甘肃窑街中侏罗世化石角质层有机质及其碳同位素组成与古环境的关系

通过对甘肃窑街中侏罗统窑街组化石银杏以及现代银杏角质层有机质组分和碳同位素组成分析．表明银杏角质层有较强的抗风化能力．化石和现代银杏角质层有机质烷烃和甾萜类化合物组成十分相似。可以通过角质层的碳同位素组成等参数进行古环境重建，结果表明中侏罗世早期古环境较为温湿．到了中期后古气候逐渐变得干旱少雨，后期降雨量又逐渐增加，温度升高，植被发育。     

植物化石角质层分析在环境地质中的应用

植物化石角质层分析一直是古生物学研究的重要课题 ,近年来自然科学之间相互交叉和渗透的结果使角质层分析成为国际学术界新的研究热点。植物化石角质层分析至少已经形成了 3个重要的研究方向 :(1)从植物分类学角度 ,分析角质层的超微结构 ,使化石植物的分类和演化研究有了长足的进步 ;(2 )从植物生理学方面 ,分析化石植物表皮气孔密度和气孔指数 ,推测古大气ＣＯ2 的浓度 ,揭示地质历史时期植物生理与环境的关系 ,进而了解环境的变化 ;(3)利用有机地球化学和生物地球化学方法 ,研究角质层的化学特征 ,进行化石植物角质层和现代植物角质层的…     

祁连山七一冰川区表层沉积物中生物标志化合物的组成特征及来源研究

利用GC和GC—MS的分析方法,对祁连山七一冰川冰雪不溶微粒、冰尘和七一冰川流域表层土壤中的烷烃、脂肪酸、脂肪酸甲酯和长链酯、酮以及多环芳烃等生物标志化合物进行了分析,研究了它们的组成和分布特征,讨论了它们的环境地球化学意义。结果表明,生物标志化合物分布特征组成和分布特征指示了七一冰川地区的有机质具有藻类、高等植物、化石燃料燃烧产物等多种来源。冰雪不溶微粒和七一冰川流域表层土壤中有机物的来源相似,且这两种介质中的有机污染物种类多于冰尘,表明快速的工业化已经对七一冰川及其周围环境产生明显影响。     

南海北部琼东南盆地BD19-2-2井中新世钙质超微生物地层及沉积环境

对南海北部琼东南盆地BD19-2-2井中新世地层中的钙质超微进行了定量和半定量分析,发现井段上部1800~2550m地层化石较丰富,而下部2574~3100m化石丰度及分异度明显降低;根据钙质超微化石标志种的存在,对该井的生物地层进行了划分,在1800~3100m井段地层中识别出9个钙质超微化石带或联合化石带,地层时代为早中新世至晚中新世,同时探讨了钙质超微划分下中新统-中中新统、中中新统-上中新统界线的化石标志。依据钙质超微化石总丰度、分异度及特征性环境指示种丰度的逐渐变化,确认BD19-2-2井从早中新世至晚中新世经历了4个沉积环境演化阶段,海水深度由浅变深,海水变暖。     

藏北高原海陆相油页岩生物标志化合物对比研究

重点报道了藏北高原双湖地区早侏罗世海相油页岩和可可西里地区中新世陆相油页岩生物标志化合物组合差异.在两套油页岩中均检出丰富的正构烷烃、类异戊二烯烷烃、萜类化合物及甾类化合物,但二者生物标志化合物组合明显不同.这种不同是在有机质演化程度差异的基础上,主要由原始生物输入和沉积环境差异造成的.海相油页岩正构烷烃具有低碳数优势, nC15、nC16或 nC17为主峰碳,无明显的奇偶碳数分布, Pr/Ph比值显示,多数海相油页岩具有姥鲛烷优势,缺乏β-胡萝卜烷,伽马蜡烷含量较低,海相油页岩原始有机母质构成中,既有丰富的菌藻类等低等水生生物,还有一定比例的陆生高等植物混合输入的特点,属贫氧-缺氧、弱氧化-弱还原沉积环境,进一步证明了早托尔期这种富碳缺氧黑色油页岩是一次全球性海平面上升事件的产物.陆相油页岩正构烷烃具有高碳数优势,主峰碳数为 nC23或 nC29,奇碳数优势突出, Pr/Ph比值显示,陆相油页岩具有强烈植烷优势,β-胡萝卜烷含量相对较高,伽马蜡烷 /αβ C30霍烷比值为 0.31～ 0.60,陆相油页岩原始有机母质构成中,既有高含量的高等陆生植物,还有一定数量低等水生生物混合输入,且在剖面序列中有由早期 C3型陆生高等植物向晚期 C4型转变,特别是剖面顶部油页岩中具有丛粒藻 Botryococus输入的特点,从而导致罕见的重δ13C异常,属缺氧、强还原湖泊沉积环境,反映了晚中新世湖泊演化历史中生态系统的转型和更新这一重要事件.古湖泊演化早期具有水体盐度分层,以出现高含量的β-胡萝卜烷和伽马蜡烷为标志,为咸水湖,晚期湖平面上升,湖泊水体盐度逐渐降低.     

植物化石角质层分析实验技术总结及探索

植物化石角质层的微细构造特征是植物化石重要的鉴定和分类依据之一,同时也是获取地质历史时期气候信息的重要途径之一。对保存有角质层的植物化石,如何更好的获取角质层特征,选择合适的实验技术尤为重要。本文采用三种不同的实验方法,即王水+次氯酸钠浸解法,次氯酸钠浸解法以及硝酸浸解法,对地质时期植物化石角质层的获取方法进行了探索性实验研究。实验结果表明,对于砂质泥岩中的植物化石适合用王水+次氯酸钠浸解法进行处理;含煤层或者聚煤期泥岩中的植物化石适合用次氯酸钠浸解法进行处理;灰白色泥岩或者含有硅藻土泥岩中的植物化石适合用硝酸浸解法进行处理。本文采用的三种角质层浸解法在角质层研究方面可根据化石材料的具体情况进行选择,也可同时进行三种方法的尝试进而获得最佳实验效果。该研究总结了不同地质时期植物化石角质层对三种实验方法的反应,为研究植物化石的角质层特征提供更加有效的实验途径。     

东南极北查尔斯王子山新生代Pagodroma群生物地层特征

东南极北查尔斯王子山Pagodroma群沉积物是冰海沉积作用的产物。Pagodroma群中发现的原位硅藻化石组合及软体动物、有孔虫等化石,可直接用于生物地层定年。Pagodroma群的4个地质单元:Mount Johnston组、Fisher Bench组、Battye Glacier组和Bardin Bluffs组的地质年代分别为晚渐新世—早中新世、中中新世、中—晚中新世和上新世—早更新世。根据生物地层特征,东南极中—晚中新世仍适宜植物生长,但气候条件相当恶劣。综合分析表明东南极中新世—上新世存在几个暖期,冰盖有几次大的波动,支持动态论观点。     

褐煤煤层中成煤植物的研究进展

褐煤中成煤植物研究在我国主要集中于成煤植物的分类鉴定;国外研究已发展到细胞和分子水平,并开展了生物标志化合物研究及用化石木炭确定火灾事件等。本文简要综述了褐煤成煤植物的研究现状、取得成果及现存主要问题。     

李雅庄煤矿煤岩中C25、C30等无环类异戊二烯烷烃的检出及其地球化学意义

对沁水盆地李雅庄煤矿煤岩样品,进行了饱和烃生物标志化合物特征研究,检测到了丰富的无环类异戊二烯烷烃,特别是C25、C30及头—头连接的高碳数无环类异戊二烯烷烃,这些化合物被认为是甲烷菌的特征标志化合物。李雅庄煤矿煤岩沉积时为偏氧化的环境,原始环境不利于细菌发育,故检出的无环类异戊二烯烷烃应主要是成煤作用后期,煤层中甲烷菌发育的痕迹。认为李雅庄煤矿煤岩样品中丰富的、与古细菌,特别是甲烷菌有关的无环类异戊二烯烷烃化合物的检出,为该地区甲烷碳同位素组成在-56.3‰-61.7‰煤层气的次生生物成因提供了地球化学依据。      

四川珙县石碑恐龙化石埋藏地红层分子化石特征及其古环境意义

利用气相色谱-质谱仪(GC/MS)从四川珙县石碑恐龙化石埋藏地早侏罗世红层中检出了包括正构烷烃、类异戊二烯烃、长链三环萜、藿烷和甾烷等系列分子化石,这些分子化石来源于低等菌藻类生物和水生、陆生高等植物。利用这些分子化石的特征讨论了恐龙生活时代的古环境特征。姥鲛烷与植烷的比值(Pr/Ph)表明该恐龙化石埋藏地的沉积环境应为淡水、弱氧化的湖泊环境。所研究样品高碳数的正构烷烃均以与水生大型植物有关的C25为主峰,并具有来自陆生高等植物的C27～C31正构烷烃,反映出研究区湖盆水体中发育水生高等植物,周围陆地上发育木本和草本植物的古植物特征,体现了分子化石在恢复古环境研究方面的潜力。     

新疆准噶尔盆地中侏罗世Sphenobaiera（楔拜拉）一新种

报道了新疆准噶尔盆地西部玛纳斯及白杨河中侏罗世西山窑组（J₂x）银杏类楔拜拉属的一个新种--准噶尔楔拜拉（Sphenobaiera junggarensis sp. nov.）的首次发现。该新种以表皮构造为双面气孔式、上表皮气孔少、下表皮气孔密度大、孔缝基本定向、普通表皮细胞具不规则角质化隆丘及气孔器保卫细胞角质化放射纹之间发育有梳状“细耙”等特征,区别于楔拜拉属已知种。 还讨论了该新种的发现在研究楔拜拉属的分类及其古气候等方面的意义。     

Dispersed angiosperm cuticles: Their history, preparation, and application to the rise of angiosperms in Cretaceous and Paleocene coals, southern western interior of North America

Cuticle — the decay-resistant outer layer of leaves and young stems — provides a reliable means of identifying fossil plant remains and reflects the vegetative adaptations of plants to climate and other environmental parameters. The study of dispersed angiosperm cuticles originated prior to World War II and has focused on the origin and paleoecology of coal. Activity in dispersed cuticles reached a high point during the 1950s and 1960s with the study of Tertiary lignites in central Europe, then subsided in central Europe as workers from other regions expanded the technique to other time-periods and geographic regions. Data from dispersed cuticles augment data from palynomorphs because dispersed cuticles originate from a different generation of the vascular plant life cycle and have different taphonomic histories. Because the analysis of dispersed angiosperm cuticles is unfamiliar to many geologists, methods for the analysis and preparation of dispersed angiosperm cuticles are detailed in an appendix.Dispersed cuticle assemblages from coals in the upper Albian Longford Member of the Kiowa Formation and the Maastrichtian-Paleocene Raton Formation of the Southern Western Interior provide new constraints on the times that angiosperms entered coal swamps and rose to dominance. The Kiowa assemblages indicate that angiosperms first entered coal swamp environments by the late Albian, while the Raton assemblages indicate that angiosperms dominated primary productivity in some subtropical coal swamps by the late Maastrichtian. Angiosperms in Kiowa coals probably comprised pioneer species in conifer-dominated vegetation; the most common family of angiosperms was Chloranthaceae. Angiosperms in upper Maastrichtian Raton coals comprised the dominant seed plants to the exclusion of conifers; magnoliid dicots and monocots were the dominant taxa and comprised diverse genera and families. Evidence from palynology and types of preserved cuticle indicates that ferns were subordinate to seed plants in biomass in Raton coals, in contrast to some described assemblages from the Northern Western Interior. Paleocene coals from the Raton Basin show the loss of many Cretaceous angiosperm taxa as well as the appearance of new taxa, including conifers belonging to Taxodiaceae. However, these Taxodiaceae were evergreen and subordinate in abundance to angiosperms. Vegetational patterns shown by Cretaceous-Paleocene coals of the Southern Western Interior contrast with those of more northerly regions and indicate a poleward gradient in the timing of angiosperm dominance in coal swamps.     

C NMR, micro-FTIR and fluorescence spectra, and pyrolysis-gas chromatograms of coalified foliage of late Carboniferous medullosan seed ferns, Nova Scotia, Canada: Implications for coalification and chemotaxonomy

The cuticles and cuticle-free compressions of three Carboniferous medullosan seed-fern leaf species (Macroneuropteris scheuchzeri, Neuropteris ovata var. simonii and Alethopteris lesquereuxii) were analyzed by elemental, ¹³C nuclear magnetic resonance (NMR), micro-FTIR (Fourier transform infrared) and coal petrographic techniques. The 13C NMR spectra of the cuticle-free compressions and the associated whole coal (high volatile A/B bituminous coal rank) are generally similar and consist of a large aromatic carbon peak, a smaller aliphatic carbon peak and a shoulder on the aromatic peak, representing phenolic carbons. In contrast, the ¹³C NMR spectra of the cuticles from the same leaves have a predominant peak for aliphatic carbons and a much smaller aromatic carbon peak. This difference in aromaticity between the cuticles and the cuticle-free compressions is also reflected in the higher atomic H/C ratios of the cuticles. Micro-FTIR spectra of the cuticles show oxygenated functional groups (carboxyl and ketone) similar to those in modern cuticles but their most characteristic feature is very strong bands in the aliphatic stretching region. The cuticle-free compressions (mainly vitrinite), in turn, show the absence or significant reduction in oxygenated functional groups, reduction in aliphatic stretching bands and, usually, increased absorbance of aromatic out-of-plane deformation in the 700–900 cm⁻¹ region. Fluorescence spectra for the cuticles from all three species show a great similarity with a λ_max at 580–590 nm, probably reflecting a similardegree of coalification, which is consistent with the similar vitrinite reflectance (R_r) and H/C and O/C ratios of the cuticlefree compressions.These results indicate that leaf cuticle-free compressions, which were initially cellulose rich ( 90% cellulose and hemicellulose, < 10% lignin), can alter, during peatification and coalification, to a macromolecular structure similar to that of coalified wood (initially 50% cellulose and hemicellulose, 30%–50% lignin). Thus, a lignin-enriched structure is not a prerequisite for the formation of the macromolecular structure of vitrinite. In addition, the micro-FTIR spectra reveal the complexity of the molecular structure in coalified seed-fern leaves. The micro-FFIR data reveal some significant differences among the cuticles that may be of chemotaxonomic value. Clearly, a combination of macro- and micro-techniques offers a better basis for the interpretation of the molecular structure of pre-macerals and their alteration during peatification and coalification. Also, the data presented in this paper provide important new information that extends the data from morphological and cuticular taxonomic studies of some seed ferns. The data are encouraging preliminary advances in the chemotaxonomy of medullosan seed fern species.Pyrolysis-gas chromatography (PY-GC) data for the cuticles of three seed-fern leaves indicate distinct chemical signatures for the two neuropterid leaves as compared to the Alethopteris leaf. This perhaps indicates a chemotaxomic factor, or it could be related to the greater thickness of the cuticle of Alethopteris. Mass spectrometric data are needed to identify individual components in the PY-GC chromatograms.     

滇西新近纪植物气孔、碳同位素组成与古环境分析

对滇西腾冲新近纪两种被子植物叶片及其现存对应种的气孔参数和碳同位素组成的综合分析表明:当时的大气CO2浓度略高于现在水平;化石种的碳同位素分馏值高于现存对应种,但水分利用效率低于现存对应种;这证明当时的气候条件比当前更为温暖湿润。受新生代全球气候变冷和喜马拉雅运动的影响,该盆地一方面受印度洋季风的影响增强,干湿季节交替明显;另一方面受地形地貌影响,沿袭了温暖湿润的气候条件。      

Analysis of modern and fossil plant cuticles by Curie point Py-GC and Curie point Py-GC-MS: Recognition of a new, highly aliphatic and resistant biopolymer

This paper investigates to what extent the chemical constituents of plant cuticles (waxes and cutin) can survive diagenesis. Recent and fossil plant cuticles were analyzed by means of Curie point pyrolysis-gas chromatography and Curie point pyrolysis-gas chromatography-mass spectrometry. Recent cuticles were analyzed without treatment, after solvent extraction and after cutin depolymerization. Extensive series of straight-chain alkanes, alk-1-enes and α,ω)-alkadienes dominate the pyrolysates, especially after removal of the wax and cutin. ¹³C-NMR spectroscopy of the residue after removal of the cutin confirmed the presence of a new, highly aliphatic biopolymer and a polysaccharide fraction.The abundance of straight-chain alkanes, alk-1-enes and α,ω-alkadienes in the fossil plant cuticles indicates the chemical resistence of the biopolymer to diagenesis and may explain the occurrence of straight-chain aliphatic moieties in organic-matter-rich sediments and coals as revealed by “C-NMR spectroscopy and flash pyrolysis methods. The highly aliphatic biopolymer may function as an important oil precursor.     

内蒙古霍林河煤田内蒙古拟刺葵(新种)Phoenicopsis (Phoenicopsis) neimengensis sp.nov.的首次发现

笔者首次发现了内蒙古霍林河煤田霍林河组(K1h)茨康类拟刺葵属拟刺葵亚属的一个新种—内蒙古拟刺葵(Phoenicopsis(Phoenicopsis)neimengensis sp.nov.)。该新种以表皮构造下气孔式,上表皮细胞未见乳突,下表皮普通表皮细胞发育中央乳突,气孔器副卫细胞多发育乳突,孔缝不定向等特征区别于拟刺葵属已知种。新种的研究对于了解拟刺葵属(Phoenicopsis)的分类,以及恢复古地理、古气候有重要作用。     

软玉子料黑皮和褐皮的致色物测试

黑皮、褐皮是软玉子料的常见皮色。文章通过岩石薄片、电子探针、差热分析等多种手段测试,综合判定软玉子料的褐皮是含褐铁矿所致,黑皮是含褐铁矿加有机质所致,这为软玉子料鉴定提供了依据,对子料成因研究也有重要意义。     

Insights into preservation of fossil plant cuticles using thermally assisted hydrolysis methylation

The chemical composition of Cretaceous leaf remains showing exceptionally well preserved cuticles was investigated using pyrolysis gas chromatography–mass spectrometry (Py-GC–MS) and thermally assisted hydrolysis methylation (THM)-GC–MS. Samples of Coniferales (Frenelopsis) and Ginkgoales (Nehvizdya penalveri) leaf remains were collected from freshwater and coastal marine depositional environments. Material for pyrolysis included (i) untreated leaves and cuticles obtained after extraction from mineral rock matrix and bleaching, (ii) kerogen fraction from both materials, (iii) non-hydrolysable fraction from kerogen. The THM-GC–MS data from untreated leaves and bleached cuticles show that the fossil cuticle geopolymer essentially released aliphatic components upon thermal treatment, with a dominance of fatty acids (FAs) and n-alkanes/n-alkenes. The FAs are essentially resistant to bleaching and remain after solvent extraction. They occur mainly as short chain compounds ranging from C₆ to C₁₆ and with maximum abundance at C₈–C₉. The n-alkanes/n-alkenes from kerogen and the non-hydrolysable residue occur mainly as short chain compounds in the range C₁₀–C₁₆, with the highest abundance at C₉–C₁₂. The THM-GC–MS pyrograms of the fossil cuticles differ from those of cutan from fresh living plants. They support the preservation model via polymerization of monomers derived from cutin or from unsaturated cell FAs.     

Functional groups in a single pteridosperm species: Variability and circumscription (Pennsylvanian, Nova Scotia, Canada)

Multiple foliar specimens of the Late Pennsylvanian fossil pteridosperm [gymnosperm] Alethopteris zeilleri (Ragot) Wagner were collected from one restricted stratigraphical horizon in the Canadian Sydney Coalfield. Variability of functional-group distribution using FTIR technique was studied in compressions, adaxial versus abaxial cuticles, and in unseparated cuticles as a function of maceration time from 48 to 168 h. The results obtained document spectral variability that could be expected within specimens of one species. For example, CH₂/CH₃ and Al/ox ratios can differ by as much as 20% of the values. Moreover, the experiments performed confirm that by using a previously established maceration protocol, long maceration periods do not bias FTIR spectra in terms of oxygenation overprinting. The inference that this cuticle is robust, under the given diagenetic level, probably reflects a reassuring degree of chemical fidelity of the Pennsylvanian plant to support Carboniferous chemotaxonomic observations.