Climate history of the middle reach of the Yangtze river over the past 9000 years: A speleothem isotopic record from Za cave, Hubei, China

A stalagmite in Qingjiang, Hubei, has yielded the records of hydrogen and oxygen as well as carbon isotopic changes and provided a climate history of 9000 years. The hydrogen iso-topic ratio in fluid inclusions and the oxygen isotopic ratio in stalagmite calcite are controlled by meteoric water, which is in response to ambient temperature or precipitation amount. The carbon isotopic ratio, sensitive to the nature of vegetation, also can be used to reconstruct the climate history. The carbon-14 and U-series dated stalagmite records reveal that climate oscillated in the middle reach of Yangtze river over the past 9000 years:(1) 9.0-6.5 kaBP, a cooler and more humid condition; (2) 6.5-4.0 kaBP,with warmer and drier weather; (3) 4.0-2.0 kaBP, cold weather with heavy precipitation, and (4)2.0 kaBP to present, tendency to be warmer and drier.     

热液硫酸盐矿物中稀土元素地球化学特征

用ICP-MS分析了印度洋中脊四块硫酸盐样品稀土元素,探讨它们的分布特征.分析结果表明,所有样品均表现出正Eu异常与LREEs相对富集的球粒陨石标准化分配模式,继承了其形成过程中热液流体的稀土元素分配模式.因而.硫酸盐矿物中的REEs主要来自基底玄武岩,当它们与海水发生混合作用时,LREEs得到高度富集,Eu正异常的出现,则指示了硫酸盐形成时的海底强还原环境以及热液流体的演化特征.     

Stable isotope and trace element record of a stalagmite in Heshang Cave, Hubei and its palaeoclimatic significance

Through a combined analysis of sedimentary characteristics, C and O isotopes, Mg and Sr trace elements of a stalagmite from Heshang Cave, Hubei, with uranium-series dating, alaeo-palaeoclimatic and palaeoenvironmental information from 19.0ka to 6.9ka in the Hubei area is obtained. The Average resolution is 17a, and the local resolution is 7a. The following results are obtained: (1) from 19.0-16.6 kaBP: C and O isotope is lighter, the climate is cold and wet;(2) 16.6-11.1 kaBP: C, O isotope is a little heavy, temperature rises, rainfall is inclined to be little;(3) 11.1-10.3 kaBP: an excursion during dry and hot period responds to Younger Dryas Event;(4) 10.3-6.9 kaBP: C, O Isotope is lighter, but Mg/Sr value is bigger, which shows temperature is continuing rising and rainfall is greater. These reflect the variation tends from wet-cold climate, to dry-hot climate, and to wet-warm climate in history, and some climatic variation trends of thousand years and hundred years cycle are     

FeCl3絮凝预处理提高酵母废水可生化性研究

采用FeCl3对高浓度、高色度及可生化性差酵母废水进行了絮凝沉淀预处理,考察废水组成的变化,发现体系在初始pH为7.5,FeCl3用量为8g·L-1,搅拌速度及时间为300 r·min-1(1min),80 r·min-1(20 min),沉降时间为30 min时废水COD从6244 mg·L-1降低到4058 mg·L-1,废水的可生化性BOD58/COD值从0.28升高到0.46.GPC,GC-MS分析结果表明,废水经FeCl3絮凝预处理后,有机物浓度明显降低,极性类物质分子减少,主要是脂肪醇类、脂肪酸类、含有多个基团的苯环化合物、含氧杂环醇类等生物难降解物质,从而提高废水可生化性.