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81.
崔胜涛 《测绘与空间地理信息》2017,(8)
根据测绘地理信息行业"十三五"规划,如何利用国情普查数据进行地理国情监测监测,成为未来几年测绘技术的一个重要课题。本文的实施以地理国情普查数据利用高分辨率航空影像确定和采集滩涂地表空间数据为范围,对为滩涂变化监测提供基础数据源进行了研究。 相似文献
82.
近百年来长江口启东嘴潮滩沉积物质来源及定量估算 总被引:2,自引:0,他引:2
河流入海输沙是海岸稳定的重要物质基础。启东嘴潮滩位于长江北支口门,与江苏海岸线交汇,陆海相互作用强烈。利用电感耦合等离子体质谱仪测定了岩芯沉积物QDZ-1的地球化学元素。根据地球化学元素的分布特征和富集系数,分析了物源指示意义,表明启东嘴潮滩沉积物受到长江物质和南黄海物质的共同影响。基于地球化学元素的沉积物端元定量判识方法,对不同物质来源的贡献率进行了定量估算。在1930年前启东嘴潮滩沉积物主要来自长江的入海输沙,贡献率为68.1%,随着长江北支河槽的衰退,贡献率逐渐减少,在1930-1972年间为38.5%,到1972年后减少到17.5%。苏北沿岸流携带向南输运的南黄海物质,贡献率逐渐增加,在1930年前为27.1%,在1930-1972年间为55.6%,到1972年后增加到75.9%,成为启东嘴潮滩主要物质来源。沉积物来源的阶段性变化,在时间上与北支水动力的阶段性变化基本吻合。 相似文献
83.
本软件项目于1997 年底最后完成。提高了人卫系统各台站观测的自动化程度, 大幅度减少了观测员各种繁琐的数据处理工作。它包括e -mail 收发报, 数据采集和处理, 静态系统差测定等功能, 可应用于人卫系统的各个观测台站。 相似文献
84.
本研究采取苗种强化培育、坑道培育大规格苗种、湖间带鲍参混养等相结合,并配套适当技术措施,促进鲍快速生长,缩短养殖周期一年左右,提高成活率15%以上,增加经济效益200%左右,形成鲍高效养殖的较理想模式。 相似文献
85.
江苏小庙洪牡蛎礁的地貌-沉积特征 总被引:6,自引:3,他引:6
利用卫星影象和野外实地勘察资料对江苏小庙洪牡蛎礁的地貌-沉积特征进行分析。结果表明,该牡蛎礁发育在强潮淤泥质潮坪上,造礁牡蛎主要是近江牡蛎和长牡蛎,表层的鲜活牡蛎为褶牡蛎。牡蛎礁区海水属盐度较高(27—30)的半成水,含沙量较大,为0.2—0.3g/L。活体牡蛎堆积体顶面高于周围潮间下带滩面1.0—1.5m。潮流较强,多在0.5—2.0m/s。海岸剖面可分为4个带,即礁后潮间带、潮沟、礁体生长带及礁前斜坡带。由于处于海岸侵蚀段,礁后潮坪缺失潮上带和大部分的潮间上带。礁后潮坪主要以粗粉砂为主,礁后潮沟冲淤变化较大,故礁体生长带时而为一沙洲,时而又与岸滩相连。礁体生长带分布在潮间下带,可看到独立的斑状礁体、带状礁体和大面积环状礁体群。环状礁的微地貌可以划分为礁塘(泻湖)、塘口和塘沟、塘口三角洲、礁墙和礁平台等。 相似文献
86.
Unusual intraclastic limestones in Lower Triassic carbonates and their bearing on the aftermath of the end-Permian mass extinction 总被引:5,自引:0,他引:5
Flat pebble conglomerates were a common carbonate facies in Cambrian to Early Ordovician open marine settings, but they become extremely rare in these environments after this time. However, the Early Triassic witnessed an anachronistic reappearance of flat pebbles, together with other intraclast types, in a range of carbonate depositional settings. In south China, flat pebble conglomerates are encountered in storm-dominated, platform carbonates to deep basinal settings, while prefossilized bivalve intraclasts and flat pebbles are common in mid-ramp facies of northern Italy. The emplacement mechanisms of the intraclast-bearing beds appear to have been diverse and to have included basinal turbidity flows and storm-generated hyperconcentrated flows: true storm beds, deposited under combined flow conditions, are rare. The cause of the widespread early lithification implied by the Early Triassic intraclasts appears to have been twofold: suppression of bioturbation, allowing the preservation of thin beds, and rapid submarine lithification. Both features appear to be a response to the widespread development of benthic dysoxia/anoxia during and following the end-Permian mass extinction. This event appears to have temporarily recreated the conditions that pertained in Cambro-Ordovician shelf seas. Flat pebble conglomerates may, therefore, constitute a proxy indicator of stressed environmental conditions associated with global anoxic/dysoxic events. 相似文献
87.
Xiutang Yuan Xiaolong Yang Anguo Zhang Xindong Ma Hui Gao Guangshui Na Humin Zong Guize Liu Yongguang Sun 《Marine pollution bulletin》2017,114(1):419-427
Spatial distribution, source apportionment, and potential ecological risks of sixteen polycyclic aromatic hydrocarbons (PAHs) and seven endocrine disrupting compounds (EDCs) in the intertidal sediment at the Shuangtaizi Estuary, Bohai Sea of China were analyzed. Results showed that the total PAH concentrations ranged from 28.79 ng g? 1 dw to 281.97 ng g? 1 dw (mean: 115.92 ng g? 1 dw) and the total EDC concentrations from 0.52 ng g? 1 dw to 126.73 ng g? 1 dw (mean: 37.49 ng g? 1 dw). The distribution pattern for the PAHs was generally different from that of the EDCs possibly due to their distinct sources and n-octanol-/water partition coefficients (KOW). Qualitative and quantitative analytical results showed that PAH sources were mainly from a mixture of pyrogenic and petrogenic contributions. The higher levels at the southeast of Geligang indicated that the EDC pollutants may have mainly originated from the plastic industry and other chemical plants located along the Liao River. Ecological risk assessment revealed that PAHs exhibited low ecotoxicological effects, whereas EDCs, especially 4-tert-octylphenol and bisphenol A, had high ecological hazard to the estuarine biota. 相似文献
88.
Chandan Chakraborty 《Geological Journal》2001,36(2):125-141
The Bhander Group, the uppermost stratigraphic unit of the Proterozoic Vindhyan Supergroup in Son Valley, exhibits in its upper part a 550 m thick, muddy siliciclastic succession characterized by features indicative of deposition in a wave‐affected coastal, lagoon–tidal flat environment suffering repeated submergence and emergence. The basic architecture of the deposit is alternation of centimetre‐ to decimetre‐thick sheet‐like interbeds of coarser clastics (mainly sandstone) and decimetre‐thick mudstones. The coarser interlayers are dominated by a variety of ripple‐formed laminations. The preserved ripple forms on bed‐top surfaces and their internal lamination style suggest both oscillatory and combined flows for their formation. Interference, superimposed, ladder‐back and flat‐topped ripples are also common. Synsedimentary cracks, wrinkle marks, features resembling rain prints and adhesion structures occur in profusion on bed‐top surfaces. Salt pseudomorphs are also present at the bases of beds. The mudstone intervals represent suspension settlement and show partings with interfaces characterized by synsedimentary cracks. It is inferred that the sediments were deposited on a coastal plain characterized by a peritidal (supratidal–intertidal) flat and evaporative lagoon suffering repeated submergence and emergence due to storm‐induced coastal setup and setdown in addition to tidal fluctuations. The 550 m thick coastal flat succession is surprisingly devoid of any barrier bar deposits and also lacks shoreface and shelfal strata. The large areal extent of the coastal flat succession (c. 100,000 km2) and its great thickness indicate an extremely low‐gradient epeiric basin characterized by an extensive coastal flat sheltered from the deeper marine domain. It is inferred that the Bhander coastal flat was protected from the open sea by the Bundelkhand basement arch to the north of the Vindhyan basin, instead of barrier bars. Such a setting favoured accumulation of a high proportion of terrigenous mud in the coastal plain, in contrast to many described examples from the Proterozoic. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
89.
90.
根据等高线数据直接建立不规则三角形网络模型往往会在山顶、山底、山脊和山谷等特殊地区出现"平三角形",导致模型失真。文中基于Delaunay三角网,通过对"平三角形"的处理,提取骨架线,并结合地形特征估计其高程值。实验证明该算法能够有效地提取各种地形骨架线,对于建立逼真的数字地面模型和进行数字地形分析具有重要应用价值。 相似文献