阳郭黄土剖面有机组分变化的周期性与古气候变迁因素

渭南阳郭黄土剖面是迄今发现的１５万年以来较完整的剖面之一，作者对出阳郭剖面中的有机质指标进行了概率分布与谱分析计算，得出它们的概率分布类型及四个稳定的周期：６７．１Ｋａ，３３．５Ｋａ，２５．２Ｋａ和１８．３Ｋａ。这四个周期与洛川黄土剖面中元素组分变化的短周期基本一致。     

趋磁细菌及磁小体对黄土-古土壤序列磁化率贡献的模拟实验研究

选择西峰和段家坡两个黄土剖面,对磁化率变化显著的L₆-S₅-L₅层段,通过对样品中的趋磁细菌(MB)用相同的培养基富集及生长培养,初步定量模拟了MB和磁小体(MSs)对黄土-古土壤序列磁化率的贡献。富集培养MB后,段家坡剖面样品磁化率表现出不同程度的增高,最大达116.4%(DS_5-1)。以古土壤样品XS_5-1、DS_5-1为介质生长培养MB,DS_5-1磁化率的增长与接种的菌液量呈近似线性关系。此外,生长培养后古土壤样品频率磁化率与FeO/Fe₂O₃比值呈现出相似的变化趋势,证实了磁小体的形成。由此表明:1)MB和MSs是影响黄土剖面磁化率的因素之一,受气候和地质环境等因素的影响,不同地区黄土剖面MB的生长和MSs的形成存在差异,因此对磁化率的贡献也不尽相同;2)MSs是黄土-古土壤序列中超细粒磁性物质的组成部分。当气候环境比较适宜MSs形成及保存时,MSs在黄土剖面中超细粒(≤50nm)磁性组分中比重会相应增高,对磁化率和频率磁化率的影响也更为突出。     

我国西沙群岛第四纪生物沉积物及成岛时期的探讨

Bioclastic sediments in the Xisha archipelago were formed during the period from late Pleisloeene to Πolocene. Except for loose coral shell sand, they can be dividcd,according to petrological features, into coral reef limestone, phosphate-cemented foraminifera (or red aglae and Eehinodermate, etc.), calcarenite or calcirudite. All of them have been subjected to raring degrees of deuterogene alterations such as phosphatization, calcitization as well as dissolution and filling. The age of formation of the Xisha archipelago, i.e., the time it finally emerged from under the sea may be dealt with as: (1) Sand bars. (1.5-3.0 meters above sea level) took shape about 2000--2500 years ago; (2) Coral reefs (3--5 meters above sea level, with the exception of rock islands) formed 400-5000 years ago, which is in agreement with the high sea level stage in the post-glacial period; (3) Rock islands(about 15 meters above sea level) formed at late Pleistocene or earlier, which can probably be correlated with the high sea level period some 80000--125000 years ago.     

碳酸岩生油岩中沥青变质程度和沥青热变质实验

Natural asphalts from carbonate rocks in South China have been studied by using microscopy, X-ray diffraction, ESR and C^-, H^- analysis and subjeeted to thermal alteration experiments under 250℃/1000 atm--500℃/1000atm. It is shown that asphalt and vitriolic behave differently under conditions of thermal alteration. In compariseu with vitriuite, asphalt is of higher reflectivity, more apparemt anisotropy,lower values of d002 and H/C ratio above 350℃. The mierostructure and charaeter of protoasphalt disseminated in carbonate rocks and diagenetic asphalt reflect the thermal history and the maximum paleotemperature to which they haxt been subjected. Reflectivity, H/C ratio, d002 etc. of the asphalts in carbonate rocks may be used as indicators for the extent of maturity of earbenate source rocks. Based on measurements carried on asphalts of pertinent occurrences. R^0=1.65.H/C=0.75, d002=3.53 A are suggested as creteria for the distinction between Oil and natural gas field in carbonate terrains in China.     

碳酸盐岩生油岩的有机地球化学、岩石学特征

Features of oil-generating carbonate rocks are studied in terms of petrology and organic geochemistry of fluorescent materials in rocks. It is postulated by the authors that the organic carbon content in oil-generatlng carbonate rocks is necessarily lower than that in shales, and the possible cause of this observation is discussed. The quality of oil-ganerating carbonate rocks may be judged by aromatic structure index,amino acid, pigment index, and DTA data on organic matter. However, the application of presently available organic geochemical criteria to non-oil-generating reservoir rocks may always give misleading results. To circumvent this difficulty, it is necessary first to make distinction between primary and secondary organic matter by cxamining the fluorescent materials under a fluorescence microscope. Measurementof radical content of the organic substances and DTA are useful techniques to determine the degree of maturation. The maturation of organic substances proceeds at a lower rate in carbonate rocks than in shales. It is likely, therefore, that some older carbonate strata can also be promising areas for petroleum exploration. Oil-generating carbonate rocks consist mainly of mierite limestones rich in organic matter and are thought to be formed under low-encrgy environment. Consequently, petrological(especially mierolithofacies) studies are very important in evaluating carbonate source rocks.     

一种分离富集中国黄土中微米级磁性物质的方法

微米级磁性矿物在黄土—古土壤序列中含量不足1％，为了满足多种测试的需要，要尽可能地富集磁性矿物。介绍一种富集方法，即程序地采用浸泡—搅拌(转速为5900r／min)—湿法磁选(磁场梯度范围为0．8—2．5T)—重液分选(d≥2．5)—干法磁选(激磁电流在1—2A之间)的方法，从西峰和段家坡第五层古土壤(分别简称为XS和DS)的上浮物和沉砂中富集出6个不同磁性的矿物组分。经磁化率(MS—2)、磁滞回线(MICROMag2900)测定、高倍显微镜(MPV—3)及扫描电镜(S—3500N)观测，矿物的分散度与磁性分选良好，精选的强磁性组分(XS—4J和DS—4J)中磁性矿物含量约占该组分的30％，富集的磁性矿物种类多，包括含铁粘土、碎屑状磁性矿物和自生磁性矿物，磁选出的矿物代表性强并能满足多项分析测试的需要。湿法磁选(程序3)是流程中操作最复杂的一步，根据XS样的实测结果，这一步磁选的回收率为87．2％。     

茂名油页岩中生物输入的标志化合物

我国油气的绝大部分产自东部地区的白垩纪与第三纪合油气盆地，其沉积环境多为陆相，陆源高等植物输入较丰富，介质条件以淡水一半咸水为主。在这方面茂名油页岩具有典型的代表性，因而深入研究其生物标志物特征与有机输入模式，对建立适用于我国油气勘探的分子有机地化参数以及发展我国陆相生油理论具有重要的现实意义。     

华北地区中上元古界、下古生界碳酸盐岩有机质成熟度与找油远景

华北地区广泛发育着厚达6000—14000m的中上元古界、下古生界海相碳酸盐岩地层，地表各类油苗达42处之多。早在50年代我国石油工作者就对这些油苗作过详细的地质调查。70年代冀中地区发现古潜山型新生古储的油藏后，对华北地区能否找到古生古储油藏的问题，立即引起了我国广大石油科学工作者的共同关注。那么华北地区这套年代古老(10-14亿年)的海相碳酸盐岩有机质丰度如何?目前处于演化的那一阶段?华北地区能否在碳酸盐岩中找到油藏，这是本文将要论述的重点。     

青海小柴旦盐湖沉积物的地球化学初步研究

本文采用地球化学与有机地球化学方法详细研究了小柴旦盐湖沉积物。结果表明,该沉积物的矿物组成与化学组成非常类似于中国东部第三纪盐湖沉积物(如江汉和东濮油田的生油岩),而区别于淡水湖相沉积物(如茂名和抚顺油页岩)。分析鉴定了盐湖沉积物的氨基酸、脂肪酸和烷烃组成。脂肪酸与烷烃的分布特征表明,生物输入以陆源植物为主,与其孢子、花粉组成的鉴定结果相符。     

鄂尔多斯盆地下古生界海相碳酸盐岩有机质分布特征及其对气田形成的意义

对鄂尔多斯盆地中北部9口井的奥陶系及其上覆的石炭系岩心和盆地东南缘两个下古生界地表剖面的86块样品,进行了野外和室内岩石薄片的反射光、透射光及荧光观察,并对总有机碳(TOC)、总有机硫(TOS)、反射率 R。进行了测定,试图从岩石中有机质的含量与赋存状态分析大中型气田的形成条件。研究揭示出下古生界海相碳酸盐岩处于从正常海向陆缘海过渡,见有含藻屑泥质碳酸盐岩(TOC 达0.30％～0.35％)和在其晶间孔隙分布的储集层沥青,表明它们曾生过油。在盆地内石炭系—二叠系 R。为1.41％～2.40％,它与奥陶系的 R。(1.68％～1.78％)基本相当,表明它们同为一个含气系统。下古生界碳酸盐岩和石炭系、二叠系煤系地层这两个烃源层为鄂尔多斯大中型气田提供了充足烃源。