试论秦岭—大别山—胶南隆起—临津江褶皱带及其周缘地区的…

具有统一发展史和构造属性的中国华北－东北南部－朝鲜北部地区构成了东亚地区较大的稳定区－中朝古陆，大量的研究工作使得其内部及其南部的大地构造格局逐渐明朗化，作为中朝地台与其南侧的稳定区－扬子地台之间的过渡带－秦岭地槽的构造轮廓、构造属性、发展史也得到了进一步的厘定。由于郯庐断裂的影响，加之研究程度的限制，在该断裂以东，中一朝古陆与扬子地台的构造关系及其间过渡带－秦岭地槽的东部延伸问题一直困绕着人们，     

胶东-朝鲜半岛中朝扬子碰撞带初析

根据对胶东半岛北缘的栖霞陡崖剖面、胶莱盆地南缘的诸城皇华店剖面以及朝鲜半岛临津江群的野外露头地层、古生物、岩性等特征的研究,推论中朝与扬子碰撞带的南部界线位于皇华店至朝鲜军事分界线之南。     

黄海海域盆地构造演化特征与中、古生界油气勘探前景探讨

黄海海域跨越扬子和华北两个板块构造单元 ,发育了北黄海和南黄海两个盆地构造单元。扬子和华北板块在这里沿五连—荣城—朝鲜的临津江断裂构造带于晚三叠至早中侏罗世碰撞缝合 ,形成了与秦岭 -大别超高压变质造山带成因意义完全相同的苏北张八岭 -朝鲜临津江超高压变质造山带。北黄海盆地就位于该变质造山带北侧的华北板块上 ,而南黄海盆地则位于该变质带南侧的扬子板块上。地震剖面和北朝鲜钻井资料证实北黄海盆地是晚中生代早期 ( J3 —K1)和新生代的叠合盆地 ,盆地基底为晚印支—早燕山期碰撞花岗岩和前寒武纪变质岩 ,局部可能残留有古…     

对南黄海境内扬子准地台界限和演化的探讨

本文根据近两年来在南黄海海域新获得的多次复盖数字地震剖面、重磁测量和钻井资料结合地质部第一海洋地质调查大队、航空物探大队909队的工作成果,试对杨子准地台在黄海境内的界限和构造演化(主要是中、新生代)问题予以探讨,尚希同志们指正.一、扬子准地台在黄海境内的界限关于杨子准地台在南黄海海域的位置,尚无一致意见,以往的研究者多以嘉山—响水—千里岩断裂带作为扬子准地台北界;后有人推测该界限可能位于从朝鲜临津江褶皱带经南黄海北缘至青岛、诸城一带,并提出临津江褶皱带乃是秦岭褶皱系的东延部分,后受郯庐断裂带的切割产生位移.地质矿产部第一海洋地质调查大队的同志们认为:苏北盆地的基底是所谓“鲁苏地盾”和扬子准地台的一部共同组成,二者之间,除古生界—中生界中、下三叠统盖层不断增厚、且呈过渡关系外,并无明显界限可寻.最近,江苏区测队在完成苏北地区1:20万地质测量工作后,根据基底时代、主要岩性、矿产及莫霍面深度等指出:扬子准地台与中朝准地台之间的界限应以海(州)-泗(阳)断裂带为界,详见表1.     

南黄海卫星重力场及构造演化

利用美国国家航空航天局1998年公布的EGM96全球重力模型,计算了南黄海区32°～37°N、120°～126°E范围内的2～360阶卫星重力场,分析了该区的卫星重力异常场特征,将南黄海区的卫星重力异常划分为8个异常区,长期的板块运动结果控制了该区的重力异常格局。晚二叠纪至早三叠纪,华北与华南古陆在秦岭—大别山—胶南—临津江带碰撞对接,南黄海区经历了一次造山运动,由此产生的挤压剪切形成南黄海盆地雏形,当时的沉积中心在南黄海中部隆起区。侏罗纪—白垩纪,Izanagi板块在亚洲大陆下向西北方向俯冲,南黄海区发生了剧烈的构造岩浆活动。晚白垩世,在拉张构造环境下发生张裂裂陷作用,南黄海区北部坳陷和南部坳陷分别裂陷,出现雏形,揭开了新生代盆地的序幕。新生代印度板块、欧亚板块及太平洋板块运动促使原坳陷区即中部隆起区上升,南、北两个断陷盆地发展成为两大坳陷。晚第三纪末期至第四纪,南黄海盆地进入区域沉降阶段。     

法尔维海盆构造特征及演化

法尔维海盆位于西南太平洋海域豪勋爵海丘东侧、新喀里多尼亚岛西侧，是全球油气勘探的前沿地区。但目前对于该海盆的构造演化研究较为薄弱，限制了该海盆油气资源的进一步勘探开发。本文通过从新西兰塔斯曼海数据库搜集到大量地球物理资料，使用2D Move软件，通过平衡剖面技术进行构造演化模拟，结合区域动力学机制将海盆北部和南部的构造演化分为7个阶段:(1)早白垩世至晚白垩世陆内裂谷阶段；(2)晚白垩世断坳过渡阶段；(3)始新世早期坳陷阶段；(4)始新世晚期一次构造反转阶段；(5)始新世至渐新世热沉降阶段；(6)渐新世至中新世二次构造反转阶段；(7)中新世至今海洋沉降阶段。由于海盆中部未发现有明显的二次构造反转阶段，所以将海盆中部的构造演化划分为5个阶段:(1)早白垩世至晚白垩世陆内裂谷阶段；(2)晚白垩世断坳过渡阶段；(3)始新世早期坳陷阶段；(4)始新世晚期构造反转阶段；(5)中新世至今海洋沉降阶段。此阶段海盆整体下坳，逐渐形成现今样貌。法尔维海盆北部受到区域构造活动影响较大，白垩系地层发育较多的断裂构造；海盆中部晚白垩统地层发生较多的底辟构造；海盆南部从形成至今，受到构造活动影响较小，发育地层完整，前新生代地层较厚。整个法尔维海盆北部构造活动较强，中部较弱，南部较小。沉积地层从北到南由厚变薄。     

下扬子陆域下寒武统烃源岩特征及其对南黄海油气勘探的借鉴

早寒武世下扬子陆块与华夏陆块均向北漂移并拼合成南方古陆,发生褶皱隆升,但对下扬子陆块北部(现今下扬子地区)影响不大,总体处于浅海台地相。因为早寒武世早期受上升流等因素的影响,下扬子地区早寒武世有机质来源丰富,在缺氧还原的沉积环境形成了优质烃源岩。下扬子地区下寒武统烃源岩呈NE向展布,受"一台两盆"构造格局影响存在2个沉积中心:一个在安吉—休宁深水陆棚区,厚度100~300m;另一个在泰州—盐城深水陆棚区,厚度50~150 m。海侵主要来自东北方向,烃源岩向东北方向减薄。从陆域烃源岩厚度分布趋势看,南黄海盆地烃源岩厚度应在50~200m之间。中生代南方古陆与华北陆块拼合形成中国大陆时,对下扬子古生代形成的油气藏产生了严重的破坏。台缘相烃源岩厚度大、埋深大、生烃早,生成的油气藏在中生代南北陆拼贴期遭到破坏,是现今古油藏的烃源供给者。我们推测南黄海下寒武统为台地相沉积,埋藏相对较浅,热演化程度相对较低,大部分烃源岩可能在燕山中—晚期发生过二次生烃,有利于常规油气藏的保存。     

南海及周边部分地区特提斯构造遗迹:问题与思考

对全球二叠纪－三叠纪古气候特征的研究表明，东特提斯地区晚三叠世古气候标志具有带状分布的特征。北巴拉望地块卡拉棉群岛科龙岛的晚三叠世沉积中发育反映较干燥古气候特征的鲕状灰岩，因此在古气候特征方面，北巴拉望地块晚三叠世地层不能与华南和印支地块同期地层对比，而应该与印度地块北缘喜马拉雅地区（向西）和琉球群岛（向东）对比。根据该古气候分析，北巴拉望地块在晚三叠世时应该位于南部亚热带较干燥气候带内，其晚三叠世的古地理位置比印支地块更靠南。对南海及南海周边部分地特提斯构造遗迹的研究，将有助于深入了解南海北部陆缘区相关构造带的性质及正确恢复南海扩张之前该区的地质发展历史。南海北部陆缘区也是研究解决特提斯构造向东延伸问题以及特提斯构造－太平洋构造时空转化问题的关键地区。     

古巴蛇绿岩侵位

根据岩性和构造特征，古巴划分出三套含蛇绿岩的构造单元：1）北部蛇绿岩带，混杂岩复合体沿古巴岛延伸长度超过1000km；2）白垩纪火山弧建造的变质岩基底；3）中古巴南部Escambray（Guamuhaya）高压变质地块中的构造片体。现有年龄分析资料表明，古巴现存洋壳年代为晚中生代，形成于两种不同的构造背景；1）晚侏罗世-纽康曼期，北美大陆及其南部大陆的漂移造成的小盆地；2）北美被动大陆边缘与阿普第-阿尔必（Aptian—Albian）期火山弧之间形成的俯冲带上部（suprasubduction）边缘盆地。Escambary（Cuamuhaya）地块中生代变质沉积岩中的蛇纹岩片体和高压角闪石形成于一小型洋盆关闭期间．时代很可能为阿尔必（Albian）期。火山弧岩层的变质岩基底来自于上侏罗统-纽康曼阶洋壳，并在中自垩世火山弧形成期间发生变质。北部蛇绿岩带可能来自上述小盆地，以及俯冲边缘盆地的，并自晚白垩世坎佩尼（Campanian）期至始新世中期发生多次侵位。古巴不同的蛇绿岩类型代表了南北美大陆之间泛古陆解体后形成的洋壳的残余物（加勒比洋盆原型）。文章提出并讨论了一种可能的板块构造模型。     

中卫及周缘地区石炭纪主要海泛期沉积体系

中卫及周缘地区位于阿拉善地块、华北板块、北祁连加里东造山带之间,该区上古生代受区域构造和全球海平面变化影响,地层发育与华北地区有较大差异。通过收集整理3条野外实测地质剖面及19条剖面资料,根据剖面岩性、沉积结构、构造、沉积旋回等,对中卫及周缘地区石炭纪岸线变迁、沉积范围、主要海泛期沉积体系及沉积相的纵向演变规律进行了研究。将研究区石炭系地层划分为三角洲、堡岛、碳酸盐岩台地、浅海4类沉积体系。早石炭世早期,南秦岭洋的海水开始入侵研究区南部,沉积范围呈狭长带东西向展布;早石炭世晚期海侵范围逐步向北、向东扩大,于早石炭世形成由阿拉善古陆、鄂尔多斯、北祁连围成的祁连海沉积区。早石炭世海水较深,沉积物以厚层灰岩为主,碳酸盐岩台地和堡岛沉积体系较为发育。晚石炭世海侵继续向北、向东扩大,晚石炭世晚期研究区祁连海与华北陆表海在中央古隆起北部汇合;早二叠世早期,中央古隆起没于水下,祁连海与华北海已广泛连通。晚石炭世至早二叠世早期海平面变化频繁,海水较浅,沉积物以碎屑岩为主并夹有灰岩,主要发育三角洲沉积体系、堡岛沉积体系以及浅海沉积体系。     

胶东—苏北构造带特征及动力学演化

提出胶东—苏北构造带以广泛出露榴辉岩和超基性岩、普遍发育韧性剪切带和糜棱岩带为特征,具混杂岩特点。它经历了早元古代大陆推覆构造事件(2000～2400Ma)、早元古代末低角闪岩相变质热事件(1800～2000Ma)和元古代末大陆推覆构造事件(6O0～800Ma)。该构造带是华北陆块与华南陆块之间的过渡带。     

东海陆架新生代砂岩锆石U-P年龄及其地球动力学意义

东海陆架西部凹陷带古新统砂岩锆石的U-P年龄表明,陆架西部古新世物源以中生代母岩为主,其次为元古代变质岩及少量古生代母岩。东海陆架东部凹陷带渐新统砂岩锆石的U-P年龄表明陆架东部渐新世物源以元古代变质岩为主,其次为中生代母岩及少量太古代变质岩与古生代母岩。陆架西部古新统砂岩锆石的U-P年龄与闽浙隆起带露头及钻孔揭示的基岩一致,而陆架东部渐新统砂岩锆石的U-P年龄比西部老。根据上述砂岩锆石U-P年龄,可以推测古近纪东海陆架盆地发育过程中,东海陆架东部地势较高。单颗粒锆石REE配分模式表明元古代锆石轻稀土(LREE)明显比其他样品高且含量相近,Ce正异常不明显;中生代锆石Ce正异常明显,但同时Eu负异常也很明显,与中生代基岩锆石相似;古生代锆石稀土元素含量偏低,La含量明显超过其他轻稀土元素。根据上述特征可以清晰指示砂岩的母岩类型与年代,推断古新世东海大陆架的基底性质与构造背景。     

Distribution of Some Rare and Trace Elements in Ice-Rafted Sediments in the Yermak Plateau Area,the Arctic Ocean

The distribution of V, Co, Ni, Sr, Nb and rare earth elements (REE) in ice-rafted sediments (IRS) collected in the Yermak Plateau area (the Arctic Ocean) during cruise ARK-XX/3 of the R/V Polarstern in September 2004 has been analyzed. It was determined that the Nb/V ratio in these IRS has an intermediate value between the average ratio values in suspended particulate matter of the Yenisei and Khatanga rivers and Mesozoic–Cenozoic basalts, on the one hand, and suspended matter of the Ob and Lena rivers and post-Archean Australian Shale (PAAS), on the other hand. The REE distribution demonstrates the same pattern. The IRS data points in Nb-Sr, Ni-Co, and Co-Sr and some other diagrams are close mainly to the average chemical composition of suspended particulate matter of the Ob and Lena rivers, i.e., waterways draining watersheds composed predominantly of sedimentary rocks. The Nb, Sr, Ni, and Co contents in the studied IRS samples are close to those in the PAAS. In accordance with this, we were able to conclude that the main provenance areas of the studied IRS samples are situated in the eastern part of the Laptev Sea and the East Siberian Sea, on shelf of which the erosion products of sedimentary and metamorphic rocks of the Verkhoyansk Fold Belt dominate.     

渤海及周边地区中新生代构造演化与火山活动

渤海湾盆地作为典型的中新生代叠合盆地,构造演化历史十分复杂,经历了多期构造演化,盆地的构造演化与东亚大陆大地构造环境密切相关。本文从板块相互作用的角度出发,综合大量文献资料,划分渤海湾盆地中、新生代构造演化为3个阶段,中生代盆地发育演化阶段、早第三纪裂陷盆地发育阶段和晚第三纪坳陷盆地发育阶段。通过对渤海地区代表性火山岩样品的岩石化学分析、微量元素及稀土元素中子活化分析结果进行岩石化学和地球化学分析,综合前人研究成果,探讨了渤海及周边地区地质构造演化特征与火山活动之间的耦合关系。     

Sequence stratigraphic framework of Proterozoic successions in eastern Brazil

First-order regional unconformities separate Proterozoic supracrustal rocks of the gas-bearing São Francisco craton and surrounding thrust-and-fold belts (eastern Brazil) into four genetic stratigraphic units, which constitute 1st-order basin-fill sequences (Espinhaço, Canastra–Paranoá–Vazante, Macaúbas and Bambuí sequences).     

Provenance identification and sedimentary analysis of the beach and bar systems in the Palaeogene of the Enping Sag,Pearl River Mouth Basin,South China Sea

During deposition in the Palaeogene, the Pearl River Mouth Basin (Enping Sag) was filled by sediments derived from northern and southern source regions. The northern sources are the fold belt Caledonian and Hercynian metamorphic rocks that are widely exposed along the South China block and stacked with Mesozoic igneous rocks, and the southern sources are Mesozoic igneous rocks from the southern Panyu lower uplift. We analysed the characteristics of the provenance and sediment-dispersal patterns of the beach and bar systems in the Palaeogene third-order sequence framework on the basis of detritus, thin section, zircon and the geophysical response test data. The source and deposition areas were distinguished based on their palaeogeomorphology. The sedimentary material composition of the deposition area was determined based on the characteristics of the detrital assemblage and cathode luminescence, and the characteristics of the age distribution were determined in detail using detrital zircon U–Pb dating. This study suggests that the provenance system in the Palaeogene mainly consisted of Palaeozoic metamorphic rocks and Mesozoic igneous rocks, with a supplement of Proterozoic metamorphic rocks. The transport capacity of three large fault troughs that delivered the northern provenances gradually increased from the Wenchang Formation (E₂w) to the Enping Formation (E₃e), whereas the southern provenances were transported by four or five incised valleys in E₂w and then submerged in E₃e. In the 3D seismic area, the features of the beach and bar sedimentary systems were described and interpreted based an analysis of the well-based sedimentary facies, seismic reflection characteristics and multiple attribute clustering. The results show that the beach and bar systems by the short-axis braided deltas mainly developed in the upper member of E₂w and that the beach and bar systems on the subaqueous high in E₃e developed during the Palaeogene. In addition, the bedrock-beach bar sedimentary system in the lower member (E₃e^L) was transferred to the braided delta–beach bar sedimentary system in the upper member (E₃e^U).     

北黄海海域的重磁场特征及其地质意义

北黄海是我国近海勘探程度最低的海区,到目前为止只进行了地球物理调查工作,没有进行钻探。根据最新的重磁数据,详细地分析了北黄海海域的重磁场特征、构造特征、基底岩相构造和岩浆岩分布。通过重磁数据处理解释推测认为:两条NW向的次级隆起将海洋岛隆起与刘公岛隆起连接起来,同时将北黄海盆地分成3部分;研究区内断裂非常发育,即有切割较深的深大断裂,又有一般的基底断裂,还存在许多较小的断裂;基底为太古界—元古界变质岩;区内岩浆岩分布广泛,以燕山期中酸性侵入岩为主。     

Origin of crude oils from oilfields in the Zagros Fold Belt,southern Iraq: Relation to organic matter input and paleoenvironmental conditions

Crude oil samples from Cretaceous and Tertiary reservoir sections in the Zagros Fold Belt oil fields, southern Iraq were investigated using non-biomarker and biomarker parameters. The results of this study have been used to assess source of organic matter, and the genetic link between oils and their potential source rocks in the basin. The oils are characterized by high sulphur and trace metal (Ni, V) contents and relatively low API gravity values (17.4–22.7° API). This indicates that these oils are heavy and generated from a marine source rock containing Type II-S kerogen. This is supported by their biomarker distributions of normal alkanes, regular isoprenoids, terpanes and steranes and the bulk carbon isotope compositions of their saturated and aromatic hydrocarbons. The oils are characterized by low Pr/Ph ratios (<1), high values of the C₃₅ homohopane index and C₃₁-22R/C₃₀ hopane ratios, relatively high C₂₇ sterane concentrations, and the predominance of C₂₉-norhopane. These biomarkers suggest that the oils were generated predominantly from a marine carbonate source rock, deposited under reducing conditions and containing plankton/algal and microorganisms source input. The presence of gammacerane also suggests water column stratification during source rock deposition.The biomarker characteristics of the oils are consistent with those of the Middle Jurassic Sargelu carbonate as the effective source rock in the basin. Biomarker maturity data indicate that the oils were generated from early maturity source rocks.     

中太平洋海山富钴结壳与基岩关系的研究

对我国首次取得的中太平洋海山基岩和富钴结壳样品的结构构造、矿物和化学组成特征的研究表明,该区主要基岩类型为碱性玄武岩、磷块岩、磷酸盐化碳酸盐岩和燧石等,碱性玄武岩分布最广,并均有不同程度的风化.观察表明,富钴结壳的载体可以是各种岩性的基岩.玄武岩、风化火山岩和磷块岩上的结壳厚度比燧石的大,有较高的经济价值,是选矿冶炼的主要对象.对于调查区内富钴结壳形态总体上可分为三种类型:板状、砾状和结核状结壳.从以下四个方面探讨结壳与基岩之间的关系:(1)海水、基岩和结壳中主要金属元素含量特点;(2)通过聚类分析方法探讨结壳与基岩之间的亲疏程度;(3)结壳的分布特征;(4)不同基岩类型对结壳生长的影响.分析结果表明,调查区内的火山岩及磷块岩对结壳形成的贡献大(比其他类型岩石).     

Upper Miocene–Pliocene provenance evolution of the Central Canyon in northwestern South China Sea

Provenance studies of the Central Canyon, Qiongdongnan Basin has provided significant insights into paleographic and sedimentology research of the South China Sea (SCS). A suite of geochemical approaches mainly including rare earth elemental (REE) analysis and detrital zircon U–Pb dating has been systematically applied to the “source-to-sink” system involving our upper Miocene–Pliocene Central Canyon sediments and surrounding potential source areas. Based on samples tracing the entire course of the Central Canyon, REE distribution patterns indicate that the western channel was generally characterized by positive Eu anomalies in larger proportion, in contrast to the dominance of negative values of its eastern side during late Miocene–Pliocene. Additionally, for the whole canyon and farther regions of Qiongdongnan Basin, the number of samples bearing negative Eu anomalies tended to increase within younger geological strata. On the other hand, U–Pb geochronology results suggest a wide Proterozoic to Mesozoic age range with peak complexity in Yanshanian, Indosinian, Caledonian and Jinningian periods. However in detail, age combination of most western samples displayed older-age signatures than the eastern. To make it more evidently, western boreholes of the Central Canyon are mainly characterized with confined Indosinian and Caledonian clusters which show great comparability with mafic-to-ultramafic source of Kontum Massif of Central Vietnam, while eastern samples largely bear with distinguishable Yanshanian and Indosinian peaks which more resemble with Hainan Island. Based on geochemistry and geochronology analyses, two significant suppliers and sedimentary infilling processes are generated: (1) the Indosinian collision orogenic belt in central-northern Vietnam, Indochina has ever played significant role in Central Canyon sedimentary evolution, (2) Hainan Island once as a typical provenance restricted within eastern Central Canyon, has been enlarging its influence into the whole channel, even into the farther western regions of Qiongdongnan Basin.