黄河口区全新世沉积物中的碳酸盐矿物

黄河口区全新世沉积物中的自生碳酸盐矿物是指相矿物.自生方解石指示淡水环境,自生白云石指示潮坪沉积.其分布受物源、环境、沉积物类型、环境对沉积物改造作用的控制.     

菊花岛海区沉积物类型及矿物特征初探

本文对菊花岛海区沉积物类型，重矿物和粘土矿物组合分区及其分布特征进行了分析，同时对测区沉积物来源进行探讨。     

长江口外表层沉积物黏土矿物分布特征

依据对长江口外表层沉积物187个站位沉积物样品的黏土矿物含量分析,研究了长江口外表层沉积物黏土矿物的组合特征和分布规律.长江口外表层沉积物伊利石为优势矿物,平均含量为60.3％;次之为蒙脱石,平均为14.9％;高岭石平均含量13.5％,绿泥石平均含量为12.3％.黏土矿物的组合类型以伊利石—蒙脱石—高岭石—绿泥石型为主...     

南黄海表层沉积物黏土矿物分布及物源

通过对南黄海表层沉积物295个站位的黏土矿物含量分析,研究了南黄海表层沉积物黏土矿物的组合特征、分布规律及与物质来源的关系.南黄海表层沉积物中伊利石含量最高,蒙脱石和高岭石含量次之,绿泥石含量最低;黏土矿物的组合类型以伊利石-蒙脱石-高岭石-绿泥石型为主,伊利石-高岭石-蒙脱石-绿泥石型次之;南黄海表层沉积物黏土矿物主...     

台湾海峡表层沉积物的粒度和碎屑矿物分布特征方建勇

应用系统聚类分析和因子分析的方法对台湾海峡283个表层沉积物样品的粒度组成和85个样品的矿物组成进行了分析,结果表明:台湾海峡表层沉积物由6种沉积物类型组成,可以划分把它们为3种与沉积动力相对应的主要沉积环境区;在表层沉积物共发现碎屑矿物61种,以轻组分矿物为主,平均含量高达97.73%,共发现轻矿物14种;重组分矿物含量较低,平均为2.27%,共发现47种重矿物。影响台湾海峡表层沉积物矿物分布及含量变化的最重要因素是物质来源,其次是水动力条件以及矿物自身的变质程度等。台湾海峡表层沉积物的主要物质来源包括来自福建和台湾省河流的入海泥沙、海峡两岸的侵蚀和剥蚀物质、韩江及部分来自浙闽沿岸流携带的长江和钱塘江物质,台湾海峡晚更新世残留物及部分自生矿物等。     

东海表层沉积物中重矿物聚类分析及其动力分布特征

各种地质营力如波浪、潮汐和海流都会对海底沉积物中的每种矿物产生影响,各种矿物也大多经历着搬运和沉积等过程。因此,能够利用沉积物中的矿物资料探讨其分布特征的控制因素。但是,东海区域广,沉积物类型较齐全,沉积时代不一,物质来源多,水动力条件十分复杂,给上述工作增加了困难。幸而,不同地区经受的地质作用过程和各种矿物对各种地质作用的反应并非一致。近岸区以现代细粒物质沉积为主,中、外陆架为残留沉积物分布区,而冲绳海槽区矿物成因以火山喷发作用为特征。就某一区域而言,某种矿物或矿物组合对某种地质作用或水动力条件反应特别敏感,因而也就     

渤海湾西部表层沉积物粒度及黏土矿物特征分析

对渤海湾西部海域和西岸入海河流中76个表层沉积物样品进行粒度及黏土矿物分析,研究表明该区有3种沉积物类型,黏土质粉砂分布于整个研究区,约占表层样的90%,是研究区最主要的沉积物类型;研究区黏土矿物以伊利石为主,黏土矿物组合为伊利石-高岭石-绿泥石-蒙皂石;渤海湾西部表层沉积物主要来源于海河等渤海湾西岸入海河流中的陆源碎屑物,滦河对研究区基本没有影响,黄河对研究区的影响变得比较小。对于研究渤海湾西岸的沉积特征及沉积物物源、了解陆地河流对于研究区海洋沉积环境的影响有着一定的科学意义。     

南黄海西部陆架区表层沉积特征与物源分析

对南黄海西部陆架区626个海底沉积物进行了沉积特征分析,包括粒度和黏土矿物测试。研究结果表明,研究区的表层沉积物类型主要包括砾石、砂、粉砂质砂、砂质粉砂、粉砂、砂质泥和泥。依据表层沉积物成因,将调查区分为4个区:苏北近岸老黄河细粒沉积物区、中东部的残留砂沉积区、西北部的准残留砾石区和东北部的山东半岛水下楔形体末端沉积区。研究区的黏土矿物组合类型主要为伊利石-蒙皂石-绿泥石-高岭石,组合类型与黄河黏土矿物组合类型相同,表明主要物质来源于黄河。研究区中东部分布有粉砂质砂和砂,具有滨岸环境的沉积特征,而与现在所处的沉积环境不相一致,它们被解译为形成于全新世早期的滨岸环境,并在海底留存至今,属"残留沉积"。     

舟山群岛表层沉积物粒度和黏土矿物分布特征与物源指示

通过对舟山群岛表层沉积物样品的粒度分析和黏土矿物含量测定,研究了表层沉积物的粒度分布特征及黏土矿物组成。利用Flemming三角图示法分析了研究区域的沉积动力环境,并探讨了沉积物的物质来源。结果表明,舟山群岛表层沉积物共有5种类型,其中粉砂含量最高,呈片状广泛分布于舟山群岛东部宽阔海域;研究区表层沉积物分选性较差,以正偏为主;沉积物样品在Flemming三角图上投影显示,粉砂沉积物集中在D-Ⅱ,E-Ⅱ,E-Ⅲ区,砂质粉砂等沉积物零星分布在D-Ⅱ,C-Ⅱ及S区,表明研究区沉积物整体粒径较细、岛屿间水动力较强,开阔水域水动力较弱。研究区黏土矿物中伊利石为优势矿物,质量分数均值为61.5%;其次为绿泥石,质量分数均值为15.0%;高岭石和蒙脱石含量较少,质量分数均值分别为12.7%和10.9%。黏土矿物组合类型以伊利石-绿泥石-高岭石-蒙脱石为主,伊利石-绿泥石-蒙脱石-高岭石次之,具有类长江型沉积物特征。舟山群岛表层沉积物以陆源成因为主,物质来源以长江为主、浙江河流入海输沙以及舟山群岛岩石风化产物为补充。     

广西南流江三角洲沉积作用和沉积相

南流江河口有四个水动力区,各动力区的沉积物类型、平均粒径、标准偏差、碎屑重矿物含量、有机碳含量等沉积特征,均受水动力强弱控制而有明显差异.沉积物的变化可从沉积物类型分布图分别得到反映.并划分三角洲平原相、三角洲前缘相、三角洲相.     

Authigenic barite nodules and carbonate concretions in the Upper Devonian shale succession of western New York – A record of variable methane flux during burial

Authigenic barite nodules associated with modestly ¹³C-depleted calcium carbonate concretions and ³⁴S-enriched pyrite at the bottom of the Upper Devonian Hanover Shale of western New York provide evidence of sulfate reduction coupled with anaerobic oxidation of methane (AOM). The methane, much of it biogenic in origin, may have diffused upward from Middle Devonian Marcellus Shale and perhaps the Upper Ordovician Utica Shale. Strong ³⁴S enrichment and high δ³⁴S/δ¹⁸O values of the barite nodules reflect: (1) substantial kinetic fractionation induced by microbial sulfate reduction perhaps intensified by a low seawater sulfate recharge rate and (2) upward delivery of Ba²⁺- and CH₄- bearing pore fluid sourced within underlying sulfate-depleted deposits. However, the association of authigenic calcium carbonate and barite in the same stratigraphic interval, especially the presence of barite overgrowths on carbonate concretions, is not consistent with what is known of AOM-related mineralization of a sediment column passing downward through the sulfate–methane transition (SMT). The documented early formation of authigenic carbonate followed by barite observed relations may reflect a diminished rate of methanogenesis and/or CH₄ supply. The tempered methane flux would have induced the SMT to descend the sediment column enabling barite to form within the same stratigraphic horizon that ¹³C-depleted calcium carbonate had most recently precipitated. Diminished methane flux may have been caused by burial-related passage of the organic-rich Marcellus Shale below the depth of peak biogenic methane generation and its replacement at that depth interval by organic-lean deposits of the upper part of the Hamilton Group. Subsidence of the SMT would have increased the preservation potential of authigenic barite. However, continued survival of the labile barite as it eventually moved through the SMT suggests that the underlying sulfate-depleted zone was strongly enriched in Ba²⁺.     

天然气水合物赋存区甲烷渗漏活动的地球化学响应特征

综述了天然气水合物赋存区甲烷渗漏活动的地球化学响应指标的研究进展,分析了应用单一指标识别甲烷渗漏活动各自所存在的问题,包括浅表层沉积物孔隙水中CH_4、SO_4~(2–)、Cl~–等离子浓度随深度的变化;浅层沉积物全岩W_(TOC)(W表示质量分数,TOC表示总有机碳)和W_(TS)(TS表示总硫)之间的相关性及比值;自生碳酸盐岩δ~(13)C和δ~(18)O;自生矿物重晶石、黄铁矿、自生石膏的δ~(34)S;有孔虫壳体和生物标志化合物的δ~(13)C等。结果表明孔隙水中的CH_4、SO4_~(2–)浓度及溶解无机碳的碳同位素组成可以用来识别目前正在发生的甲烷渗漏活动;而沉积物中的WTS、自生矿物的δ~(34)S、钡含量及其异常峰值和生物标志化合物的δ~(13)C等指标的联合使用可以更真实准确地反映地质历史时期天然气水合物赋存区的甲烷渗漏活动。因此,在实际研究过程中,可将孔隙水和沉积物两种介质的多种指标相结合。随着非传统稳定同位素(Fe、Ca、Mg等)和沉积物氧化还原敏感元素(Mo、V、U等)等研究的发展,甲烷渗漏活动地球化学响应指标的研究也将得到拓展,而多种地球化学指标的联合使用将为天然气水合物勘探及其形成分解过程识别研究提供重要的科学依据。     

长江粘土矿物示踪标记稳定性的初步研究

选择物质来源相对单一、区域较广的浙江沿岸东海内陆架区，以4种主要粘土矿物(伊利石、蒙皂石、高岭石、绿泥石)为研究对象，以探讨长江粘土矿物作为示踪标记的稳定性问题。研究区5组沉积物样品中粘土矿物的X射线衍射实验及含量分析结果表明，伊利石、蒙皂石和高岭石的相对含量较稳定，具有作为长江物源示踪标记的价值．而各区域的绿泥石含量之间不具有显著的统计相似性。现有资料还不能完全解释长江口及邻近东海内陆架区内粘土矿物组合的相对稳定状态，今后应对絮凝作用、沉积分异作用、海底生物地球化学作用等因素的效府做进一步的研究。     

海洋天然气水合物的沉积学识别标志

海洋天然气水合物的沉积学识别标志是指在海洋天然气水合物沉积层形成过程中形成的与沉积作用密切相关的特征性标志,它是海洋天然气水合物基本的和重要的识别标志。这些标志包括沉积学背景、沉积物类型、沉积速率、有机质含量、沉积相类型、自生矿物、沉积热环境和特殊沉积地质体等。     

The clay mineralogy of particulate material from some surface seawaters of the eastern Atlantic Ocean

The concentrations of the clay minerals montmorillonite and illite have been determined in 28 samples of particulate material from surface (0–～5 m) waters along the eastern margins of the Atlantic Ocean, and the concentrations of chlorite and kaolinite have been determined in nineteen of the samples.The average concentration of the four clays in the particulate material decreases in the following order: illite (～42%) > kaolinite (～25%) > chlorite (～19%) > montmorillonite (～14%). There are specific trends in the latitudinal distributions of illite and kaolinite in the particulate material; illite decreases and kaolinite increases towards low latitudes. These trends are also found in eolian dusts and deep-sea sediments from the same region, and these clays are considered to have a detrital origin.The concentrations of montmorillonite in the particulate material and deep-sea sediments are similar in the North Atlantic. However, in the South Atlantic the sediments contain about twice as much montmorillonite as does the particulate material. It is suggested that whereas the montmorillonite in North Atlantic deep-sea sediments is largely detrital, that in South Atlantic sediments is both detrital and authigenic.     

日本海西部大陆坡自生碳酸盐的特征与成因

对日本海西部大陆坡沉积物柱状样中的自生碳酸盐样品进行了X射线衍射、扫描电镜、地球化学和碳氧同位素组成的系统研究。X射线衍射和扫描电镜分析结果表明,碳酸盐主要组成矿物为颗粒状自生高镁方解石微晶,放射状自生文石微晶仅在一个层位出现。结合碳酸盐的地球化学组成,认为研究区碳酸盐来自于富Ca2+、Mg2+和HCO3-流体的沉淀。中度亏损的13C(-33.85‰～-39.53‰)表明碳来自于甲烷的厌氧氧化,同时,这也是研究区海底存在甲烷冷泉的重要证据。重氧同位素比值(5.28‰～5.31‰)则指示着富18O流体来源,而该流体应源于天然气水合物的分解。综上可知,研究区碳酸盐来自于研究区甲烷冷泉上升流的沉淀,指示着海底更深处天然气水合物的存在与分解。     

太平洋东部CC48孔沉积物稀土元素地球化学研究

研究样品于１９８８年采自太平洋东部ＣＣ４８孔。通过对沉积物稀土元素地球化学特征的分析发现：（１）各种类型深海沉积物的稀土含量有所差别，以稀土元素总量而论，深海粘土＞硅质软泥＞硅钙质软泥＞钙质软泥；沉积物中的自生矿物、硅质生物成因的非晶质ＳｉＯ２及碎屑矿物对稀土元素起富集作用，而生物ＣａＣＯ３则起分散作用。（２）稀土元素含量随深度发生变化。为地层划分提供了依据，应用元素地层学方法将岩芯分成５个层段。     

渤海、黄海、东海沉积物中矿物组合的研究

本文对黄海、渤海、东海以及长江、黄河、辽河表层沉积物中的轻、重矿物进行了研究。分析资料表明,调查区内共有三种类型的矿物:陆源矿物、自生矿物和海底火山喷发形成的火山型矿物。根据轻、重矿物组合的差异,可把调查区分成8个矿物区。其物质来源主要为黄河与长江。黄河物质主要沉积在黄海、渤海;长江物质沉积在东海陆架区,而冲绳海槽则发现有海底火山喷发物质与浊流沉积。     

Intracellular mineral grains in the xenophyophore Nazareammina tenera (Rhizaria, Foraminifera) from the Nazaré Canyon (Portuguese margin, NE Atlantic)

Xenophyophores, a group of large agglutinated foraminifera, are characterized by the presence of numerous intracellular barite grains, termed granellae, the function and origin of which is unclear. The recently described xenophyophore Nazareammina tenera (Gooday et al., in press), from abyssal depth (4300 m) in the Nazaré Canyon contains an unusually dense concentration of mineral grains in its cytoplasm. Uniquely among known xenophyophores, the intracellular grains in this species comprise a variety of different mineral types in addition to barite. They exhibit a wide range of morphologies and energy dispersive X-ray analysis indicated that they include Ti-bearing minerals, many of them rod-shaped (probably rutile), as well as those containing Fe and Ti (possibly ilmenite and anatase), and Al and Si (probably clay minerals). While the function of intracellular particles in xenophyophores remains unclear, the presence of numerous particles of various types in the cytoplasm suggests that they originate from the sediment. This suite of intracellular mineral grains is completely different from that used to construct the agglutinated test of N. tenera, suggesting that this species is able to discriminate between different kinds of particles. A second xenophyophore species, Reticulammina cerebreformis (Gooday et al., in press), which is abundant at the same site as N. tenera, is devoid of intracellular particles, suggesting that their presence in N. tenera is a species-specific characteristic.