamental and realized carrying capacities of island ecosystem: A case study in the southern Miaodao Archipelago of China   总被引：2，自引：0，他引：2  

SHI Honghu  SHEN Chengcheng  ZHENG Wei  LI Fen  WANG Xiaoli  CHI Yuan  GUO Zhen  QIAO Mingyang  GAO Liyuan  DING Dewen 《海洋学报(英文版)》2016,35(2):56-67

Research on carrying capacity, aiming at maintaining the limited ability of the Earth's life supporting system to sustain human development, requires a comprehensive and ecosystem-based approach to monitor and assess the localized sustainability of coupled social and ecological systems. A definition termed the ecosystem-based carrying capacity of island (EBCCI) was developed in this paper of which the indices of fundamental and realized carrying capacities of island (FCCI and RCCI) were highlighted to emphasize the inter-dependencies between social systems and ecological systems. In order to avoid the difficulties and uncertainties of direct assessment, the related assessment model was established on the basis of synthetic evaluation of inherent and external factors affecting the EBCCI. The southern Miaodao Archipelago (SMA) located in the intersection of the Bohai Sea and the Yellow Sea, China, was taken as a typical example to acquire integrated recognition of the island ecosystem and its carrying capacity so as to discuss its sustainable development. The index scores of FCCI and RCCI in the SMA were 0.818 5 and 0.712 9 out of 1.0, respectively, with acceptable uncertainties. The results showed a relatively well capacity to sustain progress and relatively well realization of the carrying capacity of island ecosystem, owing to a well capacity of ecologically regulating, general performance of both ecologically supporting and resource provisioning, and a relatively high level of social supporting system. The study implied that it was critical to optimize the inter-dependencies and to sustain the relative balance between social systems and ecological systems so as to improve the RCCI and further facilitate the sustainability of SMA. The approach proposed in this paper provides a powerful tool which is well applicative to the regional level of an oceanic island or archipelago to study the sustainable development and can be further popularized to the coastal zone.  相似文献   

Sedimentary heterogeneity and petrophysical characterization of Barremian tsunami and barrier island/inlet deposits: The Aliaga outcrop as a reservoir analogue (Galve sub-basin,eastern Spain)     

《Marine and Petroleum Geology》2016

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区域变质作用与中国大陆地壳的形成与演化   总被引：8，自引：4，他引：4  

耿元生  沈其韩  杜利林  宋会侠 《岩石学报》2016,32(9):2579-2608

在编制1∶500万中国变质地质图的基础上,本文总结了中国主要变质带的演化以及各变质带与中国大陆地壳形成演化之间的内在联系。虽然在华北和华南克拉通都有古太古代到中太古代的变质年代记录,但是由于后期改造其变质作用的特点及与区域构造背景的联系已难以追索。新太古代末-古元古代初期的变质作用在华北克拉通表现最明显,这期变质作用紧随大规模的TTG岩浆作用,普遍具有逆时针的P-T演化轨迹,反映了地幔柱主导的岩浆-变质事件特点。古元古代晚期的变质事件在华北、华南、塔里木克拉通都有强烈反映。这期变质作用以形成具有顺时针P-T演化轨迹的高压麻粒岩为特点,与形成Columbia超大陆的一些造山带的特点类似,但是这三个不同克拉通在与Columbia聚合的时间和空间方位上存在差异。华南克拉通是相对年轻的克拉通,是沿新元古代江南造山带扬子和华夏地块拼合的产物。新元古代江南造山带的火山岩形成时代和变质作用程度从北东向南西迁移,反映了造山过程逐渐迁移和剪刀式闭合的特点。形成华南克拉通后,在其东南缘又先后经历了加里东期和印支期的变质改造,并且由北西向南东变质带从加里东期转变为印支期,但是这两期变质作用的构造背景尚不很清楚。中国南北大陆的聚合首先从西昆仑-阿尔金-北祁连-北秦岭-桐柏开始,所反映的变质作用是早古生代的蓝片岩相和榴辉岩相变质岩相伴产出,表明经历了从洋壳俯冲到陆陆碰撞的演化过程。中国东部的南北大陆到印支期才最终汇聚,相应的变质作用以南部出现高压蓝片岩相、北部出现超高压的榴辉岩相变质带为特点,表明南方大陆向北方大陆的俯冲。超高压带内普遍含有柯石英,意味着大规模的陆壳深俯冲。华北克拉通和塔里木克拉通以北的中亚造山带内存在多条从早古生代到晚古生代的变质带和多条蓝片岩相变质带,表明这是一个由多阶段、多条变质带组成的造山区。但是其变质作用的空间和时间演化还有待进一步深入。青藏高原变质带具有北老南新的空间分布特点,最北部的印支期龙木错-双湖-澜沧江变质带反映了原特提斯和古特提斯洋的碰撞拼合过程,北部的燕山期班公湖-怒江变质带和中部的喜马拉雅早期雅鲁藏布江变质带反映了新特提斯洋的两次碰撞拼合过程,南部喜马拉雅晚期的高喜马拉雅变质带反映了印度板块向北俯冲导致的高原快速隆升过程。  相似文献   

中亚成矿域斑岩铜金成矿的地质环境问题   总被引：1，自引：0，他引：1  

薛春纪  赵晓波  莫宣学 《岩石学报》2016,32(5):1249-1261

中亚成矿域在蒙古、乌兹别克斯坦、吉尔吉斯斯坦和哈萨克斯坦产有Oyu Tolgoi、Almalyk、Andash-Taldy Bulak、Aktogai、Kounrad等众多巨型和世界级斑岩铜金矿床,中国新疆北部斑岩铜金找矿持续重大突破令人期待。中亚成矿域大规模斑岩铜金成矿于什么地质环境?新疆北部、尤其天山斑岩铜金地质找矿持续突破的前景怎样?都是颇受关注的重大地质和找矿问题。通过广泛深入文献调研和重要矿集区实地调查研究表明,中亚构造成矿域在古亚洲洋壳俯冲增生、陆陆碰撞和后碰撞伸展等不同时期地质环境中,虽然均有斑岩铜金成矿作用发生,但古亚洲洋俯冲形成不同时期的增生岛弧是中亚斑岩铜金最为重要的成矿地质环境,大规模斑岩铜金成矿出现在洋盆演化末期、或即将关闭时的成熟岛弧环境。为什么中亚重要斑岩铜金矿床多形成于年长的成熟岛弧是值得探索的重要科学问题。新疆北部、尤其天山不同时期的岛弧发育完整,岛弧岩浆作用强烈而漫长,斑岩铜金成矿条件优越,大型-超大型铜金矿地质找矿潜力巨大,有望持续发现重要斑岩铜金矿床。  相似文献   

大陆板内玄武岩数据挖掘:成分多样性及在判别图中的表现   总被引：7，自引：4，他引：3  

王金荣  潘振杰  张旗  陈万峰  杨婧  焦守涛  王淑华 《岩石学报》2016,32(7):1919-1933

通常认为,大陆溢流玄武岩(CFB)、裂谷玄武岩(CRB)、板内玄武岩(WPB)均产于板内构造环境,其地球化学特征与OIB类似,源于富集的下地幔,与地幔柱的活动有关。本文利用GEOROC数据库对全球CFB、CRB和WPB数据进行挖掘,发现上述三类玄武岩判别图投图几乎落入了全部的构造环境域,有些甚至主要落入MORB和IAB区,而不是落入WPB区。结果表明原先的玄武岩判别图的判别功能值得商榷,尤其对大陆玄武岩来说,许多判别图都存在问题。全体CFB、CRB和WPB的地球化学成分变化巨大,暗示其源区具有强烈的不均一性:部分CFB、CRB和WPB来自富集的地幔柱,仍然具有经典的OIB的特征;部分来自MORB的源区,与MORB的再循环作用有关;部分来自岛弧岩石圈之下的亏损地幔源区,以强烈亏损Nb-Ta为特征,类似岛弧玄武岩的地球化学特征。许多地区的大陆玄武岩可分为低钛和高钛两类,低钛玄武岩大多是亏损或强烈亏损的,而高钛玄武岩通常是富集型的。本文的研究表明,富集型大陆玄武岩可能来自富集的下地幔,而亏损的和强烈亏损的玄武岩可能来自具有MORB或岛弧特征的软流圈地幔。进一步指出,源区性质可能是大陆玄武岩多样性的主控因素,其次为部分熔融程度、熔融深度、结晶分离、陆壳混染以及AFC过程。  相似文献   

内蒙古营盘湾-东五分子一带的色尔腾山岩群的厘定及地质意义   总被引：1，自引：1，他引：0  

吴新伟  徐仲元 《岩石学报》2016,32(9):2901-2911

色尔腾山岩群是华北克拉通西部陆块阴山地块早前寒武纪变质基底的主要组成部分,对探讨华北克拉通早前寒武纪基底构造演化有着十分重要的意义。本文根据对营盘湾-东五分子一带的色尔腾山岩群的地质填图、剖面测量、地球化学分析和SHRIMP测年,对色尔腾山岩群的组成、原岩建造、形成环境和形成时代进行了讨论。认为色尔腾山岩群由陈三沟岩组、柳树沟岩组和东五分子岩组组成,陈三沟岩组由灰黑色细粒斜长角闪岩、浅灰色细粒黑云斜长片麻岩夹角闪斜长片麻岩组成;东五分子岩组下段由细粒含石英黑云斜长角闪岩、黑云角闪斜长片麻岩、黑云斜长片麻岩呈韵律产出,顶部为灰白色细粒黑云斜长片麻岩夹薄层磁铁黑云斜长片麻岩,上段为由细粒黑云角闪片岩与浅肉红色黑云长英片麻岩互层,顶部有薄层白色透闪石大理岩;柳树沟岩组以角闪片岩、二云母片岩、二云石英片岩、石榴黑云片岩、黑云母片岩为特征。其原岩总体构成表现为:下部以火山岩为主,上部以碎屑沉积岩和化学沉积岩为主的火山-碎屑沉积建造。火山岩明显富碱,其中酸性火山岩明显富铝、贫镁;具有较高的大离子亲石元素含量、较低的Y和重稀土元素含量;具有轻稀土富集、重稀土亏损的稀土分布形式。地球化学特征与埃达克岩类似,形成于活动大陆边缘的构造环境下。通过对东五分子岩组上部互层产出的细粒长英片麻岩和黑云母片岩分别取样,进行锆石U-Pb SHRIMP测年,分别获得1980±9Ma、1946±16Ma的成岩年龄和1901±15Ma、1893±66Ma的变质年龄。综上所述可以得出,色尔腾山岩群的形成于1.95~1.98Ga之间,是在类似埃达克岩的活动大陆边缘岛弧环境下沉积的,在1.9Ga左右发生碰撞造山而发生变质。  相似文献   

Geotechnical Investigations at the Dalian Offshore Airport,China     

Gang Li  Jin-Li Zhang 《Marine Georesources & Geotechnology》2016,34(8):747-758

Based on the geotechnical investigation data of artificial island at Dalian Offshore Airport, the spatial distribution of the physical and mechanical properties of deposit soils was statistically analyzed. The field investigation revealed that the deposit soils could be subdivided into three strata, i.e., the top marine deposit stratum, middle marine-continental deposit stratum, and deep continental deposit stratum. Field and laboratory test results demonstrated that the marine deposit soils had high water content (31.2% < w_n < 63.10%), large void ratio (0.88 < e₀ < 1.75), low permeability (k_v < 10^?6 cm/s), flow-plastic state (I_L > 1), under consolidated (OCR < 1), high compressibility (E_s < 4 MPa), low shear strength (11.7 kPa < c_u < 43.7 kPa), and low bearing capacity (0 < f_ak < 120 kPa), they could not be used as natural foundation. The marine-continental and continental deposits were normally consolidated to over-consolidated (OCR ≥ 1), medium compressibility (4 MPa < E_s < 20 MPa), high shear strength (29.7 kPa < c_u < 73.7 kPa), and high bearing capacity (f_ak > 120 kPa). In addition, regression analysis results showed that the compression ratio was positively correlated with the natural water content, the coefficient of vertical consolidation was negatively correlated with the plasticity index, and the coefficient of vertical permeability was positively correlated with the initial void ratio. The results of the field and laboratory tests were synthesized to provide a basis for reclamation design.  相似文献