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101.
重矿物组合、含量变化和特征矿物的分布及变化规律是沿海泥沙来源和运移趋势判断的重要手段之一。通过对廉州湾南部海域海底表层沉积物的重矿物分析 ,发现该区重矿物分布以北海地角为界 ,其百分含量和特征矿物南北有别 ,可能分别代表不同的物质来源区。其中廉州湾北部南流江流域来沙是该区主要物源 ,运移趋势为自 NE向 SW;地角西南岸段、岭南侧海岸侵蚀及银滩来沙也为该区提供了部分物源 ,运移趋势为绕过冠头岭沿海岸向 N方向运移。由于缺乏北海陆域陆相地层重矿物含量等相关资料 ,暂未做物质来源区的具体判断 相似文献
102.
A. Banerjee M. Jha A. K. Mittal N. J. Thomas K. N. Misra 《Marine and Petroleum Geology》2000,17(10):7
Source rock screening reveals five laterally extending potential sources (PS) in the Paleogene. The PSs are SR5 and SR6 in dominantly marine early Eocene to late Paleocene Cambay Shale formation, and SR7, SR8/9, and SR11/12 in dominantly freshwater early Paleocene Olpad formation. Only 3 PSs, SR11/12, SR8/9, and SR7 have attained vitrinite reflectance of 0.75% at 45, 7, and 2 mybp, respectively. Chromatographic and isotope data of oils and PS samples suggest that mainly the Olpad source rocks: SR7 and SR8/9 contributed to the discovered oils. The Cambay Shale source rocks, SR5 and SR6, contrary to the prevalent view, possibly have no significant contribution towards the accumulated oils. 相似文献
103.
104.
海滩是砂质海岸重要的沉积地貌单元,其沉积特征和稳定性对于海滩的开发利用与保护具有重要意义。本文根据海口湾西海岸海滩表层沉积物粒度数据,阐述了该区域海滩沉积物的时空分布规律,并通过对比滩面高程数据和水下地形数据分析了该区域的岸滩稳定性。结果表明:海口湾西海岸海滩处于滩面微蚀的轻度不稳定态,其岸外浅滩处于边坡侵蚀的轻度不稳定态。另外,根据波浪作用和泥沙来源进一步探讨了海口湾西海岸海滩沉积物动力机制及其海滩侵蚀的原因。 相似文献
105.
Numericalstudyofpollutanttransportinthesea-baywithmildslopebeachWangZeliangandTaoJianhua(ReceivedDecember22,1996;acceptedJanu... 相似文献
106.
太湖梅梁湾三维水动力学模型的研究 Ⅱ.营养盐随三维湖流的扩散规律 总被引:6,自引:0,他引:6
建立了太湖梁梁湾三维营养盐浓度扩散模型,研究了三维潮流的作用下,营养盐随风场的扩散情况。结果表明:(1)当梁溪河和闾江口两个污染源同时存在时,西北风最有利于营养盐浓度的扩散,顺着风向形成了一条西北-东南走向的污染带;而东南风却最不利于营养盐浓度的扩散,使得污染范围仅局限于污染附近。 相似文献
107.
本文对广东省近岸10个典型海湾的表层沉积物进行了系统的稀土元素(rare earth elements,REE)测试和分析,以期发现沉积物的物源组成特征及其控制因素。研究结果表明,同一海湾内沉积物的稀土丰度差异不明显,但不同海湾之间具有一定的差别(133.58—251.77mg.kg 1)。球粒陨石标准化配分曲线表现出轻稀土(La到Eu)富集、重稀土(Gd到Lu)亏损、δEu负异常等典型的陆源沉积物特征;PAAS(Post-Archean Australian Shale)标准化配分模式显示出明显的中稀土(Sm到Ho)富集特征,与已报道的国内河流沉积物REE特征相似。海湾沉积物与入海河流沉积物及流域内的原岩组成特征的比较说明,后者对海湾沉积物的控制作用明显。REE配分曲线的一致性和中稀土富集特征表明海湾沉积物主要来自汇入海湾的山溪及河流输入的沉积物。 相似文献
108.
Hypoxia is increasingly reported off the Changjiang River Estuary with the confluence of multiple high volume nutrient sources. The Regional Ocean Modeling System coupled with a biological model was used to analyze the effect of different nutrient sources on the development of hypoxia off the Changjiang River Estuary. By comparing to observed data, our model suitably captured the regional dynamics of chlorophyll a, dissolved oxygen, and nutrient concentration. A series of sensitivity experiments were conducted to investigate the hypoxia response to the various nutrient sources, such as loading from the Changjiang River, Kuroshio and Taiwan Warm Current. Our model results indicated that nutrients from different sources significantly influenced the hypoxia off the Changjiang River Estuary, and it was mostly affected by nutrients sourced from the Kuroshio. The nutrients input from the Changjiang River had larger impacts on the hypoxia in the north of 30°N than that in the south of 30°N. The nutrients sourced from the Taiwan Strait had a least influence on the hypoxia off the Changjiang River Estuary. 相似文献
109.
The Cuu Long Basin (Mekong Basin) is a rift basin off southern Vietnam, and the most important petroleum producing basin in the country. However, information on petroleum type and characteristics has hitherto been largely unavailable to the public. This paper presents petroleum geochemical data on nine oil samples from four different producing fields in the Cuu Long Basin: the Dragon (Rong), Black Lion (Sutu-Den), Sunrise (Rang ?ong) and White Tiger (Bach Ho) Fields. The oils are highly paraffinic with bimodal normal alkane distributions and show moderate pristane to phytane ratios and a conspicuous hyperbolic decrease in abundance with increasing carbon number of hopane homologues from C30 to C35. The TPP-index of Holba et al. (Holba, A.G., Dzou, L.I., Wood, G.D., Ellis, L., Adam, P., Schaeffer, P., Albrecht, P., Greene, T., Hughes, W.B., 2003. Application of tetracyclic polyprenoids as indicators of input from fresh–brackish water environments. Organic Geochemistry 34, 441–469) is equal to 1 in all samples which in combination with tricyclic triperpane T26/T25 ratios >1 and the n-alkane and hopane distributions mentioned above provide a strong indication of an origin from lacustrine source rocks. This is supported by the absence of marine C30 desmethyl steranes (i.e. 24-n-propylcholestanes) and marine diatom-derived norcholestanes. Based on the overall biological marker distributions, the lakes probably belonged to the overfilled or balanced-fill types defined by Bohacs et al. (Bohacs, K.M., Carroll, A.R., Neal, J.E., Mankiewicz, P.J., 2000. Lake-basin type, source potential, and hydrocarbon character. An integrated sequence-stratigraphic–geochemical framework. AAPG Studies in Geology 46, 3–34). The oils were generated from source rocks at early- to mid-oil-window maturity, presumably Oligocene lacustrine shales that are present in the syn-rift succession. Oils from individual fields may, however, be distinguished by a combination of biological marker parameters, such as the oleanane index, the gammacerane index, the relative abundance of tricyclic terpanes, the proportions of diasteranes and 28-norspergulane, complemented by other parameters. The oils of the Cuu Long Basin show an overall similarity to the B-10 oil from the Song Hong Basin off northern Vietnam, but are markedly different from the seepage oils known from Dam Thi Nai on the coast of central Vietnam. 相似文献
110.