长江口北槽一期工程后滩槽沉积物分布特征及其影响因素

根据2000年7月和2001年5-6月份长江口北槽航道及两侧滩地进行的沉积物采样分析结果,对长江口深水航道一期工程实施后的滩槽泥沙交换情况以及在自然与工程双重影响下的沉积物分布情况进行了较为详细的讨论。长江口深水航道工程的实施,影响了长江口尤其是北槽及两侧滩地的水沙条件和沉积物分布。强劲的径流和潮流作用和风浪作用造成航槽及两侧滩地的冲淤转换及沉积物分布的变化;深水航道治理工程的实施使工程段内航槽泥沙粒径粗化,两侧滩地和工程段下游泥沙中值粒径变细,这反映了在工程实施后滩槽泥沙交换的变化。

卡拉库里区块碳酸盐岩沉积相分布特征研究

卡拉库里区块构造形态呈北西高、南东低的趋势,总体上向东南倾伏。各小层顶界构造均表现为构造起伏程度低、构造形态继承性明显的特征。本次研究区内有西莎、西吉、东阿拉特共3个气田,总井数为11口,目的层为上侏罗统卡洛夫-牛津阶(J3k+o)海相碳酸盐岩沉积。利用测井、薄片鉴定、取心、地震等资料开展了目的层的沉积分布特征研究,总结出卡洛夫-牛津阶储层主要发育台地边缘滩、开阔海台地、局限台地3类亚相沉积。

珠江口内伶仃洋水体和沉积物石油烃的分布特征

根据2005年8月的调查结果,研究珠江口内伶仃洋海域海水及沉积物中石油烃含量及分布。结果表明:调查水域海水中石油烃含量分布范围为0.039~0.108mg/L,平均含量为0.069mg/L,属于三类水质,在我国各海域中污染较重;水体中石油烃含量分布呈现表层高于底层、涨潮高于落潮的特征;沉积物中石油烃平均含量186.2 mg/kg,符合《海洋沉积物质量》一类标准限值,在我国各海域中污染较轻;水体和沉积物中石油烃含量之间相关性不显著。

海拉尔盆地苏德尔特油田兴安岭群Ⅰ油层组沉积微相及其含油气性

砂岩油藏沉积相带分布及其引发的储层非均质性已经成为制约油藏滚动勘探和开发生产的瓶颈。在系统观察岩心的基础上并结合钻井、测井资料研究了海拉尔盆地苏德尔特油田兴安岭群Ⅰ油层组的沉积微相特征和分布。结果表明,苏德尔特油田兴安岭群Ⅰ油层组主要发育辫状河三角洲前缘水下分流河道、河口坝、远砂坝以及湖底扇主沟道、主沟堤等沉积微相,其中水下分流河道为最主要的沉积微相。在此基础上,剖析了沉积微相与储层物性、油气分布的关系,指出水下分流河道和河口坝微相砂体为该区有利的油气聚集区。

余杭塘河沉积物重金属污染现状及潜在生态危害评价

为了解京杭大运河支流余杭塘河沉积物中重金属的污染特征及潜在危害程度,测定了83个采样点枯水期和丰水期沉积物中铜(Cu)、锌(Zn)、铅(Pb)、镉(Cd)4种重金属元素的含量.结果表明:1)4种重金属含量在时空上都表现出不同的差异性,无论是丰水期还是枯水期,余杭塘河沉积物中Cu、Zn的含量均高于浙江省土壤环境背景值,Cd的含量低于背景值,Pb在丰水期上游(第I段)高于背景值,枯水期低于背景值.2)余杭塘河沉积物中重金属的潜在生态危害程度属于轻微级别,Cu是对余杭塘河生态环境具有潜在影响的重金属元素,仍需警惕.3)在枯水期阶段,Pb与Cu、Zn具有显著的相关性,在丰水期阶段,Cu与Zn、Pb具有显著的相关性,表明它们的来源可能相同.在杭州未来科技城的建设与运行过程中,仍需要对这些重金属污染加以防范.

低阻油层成因机理评述

低阻油层在世界范围内分布广泛,由于其在石油勘探寻找新油藏或油田开发中后期寻找剩余油潜力层分布中占有重要地位,成为各油田迫切需要解决的问题之一。文章从低阻油层的沉积分布特征着手,总结了低阻油层地质与测井方面的成因机理,具有一定指导意义。

Vertical Distribution Characteristic of Nitrogen in the Core Sediments of Three Rivers Estuary in Poyang Lake

The vertical profile distribution characteristics of nitrogen in core sediments of Three Rivers Estuary in Poyang Lake were studied.The results showed that TN content in core sediments ranged from 480.0 to 1 900.0 μg/g with the change of depth,which was divided into three distribution types as follows:TN content decreases gradually with the increase of depth,TN content increases gradually with the increase of depth or higher content in the middle but lower content in two ends.NH4+-N content ranged from 8.7 ...

Petroleum Hydrocarbon Distribution Features in Water and Sediment off Fujian Shore

This study on the distribution features of petroleum hydrocarbon in water and sediment off the Fujian shore using data obtained from the baseline research on oceanic contamination in Fujian showed that: during the research period, petroleum hydrocarbon concentrations in water varied from 5.77 μg/L to 37.28 μg/L, averaged 14.48 μg/L; was lower in the wet season than in the dry season; and was highest in the Minjiang Estuary and Jiulong Estuary in both seasons. The petroleum hydrocarbon concentrations in shore sediment varied from 14.48 mg/kg to 784.36 mg/kg, averaged 133.3 mg/kg, and was closely related to sediment types (granularity).

Braided river and distribution patterns of sand bodies of Jurassic Badaowan formation in Block T13 of Junggar basin

In order to determine the planar and volume distribution of sand bodies of the Jurassic Badaowan formation in Block T13 of Junggar basin,we used analysis of field outcrop and 3D seismic data,which play an essential role in areas of sparse well coverage.We describe sedimentary facies characteristics,sand body planforms,width and connectivity patterns of sand bodies,and vertical associations and successions by acoustic impedance inversion technology and sedimentological theory.Results of our study show braided fluvial strata deposits in the Jurassic Badaowan formation.Each sand body is approximately lenticular in shape.The width of each sand body falls in the range 100～800 m,with most between 200 and 400 m.The sand bodies vary in thickness from 4 to 13 m,with most below 9 m.The width/thickness ratios lie in the range 20～55.The connectivity of braided fluvial channel sand bodies is controlled by changes of accommodation space.One fining-upward sedimentary cycle of base-level rise is recognized in Badaowan formation,representing an upward rise of base level.The connectivity of sand bodies was found to be greatest in the early stage of base-level rise,becoming progressively worse with increasing base-level rise.

Molecular Characterization of Sulfate-Reducing Bacteria Community in Surface Sediments from the Adjacent Area of Changjiang Estuary

Sulfate-reducing bacteria(SRB),which obtain energy from dissimilatory sulfate reduction,play a vital role in the carbon and sulfur cycles.The dissimilatory sulfite reductase(Dsr),catalyzing the last step in the sulfate reduction pathway,has been found in all known SRB that have been tested so far.In this study,the diversity of SRB was investigated in the surface sediments from the adjacent area of Changjiang Estuary by PCR amplification,cloning and sequencing of the dissimilatory sulfite reductase beta subunit gene(dsr B).Based on dsr B clone libraries constructed in this study,diversified SRB were found,represented by 173 unique OTUs.Certain cloned sequences were associated with Desulfobacteraceae,Desulfobulbaceae,and a large fraction(60%) of novel sequences that have deeply branched groups in the dsr B tree,indicating that novel SRB inhabit the surface sediments.In addition,correlations of the SRB assemblages with environmental factors were analyzed by the linear model-based redundancy analysis(RDA).The result revealed that temperature,salinity and the content of TOC were most closely correlated with the SRB communities.More information on SRB community was obtained by applying the utility of Uni Frac to published dsr B gene sequences from this study and other 9 different kinds of marine environments.The results demonstrated that there were highly similar SRB genotypes in the marine and estuarine sediments,and that geographic positions and environmental factors influenced the SRB community distribution.

Characteristics of Heavy Minerals Composition and Distribution in Jiulong River Estuary Sediment

The bottom sediment samples were gathered during island investigation in 1994 and in the period of carrying out the natural science fund project of Fujian in 1999. The composition, distribution and assemblage characteristics of heavy minerals which granularity distributes from 0.063 to 0.125 mm in the sediment from Jiulong River estuary are studied in the paper. The results show that there are 49 kinds of heavy minerals and the average content of them is 9.38 %. The dominant and characteristic minerals are magnetite, hematite, epidote, ilmenite, limonite, hornblende, zircon, andalusite, biotite and so on. 4 mineral assemblage ⅠⅡzones (.The watercourse gateway of Jiulong River mineral zone, . The northern estuary ⅢⅣof Jiulong River mineral zone, . The southern estuary mineral zone, . The eastern estuary of Jiulong River mineral zone ), can be divided based on the heavy mineral contents and the distribution characteristics, which not only relates to the matter sources but also is controlled by hydrodynamic condition and the sedimentary environment in the Jiulong River estuary.

Characteristics of Vertical Distributions of Fatty Acids in Surface Sediments of the Yellow Sea and East China Sea

Fatty acids(FAs) in sediment collected from three different stations in the Yellow Sea and the East China Sea were analyzed for their distributions and to determine evidence of harmful algal blooms in the sediment core.Less diverse FAs were found in the Yellow Sea(YS) station,whereas in the two stations of the East China Sea(ECS) the FAs were more diverse.Concentrations of some FA species in the two ECS stations displayed an occasional surge in their vertical profile.The highest concentration of FAs was found in the surface layer of station QT3(43.28 μg g^(-1)).Monounsaturated FAs were more susceptible to degradation compared to their saturated counterparts,and changes of 16:0,18:2 and 20:5 accounted for the most variability in total concentrations of FAs as those species made up most of the quantified FAs.The origins of the major fraction of FAs were attributed to autotrophic sources,and bacterial FAs accounted for only a small fraction of the total FAs in the region.Nutrient availability was a possible regulating factor controlling bacteria abundances in marine sediments in the ECS and the YS.A principal component analysis(PCA) was applied to analyze the FA dataset and to reveal the principal environmental factors that control the composition of FAs in the sediments.PC2,which explains 15% of the variance,was estimated to reflect the diagenetic effects on the FA compositional changes in sediments influenced by bacterial degradation.

Distribution of fatty acids in the alpine grassland soils of the Qinghai-Tibetan Plateau

As an important biomarker, fatty acids(FAs) have been extensively used to trace the origin of organic matter in sediments and soils. However, studies of the distribution and abundance of FAs in alpine grassland soils are still rare, especially on the Qinghai-Tibetan Plateau(QTP), the highest plateau in the world, which contributes sediments to many large rivers in Asia. This study investigates the composition, distribution and source of FAs with increasing soil depths from 17 typical alpine grassland sites in the QTP. The most abundant FAs included the ubiquitous C16 FA and even-numbered long-chain FAs(C20–C30), indicating mixed inputs from microbial and higher plant sources. Source apportionment showed that higher plants were the dominant contributor of FAs(approximately 40%) in QTP soils. The abundance of FAs decreased with soil depth, with the highest value(1.08±0.09 mg/g C) at a 0–10 cm depth and the lowest value(0.46±0.12 mg/g C) at a 50–70 cm depth, due to much lower plant inputs into the deeper horizons. The total concentration of FAs was negatively correlated to the mean annual temperature(MAT; P<0.05) and soil p H(P<0.01), suggesting that the preservation of FAs was favored in low-MAT and low-p H soils on the QTP. The abundance of fresh C source FAs increased significantly with the mean annual precipitation(MAP; P<0.05), indicating that high MAP facilitates the accumulation of fresh FAs in QTP soils. Other environmental parameters, such as the soil mineral content(aluminum and iron oxide), microbial community composition as well as litter quality and quantity, may also exert a strong control on the preservation of FAs in QTP soils and warrant further research to better understand the mechanisms responsible for the preservation of FAs in QTP soils.