Characteristics of karst groundwater system in the northern basin of Laiyuan Spring area          下载免费PDF全文

LI Bo  LI Xue-mei 《地下水科学与工程》2018,6(4):261-269

Guided by the theory of groundwater system, based on the groundwater level data from the northern basin of Laiyuan Spring area, the authors took into account factors such as the lithology, geological structure and topography to study the relationship between groundwater recharge, runoff and drainage in this area. It was concluded that the infiltration of atmospheric precipitation is the main source of groundwater supply in this area; the upper layer of the Spring area is distributed with the Cambrian-Lower Ordovician karst water, and the lower layer is filled with the Jixian system karst water. The upper layer of karst water supplies to the lower layer of karst water or the pore water in loose strata through the fault while the lower layer of karst water runs to the three strong runoff belts from the east and west sides of the watershed, southwards into the basin, partially replenishing the pore water in loose strata, or forming fault Springs (e.g. Nanguan Spring, Beihai Spring) when dolomite movement encounters faults. Replenished by atmospheric precipitation and the upper and lower layers of karst waters, the pore water in loose strata joins the groundwater in the southern basin and then flows eastwards, in the end it flows out of the system in Shangfanpu. Through the analyses of groundwater level data and hydrogeological drilling data, based on groundwater D and 18O isotope test results, the karst groundwater circulation system in the northern basin of Laiyuan Spring area is further verified, which provides hydrogeological basis for water resources development and utilization as well as protection in this area.  相似文献   

嫩江科洛地区晚侏罗世深熔花岗岩对嫩江-黑河构造带的响应          下载免费PDF全文

杨晓平  汪岩  杨超  谭红艳 《中国地质调查》2018,5(3):36-42

通过对嫩江-黑河构造带内的岩石建造研究,在嫩江科洛地区识别出一套深熔花岗岩体,岩石宏观上为一套具非典型花岗岩结构的深熔型侵入岩,具交代结构、斑杂状构造和眼球状构造。对深熔花岗岩进行了锆石LA-ICP-MS U-Pb年龄测试,获得了3组不谐和的U-Pb年龄: 390 Ma、157~163 Ma和113 Ma。其中,113 Ma年龄代表了岩石遭受后期变质热事件年龄; 157~163 Ma的年龄代表了原岩结晶年龄。综合分析深熔花岗岩成因,认为其主要与嫩江-黑河断裂深部韧性剪切热效应作用下发生的深熔有关,深熔花岗岩的划分和厘定为深入研究嫩江-黑河断裂带在中生代的活动提供了新的素材。  相似文献   

湖南省岳家桥典型岩溶发育区电性特征及构造格架研究     

曹创华  徐定芳  康方平  文武飞  尹欧  邓专 《中国地质调查》2018,5(6):68-74

为探讨湖南省益阳市岳家桥地质灾害现状,以区内典型岩溶发育区为研究对象,通过长剖面高密度电法、视电阻率联合剖面法等地球物理方法,研究了地层电性响应特点,利用钻孔数据和综合电法勘探数据建立了三维地层结构模型,揭示了典型区域近地表电性结构形态,构建了区内三维地层构造格架,圈定了岩溶发育范围,并评价了地质灾害程度。研究表明: 因地制宜地利用综合电法勘探,有助于在我国南方含水较多的岩溶发育区快速、有效地进行灾害范围的圈定和评价。  相似文献   

吉林永吉县头道沟地区镁铁—超镁铁质岩U-Pb年代学研究及地质意义     

付俊彧  孙巍  汪岩  钟辉  那福超  杨帆  张广宇  于宏斌 《地质学报》2018,92(9):1859-1872

吉林省永吉县头道沟地区出露许多与头道沟岩组相伴产出的镁铁—超镁铁质岩,鉴于其处于长春-延吉构造带附近而受到业内关注,但由于缺少高精度年代学资料,制约了对区域大地构造的深入研究。本文采用锆石U-Pb(LA-ICP-MS)方法,对镁铁—超镁铁质岩进行了年代学研究。变质辉绿岩年龄为270±5 Ma,变质橄榄岩中捕获锆石最小年龄为297 Ma,考虑岩石组合及二者紧密相伴产出,认为二者均形成于中二叠世。镁铁—超镁铁质岩中捕获的锆石记录了华北克拉通及其北缘多次重要的构造热事件。其中,变辉绿岩中获得446±6 Ma的年龄与变质橄榄岩中获得的不一致线下交点434±240 Ma年龄共同对应了华北克拉通北缘早古生代的重要构造岩浆热事件;大量的1.8~2.4Ga年龄对应古元古代辽吉造山带热事件;1377 Ma、1542 Ma与蓟县系建造时代对应;869~997 Ma与青白口系建造时代对应;在变质辉绿岩中还存在众多3.0~3.2Ga锆石年龄。分析上述年龄结构及龙岗陆块北缘古生代地质体分布特征,推测研究区深部可能存在古老的变质基底,同时也表明研究区出露的镁铁—超镁铁质岩形成于陆内构造环境,而非蛇绿岩的组成成分,这对深化区域大地构造研究具有重要意义。  相似文献   

扬子地台东南缘下寒武统清虚洞组风暴沉积特征及其重要意义   总被引：3，自引：0，他引：3  

郑斌嵩  牟传龙  梁薇  陈超 《地质学报》2018,92(7):1524-1540

在扬子地台东南缘,下寒武统龙王庙阶清虚洞组主要由浅水碳酸盐岩组成。在野外露头剖面实测和室内镜下薄片观察的基础上,大量风暴沉积被发现于不同剖面清虚洞组的不同层位中,同时大量风暴诱发形成的沉积构造被识别出来,包括侵蚀基底、粗粒滞留沉积、粒序层理、平行层理、丘状交错层理(少见并且值得怀疑)以及沙纹层理,组成了多种类型的风暴沉积序列。结合更靠扬子东南缘的深水剖面中重力流沉积的缺乏,可以推断早寒武世龙王庙期扬子地台的沉积模式为碳酸盐缓坡。结合风暴的形成机制以及清虚洞组风暴沉积的发育特征(尤其是粗粒滞留砾屑的定向排列和典型丘状交错层理的缺乏),可以推断研究区风暴沉积形成于强烈的冬季风暴作用,并且早寒武世龙王庙期华南的古地理位置应当位于中纬度地区,这一结论对一些著名的全球古地理重建方案提出了质疑。同时中纬度地区大规模发育蒸发岩和碳酸盐岩还佐证了寒武纪地球处于热室(Hothouse)时期。  相似文献   

Early Cretaceous K-rich rhyolites from the Duolong Cu–Au deposit,southern Qiangtang,China: evidence for crustal growth     

Wei Wang  Cai Li  Jian-Jun Fan  Wei Xu  Yu-Chao Dong 《International Geology Review》2018,60(9):1098-1115

We report new zircon U–Pb age, Hf isotopic, and major and trace element data for rhyolites from the Duolong Ore Concentration Area of the Southern Qiangtang Terrane. Building on previous studies, we constrain the tectonic setting and propose a model to explain the geodynamics and crustal growth during regional magmatism in the Early Cretaceous. The analysed rhyolites yield laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) zircon U–Pb ages of 115 and 118 Ma. The rocks are K-rich (K₂O = 6.66–9.93 wt.%; K₂O/Na₂O = 8.2–19.7 wt.%), alkaline and peraluminous (A/CNK = 1.02–1.46), and are characterized by high SiO₂ contents (72.8–78.8 wt.%) similar to highly fractionated I-type granites. Fractionation of Fe–Ti oxides, plagioclase, hornblende, Ti-bearing phases, apatite, monazite, allanite and zircon contributed to the variations in major and trace element chemistry. High K₂O contents are likely due to partial melting of the continental crust. The samples have positive zircon εHf(t) values ranging from +7.1 to +11.2. These features, together with young zircon Hf crustal model ages of 489–721 Ma, indicate that the K-rich rhyolites were derived from juvenile lower crust with an input of a mantle-derived component. We suggest that the Early Cretaceous K-rich rhyolites formed in a continental arc setting during northward subduction of Bangong Co–Nujiang oceanic lithosphere. Basaltic magma underplating was responsible for vertical crustal growth, triggered by slab roll-back in the Duolong Ore Concentration Area in the Early Cretaceous.  相似文献   

The terrestrial fauna of the Late Triassic Pant-y-ffynnon Quarry fissures,South Wales,UK and a new species of Clevosaurus (Lepidosauria: Rhynchocephalia)     

Emily Keeble  David I. Whiteside  Michael J. Benton 《Proceedings of the Geologists' Association. Geologists' Association》2018,129(2):99-119

Pant-y-ffynnon Quarry in South Wales yielded a rich cache of fossils in the early 1950s, including articulated specimens of new species (the small sauropodomorph dinosaur Pantydraco caducus and the crocodylomorph Terrestrisuchus gracilis), but no substantial study of the wider fauna of the Pant-y-ffynnon fissure systems has been published. Here, our overview of existing specimens, a few described but mostly undescribed, as well as freshly processed material, provides a comprehensive picture of the Pant-y-ffynnon palaeo-island of the Late Triassic. This was an island with a relatively impoverished fauna dominated by small clevosaurs (rhynchocephalians), including a new species, Clevosaurus cambrica, described here from a partially articulated specimen and isolated bones. The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of clevosaurs in the palaeo-archipelago. The larger reptiles on the palaeo-island do not exceed 1.5?m in length, including a small carnivorous crocodylomorph, Terrestrisuchus, and a possible example of insular dwarfism in the basal dinosaur Pantydraco.  相似文献   

渝东北城口地区Y1井页岩有机地球化学特征及勘探前景   总被引：1，自引：0，他引：1  

何廷鹏  栾进华  胡科  李甜  杨柳  张跃磊 《岩矿测试》2018,37(1):87-95

基于钻井资料,以总有机碳(TOC)、干酪根显微组分、等效镜质体反射率(Ro)及碳同位素等测试数据系统分析了渝东北城口地区Y1井五峰组—龙马溪组页岩的有机地球化学特征,利用页岩流体包裹体的显微特征、均一温度及激光拉曼数据深入分析了Y1井页岩气成藏特征。结果表明:Y1井上奥陶统五峰组—下志留统龙马溪组炭质页岩发育,TOC含量2%的富含有机质页岩厚度达83 m,干酪根类型以Ⅰ型干酪根为主,处于湿气生烃阶段。页岩裂缝脉体中大量烃包裹体和富含甲烷气体的含烃盐水包裹体证实城口地区五峰组—龙马溪组页岩发生了充足页岩气供给,具有高均一温度、高盐度的伴生盐水包裹体表明城口地区页岩气成藏时期的保存条件良好。这些Y1井页岩有机地球化学特征研究成果揭示了城口地区下古生界具备良好的页岩气勘探前景。  相似文献   

安徽省凤阳江山金矿床赋矿地层和相关岩浆岩锆石年代学研究及其意义     

陈杨  范裕  刘青  李朝维  黄岩  陈曦  王彪  刘一男 《矿床地质》2018,37(6):1217-1236

安徽省北部蚌埠隆起区被认为是山东胶东招远金成矿带以西的延伸部分,但蚌埠隆起区内之前一直未发现成规模的金矿床。江山金矿床是最近新发现的中型金矿床,区内成矿作用的时代、赋矿地层的归属仍缺乏系统的年代学证据。文章对蚌埠隆起区内江山金矿床的赋矿地层和相关岩浆岩开展系统的年代学研究,明确了赋矿地层时代归属,并限定了成矿时代的上限和下限。矿床赋矿围岩浅粒岩的结晶年龄为(2496±19)Ma,变质年龄为(2452±47)Ma;斜长角闪岩的变质年龄为(1824±11)Ma,对比区域地层岩性和时代,确定矿床的赋矿围岩为新太古代五河群西堌堆组,而非过去认为的庄子里组。矿床中穿切矿体的脉岩花岗闪长斑岩的结晶年龄为(121.2±1.4)Ma,代表成矿时代的下限;赋矿岩体巨斑花岗斑岩的结晶年龄为(128.3±1.7)Ma,代表了成矿时代的上限。通过与胶东金成矿带的对比,认为蚌埠隆起区与胶东地区的前寒武纪变质基底演化历史相似,江山金矿床的成矿作用类型属于胶东焦家式金矿,在此基础上,推测蚌埠隆起区西芦山岩体和淮光岩体有较大的成矿潜力。  相似文献   

西藏多龙矿区生态环境遥感调查研究     

王俊华 《地质与勘探》2018,54(4):781-790

本文依托项目《西藏多龙矿床技术经济与环境综合评价》,利用高分二号、资源三号及landsat8等多源遥感数据对西藏多龙矿区生态地质环境进行调查研究。通过遥感技术与实地调查结合,查明了矿区生态地质环境现状,取得了涵盖人类活动、矿山地质活动、河流湖泊现状、植被覆盖与荒漠化情况等内容的专题成果。研究结果表明,砂金矿开采及尾矿堆积物给当地生态环境造成不可逆破坏,同时探槽、钻孔及地表金属污染等也给生态环境带来一定程度的影响。通过对目前中国矿储量第一的多龙铜多金属矿床进行开发前全面、综合的生态地质环境调查研究,能够为藏北矿山开发对生态地质环境的影响评估提供科学依据,为西藏多龙矿区建设绿色矿山和绿色开发提供建议及决策依据。  相似文献