中文摘要：

火山灰的研究作为探讨古气候和古环境的一种手段,近十年来引起了国内外学者的广泛关注。气候学和古环境学的研究表明,火山喷发可以导致某一区域内短期的气候变化或者对冰期产生强烈影响。同时,火山灰层的成因机制决定了其空间分布的等时性和广泛性,因此,火山灰的地层学特征和精确定年,具有重要的地层对比意义。目前,全球各地已经开展了许多火山灰年代学与地层学的研究。在中国,尤其是东北地区,虽然有着丰富的火山资源,但是火山灰年代学与地层学的研究工作依然比较匮乏,本文简要回顾了一下中国东北、欧洲、新西兰、日本、俄罗斯等地区的火山灰研究工作,旨在为以后的研究提供一定的参考资料。

英文摘要：

Background, aim, and scope As a dating method, Quaternary tephrochronology and tephrostratigraphy have now been employed in many areas of the world. This article presents a brief review of tephra studies in some countries in Europe, New Zealand and the countries around NE China（Japan and Russia）. Tephrochronology and tephrostratigraphy are well established in Europe and New Zealand, however only few work has been done in NE China（to date）. Since the 1930 s, tephrochronological methods have been used extensively to solve problems in Quaternary geology, archaeology, paleopetrology, and paleogeography. A pioneer in the use of tephra layers to establish chronology was Sigurdur Thorarinsson, who began by studying the layers he found in the deposits of his native Iceland. In the early stage of tephra studies, the layers were often mapped with their source volcanoes by observing the colour and petrology of the tephra, as these are characteristics of a particular volcano. Then, the real age of the tephra layers was dated directly with reasonable accuracy using radiometric dating methods such as glass-fission-track, Potassium-Argon（K-Ar）, Argon-Argon（~（39）Ar-~（40）Ar）, radiocarbon（~（14）C）, uranium series, thermo-luminescence and electron spin resonance. Therefore, more and more tephras have been dated indirectly by correlation and now many improved reference sets for indirect dating through tephras from most volcanic centers are accessible in geological databases such as Tephrabase available at http：//www.tephrabase.org/. Further information can be added to the Tephrabase in the future, whenever the details are available. Therefore, more and more tephras have been dated indirectly by correlation. Materials and methods Glass shards which were detected in the sediments need to be concentrated and purified in the lab and then made slides for the geochemical analysis. Laboratory procedures for the determination of loss-on-ignition and extraction of glass shards from the sediments could follow