首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
我国河流输沙对海岸和大陆架沉积的影响   总被引:3,自引:0,他引:3  
我国现代海岸跨越构造沉降带和隆起带。据统计,在沉降带海岸入海的河流,其输沙量占我国人海河流输沙总量的90%以上,而在隆起带沿岸入海者,其输入量不足10%。沉降带沿岸以潮坪沉积为主,并出现巨厚的第四系沉积层;隆起带沿岸主要为海滩砂砾质沉积及与之相伴生的风成沉积,只在大河细粒物质沿岸运移所及之处,才形成潮坪沉积,且第四纪沉积层较薄,原地沉积物呈斑块状分布。东海和南海所接受的河流输沙量较少,异地沉积虽占据相当的范围,但原地沉积分布较广,并构成连续的沉积带。大河输沙通过海洋因素的搬运而沉积于相邻的小河口内,并构成堆积体,这是通过海、河泥沙交换,河流沉积物影响海岸沉积的另一个重要途径。在我国沿岸尚未发现主要由大陆架直接来沙产生的河口海岸沉积体。  相似文献   

2.
重点分析了渤海形成大油田的石油地质条件。渤海晚期构造活动强,是渤海湾盆地渐新世—上新世的沉降—沉积中心,由此决定了它比周边陆地油区多出了东三段烃源岩,上覆馆陶—明化镇组沉积厚度大,使东三段生油岩深埋、成熟;东二段大型三角洲发育,明化镇组盖层条件好,这些为大油田形成提供了良好的储-盖组合;凸起上大型的潜山-披覆背斜和大断层下降盘的逆牵引背斜,数量多、面积大,为石油聚集提供了场所;基底不整合面及控凹大断层是运移的优质通道,为石油的汇聚提供了条件。以上优越的源、储、盖、圈、运等条件,奠定了渤海大油田形成的基础。  相似文献   

3.
黄,东海海域水团发育对底质沉积物分布的影响   总被引:5,自引:1,他引:5  
通过对黄,东海海域底质沉积物中的细粒级粘土矿物组合特征和全粒级碳酸盐含量分析,对比上覆水团和悬浮体资料,探讨研究区水团发育消长对底质沉积物分布的影响作用。结果表明研究区可以划分为长江冲淡水影响的长江型物质沉积区;黄海水影响的黄河型物质沉积区和轩潮水以及东少次表层水物残留型物质沉积区。而水团发育消长可直接影响下伏底质的分布特征。黄河型物质沉积区与残留型物质沉积区的分界相应于黄海冷水向东南扩展与黑潮次  相似文献   

4.
渤海及黄海北部的风海流数值计算及余流计算   总被引:3,自引:0,他引:3  
依据黄渤海实测风的资料对渤海及北黄海进行了月平均风海流数值计算。计算表明,1月份在西北风的作用下,在渤海出现1个逆时针旋转的环流,在辽东湾北部及黄海北部出现1个顺时针旋转的环流,渤海海峡的海流北进南出。7月份在南风和东南风的作用下,风海流的变化形式与1月份大致相反,海峡处呈南进北出的形式。对渤海中部某点1年的潮流资料通过低通滤波的方法计算逐时的余流值,得到该点1年内表层最大的实测余流为31.9cm/s,全年90%多的时间内表层余流小于10cm/s。对辽东湾北部某点和渤海湾西南部某点数月潮流资料也进行了低通滤波,并将得到的逐时余流与同步风作了比较。依据该2点风和余流的关系以及黄海北部6个点风和余流的关系验证了风海流数值计算的结果,表明在这些点上实测与计算结果拟合良好。  相似文献   

5.
渤海水交换的数值研究—水质模型对半交换时间的模拟   总被引:18,自引:0,他引:18  
介绍了几种关于水交换的概念和模型。认为以水质模型模拟半交换时间研究海域的水交换能力更全面、客观。对渤海水交换的研究表明,由于渤海环流结构及季节变化,使得渤海3个海湾及渤海中部交换能力相差很大,莱州湾交换能力最强,辽东湾特别是其西部海域交换能力最弱。交换时间与物质初始浓度无关,与投放时刻、外源强迫密切相关。在治理渤海环境时,应分区进行,注意选择污染物排放时间和位置。  相似文献   

6.
利用野外地质剖面、关键钻井剖面和区域地质资料,在地层划分对比和构造格局研究基础上,运用沉积相分析的方法,探讨了东北地区早二叠世岩相古地理特征,将早二叠世分为阿瑟尔期-亚丁斯克期、空谷期两个编图单元进行岩相古地理编图,恢复了东北地区早二叠世的岩相古地理面貌。研究表明,早二叠世东北地区主要发育半深海沉积体系、浅海陆棚沉积体系、碳酸盐台地沉积体系、无障壁海岸沉积体系、障壁海岸沉积体系及河流沉积体系;阿瑟尔期-亚丁斯克期存在漠河古陆、松辽古陆、佳木斯古陆及华北北缘高地四个古陆,物源区碎屑物质供应充分,研究区为浅海、海陆交互及河流沉积区,周边古陆的格局;至空谷期,松辽古陆消失,研究区为浅海-半深海沉积,周边古陆的格局。  相似文献   

7.
厦门海域大气气溶胶中磷的沉降通量   总被引:4,自引:0,他引:4  
1993年8月至1994年5月四个季度对厦门海域的气溶胶样品总磷含量测定的结果表明,厦门海域大气气溶胶总磷含量平均为6.03×10-2μg/m3,并呈现干湿季变化特征,夏季雨量丰沛时节含量最低,与降水、风向等气象条件有关.磷的大气沉降通量约9.5×10-2g/m2.a,比北太平洋和南极半岛海域高一个数量级,湿式沉降通量大于干式沉降.与沉积物释放等过程比较,大气沉降不是磷的主要的输入过程,但不可完全忽略  相似文献   

8.
根据近50年的全球海洋和大气再分析资料,利用奇异值分解和子波变换分析方法及绕极涡分析途径,揭示了冬季太平洋海表温度(SST)与北半球中纬度大气环流异常共变模态的时空特征.结果表明,冬季太平洋SST与北半球中纬度大气环流异常之间主要表现为两种时空结构显著不同的共变模态,即年际的ENSO模态和准20a时间尺度的年代际北太平洋模态.二者在空间结构上具有明显差异.对于年际ENSO模态,海洋异常表现为典型的ENSO型SST异常分布.其主信号在热带中东太平洋,次信号在北太平洋,两者变化位相相反;大气异常主要为PNA型波列,局限于太平洋一北美地区,具有局域性特征,对于年代际北太平洋模态,SST异常则主要限于中纬度北太平洋地区,表现为北太平洋中西部与北美西岸SST异常呈反相变化;大气异常则表现为整个中纬度西风带上纬向波列分布,具有纬向全球性特征,即不仅与PNA遥相关型联系,而且与太平洋上游的欧亚大气环流异常也有密切关系,当中纬度北太平洋异常冷时,则中纬度大气整个定常槽脊系统加强,反之,则减弱.进一步对大西洋分析表明,年代际北太平洋模态的产生很有可能与“两个海洋与一个大气”的耦合相互作用机制有关.  相似文献   

9.
为了解渤、黄海秋季浮游动物群落的结构和分布特征,于2014年11月在南黄海、北黄海和渤海采集浮游动物样品,研究了浮游动物的种类组成、丰度、生物量、优势种、生物多样性和分布情况等.结果表明:研究海域共记录浮游动物成体70种,浮游幼虫22类;3个海域的浮游动物种类组成、丰度和生物量均存在差异,种类数和香农-威纳多样性指数均以南黄海最高.南黄海、北黄海和渤海的浮游动物平均丰度(不包含夜光虫)分别为225.5,295.1和128.2ind/m~3,高丰度主要分布在南黄海冷水团海域.南黄海、北黄海和渤海分别有6,5和4个优势种,其中中华哲水蚤(Calanus sinicus)和强壮箭虫(Sagitta crassa)是3个海域共有的优势种.调查海域的浮游动物优势种在水平分布格局上可划分为4种类型.聚类分析表明,渤、黄海的浮游动物可划分为渤海及黄海近岸群落、黄海北部及中部群落和黄东海交汇水混合群落.冗余分析显示,对浮游动物群落影响显著的环境因子为表层盐度.  相似文献   

10.
基于收集的1975—1999年间渤海与北黄海现场实测数据,分析溶解氧(DO)、磷酸盐(PO_4-P)和硅酸盐(SiO_3-Si)的年际变化特征.结果表明:在这25年间,渤海和北黄海溶解氧浓度均呈降低趋势,冬季年际降低程度比夏季明显,且冬季溶解氧与温度负相关性较夏季更显著.溶解氧最显著变化是夏季北黄海中部海域底层高值区逐渐缩小,至20世纪90年代全部低于6.0 mL/L.除夏季渤海北部和北黄海底层磷酸盐在20世纪80—90年代表现为升高趋势外,夏季研究海域内磷酸盐和硅酸盐浓度表现为波动性降低趋势,且在20世纪80年代中期(1984—1987年)下降到历史性最低水平;冬季研究海域内磷酸盐浓度表现为波动状态,硅酸盐却有着显著降低趋势.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

14.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

15.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

16.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

17.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

18.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

19.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

20.
The non-orthogonal localized molecular orbital(NOLMO)is the most localized representation of electronic degrees of freedom.As such,NOLMOs are thus potentially the most efficient for linear scaling calculations of electronic structures for large systems.However,direct ab initio calculations with NOLMO have not been fully implemented and widely used,partly because of the slow convergence issue in the optimization of NOLMO.We devel-  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号