新疆博斯腾湖沉积岩心的~(210)Pb、~(228)Th、~(239,240)Pu和~3H的分布及意义     

林瑞芬  卫克勤  程致远  王志祥  廖莎  梁卓成 《地球化学》1992,(1)

作者测定了博斯腾湖沉积岩心~(210)Pb、~(228)Th和核试验释放核素~(239,240)Pu、~3H的分布,并据~(210)Pb、~(228)Th、~(239,240)Pu的结果估算湖泊的沉积速率,分别为0.31cm/a,0.26cm/a和0.33cm/a。它表明该湖泊近百年来沉积环境十分稳定。沉积物岩心极好地保存了人类大气核试验的历史记录。~(239,240)Pu分布在1963±2出现峰值,与60年代核试验高峰期相当吻合。沉积物孔隙水~3H分布的峰值出现在1969年,与湖水的混合过程有关。  相似文献   

光强度对附着的玻片上的幼鲍饵料生物的影响     

李进道  胡晓燕 《海洋湖沼通报》1996,(2):52-57

幼鲍初期饵料生物在玻片上着生物量的消长与光强度的关系进行了试验，光强度超过２５００Ｌｕ时微生物膜增长较快，膜脱落较早；光强度低于１０００Ｌｕｘ时微生物膜净生产量较低，光强度在１５００－２０００Ｌｕｘ时有利于膜生物量的积累，舟形藻和菱形藻的纯培养在玻片上附着的生物量呈稳定性高速增长并能延迟生物膜脱落现象的发生。  相似文献   

莱州湾南岸潍河下游地区咸水入侵灾害成因及特征   总被引：8，自引：1，他引：7  

刘恩峰  张祖陆  沈吉  宋俊峰 《地球科学与环境学报》2004,26(3):78-82,87

通过对莱州湾南岸咸水入侵较严重地潍河下游地区晚更新世以来沉积特征及现代自然环境条件变化的分析，探讨了沉积相对咸水入侵产生及空间范围特征的环境机理。晚更新世以来的三次海平面升降变化造成了潍河下游地区海陆沉积环境交替，形成了巨厚的海陆交互相沉积层。海进时期，大面积的滨海平原被淹没，在近海平原洼地滞留的海水经过蒸发、浓缩变为卤水，成为咸水入侵的物源；海退后陆源碎屑在滨海地区沉积形成了巨厚的古河道砂层。20世纪70年代末期以来，随着对地下淡水的过度开采，淡咸水水头压力差减小．卤水通过古河道砂层快速南侵。通过对潍河下游地区100余个地质钻孔水化学连续监测资料分析，阐明了咸水入侵的特征，有针对性地提出了咸水入侵的防治措施。  相似文献   

IGCP450 Project：Proterozoic Sediment—Hosted Base Metal Deposits of Western Gondwana     

《《幕》》2003,26(1):43-45

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22nd IAS Meeting of Sedimentology     

DavorPavelic IgorVlahovic JosipHalamic 《《幕》》2004,27(3):214-215

The 22nd IAS Meeting of Sedimentology was held in the Convention Centre of the Grand Hotel Adriatic, in a small touristic town Opatija, located on the eastern Adriatic coast where Central Europe and the Mediterranean meet. It was the second IAS Meeting held in Croatia--the first one, 4th IAS Regional Meeting of Sedimentology, was held in Split in 1983. The Meeting in Opatija was organized by the Institute of Geology (Zagreb) and the Croatian Geological Society. The sponsor was Ministry of Science and Technology of the Reoublic of Croatia.  相似文献   

右江盆地二叠纪孤立碳酸盐岩台地边缘海绵礁特征、时代及海绵礁相   总被引：3，自引：0，他引：3  

黄志强  陆刚  梁军  沈健全 《南方国土资源》2003,(10):23-26

右江盆地二叠纪孤立碳酸盐岩台地边缘海绵礁由于生长在不同的古地理位置,因而具有两种类型的海绵礁特征;成礁期可确定在中二叠统祥播阶晚期→晚二叠统;海绵礁造礁旋回由礁基→礁核→礁坪→礁滩→礁顶组成。对Ⅰ类海绵礁底部所产生的不整合面,文章首次提出属事件沉积不整合面,并对其成因做了探讨。  相似文献   

新西兰奥塔戈东部马可罗斯地区石墨片岩中变质...     

Mcke.  SA 王文珍 《世界地质》1992,11(1):108-117

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福建省早三叠世溪口期岩相古地球与构造活动性质     

郑云钦  吴岐 《福建地质》1992,11(1):33-47

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EFFECT OF LIGHT INTENSITY ON THE TOTAL LIPID AND FATTY ACID COMPOSITION OF SIX STRAINS OF MARINE DIATOMS     

梁英麦康森  孙世春于道展 《中国海洋湖沼学报》2001,19(3):249-254

The effect of light intensity ( 1500 Ix and 5000 Ix) on the total lipid and fatty acid composition of six strains of marine diatoms Cylindrotheca fusiformis (B211 ), Phaeodactylum tricornutum (Bl14, Bl18 and B221) Nitzschia closterium (B222) and Chaetoceros gracilis (B13) was investigated.The total lipids of B13, Bl14, and B211 grown at 5000 Ix were lower than those grown at 1500 Ix. No evident changes were observed in Bl18, B221 and B222. Fatty acid composition changed considerably at different light intensity although no consistent correlation between the relative proportion of a single FA and light intensity. The major fatty acids of the 6 strains were 14:0, 16:0, 16:l(n- 7) and 20:5(n-3) . Cylindrothecafusiformis had high percentage of 20:4n - 6 (9.2 - 10.9% ) . The total polyunsaturated fatty acid /rl all 6 strains decreased with increasing light intensity. The percentage of the highly unsaturated fatty acid eicosapentaenoic acid (EPA) decreased with increasing light intensity in all strains except Chaetoceros gracilis.  相似文献   

凤太矿田层控铅锌(铜)矿床的成矿物质来源探讨     

隗合明  吕仁生 《地球科学与环境学报》1990,(1)

秦岭凤太矿田层控铅锌(铜)矿床的金属物质、硫和成矿溶液主要来自深部基底的岩石,属海底喷流—沉积成因矿床。从这一理论认识出发可进一步分析控矿地质条件及今后在该区有效地寻找同类矿床。  相似文献