燕山地区印支期构造应力场的计算分析

在区域构造解析的基础上,作者建立起燕山地区印支期古构造应力场,并利用有限元迭代法进行了构造应力场的数学模拟,取得了较为满意的结果。      

Clay mineralogy of an Eocene fluvial-lacustrine sequence in Xining Basin,Northwest China,and its paleoclimatic implications

The Eocene was marked by significant cooling during which the global climate was transformed from greenhouse to icehouse conditions. Notable coeval events were the India-Asia collision and the retreat of the Paratethys Sea in Asia. The Eocene section of the long and continuous sedimentary succession of the Xining Basin in Northwest China is characterized by red mudstones with intercalated gypsum and muddy-gypsiferous layers. In this study, we conducted a semi-quantitative analysis of the mineralogy of bulk samples and the clay fraction using X-ray diffraction, with the aim of characterizing the Eocene climatic evolution of the northeastern margin of the Tibetan Plateau and inland Asia. We used a new pretreatment method to address the problem of extracting sufficient clay particles from the gypsum and gypsiferous layers. The bulk mineralogy is dominated by quartz, feldspar, calcite, gypsum and dolomite; and the clay mineralogy is dominated by illite, chlorite, and smectite(including irregular mixed-layer illite-smectite(I/S)). The variations of the clay mineral assemblages indicate the occurrence of alternations between warm humid conditions and hot dry conditions, with relatively high humidity during ～52–50,～41.5–39 and ～35–34 Ma. Comparison of the results with the timing of Tibetan Plateau uplift, transgressions and regressions of the Paratethys Sea, and the marine oxygen isotope record suggest that the Eocene climatic evolution of the study region was driven fundamentally by global climate change.     

西湖凹陷始新世平湖运动的地质表征及其油气地质意义

针对西湖凹陷始新世平湖运动认识不深入的问题,以三维地震资料精细解释和综合地质分析为基础,系统总结了西湖凹陷平湖运动的地质表征.研究表明,平湖运动是西湖凹陷一次重大的构造事件,控制了始新世伸展应力场从前平湖组沉积时期的北西-南东向转为平湖组沉积时期的北西西-南东东向.在平湖运动过程中,西湖凹陷构造变形和沉积充填发生了巨大...     

东太平洋地区573孔始新世末-渐新世初地层矿物学

根据Ｘ射线衍射分析结果,对东太平洋地区妈新世末－渐新世初的地层进行了矿和学研究。始新世末的含金属粘土层,矿物组合比较复杂,含有蒙脱石、针铁矿、重晶石、方英石、伊利石、石英、斜发沸石、钙十字沸石等多种矿物,且该粘土层（顶、底部除外）不含方解石,说明它的沉积环境处在方解石补偿深度以下,突变的海洋沉积环境和含金属粘土层中有微玻璃陨石以及富含指示地外成因的Ｎｉ、Ｃｏ、Ｉｒ等亲铁元素的存在,推测该金属粘土层     

可可西里北缘中新世火山活动带的基本特征

可可西里北缘火山活动带为可可西里中新世火山活动区数条火山活动带之一,其特征十分典型。本文以火山地质、同位素、岩石化学以及稀土元素地球化学为基础对其岩浆来源、演化、火山活动规律进行了研究。该火山带粗安岩-粗面岩-亚碱性流纹岩组合与世界高原溢流玄武岩类似,同时反映大陆伸展的构造环境。     

论浙江东部早白垩世中期断陷事件和断陷岩套

早白垩世中期中国东南部发生过一次断陷事件,并形成一事件地层单元——断陷岩套。叙述了断陷岩套的形成机理、特征和类型,并利用事件地层单元同时性原理,论证了建组剖面"塘上组"的层位与永康群下部馆头组相同,而非高居永康群之上的"新构造亚层";也论证了嵊县三界一带的所谓"大爽组二段"应为馆头组。这两个断陷岩套中所含生物群证实:事件地层学原理所得的关于其层位与时代的结论是正确的。     

Approaches to stratigraphy of the paleogene volcanogenic sequences in northwestern Kamchatka

“Volcanogenic Complex” as a stratigraphic term is substantiated. Also discussed are peculiarities of the volcanic process, the nature and evolution time of the volcanic structures, the complete and incomplete volcanic cycles. Data of comprehensive geological, stratigraphic and paleovolcanologic study are used to subdivide the Kinkil’skii Formation of Paleogene volcanogenic rocks in the northwestern Kamchatka, which has undivided previously, into the Shamanka, Rebro, Bozhedomova, and Geeklen volcanogenic complexes of concurrent or different ages. As a result, two epochs of volcanism (the late Ypresian-Lutetian and late Bartonian-Priabonian) are distinguished. A hiatus separating the epochs was a time of intense scouring and leveling the landforms and of the weathering crust formation. In conclusions, some problems of the paleogeography in Kamchatka and adjacent territories are discussed.     

New data on the Baraba Formation age (the Sredinnyi Range of Kamchatka)

In the Sredinnyi Range of Kamchatka, the Baraba Formation of continental conglomerates is assumed to be of the late Campanian age based on found flora remains, but data of isotopic geochronology suggest the Eocene age of these deposits. New data on radiolarians from cherty pebbles are considered in this work along with results of fission-track dating of zircons from pebbles and matrix of the Baraba conglomerates. Fission-track dates obtained for zircons from matrix approve the Eocene age of the Baraba Formation, and new dates characterizing pebbles are not contradicting this conclusion. The Baraba Formation structural position can hardly be lower, therefore, than that of the Irunei Formation.     

A point-sourced calciclastic submarine fan complex (Eocene Anotz Formation, western Pyrenees): facies architecture, evolution and controlling factors

A complete transect of a fossil carbonate ramp slope has been reconstructed using outcrop data from the Lower-Middle Eocene Anotz Formation in the western Pyrenees. The Anotz Formation contains four calciclastic (mostly bioclastic) members encased within hemipelagic marl/limestone alternations, each calciclastic member representing a submarine fan system. Individual fans are composed of a gullied upper slope, a leveed feeder channel, a channelized lobe area, an unconfined lobe zone and a peripheral lobe fringe that grades downcurrent into basinal deposits. Quantitative data on the dimensions and degree of lateral continuity and vertical connectivity of the Anotz calciclastic fan elements are presented. These data provide information for a better understanding of the intrinsic nature of calciclastic submarine fans and to model their reservoir potential. The long-term evolution of the Anotz carbonate slope was generally progradational, as evidenced by the four discrete episodes of calciclastic-fan development. The location of the fans was controlled by the synsedimentary tectonic activity of the Pamplona fault, which created a slope valley along which the reworked shallow-water calciclastic sediments were funnelled. In addition, episodic basinward tilting of the shallow-water carbonate ramp, linked to the development of the South Pyrenean foreland basin, switched on and off the process of calciclastic resedimentation and determined the growth or abandonment of the fan systems.     

山东东营凹陷沙河街组纹层年龄估算方法探讨

渤海湾盆地位于北纬35°—42°之间,中始新世沙河街组四段上部和三段沉积期间,在气候上属于中亚热带,湖泊水体较为稳定,并出现季节性分层,因此沉积常显示出暗灰和浅灰色的年纹层(或称偶层)。根据不少国内外湖泊纹泥统计和14C测定和频谱分析的对比,认为纹层可以作为地层定年工具。纹层年龄计算方法研究对含油盆地成烃成藏定量研究具有重要意义。东营凹陷年纹层计算方法有两种,或选定含纹层岩芯样品进行岩石薄片和电子探针观察和测定,取得年纹层间隔与元素峰值统计;或选取一段含纹层的测井数据作天文400ka、40ka或20ka周期地层年龄计算。通过两种方法求出东营凹陷通29井等沙三段—沙四上亚段堆积速率的比较,前者薄片和探针方法得到的平均速率为0.1078mm/a,后者天文的方法得到的是0.1280mm/a,两者计算差只有0.0172mm/a。因此应用两种方法来计算地层年龄和对比是可行的。前者求纹层方法更为直观,但岩芯和电子探针的测定费用较大,而相比而言,用油田测井数据作天文地层堆积速率和年龄的计算,在经济上、时间上可能胜于前者。