长白山天池火山炭化木的^(14)C年代及其意义  

THE RADIOCARBON AGE OF CARBINIZED WOOD IN TIANCHI VOLCANO, CHANGBAISHAN MOUNTAINS AND ITS IMPLICATION

作　　者：尹金辉[1] 郑勇刚[1] 刘粤霞[1] 

机构地区：[1]中国地震局地质研究所

出　　处：《地震地质》2005年第1期83-88,共6页Seismology and Geology

基　　金：国家自然科学基金(40202015);国家科技攻关计划项目(2001BA601B0604)共同资助

摘　　要：摘　要　　对长白山天池火山喷发形成的灰白色空降浮石层、黑色熔结凝灰角砾层和火山碎屑堆积物中 16个炭化木作了系统的14C年龄测定,结果表明天池火山喷发年代为 (1215±15)AD。从火山碎屑堆积中采集的炭化木测定的14C年代要比火山喷发年代偏老,最大可偏离 800a;炭化木树皮的测定结果比较接近火山喷发年代;黑石河、浮石林、锦江大峡谷等地的黑色熔结凝灰角砾层的14C年代结果表明它们也属于(1215±15)AD大喷发的产物。The largest eruption of the Tianchi Volcano in historical period had not been recorded in historical document. Therefore, the determination of the accurate date of this largest eruption event is of great importance to the estimation of the eruption interval, the evaluation of the eruption risk and the hazard prediction of the future eruption. Basing on the systematical 14C dating of a well-preserved large carbonized wood, Liu Ruo-xin et al (1997) concluded that the largest historical eruption of the Tianchi Volcano occurred in 1215±15 AD. However, this conclusion has evoked much controversy. Horn et al (2000) suggested that the eruption time of Tianchi Volcano should be in 969±20 AD as determined from the age of a slab of carbonized wood collected from the North Korean side in a pumice fallout deposit. Earlier, Dunlap (1996) reported a wiggle-matched age of 1039±18 AD determined at the University of Arizona. Moreover, some experts favor 870±170 AD, which was the average of 53 radiocarbon ages of carbonized wood collected from the ignimbrite. In this paper, the eruption time of the Tianchi Volcano has been studied through detailed field investigation and careful selection of representative profile for collecting radiocarbon samples. The radiocarbon dates of 16 samples of carbonized wood including a piece of bark collected from ignimbrite around the Tianchi Volcano show that it is reasonable to consider the age of 1215±15 as the eruption time of the Tianchi Volcano. All of the radiocarbon ages of the carbonized wood are older than the true age of volcanic eruption, the largest deviation from which is 800yr, but the age of the bark is close to that of the Tianchi Volcano eruption. This may imply that the age of bark sample may provide better constraint on the date of volcanic eruption. The radiocarbon ages of black ignimbrites from Heishihe River, Pumice Forest, and Jinjiang Gorge show that they are also the product of 1215±15 AD eruption.

关 键 词：长白山天池火山 火山喷发 年龄测定 年代 浮石 堆积 峡谷 碎屑 炭化 

分 类 号：P317[天文地球—固体地球物理学] P588.14[天文地球—地球物理学]