EXTREME RESERVOIR SEDIMENTATION IN AUSTRALIA:A REVIEW     

Hubert CHANSON 《国际泥沙研究》1998,(3)

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PREDICTING RESERVOIR SEDIMENTATION WITH 2D MODEL FLOODSIM     

W.BECHTELER  M.NUJIC 《国际泥沙研究》1998,(1)

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华南晚古生代礁硅岩套的组成和分类及地质涵义   总被引：4，自引：0，他引：4  

陈多福  陈光谦 《地质学报》1998,72(2):97-102

礁硅岩套是一种重要的含矿岩石组合,它是由生物礁相碳酸盐岩、热水沉积岩（矿）、细碎屑岩和泥灰岩、同怪位或相邻地区地层中的火山质岩或潜火山岩,以较为固定的时空有序的状态组合而成。根据生物礁的形成环境和热水沉积作用的产出方式,礁硅岩套可分为盆地型、台地型和过渡型三类。它是在特征地质背景下,在盆地演化的一定阶段内,由盆地正常沉积作物、盆地中的生物作用、盆下源的热水沉积作用和岩石圈深部岩浆作用综合形成的产物  相似文献   

Some fine-grained sedimentation phenomena in caves     

Peter A. Bull 《地球表面变化过程与地形》1981,6(1):11-22

Fine-grained sedimentation in caves often occurs by the parallel accretion of laminations upon the underlying bedforms. These laminations show remarkable persistence in unit thickness and grain size in a down-passage direction. A translatory flow mechanism ofdeposition is postulated which results in the rhythmic pulsing of sediment-laden water into subterranean lakes in response to variations in surface climate. The sediments are pulsed into standing water via multiple inputs, often resulting in coarser sediment being deposited on steeper slopes than on more gentle slopes. The final extension of this sediment input is the complete filling of the cave passage to the roof. The problem of sediment stability on steep slopes remains an unanswered anomaly.  相似文献   

Holocene coastal environmental changes on the periphery of an area of glacio‐isostatic uplift: an example from Scapa Bay,Orkney, UK     

A. C. de la Vega‐Leinert  D. E. Smith  R. L. Jones 《第四纪科学杂志》2007,22(8):755-772

The first detailed investigation of a deep, coastal, sedimentary basin in Orkney reveals a complex Holocene history of back‐barrier morphodynamics. At Scapa Bay, the sea flooded a freshwater marsh after ca. 9400 yr BP at ca. ?5.4 m OD. Before ca. 7800 BP, abundant sediment from nearby cliffs was mobilised inland into a series of gravel barriers across the valley mouth. By ca. 7500 BP, direct marine influence was restricted in the back‐barrier area, although saltmarsh persisted until ca. 5900 BP. By then, at least four gravel ridges had enclosed the backing lagoon, where freshwater inputs became dominant. As terrestrial sediments filled the basin, another freshwater marsh developed. The multiple barrier complex demonstrates progradation resulting from continuous sediment supply in a sheltered embayment. The progressively rising height of the barrier crests seawards probably resulted from a combination of factors such as barrier morphodynamics, increased storminess and long‐term rising relative sea levels. The dominant vegetation surrounding Scapa Bay changed from open grassland to scrub ca. 9400 BP, then to deciduous woodland ca. 7800 BP, and to dwarf‐shrub heath ca. 2600 BP, the latter probably a response to a combination of climate change and human activity. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Impact of Human Activities on Depositional Process of Tidal Flat in Quanzhou Bay of China   总被引：2，自引：0，他引：2  

WANG Aijun 《中国地理科学(英文版)》2007,17(3):265-269

As a very important component of a coastal system,tidal flats come to be a focus of the studies on land-ocean interaction in the coastal zone because those areas are subjected to intense human activities and are highly sensitive to the global change.The Quanzhou Bay,located along the middle part of Fujian coast of China,covers about 136.4km2,and the area of coastal wetland in the entire bay from intertidal to subtidal with 6m of water depth accounts for 96% of the total area.Seven short cores were collected and divided in situ with the interval of 5cm on the coastal wetlands of Quanzhou Bay on April 19,2006.The sediment samples were scattered and the grain sizes were measured by using Mastersizer 2000.Human beings' activities on tidal flat have disturbed the vertical distribution of sediments in stratigraphic sequence and accelerated the sedimentation rates.Grain size analysis results show that the grain size diameters increase and sediment becomes worse sorted towards the sea under the strong human disturbance;Spartina alterniflora can play a role of trapping the fine sediment;but near the bank,the sediment becomes coarse and there are two peak values on frequency curve influenced by the sandpile.The trough formed by human activities along the coastline changes the transport path of water and suspended sediment.The sediments are transported through the trough and deposit in it during the flood;the ebb flow is retarded by the flow output through the adjacent trough,and the deposited sediment can not be re-suspended;then,the sedimentation rate increases.In situ observation show that the sedimentation rate is about 8-10cm/yr.  相似文献   

南渡江河口洪、枯季节水文泥沙变化特征及台风“海鸥”对入海水沙的影响   总被引：1，自引：0，他引：1  

陈斌  高飞  印萍  刘金庆 《海洋与湖沼》2015,46(6):1279-1291

基于2014年最新的洪、枯季节实测资料,分析了南渡江河口海域水文泥沙的季节性变化特征,借助台风"海鸥"过境期间的河道监测数据,研究了台风天气造成的洪水事件对河流入海水沙通量的影响。研究结果表明:(1)洪、枯季节河口海域的水体层化作用不强,洪季的水温高于枯季,但盐度低于枯季。水温呈现向海递减的趋势,而盐度整体分布较为均匀;(2)河口水体含沙量近岸大于远岸,枯季河口三角洲泥沙向西输运。洪季含沙量明显高于枯季,大量泥沙在台风季节被冲刷入海,而后向海或向西输运扩散;(3)河口海域为不规则全日潮,呈现东西向往复流特征。温度、盐度和浊度均呈现较强的潮汐性变化特征;(4)枯季河道内存在明显的盐水楔,锋面处的垂向梯度很大,在口门向陆大约12—15 km以远的河道水体不再受潮汐影响;(5)台风"海鸥"影响下,南渡江洪峰期间的径流量和含沙量均远远超过多年平均值,反映了南渡江河口地区"台风季节"的特点。  相似文献   

Intertidal sand‐dwelling Peracarid fauna of North Island,New Zealand     

A. A. Fincham 《新西兰海洋与淡水研究杂志》2013,47(4):677-696

Abstract

Substrate and infauna samples were taken at four tidal levels (mean high water springs, high mid beach, low mid beach, and mean low water neaps) with a 0.0625 m² quadrat at 14 North Island beaches in New Zealand. The distributions of Peracarida (Crustacea) were correlated with sediment type, tidal height, and degree of exposure; sampling began in March 1972 and was completed in November 1973.

Substrate samples were sieved and median diameter of the particles ranged from very coarse sand of — 0.60? to very fine sand of + 3.259?. Substrates were variously sorted: ? quartile deviation ranged from 0.14? to 0.66?, skewness from ‐ 0.08? to + 0.07?.

Peracarid fauna was moderately abundant; the maximum value was 720 animals per square metre on a fully exposed beach. Highest average abundance (303 per square metre) for the 14 beaches was recorded from the mean low water neap station. Amphipoda was the dominant group (54% of all Peracarida recorded), followed by Isopoda (33%) and Cumacea (13%). Frequency of occurrence at the 56 stations was headed by Amphipoda (64%), followed by Isopoda (46%), and Cumacea (20%).

The results are compared with data from Stewart Island beaches, and the biogeographical distributions of recorded Peracarida are discussed. An unexpectedly high degree of endemism exists for a warm‐temperate region, caused by the isolation of New Zealand, which has no direct shallow water contact with tropical or cold temperate regions.  相似文献   

Hydrolytic enzymes of the paua Haliotis iris,a marine gastropod (note).     

A. G. Clark  D. A. Jowett 《新西兰海洋与淡水研究杂志》2013,47(2):221-222

Extracts of the viscera of Haliotis iris (Martyn, 1784) were shown to hydrolyse 2‐hydroxy‐5‐nitrophenyl sulphate at pH 5.5, and the p‐nitrophenyl derivatives of α‐ and β‐D‐galactose, α‐ and β‐D‐mannose, α‐L‐lucose, β‐D‐glucuronic acid, β‐N‐acetyl glucosamine and phosphate at pH 4.0 and 5.5: p‐nitrophenyl‐β‐L‐fucose was not hydrolysed.  相似文献   

大气干湿沉降样品处理及配套分析方法     

张跃春  王蕊  尹春梅  郭爽  陈孝研  李艳梅 《吉林地质》2010,29(3):95-96

本文介绍了干湿沉降样品处理方法及测定其各元素含量的配套分析方法。  相似文献