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1.
辽西地区中生代盆地构造演化   总被引:7,自引:1,他引:7  
杨庚  郭华  刘立 《铀矿地质》2001,17(6):332-340
辽西地区为华北地台北缘阴山-燕山造山带的东延部分,中生代发育火山-碎屑岩沉积盆地。盆地地质分析表明,该区在早白垩世早期之前发育的沉积盆地为挤压型盆地,早白垩世中期以后属伸展断陷盆地。根据沉积-构造分析,该区中生代盆地构造演化可划分为5个构造演化阶段;(1)早三叠世--早侏罗世;(2)早侏罗世-中侏罗世;(3)中侏罗世-晚侏罗世;(4)早白垩世早期;(5)早白垩世中期-晚白垩世。  相似文献   

2.
吐哈盆地煤成油形成的地质条件   总被引:5,自引:0,他引:5  
赵长毅  赵文智 《沉积学报》1997,15(A12):16-23
吐哈盆地是典型的煤成油气盆地。通过对该盆地煤成油形成的地质条件分析,认为煤成油藏的形成是特定地质条件下的产物。(1)盆地构造演化控制了煤系生储油岩系发育;(20存在低成熟成烃母质以利于烃类排出:(3)成煤沼泽氧化还原环境与成煤植物差异造成了煤原始怪程度的不同。下三角洲平原沼泽及分流间湾沼泽是煤成烃发育的有利场所,流水沼泽相是煤成烃最有利的相带;(4)适合古地温梯度及后续盆地继承发展以保持源岩熟化,  相似文献   

3.
地质统计学发展现状及对若干问题的讨论   总被引:13,自引:0,他引:13  
探讨了有关地质统计不发展现状的几个问题:(1)数学地质的发展现状及研究内容;(2)地质统计学的发展现状及研究内容;(3)普通克立克法及泛克立克法的方法及应用;(4)非参数地质统计学的方法及应用;(5)地质统计学方法在储量计算中的应用情况;(6)关于处理特异值的地质统计学方法;(7)关于矿石储量定量分级的地质统计学研究;(8)关于最优勘探网度的地质统计学研究;(9)可回采储量总体的问题。  相似文献   

4.
王宗起  汤耀庆 《地学前缘》1996,3(3):131-137
流体活动研究已从俯冲带转移到造山过程。主要研究如下几个问题:(1)造山过程中流体的运移方式和分布规律,即造山带古流体场的重建;(2)流体在造山过程中对各种地质作用的参与;(3)造山带演化特征与流体活动幕次的关系;(4)盆山成矿与流体活动的关系等。选择研究程度高、具明显的流体活动特征,同造山成矿发育的年轻造山带或其中一段通过多学科综合研究,将使人们更深入地理解造山过程中的各种地质作用和盆山转化规律及动力学特征。  相似文献   

5.
北京西山青白口—下苇甸一带印支期侵入活动特征   总被引:1,自引:0,他引:1  
本文根据青白口─下苇甸一带发育的基性→中性→酸性岩脉(床)的变形与围岩一致;变质作用特点与发育于石炭─二叠系及三叠系双泉组岩石中的变质作用特点相似;在下苇甸穹隆中发育的辉长岩中获得了K─Ar全岩稀释法年龄229Ma,证实这套岩脉(床)是印支期岩浆侵入活动产物,并对其地质特征和岩石地球化学特征进行了讨论。  相似文献   

6.
张加桂 《地球学报》2001,22(2):145-148
巫山县新城址巴东组三段泥质灰岩在地质历史上已全部发生了滑坡,滑坡体可分为上、中、下三段,滑坡的发育经历了(1)印支期和燕山期构造;(2)新构造上升、长江切割引起岩体松动卸荷及岩溶作用;(3)巴东组三段沿二段顶部泥化层滑动;(4)中部陡坡带形成,滑坡分解;(5)上、下两段滑坡格局形成;(6)上段滑坡进一步分离形成中段滑坡;(7)后期溶蚀、风化。滑坡的后期改造过程仍在继续。  相似文献   

7.
地质雷达及其在地质和工程勘察中的应用   总被引:2,自引:0,他引:2  
地质雷达及其在地质和工程勘察中的应用茹瑞典,张金才,耿德庸(煤炭科学研究总院开采研究所北京100013)王进学,姜兴阁(河北省邢台矿务局邢台矿邢台054021)关键词地质雷达;原理;应用中国图书资料分类法分类号P631·3地质雷达是利用高频电磁脉冲来...  相似文献   

8.
文中分析了中生代大型、超大型火山岩型铀矿床产出的特异部位──含矿火山塌(断)陷的地质环境,将其归纳为"近带、伴盆、早洼、晚隆、切壳、酸底、泥化"14字特征。在讨论该类铀矿床的形成机制的基础上,提出了特异部位的9条定位标志,即:位处1,2级构造单元结合部位的构造岩浆活动带;构造岩浆活动带边部的大型火山沉积盆地;火山沉积盆地边部的港湾状小型火山塌(断)陷;火山塌(断)陷的火山岩发育充分;火山塌(断)陷在盆地发展晚期隆起;火山塌(断)陷受一条长期活动的切壳断裂控制;火山塌(断)陷的基底发育有多期花岗岩体;火山塌(断)陷的盖层遭受强烈的以泥化为主的中低温蚀变作用;蚀变带有硅化、低温钠长石化、铁绿泥石化等蚀变作用叠加,并见有铀及其相关元素异常。  相似文献   

9.
地理信息系统技术发展快,并且越来越多地应用于地质研究中。本文主要介绍了地理信息系统的概念,功能和类型以及GIS在地质研究中的某些应用,包括(1)利用GIS进行区域地质填图;(2)利用水文地质图;(3)利用GIS定量模拟矿床;(1)利用GIS进行岩石地球化学分析;(5)利用GIS处理海洋地质资料。  相似文献   

10.
有色地质50余年矿产地质勘查与科研成果显著;(1)发现了许多重要矿床,探明了大量的矿产储量;(2)在保矿山和提供许多重要矿产资源建设基地中,做出了重大贡献;(3)地质科技重要成果;(4)有色地质部门在找矿,科研工作中值得纪念的大事和对今后矿产地质勘查工作的建议。  相似文献   

11.
The Lick Observatory 7.5-minute quadrangle exposes evidence of geologic events that range from subduction of Mesozoic Franciscan Complex, through accumulation of marine Miocene porcellanite and clastics, to the development of the San Andreas fault system and deformation within it. The active Calaveras fault zone, with its linear valleys and subparallel strike-slip strands, transects the quadrangle and, northwest of San Filipe Valley, joins and incorporates the older Madrone Springs fault. The topography has formed in the past 1 to 2 million years and rises northeastward from the East Evergreen range-front thrust, across the Calaveras and several inferred mountain-building faults, to the 1280 m crest of Mt. Hamilton.

The stratigraphy includes coherent, variously schistose metagraywacke of the late Mesozoic Franciscan Complex; discordant zones of melange of sheared shale and blocks that include blueschist and eclogite; serpentine that may represent the Coast Range Ophiolite; relatively undeformed sandstone, shale, and conglomerate of the late Mesozoic Great Valley sequence; marine Miocene Claremont Porcellanite, mudstone, and Briones Sandstone; and deformed nonmarine gravels of the Pleistocene and Pliocene Santa Clara Formation.

The Franciscan sandstones are complexly deformed and discordantly transected by tectonically emplaced melange zones; a local chert mass marks the remnant of a discordantly overlying thrust sheet. Southwest of the Calaveras zone, folded Miocene rocks are faulted over the more strongly deformed Great Valley sequence. Those rocks, in turn, are thrust over small windows of Franciscan rock, and the entire mountain mass is thrust over Santa Clara gravels at the foot of the range. These latter structures postdate the 3.5 Ma imposition of compression across the plate margin suggested by plate tectonic reconstructions.  相似文献   

12.
In this paper, we present whole-rock and mineral geochemistry of serpentinized peridotites from the Suru Valley ophiolite slice Ladakh Himalaya, in an attempt to put constraints on their petrogenesis and tectonic evolution in the context of Mesozoic Neo-Tethys Ocean. On the basis of petrographic study, Suru Valley serpentinized peridotites can be identified as serpentinized harzburgites. Relative to primitive mantle these rocks have depleted major and rare earth element (REE) geochemical characteristics comparable to ocean floor mantle rocks reflecting their mantle residual nature. However, higher abundance of highly incompatible large ion lithophile elements (e.g., Rb, Ba, Th, U, Pb and Sr), reflect metasomatism in a subduction zone environment. The presence of silicate assemblage includes Mg-rich olivine (Fo90-92) and orthopyroxene (En91-93 Fs6.4-8.7) of supra-subduction zone affinity. Evaluation of mineral and whole-rock geochemistry suggests that the Suru Valley ophiolitic peridotites represent residues left after moderate degrees of partial melting thereby underwent metasomatism in a supra-subduction zone environment related to north dipping intra-oceanic island arc during Cretaceous in the context of Mesozoic Neo-Tethys ocean.  相似文献   

13.
加利福尼亚弧-盆-沟体系的地质特征   总被引:1,自引:0,他引:1       下载免费PDF全文
加利福尼亚中生代弧-盆-沟系的构造和演化模式一向为世人所重视。作者应邀有机会对加州内华达岛弧地块、弗兰西斯科杂岩和大谷弧前盆地进行了实地地质考察。本文仅就这3个岩性-构造单元的一些独特地质特征和地质景观作一简介。  相似文献   

14.
Summary Mercury deposits in western California are near a thrust fault that separates two groups of Mesozoic rocks. The Franciscan Assemblage, a metamorphosed melange with serpentine and graywacke, is structurally overlain by the Great Valley Sequence, a sedimentary series resting on oceanic crust. These Mesozoic rocks are partly covered by volcanic and sedimentary rocks of Cenozoic age. Cinnabar with silica minerals, dolomite, native mercury, and bituminous matter occurs around the fractured margins of serpentine bodies and around hot springs that emanate from the Franciscan Assemblage. Fluid inclusions and hot springs suggest that cinnabar precipitated from CO2-H2O fluids with <2 wt% chlorine at T<250 °C. Prograde metamorphism of Mesozoic sediments expulsed mercury-bearing fluids that migrated up serpentine-related fractures and exhaled onto the surface.  相似文献   

15.
长江中下游成矿带地质与矿产研究进展   总被引:45,自引:25,他引:20  
周涛发  范裕  袁峰  钟国雄 《岩石学报》2012,28(10):3051-3066
长江中下游成矿带是我国重要成矿带之一,矿产资源开发利用历史悠久.自20世纪20年代至今,国内外学者在该地区开展了广泛深入研究工作,取得了丰硕的研究成果,并发表了大量科学研究论文和50余部专著.据统计,1959年~2012年间在公开发行的中文地质学期刊中,有关长江中下游地区的学术论文共888篇;1990年~2012年间公开发表的SCI检索论文中该区有185篇.这些论文中涉及矿床学方面的研究最多,约占论文总数的一半.成矿带内,铜陵矿集区研究程度最高,发表的相关论文数量也最多.有关成矿带的论文发表数量总体趋势逐年增加,在20世纪90年代初和2010~2012年出现两个研究高峰,反映了长江中下游成矿带近年来仍然是我国地质学研究的热点地区之一.近年来,长江中下游成矿带的地质找矿和科学研究均取得了重要进展,地质与矿产研究主要集中在以下几方面:(1)中生代构造转换与成岩成矿的地球动力学背景;(2)岩浆作用与深部过程;(3)成矿系统及其演化;(4)成矿潜力.本专辑收录的26篇论文基本反映了当前长江中下游成矿带及邻区的最新研究进展,所报道的大量地质学新观察、矿床学和岩石学研究、元素和同位素地球化学数据、同位素年代学特别是高精度锆石U-Pb年龄等对深入进一步探讨长江中下游成矿带形成与演化具有重要参考价值,对于推动成矿带基础理论研究和指导找矿勘探均有重要意义.  相似文献   

16.
The giant East China Mesozoic metallogenic province hosts some of the World’s largest resources of tungsten, tin, molybdenum, antimony and bismuth. Ores of gold, silver, mercury, lead, zinc, copper, uranium and iron are also of major importance. The province and its constituent metallogenic belts or regions (South China; Middle–Lower Yangtze River Valley; East Qinling–Dabie; Interior of North China Craton; Yan-Liao and North-east China) are the products of several pulses of igneous activity and mineralisation between ~240 and ~80 Ma. Each successive stage has produced a distinctive suite of deposits that can be readily related to the geodynamic evolution of the region during the Mesozoic. This geodynamic evolution is linked to a complex series of tectonic events, involving far-field-subduction, plate collisions, crustal thickening, post-collision collapse and rifting.  相似文献   

17.
The Yangtze Valley was one of the most important metallogenic regions during the Jurassic-Cretaceous period in East China, where more than 200 polymetallic Cu-Fe-Au, Mo, Zn, Pb, Ag deposits have been found. Trace elements were chemically analyzed and the relevant data were collected from literature for the Yanshanian (Mesozoic) igneous rocks which have close relationship with Cu-Au mineralization. Copper mineralization in the lower Yangtze Valley can be divided into three major types: skarn type, porphyry type and volcanic type. The porphyry type is of rare occurrence, such as the Shaxi porphyry copper deposit in the northern part of the lower Yangtze metallogenic valley. This paper focuses on the REE and trace element geochemistry of several Cu-Au deposits along the lower part of Yangtze metallogenic valley in Anhui. The results showed that there are differences in REE distribution for these four types of Cu-Au mineralization, which confine the sources of REE and trace elements as well as other mantle and transitional compatible elements. The results of both REE and trace element geochemical studies showed that these elements with different characteristics have different origins, probably representing different sources of Cu-Au deposits in the deep crust and upper mantle environments. The 40Ar/39Ar dating of one biotite sample gave an age of 131 Ma with a high level of confidence, which represents the age of formation of the Shaxi porphyrite intrusive with porphrytic Cu-Au mineralization, which is consistent with that of the majority of the adjacent acid intrusives with mass Cu-Au mineralization along the Yangtze metallogenic belt in the Yanshanian period (Mesozoic). This is the first attempt to use the high precision method to date the Shaxi porphyrite intrusive.  相似文献   

18.
New fossil material of ripiphorid beetles (Tenebrionoidea: Ripiphoridae) is described and figured in lowermost Cenomanian amber from the Hukawng Valley of northern Myanmar. Flabellotoma heidiae gen. et sp. nov. is the Mesozoic representative of the putatively primitive subfamily Pelecotominae, represented by an almost completely preserved male. The new genus is compared with all extant members of the subfamily and is most notably distinguishable by an autapomorphic combination of a reduced tibial spur formula and unique ventral abdominal sclerite, and presumably in antennal structure as well. In addition, a syninclusion of eight males of Ripidiinae is discussed. The males are similar to Paleoripiphorus deploegi Perrichot, Nel, et Néraudeau in roughly coeval amber from western France. The syninclusion is interpreted as a result of aggregative behaviour during the flight activity of males, thereby representing the earliest documented evidence of such ethology. Brief remarks are made regarding the similarities among Cretaceous amber beetle faunas, and Mesozoic taxa previously attributed to Ripiphoridae are newly reconsidered.  相似文献   

19.
Abstract

Large outcrop areas in the Canning Desert and the Fitzroy Valley of northwestern Australia consist of marine Jurassic and Upper Triassic rocks, not of Permian as formerly believed. On present knowledge, outcrops of the Triassic formations are restricted to parts of the Fitzroy and Bonaparte Gulf Basins, whereas the distribution of Jurassic (Kimmeridgian to Tithonian) rocks provides evidence for a major marine invasion that affected the Canning Desert area and may have advanced into the centre of the Australian continent and beyond. The late Jurassic transgression did not enter the Fitzroy Basin area.

From the distribution and nature of the Mesozoic formations it is concluded that the main phase of post-Permian folding in the Fitzroy Basin is early Triassic. Later movements affected minor northern parts of the Canning Desert area in early Jurassic and in early Cretaceous time.

As an alternative working hypothesis to the traditional basin concept it is suggested that during the Mesozoic the Canning Desert area was an epicontinental shelf platform.  相似文献   

20.
Marine geophysical data from the southern Natal Valley and northern Transkei Basin, offshore southeast Africa, were used to study the structure of the crust and sedimentary cover in the area. The data includes seismic reflection, gravity and magnetics and provides information on the acoustic basement geometry (where available), features of the sedimentary cover and the basin's development. Previously mapped Mesozoic magnetic anomalies over a part of the basin are now recognized over wider areas of the basin. The ability to extend the correlation to the southeast within the Natal Valley further confirms an oceanic origin for this region and provides an opportunity to amplify the existing plate boundary reconstructions.The stratigraphic structure of the southern Natal Valley and the northern Transkei Basin reflects processes of the ocean crust formation and subsequent evolution. The highly variable relief of the acoustic basement may relate to the crust formation in the immediate vicinity of the continental transform margin. Renewed submarine seismicity and neotectonic activity in the area is probably related to the diffuse boundary between the Nubia and Somalia plates.2.5-D crustal models show that a 1.7–3.2-km-thick sediment sequence overlies a 6.3±1.2-km-thick normal oceanic crust in the deep southern Natal Valley and Transkei Basin. The oceanic crust in the study area is heterogeneous, made up of blocks of laterally varying remanent magnetization (0.5–3.5 A/m) and density (2850–2900 kg/m3). Strong modifications of accretionary processes near ridge/fracture zone intersections may be a reason of such heterogeneity.  相似文献   

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