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煤基石墨微结构的高分辨电镜研究 总被引：3，自引：0，他引：3
煤体经热变质作用形成的石墨叫煤基石墨。湖南省鲁塘地区煤基石墨,经与之共生的红柱石的相图分析,它属于低压相系矿物,在200—800℃和5.5×10~5Pa以下条件下形成。它的高分辨电子显微象显示,煤基石墨按其石墨化程度有四种类型微结构。因而。将煤基石墨划分为相继的四个石墨化阶段。同时有四种石墨产物,它们是:前石墨化阶段——芳层石墨;初石墨化阶段——微柱石墨;中石墨化阶段——柔绉石墨;高石墨化阶段——平直石墨 相似文献
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煤系石墨属战略性矿产资源,在核石墨、军用飞机轮胎等方面具有独特优势,煤系石墨矿产资源评价对于煤系石墨矿产资源勘查开发、提级增储及战略资源保障至关重要。由于煤系石墨与高变质煤存在连续过渡性质,导致部分煤系石墨被当作无烟煤处理,现有煤系石墨查明资源量可能被大大低估,实际上煤系石墨资源量与高煤级煤的资源量有直接关系。因此,在我国无烟煤等高煤级煤勘查区内,开展煤系石墨资源调查评价工作,将会取得较好效果,预期发现一批新的煤系石墨资源潜力区。通过分析我国目前已知的湖南、福建、吉林等地典型煤系石墨资源分布特征,总结了煤系石墨找矿标志,包括层位、矿化、岩体、构造和围岩蚀变等标志。在高煤级煤勘查区内,基于煤田构造、含煤岩系沉积环境、岩浆活动、煤岩煤质特征、煤类分布与变质情况等资料,结合煤系石墨找矿标志,进行煤系石墨资源调查评价。以科学性、系统性和可操作性为评价原则,依据工作程度、地质条件、矿产条件3类参数,采样点密度、构造变形程度、构造应力、岩体规模与热作用强度、岩体与煤层距离、初步鉴定、精确鉴定7个指标,初步提出了煤系石墨矿产资源评价方法。将实测数据分别与对应指标的预设值比较,利用平面直线拟合方程计算... 相似文献
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为查明我国典型矿石墨的矿物学特征,采用XRD、FESEM-EDS、TEM和Raman光谱等表征手段对来自不同产地石墨样品的成分、结构与性质进行了研究。结果表明,晶质与隐晶质石墨分别由微米级和纳米级石墨鳞片组成,主要的区别为前者有更大的微晶尺寸;各样品均为2H型石墨结构,同时不同程度地含有3R型多型,轴长a=0.243~0.249 nm,c=0.672~0.677 nm,晶胞体积V在0.0347~0.0362 nm3之间,晶胞体积随晶体结构中O含量的增加而增大。天然产出石墨的石墨化度较高,最高可达1,由于后期地质作用或人工加工改造,引入次生缺陷,导致其石墨化度降低,结构无序度增高。晶质和隐晶质石墨的氧化起始温度分别为700~800℃和600~650℃,粒度越细的晶质石墨氧化起始温度越低。在水中石墨表面荷负电,p H为10.5时具有带电量的极大值,晶质石墨疏水性和导电性均强于隐晶质石墨。 相似文献
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煤基石墨的喇曼光谱学研究 总被引：1，自引：0，他引：1
煤体经热变质作用形成的石墨叫煤基石墨。本文研究了煤基石墨的一级和二级喇光谱。作者认为，石墨及有关的碳质物质的一级喇曼光谱是由层内振动激发的，反映了它们作为二维晶格的完整性程度。煤基石墨中存在的层内结构缺陷分为两种，一是煤中特有的，在石墨化过程中逐渐消失，另一是由研磨（剪切应力）作用带入的，可能与构造应力作用有关，石墨化过程和剪切应力作用过程是效果近于相反的两过程，而石墨的二级喇曼光谱则可揭示其作为 相似文献
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0 引言
球状石墨是一种罕见的天然石墨.日本北海道广尾郡广尾町音调津有镍铁硫化物矿床,为一基性岩浆岩成因矿床[2-4],其中存在石墨矿体.音调津矿山产出块状、球状和脉状等类型的石墨[2].块状和脉状石墨矿受地质构造,沿断层和剪切带分布.球状石墨与镍铁硫化物矿紧密共生,主要出现在辉长岩体中[2-4].本文采用体视显微镜、光学显微镜、X射线衍射仪、透射电子显微镜等手段,观察分析了日本北海道日高带音调津天然形成的球状石墨. 相似文献
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全热解石墨管石墨炉原子吸收法测定痕量锶 总被引：2，自引：0，他引：2
研究了热解涂层和全热解石墨管中Sr的原子吸收信号形状和原子化行为,讨论了CaCl_2、FeCl_3和HClO_4,抑制Sr吸收信号的原因。采用EDTA铵盐作基体改进剂,全热解石墨管石墨炉原子吸收法直接测定河泥中痕量Sr,方法的特征量为6.9pg/0.0044A。 相似文献
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初步概括了中国石墨矿产资源现状,总结了晶质石墨矿床的成矿规律、成矿模式及主要找矿标志。中国石墨矿产资源储量巨大、种类齐全,资源分布呈现“分布广泛、东多西少、个别富集”的特征,区域变质型晶质石墨矿床是主要矿床类型,晶质石墨主要成矿规律为“构造定区、沉积控源、变质限量、热液提质”,即大地构造格局决定晶质石墨矿床的有利区分布,富有机质陆源碎屑沉积体系主控炭源供给和赋矿层位分布,变质作用深度及期次限定石墨矿体总量,混合岩化过程对提升矿石品质具有不可忽视的作用。典型晶质石墨矿床的形成一般经历沉积成岩—区域变质—混合岩化3个阶段。地层、岩性、沉积环境、构造以及地球物理异常等是石墨找矿的良好标志。 相似文献
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煤系石墨是在岩浆接触热变质及构造变质作用下形成的煤系非金属矿产。煤系石墨与晶质石墨相比,具有品位高、易开发的特点,将成为高技术产业和新能源领域的重要原材料。综合概述了煤石墨化作用模式、影响因素以及煤显微组分对煤石墨化的影响,分析了煤石墨化研究的主要问题和发展趋势。目前,煤的物理化学结构和煤系石墨的相关研究已取得了较为显著的进展,但煤石墨化作用机制仍存在许多问题亟待解决。大量的研究集中在煤石墨化的外部地质因素,如温度、压力和介质条件对煤石墨化的控制作用,而对煤显微组分在煤石墨化过程中的作用研究相对较少。由于镜质组、惰质组和壳质组的芳环缩合程度不同,各种显微组分具有不同的芳氢和侧链取代基,从而对煤中芳香结构的演化和纳米结构的形成产生差异影响,造成煤石墨化作用效果和作用机制的复杂性。因此,充分认识显微组分对煤石墨化作用的影响可能是揭示煤石墨化机制的重要途径之一。 相似文献
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R. A. Reyment 《Cretaceous Research》1980,1(4):299-327
The first trans-Saharan epicontinental transgression began in the Late Cenomanian and peaked in the Early Turonian. The sea entered through rifts (Nigeria) and subsiding areas (north Africa) and, at maximum extent, spilled out onto stable craton. The central Sahara was land in late Early Turonian time; the sea seems to have remained in the central part of the Benue rift, to sally forth again during the minor Coniacian transgressive pulse. The Coniacian transgression went no further than eastern and central Niger Republic. For a short time during the Cenomanian-Turonian link-up between the Tethys and the South Atlantic, some organisms (mainly ammonites and pelecypods) passed across the Sahara. The Coniacian marine deposits of eastern Niger contain several elements typical of the Mungo River Formation of Cameroun, and coastal Nigeria. These faunistic indications imply that the topographical obstacle formed by the Zambuk ridge of northeastern Nigeria was swamped at maximum transgression. A third, very extensive epicontinental transgression began in latest Campanian time and reached its acme in the Early Maastrichtian. In the central Sahara, at least, there was a retreat of the sea in later Maastrichtian times. A final transgression peaked during the Paleocene, after which the sea withdrew permanently from the northwest African hinterland. The same marine ostracod associations occur in the Paleocene of coastal Nigeria, the Sokoto embayment, Mali and Libya, thus providing strong evidence of a marine connexion, albeit brief, between the South Atlantic and the Tethys, despite the lack of outcrop evidence in the crucial Niger valley region. 相似文献
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Planning versus youth: Stamping out spatial unruliness in Harare 总被引：1，自引：0，他引：1
The paper examines the illegal occupation and use of urban spaces by Harare’s youth and the ensuing tussles with the repressive machinery of the local authority and the nation-state. It analyses efforts by planning to contain rampant spatial unruliness. The paper maps the patterns of official hostile responses to the illegal activities of the youth whose daily routines inevitably entail the disregard of the spatial planning framework as reflected in existing legal and regulatory controls. The analysis reveals the reliance by the urban planning and management system on the use of force and violence, a feat made possible by the mobilisation of the repressive state apparatus. The discussion argues that what comes out in the relationship between the order-imposing planning system and the regulation-flouting youth is a situation that can largely be comprehended by turning to the non-progressive side of planning. 相似文献
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This paper explores the inherent contradiction and conceptual conflict that arises when sacred sites are marketed as secular for the purpose of promoting tourism. The question of conflict is further frustrated within the context of Israel’s contested religious landscape and Israeli policy. Using a Lefebvrian framework, the historical development of the Bahai Gardens in Haifa, Israel, the tourism board’s promotion of the site as Haifa’s primary tourist designation, and the distinct spatial practices that have been used by both constituencies are investigated. Further, the authors posit that the Bahai Gardens are multi-dimensional spaces characterized by two different socio-spatial processes and practices that co-exist—the tourist’s and the pilgrim’s. These practices transform the holy site into a secular shared community asset. The paper concludes with a discussion of the socio-spatial implications of the case and its broader implications concerning the globalization of tourism and the efficacy of developing “layered” Lefebvrian triad to try and avoid conflict. 相似文献
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The post-glacial environmental history of Voua de la Motte, a small pond, was studied by the lipid geochemistry of a 6 m long core. Palynological studies show that the deepest part of the core goes back to 10,000 yr BP corresponding to the time of formation of the lake following the retreat of the Rhodanian glacier. Hydrocarbons, aldehydes, linear alcohols, sterols, monocarboxylic and monohydroxy fatty acids, were determined throughout the core both in the free and bound lipid fractions, as well as in the tightly bound fraction for the carboxylic acids. There is no clear evidence of a transformation from the unbound to the bound form, except perhaps for the α-hydroxy acids.Qualitative as well as quantitative fluctuations in the distributions of these lipid classes were observed upward in the core. An attempt is made to correlate these fluctuations with the bioenvironmental and climatological evolution of the Basin on the basis of information obtained from palynology. 相似文献
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A Barremian microflora is recorded in the terrigenous facies (Weald) of the Lower Cretaceous in the northern region of the Province of Valencia (Spain), these beds have been poorly dated up to now due to the absence of fossils. The Villar del Arzobispo microflora correspond unquestionably to the Barremian-Aptien period, but the numerical importance of derived forms from the Jurassic, the remarkable variety of forms of Cicatricosisporites, and the rareness of pollen of Angiosperms, indicate a Barremian age to be more likely.This discovery permits us to establish the stratigraphical relationship of this terrigenousfacies of Villar del Arzobispo with the dated “Weald” of other areas of the Iberian Chain and to give a complete chrono-stratigraphical interpretation to the different litho-stratigraphical units that constitute the Lower Cretaceous of this region. 相似文献
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The explanation normally given for the tectonics of Sainte-Victoire Mountain, a dozen kilometres east of Aix-en-Provence, to the north of the limestone Provence, is incorrect. To the east, the morphology of the Sainte-Victoire is subdued, whereas to the west, before the mountain breaks savagely, the morphology is that of a young mountain as appears in Alpine landscapes. This unusual aspect in the region and the large subvertical faults with vertically striated surfaces that mark the massif to the south and to the west, induce the idea of strong vertical uplifts and caste doubt on the tectonic interpretation given in 1962 by Corroy et al. According to those authors, the Sainte-Victoire is a unit of Jurassic and Cretaceous formations overthrusting 1800 m to the south conglomerates of the Late Cretaceous or Palaeocene. New observations about the conglomerate transgression over the Jurassic and Cretaceous beds, and about the faults around and on the massif do not give evidence of an overthrusting but, on the contrary, induce the idea of a uplift, perhaps still active, in the form of a ‘piano key’ inclined to the northeast. To cite this article: J. Ricour et al., C. R. Geoscience 337 (2005). 相似文献
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Jean-Louis Feybesse Marie-Christine Bailly-Maître Jean Feraud 《Comptes Rendus Geoscience》2004,336(14):1255-1264
This study of the Pontet mine aimed at updating the understanding of ore-structural geology setting and, in terms of archaeology, at pointing out how the geometry of structures influenced the medieval workings and the shape of the galleries. The mineralisation and the WNW–ESE dextral normal faults controlling its emplacement are assigned to the Eocene by analogy with the neighbouring La Gardette structure. This confirms the Late Eocene to Oligocene age classically proposed for Phase 1 and places it in the Eocene. The Prégentil-type P1 folds described by Lameyre (1958) are here attributed to Phase 1, which raises the question as to whether the contemporaneous tectonic uplift of the crystalline basement should also be assigned to Phase 1 rather than to Phase 2. To cite this article: J.-L. Feybesse et al., C. R. Geoscience 336 (2004). 相似文献
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贵州罗甸二叠纪末生物大灭绝事件后沉积的微生物岩时代和沉积学特征 总被引：9，自引：1，他引：8
二叠纪末期发生的显生宙以来最大的生物绝灭事件,使海洋生态系统和陆地生态系统均受到重创之后,微生物岩广泛分布于全球正常浅海地区。研究认为,扬子地台在二叠纪末期存在一次海平面降低的事件,造成研究区二叠纪地层与早三叠世微生物岩之间存在沉积间断或剥蚀,并使三叠纪牙形石混入二叠纪末期的沉积物中。二叠-三叠系界线位于微生物岩层的底界;微生物岩形成于早三叠世最早期,相当于Hindeodus parvus带,是早三叠世最早期开始的海侵事件为其提供生长所需的可容纳空间。在Isarcicella staeschei带-I. isarcica带早期再次发生相对海平面降低事件,之后海平面开始快速上升。研究区早三叠世早期的微生物岩以凝块构造发育为特征,具有斑状、层状、枝状和网状凝块构造4种典型中型构造。结合前人的工作,认为微生物群落通过生物沉积和物理沉积作用形成球状体,球状体汇聚形成不同的中型凝块构造。研究扬子地台早三叠世凝块石的确切时代和结构、构造类型特征,为准确恢复生物大灭绝事件前后的环境变迁以及生物演化事件与环境变化的相互作用关系提供重要的证据。 相似文献
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国际二叠纪年代地层划分新方案 总被引：15，自引：0，他引：15
国际二叠纪地层分会已就二叠系的统和阶的划分,命名及下界的层位达成统一意见,提出新的二叠系年代地层表,该表由３个最佳的区域性地层序列组成,即代表下二叠统的俄罗斯和哈萨克坦乌拉尔地区的乌拉尔统（ＣｉｓｕｒａｌｉａｎＳｅｒｉｅｓ）上二叠下部和上部的美国西南部的瓜德鲁普统（ＧｕａｄａｌｕｐｉａｎＳｅｒｉｅｓ）和中国华南地区的乐平统（ＬｏｐｉｎｇｉａｎＳｅｒｉｅｓ）。新表为建立二叠系内部界线的全球层型及点位 相似文献
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寒武纪年代地层的研究现状和研究方向 总被引：9，自引：6，他引：3
全球寒武系的底、顶界层型已被确定 ,但寒武系内的统和阶一级的全球标准划分尚待进行。介绍了国际地层委员会寒武系分会有关建阶的意见和推荐的 13个分阶的层位 ;同时介绍了劳亚大陆新近提出的 4统 6阶的年代地层划分方案。回顾了我国的建阶过程 ,指出我国现有的阶一级单位实质上仍然是岩石地层单位 ,具有建立在单位层型上、底界被粗略界定因而时间意义不明确、对比性差、与岩石地层单位重名和不利于竞争国际标准阶和GSSPs等一系列缺点。在湘西、黔东地区新建的 5个阶可取代我国现有的中—晚寒武世年代地层系统。建议暂将我国寒武系划分为 3统和 9个阶 ,即 :下寒武统梅树村阶、筇竹寺阶、沧浪铺阶和龙王庙阶 ;中寒武统台江阶和王村阶 ;上寒武统酉水阶、瓦儿岗阶和桃源阶。 相似文献