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1.
山东石臼所近岸带沉积物中极细砂粒级的矿物学研究，揭示了沉积物的不同来源和扩散趋势。河流沉积的矿物组成及其含量取决于流域区的岩石学特点。沿岸流域区的不同地质条件是北区两城——白马河、沿岸基岩和南区傅疃河泥沙，在矿物学上有明显差别的主要原因。近岸带沉积物的不同矿物组合区，即为不同来源的物质及其在近岸水动力因素作用下沉积的综合结果。 相似文献
2.
长江、黄河入海沉积物中元素组成的对比 总被引：3，自引：0，他引：3
使用X射线荧光分析仪对取自长江大通站(包括部分南京段)和黄河利津站入海沉积物进行了分析,研究了25种元素的含量特征及它们在长江和黄河里的差异,并与前人研究成果作了比较.研究表明,长江、黄河中的沉积物存在较明显差异,黄河沉积物中明显富集Ca,Sr,Si等元素;长江沉积物中明显富集Al,Fe,Ti,Mn,Cu,Zn,Pb,Rb,P,V等元素.这与2条河流流域的地质背景、气候带特征、风化程度以及人为活动影响关系密切.与前人研究结果相比,2类沉积物中重金属元素的含量有明显增加的趋势,但是用Al标准化之后发现只有部分重金属元素含量有所增加.重金属的变化可能与近年来中国工业快速发展及两河流域污染物质的排放增加有关. 相似文献
3.
福建兴化湾表层沉积物中重矿物组分及其分布特征 总被引：4，自引：0，他引：4
对兴化湾17个站位表层沉积物中63～125μm粒级重矿物组分、含量、组合及分布特征进行了分析研究,并探讨了泥沙物质来源及重矿物与沉积环境的关系.结果表明,兴化湾重矿物平均含量(质量分数)为12.08%,高出其邻近的湄州湾(5.67%)6个百分点;重矿物共计37种,以磁铁矿、角闪石、绿帘石、钛铁矿、赤铁矿、褐铁矿、锆石为主.矿物种类揭示该海湾的泥沙主要来源于湾顶河流输入和周边陆域及湾内岛屿基岩风化侵蚀产物,而湾口以外海域的输入物质较少;依据主要重矿物含量和分布特征,将兴化湾划分为4个矿物组合区,各区重矿物组合类型不仅与物质来源有关,而且受水动力条件和沉积环境制约. 相似文献
4.
台湾海峡表层沉积物的粒度和碎屑矿物分布特征方建勇 总被引：1，自引：0，他引：1
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。 相似文献
5.
6.
《海洋地质与第四纪地质》2010,(5)
用XRF和ICP-AES方法,分别测出中坝遗址地层中Rb、Sr和Ti含量,结果显示Ti元素在地层中含量的变化与对应地层中指示环境干湿的Rb/Sr值变化呈显著的正相关。对比泔井河流域含Ti矿物物源和化学蚀变指数(CIA),发现地层中Ti变化与流域元素迁移集聚无本质关联;而对应地层中的TOC含量与Ti含量有对应关系,同时有机物产生的有机酸可使含Ti矿物(如钛铁矿)发生离解过程,中坝遗址地层中Ti含量变化取决于沉积环境的Eh值和有机质的分解产物。通过与其他环境指标对比后,认为在准静水沉积地层中Ti元素对干湿环境变化具有普遍指示意义。 相似文献
7.
8.
中国河口地球化学研究的若干进展 总被引：15，自引：0，他引：15
在过去１０年的河口地球化学研究的基础上，总结了中国一些大的河口体系中的化学要素的行为特点。与世界上的大河流相比，中国河流中具有较高的营养元素和较低的痕量元素浓度。流域盆地的风化作用指数由北向南逐渐增加，这与世界上其它地区十分相似。在河口淡－咸水混合过程中，颗粒态的化学要素多呈稳定态分布模式，这与高的泥沙量，较轻的污染程度和水文动力作用相对较弱有关，并县对生态系统有显著的影响。考虑到化学要素在中国河 相似文献
9.
中国海岸侵蚀主要出现于废弃三角洲前缘地带和现代三角洲局部地区。其次出现在堆积性海岸阶地或沙坝区域。 河流沉积中心转移、流域来沙减少、河口水动力变异是废弃三角洲和现代三角洲侵蚀的重要条件;陆架供沙不足是海岸砂质堆积体蚀退的主要原因;较高能量的海浪、风暴和近岸水流作用是海岸侵蚀的主要动力因素;海平面上升对海岸蚀退有一定影响。 目前,中国海岸侵蚀仍在继续。今后,随着海岸带的开发建设,必须重视对海岸侵蚀的防护。 相似文献
10.
《海洋湖沼通报》2021,(3)
黄河下游频繁的黄河决口和改道在该区域形成了众多湖泊,其沉积物是研究该流域侵蚀和气候变化的重要材料。本文基于高精度的AMS-~(14)C测年,通过分析大野泽DYZ-1钻孔550 cm柱样中的元素含量组成、粒度、CaCO_3含量及元素主成分数理统计综合分析,重建了大野泽流域近1400 a的侵蚀变化序列。结果表明,大野泽流域侵蚀变化大致划分为5个阶段:625—940 AD期间,气候较冷干,流域侵蚀较弱;940—1250 AD期间,对应"中世纪暖期",气候暖湿,降水增多,同时大野泽湖盆频受黄河洪水注入,流域侵蚀强劲;1194 AD之后,黄河进入第四次大改道期,河道南迁夺淮河入黄海,1250—1540 AD期间,黄河洪水较少影响到大野泽湖区,但该时期气候相对暖湿,流域侵蚀相对较强;1540—1860 AD期间,对应"小冰期",气候较冷干,流域侵蚀较弱;1860 AD之后,在气候变暖背景下,降水开始增多,同时,黄河再次改道北迁,大野泽再次受到黄河洪泛影响,流域侵蚀再次加强。以上结论为深入理解黄河下游侵蚀变化特征及规律与黄河改道决溢洪水、气候变化的关系提供了重要科学参考。 相似文献
11.
M. D. Kravchishina V. P. Shevchenko A. S. Filippov A. N. Novigatskii O. M. Dara T. N. Alekseeva V. A. Bobrov 《Oceanology》2010,50(3):365-385
The grain-size and mineral composition of the suspended particulate matter (SPM) of the Severnaya Dvina River mouth is studied,
as well as the content of several lithogenic elements in the SPM during the spring flood in May 2004. The data published on
the composition of the riverine SPM in the White Sea basin are very poor. The spring flood period when more than half of the
annual runoff is supplied from the river to the sea in a short time is understood more poorly. The report considers the comparison
results for the grain-size compositions of the SPM and the bottom sediments. The data of laser and hydraulic techniques of
the grain-size analysis are compared. The short-period variations of the SPM concentration and composition representing two
diurnal peaks of the tide level are studied. It is found that the SPM is mainly transferred during the spring flood as mineral
aggregates up to 40 μm diameter. The sandysilty fraction of the riverine SPM settles in the delta branches and channels, and
the bulk of the fine pelitic matter is supplied to the sea. The mineral and chemical composition of the Severnaya Dvina River
SPM is determined by the supply of substances from the drainage basin. This substance is subjected to intense mechanic separation
during the transfer to the sea. The key regularities of the formation of the mineral composition of the SPM during the flood
time are revealed. The effect of the grain-size composition of the SPM on the distribution of the minerals and elements studied
in the dynamic system of the river mouth are characterized. 相似文献
12.
本文分析了南黄海近岸沉积物中P_2O_5,CaCO_3、有机碳及一些金属元素的地球化学特征;探讨了这些特征与沉积物类型、水动力状况、入海河流、生物活动及沉积环境的关系。 相似文献
13.
黄河口毗邻渤海陆架区悬浮体成分 总被引：1，自引：0，他引：1
扫描电镜配合能谱分析、X射线衍射及光学显微镜分析表明,黄河口毗邻的渤海陆架区悬浮体主要由矿物、浮游生物和有机包膜三类成分组成。在悬浮体中鉴别出23种矿物,主要是石英、长石、云母、方解石和粘土矿物(依次为伊利石、蒙皂石、绿泥石和高岭石),特征矿物是云母、方解石、蒙皂石和角闪石。辨识出21种藻类,大多数是硅藻,少数为钙藻和鞭毛藻。生物成分主要集中在水体上层。首次在渤海悬浮体中发现了有机包膜。并讨论了悬浮体成因及其沉积作用。 相似文献
14.
Suspended sediments from large and middle size Chinese estuaries, including the Yalujiang, Shuangtaizihe, Luanhe, Jiaojiang and Zhujiang, were analysed to understand trace metal transport in the coastal zone. The determinations of 13 major and trace elements plus organic carbon were made of total concentrations and were fully validated by certified reference materials (CRMs). The combination of the data sets with other Chinese estuaries, such as Changjiang and Huanghe, provides an overview of particulate trace metal geochemistry in this region. Trace metal levels in Chinese rivers are relatively low compared with those draining industrialized regions of Europe and North America. In the estuaries, most particulate elements illustrate stable distribution in the mixing zone until a salinity of 30, especially when absolute concentrations are normalized to aluminium, although the total suspended matter (TSM) is quite different in time and space. Using Al as a reference, it was estimated that 25–40% for Cu, and 5–20% for Pb could remain in labile part in the Jiaojiang, Shuangtaizihe and Zhujiang, whereas different features of labile elements were found in the Changjiang and Luanhe. The mean enrichment factor (EFm) increases with higher sewage to river runoff ratio (S/R) over the drainage basin and EFm for suspended matter is higher than that for bottom sediments. Finally, inputs of particulate trace metals to the coast are estimated based on the riverine sediment load and chemical compositions. 相似文献
15.
《Estuarine, Coastal and Shelf Science》2006,66(1-2):267-279
The composition and behavior of allochthonous particulate organic matter (POM) in the northern part of Ise Bay, Japan were investigated to elucidate the short-term variation in POM accompanying changes in river discharge. The behavior of POM was significantly regulated by hydrographic conditions, but behavior was different in the upper layer versus the middle and lower layers. The former showed simple dynamics controlled by the river plume, while the latter showed complex dynamics because of changes in river discharge and subsequent variation in estuarine circulation. During normal discharge, the contribution of riverine materials to POC in the surface water within the bay was negligible because most riverine organic matter is deposited before flowing into the bay. During high discharge, on the other hand, the contribution of riverine organic matter to total POM increased to 50% at ∼10 km from the river mouth. Though riverine organic matter loads increased, the total amount of POC decreased around the river mouth due to flushing of phytoplankton. After river discharge, the contribution decreased rapidly.The behavior of POM in the middle and lower layers differed from that in the surface layer. At normal discharge, the influence of riverine organic matter was weak. During high discharge, high flooding temporarily weakened the bottom inflow, resulting in heavier riverine organic matter distributed from the river mouth to mid regions within the bay in the lower layer. The maximum contribution of riverine organic matter to total POM was estimated to be ∼60% around 25 km from the river mouth. After high discharge, riverine POM in the lower layer was pushed to the bay head by enhanced estuarine circulation and was uplifted to the middle layer. The behavior of riverine POM dynamically changed in relation to river discharge, and exerted a significant influence on bottom water conditions in the bay. 相似文献
16.
罗纳河中悬浮物质的痕量元素的研究 总被引：5，自引：0，他引：5
于1989年5月－1990年4月间,在罗纳河下游近河口处进行每月一次为期间个月的样品采集工作,并且样品用HNO3－HF－HCIO4湿法消化后,用原子吸收分光光度法测定了悬浮颗粒物中的Co,Cr,Cu,Mn和Pb含量。结果表明,在不同月份之间悬浮物中的痕量元素组成具有显著地差别,其中一些元素的浓度随流量的增加而减少,而另外一些似乎与流量之间没有显著的关联。在稳定体系的假设下,所估计的人文活动对痕量元素的贡献可占观测浓度的10％－50％。当与其它河流对比时,发现罗纳河中的颗粒态痕量元素的浓度明显高于那些受人文活动影响较小的体系,而与北美的河流系统接近,表明罗纳河流域的人文活动对河流中颗粒态痕量元素的影响是显著的。 相似文献
17.
论新疆巴里坤湖沉积地球化学指标的累积规律 总被引：14，自引：1，他引：14
于１９８９年８月，在新疆巴里坤湖区进行多次野外调查和钻孔取样，将１１６块岩芯样用等离子发射光谱对各种微量元素和氧化物进行全面分析，以研究古气候与古环境的演变关系。研究得知，本区多数微量元素以碎屑形式机械迁移为主，因此，在地表径流较丰富的凉湿或冷湿环境，湖底沉积的元素相对富集；反之，在地表径流减少的暖干环境，元素富集减少。这种元素的迁移规律，表明干旱区内陆确存在冷湿暖干型的气候特征，不同于东部季风区 相似文献
18.
长江干流悬浮物中元素相态组成与环境指示 总被引：1，自引：0，他引：1
三峡水库蓄水后长江中下游干流和水库内悬浮物地球化学组成如何变化是一个重要科学问题。相态分析表明,在长江重庆至南通段干流悬浮沉积物中,不同元素在酸不溶相和酸溶相所占比例不同,且存在一定的区域变化,Ca和Mg在酸溶相中比例相当高,而Al、Fe、K、Na等元素主要赋存于酸不溶相中。长江悬浮沉积物元素组成的空间变化特征主要受流域风化物质的来源、风化程度和水动力环境控制。重金属元素组成研究显示,在三峡库区及下游地区由于受人类活动影响,Pb、Zn、Co、Cu等在悬浮沉积物中呈现明显的累积趋势。三峡水库内沉积动力环境的不均一性导致水体中元素组成的垂向变化。 相似文献
19.
M. Giani D. Berto F. Rampazzo F. Savelli F. Alvisi P. Giordano M. Ravaioli F. Frascari 《Estuarine, Coastal and Shelf Science》2009,84(4):573-583
In order to evaluate the origin and the transformation of organic matter on the shallow shelf of the NW Adriatic Sea, organic carbon, total nitrogen and stable isotope ratios of organic carbon were analysed in riverine suspended matter and sediments as well as in marine suspended and sedimentary organic matter, in marine phytoplankton and zooplankton.The deposition of organic matter is influenced by fine sediment concentration. Surface sediments were characterised by highly variable biogeochemical conditions on the sea floor, whereas sub-surface sediments showed a more homogeneous hypoxic/anoxic environment.Low Corg/N ratio and high organic carbon and nitrogen concentrations in riverine suspended organic matter indicate an important contribution of freshwater phytoplankton within rivers, particularly during low flow regimes, which adds to the marine phyto- and zooplankton at shelf locations.In order to evaluate the importance of terrestrial, riverine and marine sources of OM in shelf sediments, a three end-member mixing model was applied to shelf surface sediments using 13C/12C values for organic matter and N/C ratios. The model showed an elevated contribution of terrestrial organic substances at intermediate depths (10–15 m), mostly corresponding to an area of coarser grain-size, whereas the riverine and marine organic fractions were mainly accumulating near the coast and offshore, respectively. 相似文献
20.
Estuaries have long been thought to be effective traps for river-borne contaminants; however, accurately predicting removal efficiencies remains problematic. In the Quinnipiac River, CT, marsh system, patterns of metal accumulation (Ag, Cd, Cu, Pb) in sediments were used to estimate heavy metal removal efficiencies. Linear and multivariate regression models were fit to sediment metal concentrations to estimate removal curves and surfaces, which avoided the large temporal variability commonly encountered when using direct water column measurements. Second order regressions normalized to the shortest distance to the river channel were found to have the best fit (r>0.67) with the lowest standard error (<32%). The heavy metal removal efficiencies estimated by comparing total metal accumulation in marsh sediments with riverine flux were Ag=21%, Cd=6%, Cu=14%, and Pb=17%, which are comparable to the maximum removal efficiency of riverine suspended particulate matter (28%). 相似文献