共查询到20条相似文献，搜索用时 15 毫秒
1.
Fikry Ibrahim Khalaf 《Arabian Journal of Geosciences》2011,4(5-6):703-718
A paleokarstic zone capping the Middle Eocene dolomitic Dammam Formation delineates a regional disconformity with the overlying Mio-Pleistocene fluvial deposits in Kuwait. This formation outcrops in a quarry located in the southeast of Kuwait and occurs in the subsurface of Umm Ghudair water field, west Kuwait. Karstification has affected the upper member of the Dammam Formation, which is formed of extensively chertified, vuggy chalky biodolomicrite. Karstification is manifested by two phases: a dissolution phase that was responsible for the occurrence of surface and near surface karst features and a precipitation phase during which a karst carapace and dolocretic and calcitic pseudobreccias were developed. Petrographic investigations of both the biodolomicrites host rock and the karst lithotypes revealed a complex diagenetic history that encompasses the following diagenetic events, arranged in a chronological order: (a) replacive dolomitization, (b) precipitative dolomitization, (c) precipitative silica, (d) replacive silica, (e) karstification, (f) development of karst carapace [calcretization and calcitization (development of calcitic psuedobreccia)], (g) dolocretization (development of dolocretic psuedobreccia), (h) mild karstification, (i) calcite precipitation, and (j) silica precipitation. The development of the karst carapace at the unconformity surface between the Eocene Dammam Formation dolomicrites and the overlying Mio-Pleistocene Kuwait Group clastics has played a significant role in the hydrological characteristics of Kuwait usable groundwater resources. It is recommended that the occurrence of similar diagenetic processes within the Arabian carbonate shelf deposits be investigated. 相似文献
2.
Hydrogen sulfide occurs in high concentration (10–200 mg/l) in different parts of Kuwait City and its suburbs at relatively
shallow depths (15–40 m from the surface). This was revealed by drilling through the aquifer system underlying the city and
sampling and analyzing the ground water at the drilled locations. The near-absence of coliform bacteria in the sulfide-rich
zones, the presence of sulfur-reducing bacteria in the deep (>80 m) Dammam Formation aquifer and a linear positive relation
between the concentration of hydrogen sulfide and the total dissolved solids content suggested non-anthropogenic origin of
the sulfide in the ground water of Kuwait. The upward movement of sulfide-rich water from depth and its differential flushing
by surface recharge through outcrops of the aquifers appear to have given rise to the present distribution of hydrogen sulfide
in the aquifers underlying the Kuwait City. 相似文献
3.
根据鲁家坪组的岩性、岩相和变质程度的变化以及区域分布特征,原定义所包含的岩石内容过于庞大,混淆了岩石地层单位和年代地层单位。通过对鲁家坪组的命名地点和标准剖面所在地——北大巴山南部的陕西紫阳县鲁家坪村的鲁家坪剖面及其他剖面的详细研究,原鲁家坪组按岩性可分为三段,下段以白云岩为主;中段以厚层硅质岩为主,中段下部的硅质岩中夹磷质白云岩和灰岩,其中产小壳化石Archaeooidessp.、Protohertinasp.、Chan-celloriasp.和Hyolithids,中段上部的硅质岩中夹多层毒重石或重晶石矿层以及砂炭(石煤)和火山岩层,即以硅质岩类为主;上段以黑灰色(风化后为浅灰色)含硅炭板岩和泥灰质含炭板岩为主。根据原鲁家坪组各段岩层的岩性、岩相、岩层层序、厚度和分布范围等,原鲁家坪组的下部的厚层状灰质白云岩和硅质白云岩等与原鲁家坪组中部的厚层硅质岩及硅质板岩,以及上部的板岩和千枚岩和页岩的岩性和岩相差别较大,应从原鲁家坪组划出,暂仍称为灯影组,与三峡地区的灯影组可对比;原鲁家坪组的中上部为鲁家坪组的主体,仍称鲁家坪组。厘定后的鲁家坪组与扬子地台的下寒武统的筇竹寺组(云南)、牛蹄塘组(贵州)和宽川铺组(陕南宁强)可以对比,而与后者的主要区别在于后者的下部以黑色页岩为主、硅质岩岩层薄,而鲁家坪组下部的硅质岩特别发育,厚度大,常常夹有毒重石矿层、砂炭和火山岩等。 相似文献
4.
湖南郴县华塘地区的长兴阶 总被引：2，自引：0，他引：2
<正> 湖南南部郴县、桂阳交界的华圹地区,晚二叠世晚期地层发育良好。在东西长6公里,南北宽1.3公里的华塘向斜范围内(图1),岩相变化很大,既有以硅质岩为主含菊石的“大隆组”,又有以厚层白云质灰岩为主,含筵类、菊石、腕足类等的“长兴组”。笔者在采集化石、测制剖面进行生物地层工作的同时,对上述两种岩相的变化关系进行了追索和研究,现将我们的认识概述如下。 (一)郴县华塘公社三合小学剖面 相似文献
5.
塔河油田上奥陶统良里塔格组下段以泥微晶灰岩、瘤状灰岩为主,上段以鲕粒灰岩、生屑灰岩、砂砾屑灰岩为主,纵向上构成了一个向上水体变浅的沉积序列。根据层序地层学研究结果,将良里塔格组划分为一个三级层序,细分为两个体系域。通过对各体系域地层单元的岩相学和地球化学分析研究,恢复了各时期的古地理面貌及沉积相带的空间展布。最终研究结果表明良里塔格组沉积相带具有开阔台地、台地边缘和斜坡3种类型,平面上由北向南顺序展布,走向近东西。微量元素分析进一步佐证和完善了该区沉积相带分析,V、Ni和Cr微量元素的含量显示从浅水到深水总体呈增加之势,Ce异常曲线对沉积环境也有良好反映,而台地边缘相的Sr/Ba比值表现出异常高值。 相似文献
6.
An overview of the Tertiary geology and hydrogeology of the northern part of the Arabian Gulf region with special reference to Kuwait 总被引：2，自引：0，他引：2
Tertiary sediments constitute the main source of usable groundwater in Kuwait. Tectonics, depositional environment, lithology and the hydrogeology of these sediments have been reviewed on a regional scale, with special reference to Kuwait. The review showed that Kuwait was situated at the boundary of the stable shelf towards southwest and the unstable shelf towards northeast throughout the Tertiary period. The Tertiary sedimentation started in this area with a marine transgression in the Palaeocene. Shallow marine to sabkha conditions prevailed in the area until the end of the Eocene; a carbonate-evaporite sequence (Umm Er-Radhuma, Rus and Dammam Formation) was deposited during this period. The sea regressed at the end of Eocene, and a widespread unconformity, causing the absence of Oligocene deposits over most of the area, marked the event. The karstification of the Dammam Limestone Formation, that provides localized easier pathways for ground water, took place during this period. The deposition of the clastic sediments of the Kuwait Group and its equivalents on the stable shelf, under mostly continental conditions, started in the early Miocene. The Tertiary aquifers of the area are recharged by occasional rainstorms in the outcrops of Saudi Arabia and Iraq. The water flows towards the north and east in the direction of the regional dip and discharges along the present-day coast of the Gulf. The water quality deteriorates in the same direction, being more mineralized as it flows through the aquifers. The aquifers are presently being exploited at a comparatively high rate. Since the aquifers extend beyond the political boundaries, cooperation among the countries of the region is recommended to ensure the optimum utilization of the scarce water resources of this desert environment. 相似文献
7.
The Julian Alps are located in NW Slovenia and structurally belong to the Julian Nappe where the Southern Alps intersect with
the Dinarides. In the Jurassic, the area was a part of the southern Tethyan continental margin and experienced extensional
faulting and differential subsidence during rifting of the future margin. The Mesozoic succession in the Julian Alps is characterized
by a thick pile of Upper Triassic to Lower Jurassic platform limestones of the Julian Carbonate Platform, unconformably overlain
by Bajocian to Tithonian strongly condensed limestones of the Prehodavci Formation of the Julian High. The Prehodavci Formation
is up to 15 m thick, consists of Rosso Ammonitico type limestone and is subdivided into three members. The Lower Member consists
of a condensed red, well-bedded bioclastic limestone with Fe–Mn nodules, passing into light-grey, faintly nodular limestone.
The Middle Member occurs discontinuously and consists of thin-bedded micritic limestone. The Upper Member unconformably overlies
the Lower or Middle Members. It is represented by red nodular limestone, and by red-marly limestone with abundant Saccocoma sp. The Prehodavci Formation unconformably overlies the Upper Triassic to Lower Jurassic platform limestone of the Julian
Carbonate Platform; the contact is marked by a very irregular unconformity. It is overlain by the upper Tithonian pelagic
Biancone (Maiolica) limestone. The sedimentary evolution of the Julian High is similar to that of Trento Plateau in the west
and records: (1) emergence and karstification of part of the Julian Carbonate Platform in the Pliensbachian, or alternatively
drowning of the platform and development of the surface by sea-floor dissolution; (2) accelerated subsidence and drowning
in the Bajocian, and onset of the condensed pelagic sedimentation (Prehodavci Formation) on the Julian High; (3) beginning
of sedimentation of the Biancone limestone in the late Tithonian. 相似文献
8.
Amitabha Mukhopadhyay 《Hydrogeology Journal》2003,11(3):343-356
The ability of artificial neural network to differentiate water samples from the two aquifers of Kuwait on the basis of their
major ion chemistry has been demonstrated. The major ion concentration distribution in the groundwater of the Kuwait Group
and the Dammam Formation aquifers of Kuwait appears very similar. Cross-plots, supported by the discriminant function analysis
of the data, however, suggest that there are some subtle differences in the overall composition of the water from the two
aquifers that make it possible to differentiate the water from the two aquifers in almost 80% of the cases. An artificial
neural network improved the differentiation capability to 90% of the cases. It is also possible to estimate the fraction of
Kuwait Group water in the flow stream of dually completed wells with the help of an artificial neural network developed for
this purpose.
Electronic Publication 相似文献
9.
延庆千家店盆地土城子组底部不整合接触蓟县系雾迷山组,不见顶,主要分为3个岩性段,一段以复成分砾岩、砂砾岩为主;二段以紫红色、黑色薄层泥页岩和泥质粉砂岩为主;三段以复成分砾岩、含砾粗砂岩为主。前人在该盆地二段地层中发现大量动植物化石,有双壳类、叶肢介、昆虫、木化石、恐龙足迹等,但一直没有介形类、孢粉及恐龙化石的相关报道。在化石层位发现疑似"恐龙骨骼"化石,丰富了该区化石种类。通过LA-ICP-MS测年,得出一段底部年龄为157.62±0.69Ma;二段中上部年龄为157.13±0.96Ma。分析认为,千家店盆地土城子组主体沉积时代为晚侏罗世早期,在前人研究的基础上,通过多样的古生物化石来探讨该盆地古气候背景及沉积环境。 相似文献
10.
塔中Ⅰ号断裂带奥陶系良里塔格组礁滩储集体模式与预测 总被引：1，自引：0，他引：1
塔里木盆地奥陶系良里塔格组礁滩储集体位于塔里木盆地塔中Ⅰ号断裂带的东部。研究目的层良里塔格组,由下部泥灰岩段、中部颗粒灰岩段和上部泥灰岩段组成。礁滩储集体主要发育在良里塔格组9个准层序中的PS7和PS8准层序组。从岩心观察入手,建立了良里塔格组礁滩体的地质模式,在此基础上,通过对已知礁滩体测井响应和地震反射特征分析并结合地震特征属性建立了地震识别模式。利用该模式预测研究区礁滩储集体有利分布区,预测结果为近年钻探的塔中821井等井所证实,获得高产油流,说明建立起来的地质—地球物理综合模式符合客观实际,能有效地指导勘探。 相似文献
11.
G.I. Abdel-Gawad S.G. Saber S.H. El Shazly Y.F. Salama 《Journal of African Earth Sciences》2011,59(4-5):359-372
Five radiolitid rudist species are described from the Turonian sequence of Abu Roash area. They are recognized in three rudist biostromes that occur in two informal members of Abu Roash Formation; the Rudist- and the Actaeonella-bearing limestone–marl members. The three biostromes show autochthonous and parautochthonous fabrics and moderate to high packing potential. The first rudist biostrome at the base of the Rudist-bearing limestone–marl member (Middle Turonian) contains Durania gaensis, Praeradiolites ponsianus and Bournonia fourtaui. The second biostrome in the same member consists of Bournonia roashensis. The third biostrome that recognized in the Actaeonella-bearing limestone–marl member (Late Turonian) consists of Durania arnaudi. Rudist biostromes in the Rudist-bearing limestone–marl member were deposited on subtidal rudist shoals with moderate to high energy versus that of the Actaeonella-bearing limestone–marl member that deposited in low to moderate energy on deeper part of subtidal rudist shoals. The exposed Turonian succession at Abu Roash area could be divided into three depositional sequences bounded by three sequence boundaries (paleosols and angular unconformity).The first rudist biostrome in the Rudist-bearing limestone–marl member represents the lower part of the transgressive systems tract of the first depositional sequence. The deepening upward trend of the transgressive systems tract is due to increase of accommodation space in transgressive context during relative sea-level rise episode. On the other hand, the second rudist biostrome in the Rudist-bearing limestone–marl member and the third rudist biostrome in the Actaeonella-bearing limestone–marl member are in shallowing-upward set sequence forming the highstand systems tract of the first and third depositional sequences. This indicates that, the accommodation space was being filled more rapidly than was being created during the highstand stage. 相似文献
12.
沉积盆地的研究对于理解造山带的构造演化具有重要意义.内蒙古狼山地区位于中亚造山带中段,构造演化历史复杂,晚古生代沉积盆地的大地构造背景存在争议.在对狼山西北缘乌兰敖包地区出露的"阿木山组"岩性特征、沉积构造及沉积环境的系统研究基础上,将该组分为3个岩性段.一段主要为粗碎屑岩,交错层理发育,沉积环境为辫状河三角洲;二段底部主要为粗碎屑岩,向上沉积物粒度变细,顶部出现生物碎屑灰岩,在岩屑石英砂岩中新发现芦木Calamites sp.,座延羊齿Alethopteris sp.,带科达Cordaites principalis Gein等植物化石,沉积环境由辫状河三角洲向滨海环境过渡;三段主要岩性为结晶灰岩,含生物碎屑,沉积环境为滨-浅海环境."阿木山组"一、二段砂岩碎屑锆石年龄可分为~2.5 Ga、~1.8~1.2 Ga、~826 Ma、461~440 Ma和313~273 Ma五个时间段,其中最小年龄为273 Ma,结合植物化石鉴定结果以及上覆火山岩地层年代,确定"阿木山组"沉积时代为265~273 Ma.研究区内同时代的岩浆岩指示该区在早中二叠世处于古亚洲洋向华北板块俯冲的岩浆弧环境,结合"阿木山组"的沉积特征、沉积时代及所处构造位置,对其地层划分与对比方案提出建议. 相似文献
13.
Geophysical investigation for shallow subsurface geotechnical problems of Mokattam area,Cairo, Egypt
Sultan Awad Sultan Araffa 《Environmental Earth Sciences》2010,59(6):1195-1207
Nine vertical electrical soundings of Schlumberger configuration were measured with AB/2 = 1–500 m. Manual and computerized interpretation were done to detect the subsurface stratigraphy of the study area. The
results show that the subsurface section consists of alternated units of limestone, clay, marly limestone and dolomitic limestone
and the thickness of clay unit ranged from 10 to 40 m. Nine dipole–dipole sections have also been constructed to give a clearer
picture of the subsurface at the study area. The length of each dipole–dipole section is 235 m, with a electrode spacing ranging
between 5 and 25 m. The Res2Dinv software was used for processing and interpretation of field data. The dipole–dipole sections
at the upper plateau display high resistivity values at most parts of the plateau. Twelve shallow seismic refraction profiles
are measured at selected locations for the dipole sections to define the interface between the fractured limestone and the
upper surface of the clay layer. Each profile consists of 24 geophones with a geophone spacing of 2–3 m. Interpretation of
seismic data indicates that the surface layer of the upper plateau consists of fractured limestone with a velocity range of
1.16–1.56 km/s and another layer of compacted clay with a velocity range of 1.38–1.88 km/s. Furthermore, the surface layer
of the middle plateau consists of marl and marly limestone with a velocity about 2.1 km/s and its underlying layer consists
of massive limestone with a velocity of 4.94 km/s. 相似文献
14.
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
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
15.
G. V. Ovchinnikova A. B. Kuznetsov I. M. Gorokhov E. F. Letnikova O. K. Kaurova B. M. Gorokhovskii 《Doklady Earth Sciences》2011,437(1):331-334
The U-Pb(Pb-Pb) age was determined for limestone from member III of the Sorna Formation out- cropped on the Azyr-Tal Range,
Kuznetsk Alatau. The weighted average value from three calculated values is 523 ± 5 Ma (MSWD = 0.02, 2σ). This age coincides
with the Early Cambrian age interval determined with Sr isotopic chemostratigraphy (87Sr/86Sr ratio is 0.70850–0.70852). The low value of μ2 = 238U/204Pb for limestone is due to the evolution of diagenetic fluid containing lead from the mantle reservoir into the Sorna sediments. 相似文献
16.
滇西南昌宁—孟连构造带火山岩地层学研究 总被引：6，自引：0，他引：6
昌宁—孟连构造带火山岩非常发育,是重要的含矿岩系。在构造带南段,火山岩统称为依柳组,北段统称为平掌组下段,以往时代均归属早石炭世。本文工作表明,该区火山岩可分为两套:一套为早石炭世火山岩,分布于该构造带西部,以拉斑玄武岩系列为主,代表大洋中脊、洋岛残留物,仍称为依柳组;另一套为晚二叠世火山岩,分布于构造带中、东部,以碱性玄武岩系列为主,可能属亚速尔型洋岛火山岩范畴,而非大洋蛇绿岩套,新命名为老厂组。 相似文献
17.
安徽泾县-南陵地区二叠纪沉积相与沉积环境分析 总被引：1，自引：0，他引：1
安徽泾县—南陵地区二叠系较发育,主要由碳酸盐岩、硅质岩和碎屑岩组成。二叠系船山组为浅水碳酸盐台地相;栖霞组底部碎屑岩段是滨海沼泽相,臭灰岩段和上、下富硅质灰岩段是水体较深的斜坡中部相,中部灰岩段是浅水开阔碳酸盐台地相,而顶部灰岩段是缓斜坡上部相;孤峰组和大隆组是缺氧滞流环境下的深水盆地至盆地边缘相;武穴组是碳酸盐台地相,银屏组属于滨海潟湖相;龙潭组是一套海陆交互的三角洲相沉积,包括从三角洲前缘到三角洲平原两个亚相,而泾县昌桥龙潭组顶部发育的生物碎屑灰岩属于开阔碳酸盐台地相。纵观二叠纪有三次大的海侵和两次大的海退旋回,海侵时间分别是:栖霞早期、茅口早期和长兴早期,海退时间分别是:紫松—隆林期末和茅口期末,其中栖霞期还包含两个海侵海退的亚旋回。 相似文献
18.
河北柳江盆地中晚寒武世藻类丘礁的演化 总被引：5，自引：0，他引：5
河北柳江盆地中晚寒武世藻类丘礁十分发育，并形成完好纵向演化序列。藻礁具有两个演化方向，其一是骨骼钙藻Ｅｐｉｐｈｙｔｏｎ向非骨骼蓝绿藻方向演化；其二是块状藻丘向厚层状叠层石礁方向演化。藻类丘礁的演化特征及其沉积相序揭示了该区中晚寒武世时从碳酸盐台地边缘斜坡至台缘浅滩和潮坪环境的演化历史。 相似文献
19.
吉林南部通化二道江剖面新元古界万隆组臼齿构造及其沉积特征 总被引：1，自引：3，他引：1
吉林南部通化二道江剖面新元古界万隆组广泛发育缓坡碳酸盐岩沉积,其中发育的一种特殊的碳酸盐岩——臼齿碳酸盐岩,近年来引起了中国乃至世界各国地质学家的重视。通过对野外露头的详细观察和描述、室内薄片观察、扫描电镜、能谱分析等测试手段,揭示了二道江剖面万隆组的地层、岩石、臼齿构造(MT)及沉积岩相和沉积环境特征。臼齿构造是特指那些发育在前寒武纪细粒碳酸盐岩中有清晰边界、粒度在0·01mm左右的由等轴或多边形的微亮晶方解石组成的集合体,其形态可分为条带状构造、瘤状构造及棱角碎块状构造。臼齿构造的形成严格受沉积岩相和沉积环境的控制。万隆组由下而上可分为3段第1段下部为发育臼齿构造的纹层状泥晶灰岩、砂屑灰岩及风暴砾屑灰岩,为中—深缓坡沉积环境的产物;上部由浅缓坡相的泥灰岩、钙质页岩、砂屑灰岩与叠层石灰岩组成;第2段为厚层泥晶灰岩和粉屑泥晶灰岩、瘤状灰岩组成的深缓坡相沉积;第3段本剖面未出露。万隆组形成于缓坡沉积环境,其中浅缓坡相可分为4种岩相组合,中缓坡相可分为11种岩相组合,深缓坡相有6种岩相组合。 相似文献
20.
桂林地区上泥盆统碳酸盐岩沉积相 总被引：2，自引：0，他引：2
前言 桂林地区上泥盆统主要是一套海相碳酸盐地层,为岩溶发育的主要岩石之一。同期异相明显,可以划分为两个岩相:一是白云岩灰岩相,下部为桂林组,上部为融县组,整合接触,二是硅质岩扁豆状(瘤状)灰岩相,下部为榴江组,上部为三里组,整合接触。桂林组可与榴江组对比,属晚泥盆世早期沉积,融县组与三里组相当,属晚泥盆世晚期沉积。它们与下伏的中泥盆统东岗岭组为整合接触,而与上覆的下石炭统岩关阶呈整合或假整合接触关系。 相似文献