Two new species of the genus <Emphasis Type="Italic">Cobitis</Emphasis> Linnaeus (Teleostei: Cobitidae) from southern China     

陈咏霞  隋晓云  梁娜  陈毅峰 《中国海洋湖沼学报》2016,34(3):517-525

Two new species of the genus Cobitis from southern China, C. hereromacula from the Luohe River in Guangdong Province and C. baishagensis from the Nandujiang River in Hainan Province, are described and illustrated here. C. hereromacula can be distinguished from its congeners by possessing the following combination of characteristics: absence of the second and third pigmentary zones of Gambetta; 13–16 oval blotches on the dorsum and 10–13 vertical, elongated triangular blotches below the midlateral line with more than 20 vertical dark brown bars between them; 6–7 narrow rows of dark spots on the caudal fin; a vertical oval spot smaller than the eye diameter on the upper part of the caudal peduncle; pointed mental lobes of the lower lip pointed with a slightly filiform tip; one slender and long needle-shaped lamina circularis at the base of the first branched ray of the male pectoral fins. C. baishagensis can be distinguished from its congeners by the fourth Gambetta zone being covered by 10–12 transverse elongated blotches; 4–5 narrow rows of dark spots on the caudal fin; a vertical blotch smaller than the eye diameter on the upper part of the caudal peduncle; males with a slender and long needle-shaped lamina circularis at the second branched pectoral fin ray in males; large scales with a slightly large focal zone; undeveloped mental lobes with a lower lip that does not end posteriorly in a filiform tip.  相似文献   

滇西丽江地区新生代富碱斑岩年代学、地球化学特征及其地质意义   总被引：2，自引：0，他引：2  

黄永高  罗改  张彤  熊昌利  贾小川  杨学俊 《现代地质》2018,32(1):28

滇西丽江地区新生代富碱斑岩位于滇西“三江”褶皱造山带与扬子板块西南缘结合部位,岩石类型多样,可分为碱性岩和碱性花岗岩,前者主要有正长斑岩、正长岩及粗面斑岩;后者主要包括花岗斑岩、二长花岗斑岩及石英二长斑岩。锆石LA ICP MS U Pb定年研究确定区内斑岩结晶年龄为346～371 Ma,侵位于始新世晚期。碱性岩石的SiO2含量为5454%～6770%,K2O＞Na2O,具有钾玄岩的特征;碱性花岗岩的SiO2含量为6716%～7066%,K2O＜Na2O,具有高钾钙碱性的特征。两类岩石都具有富碱(Na2O+K2O=703%～1170%)和准铝质—弱过铝质(A/CNK=064～115)的特征。富集轻稀土元素和大离子亲石元素(Sr、Ba、K、Pb等),相对亏损重稀土元素和高场强元素(Nb、Ta、Ti等),且具有高Sr、Sr/Y和La/Yb比值及低Y、Yb和镁值(Mg#＜05),表明区内斑岩兼具钾玄质岩石和埃达克质岩石的特征。综合研究认为,区内斑岩形成于印度－亚洲大陆碰撞造山的后碰撞阶段,其形成与减压熔融及幔源岩浆底侵促使增厚下地壳底部岩石发生部分熔融有关,是青藏高原东南缘构造转换带对主碰撞带造山作用过程的岩浆事件响应,进而分析确认本区具有斑岩-热液型金多金属矿床的找矿潜力,为深入认识丽江地区构造-岩浆-成矿作用提供了重要约束。  相似文献   

川西坳陷东坡沙溪庙组气藏成藏演化模式   总被引：1，自引：0，他引：1  

徐敏  刘建  林小云  熊山  牛斌莉 《现代地质》2018,32(5):953

川西坳陷东坡气藏主力产层为沙溪庙组,其圈闭类型以构造-岩性圈闭为主,多为致密砂岩储层,但断层发育,有效改善了储层物性,断砂匹配样式与构造演化对油气成藏过程有重要影响。基于前人已有的认识,通过沙溪庙组气藏成藏动力演化、气水分布特征及生烃期次分析,结合构造演化、成藏幕次等研究,认为沙溪庙组天然气成藏受构造古隆起、断砂配置、储层物性、构造演化影响,形成了“构造控向、断砂控运、储层控藏、演化控调”的成藏演化模式,同中存异,高庙子地区古构造的控制作用更为明显,而中江地区岩性控制作用占主导。沙溪庙组气藏间歇性充注具“燕山期三幕成藏,喜山期调整改造”的成藏特征,多期构造演化和较强的储层非均质性影响了含气饱和度,导致沙溪庙组气藏分布、气藏产能差异大。  相似文献   

Petrology and PGE Abundances of High‐Cr and High‐Al Podiform Chromitites and Peridotites from the Bulqiza Ultramafic Massif,Eastern Mirdita Ophiolite,Albania     

QIU Tian  YANG Jingsui  MILUSHI Ibrahim  WU Weiwei  MEKSHIQI Nezir  XIONG Fahui  ZHANG Cong  SHEN Tingting 《《地质学报》英文版》2018,92(3):1063-1081

The Bulqiza ultramafic massif, which is part of the eastern Mirdita ophiolite of northern Albania, is world renowned for its high-Cr chromitite deposits. High-Cr chromitites hosted in the mantle section are the crystallized products of boninitic melts in a supra-subduction zone (SSZ). However, economically important high-Al chromitites are also present in massive dunite of the mantle-crust transition zone (MTZ). Chromian-spinel in the high-Al chromitites and dunites of the MTZ have much lower Cr# values (100Cr/(Cr+Al)) (47.7–55.1 and 46.5–51.7, respectively) than those in the high-Cr chromitites (78.2–80.4), harzburgites (72.6–77.9) and mantle dunites (79.4–84.3). The chemical differences in these two types of chromitites are reflected in the behaviors of their platinum-group elements (PGE). The high-Cr chromitites are rich in IPGE relative to PPGE with 0.10–0.45 PPGE/IPGE ratios, whereas the high-Al chromitites have relatively higher PPGE/IPGE ratios between 1.20 and 7.80. The calculated melts in equilibrium with the high-Cr chromitites are boninitic-like, and those associated with the high-Al chromitites are MORB-like but with hydrous, oxidized and TiO2-poor features. We propose that the coexistence of both types of chromitites in the Bulqiza ultramafic massif may indicates a change in magma composition from MORB-like to boninitic-like in a proto-forearc setting during subduction initiation.  相似文献   

Petrological and Os Isotopic Characteristics of Zedong Peridotites in the Eastern Yarlung–Zangbo Suture in Tibet     

LAI Shengmin  YANG Jingsui  Yildirim DILEK  XIONG Fahui  JIANG Rui  CHEN Yanhong 《《地质学报》英文版》2018,92(2):442-461

The Zedong ophiolites in the eastern Yarlung–Zangbo suture zone of Tibet represent a mantle slice of more than 45 km~2. This massif consists mainly of mantle peridotites, with lesser gabbros, diabases and volcanic rocks. The mantle peridotites are mostly harzburgite, lherzolite; a few dike-like bodies of dunite are also present. Mineral structures show that the peridotites experienced plastic deformation and partial melting. Olivine(Fo89.7–91.2), orthopyroxene(En_(88–92)), clinopyroxene(En_(45–49) Wo_(47–51) Fs_(2–4)) and spinel [Mg~#=100×Mg/(Mg+Fe)]=49.1–70.7; Cr~#=(100×Cr/(Cr+Al)=18.8–76.5] are the major minerals. The degree of partial melting of mantle peridotites is 10%–40%, indicating that the Zedong mantle peridotites may experience a multi–stage process. The peridotites are characterized by depleted major element compositions and low REE content(0.08–0.62 ppm). Their "spoon–shaped" primitive–mantle normalized REE patterns with(La/Sm)_N being 0.50–6.00 indicate that the Zedong ultramafic rocks belong to depleted residual mantle rocks. The PGE content of Zedong peridotites(18.19–50.74 ppb) is similar with primary mantle with Pd/Ir being 0.54–0.60 and Pt/Pd being 1.09–1.66. The Zedong peridotites have variable, unradiogenic Os isotopic compositions with ~(187)Os/~(188)Os=0.1228 to 0.1282. A corollary to this interpretation is that the convecting upper mantle is heterogeneous in Os isotopes. All data of the Zedong peridotites suggest that they formed originally at a mid-ocean ridge(MOR) and were later modified in supra–subduction zone(SSZ) environment.  相似文献   

FTIR spectroscopy data and carbon isotope characteristics of the ophiolite-hosted diamonds     

XU Xiangzhen  Pierre CARTIGNY  YANG Jingsui  Yildirim DILEK  XIONG Fahui  GUO Guolin 《《地质学报》英文版》2018,92(Z2):38-38

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Petrogenesis and PGE abundances of high-Cr and high-Al chromitites and peridotites from the Bulqiza Ultramafic Massif, eastern Mirdita Ophiolite, Albania     

QIU Tian  YANG Jingsui  Ibrahim MILUSHI  WU Weiei  Nezir MEKSHIQI  XIONG Fahui  ZHANG Cong  SHEN Tingting 《《地质学报》英文版》2018,92(Z2):25-25

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Detailed structure of the lithosphere and deep dynamics beneath the Three River belt and western edge of the Yangtze craton     

LI Qiusheng  FENG Shaoying  BAI Zhiming  GAO Yuan  GAO Song  XIONG Xiaosong  WANG Xiaoran 《《地质学报》英文版》2018,92(Z1):45-46

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中国航磁大地构造单元划分   总被引：4，自引：3，他引：1       下载免费PDF全文

熊盛青  杨海  丁燕云  李占奎 《中国地质》2018,45(4):658-680

本文以我国截止到2011年基本覆盖陆域及部分海域的航磁数据编制的全国航磁系列图为基础,以航磁反映的区域磁场和磁性基底起伏特征为依据,汲取主流大地构造观的划分理念,以板块构造理论及大陆动力学思想为指导,以磁场反映的构造特征为切入点,结合重力、遥感、地质资料对中国陆域构造单元进行划分。大地构造单元划分4个级别:一级构造单元为陆块区和造山系,共划分出8个;二级构造单元为陆块、弧盆系和地块,共划分出32个;三级构造单元为盆地、坳陷带(区)和隆起带(区),共划分出85个;四级构造单元为隆起和坳陷,共划分出332个。本划分方案旨在为油气地质构造背景研究及油气勘探提供一份地球物理资料。文中重点讨论了一、二级构造单元界线厘定的磁场依据及与前人划分存在的不同之处,而三、四级构造单元完全依据磁场及磁性基底起伏情况进行划分,并在盆地和坳陷区给出了深度信息,这为油气勘探者提供了必要的技术支撑。同时,借助丰富的航磁信息提示出一些地质构造方面难解现象,供同行专家参考与讨论。  相似文献   

锚固岩体的单轴压缩力学特性及其各向异性特征分析          下载免费PDF全文

熊良宵  虞利军 《水文地质工程地质》2018,(4):46-52

通过对含有锚杆的水泥砂浆试件进行单轴压缩试验,系统地研究了锚杆的布置方式对试件强度和变形特性的影响。研究结果表明:(1) 当锚杆横截面的连线呈直线或者正方形时,随着锚杆数量的增加,试件的抗压强度、弹性模量均会逐渐增加,试件峰值应变的变化没有固定规律;(2) 当锚杆横截面的连线呈直线时且试件中的锚杆数量相同时,荷载方向垂直于锚杆横截面的连线时试件的抗压强度和弹性模量,大于荷载方向平行于锚杆横截面的连线时试件的抗压强度和弹性模量。  相似文献