摘要
分析了冲绳海槽北部的CSH1岩芯沉积物中矿物组成、化学元素质量分数和粒度的变化规律，研究结果表明，在全新世期间，日本九州岛发生了2次大规模火山喷发活动，造成大量的火山物质沉积在冲绳海槽北部。从岩芯最上部的沉积物中可识别出2层火山碎屑沉积，它们都具有沉积物粒径突然变粗、SiO2和Na2O等化合物的质量分数突然增加以及粘土矿物、挥发份、Fe2O3、MgO、CaO和Sr的质量分数迅速下降等特征。沉积物粒度数据的端员分析结果表明，冲绳海槽北部全新世沉积物中的硅酸盐碎屑是由陆源碎屑物质和火山灰按不同的比例混合而成的。有火山物质混入的沉积物的粒度分布多呈现双峰模式，粒度众数值分别为74．3和7．81μm。浮游有孔虫壳体的AMS^14C测年结果表明，2层火山碎屑所对应的火山喷发年代分别为7210和10870cal．aBP。其中前者与K—Ah火山的喷发时间一致，后者可能与Kuju火山在12～10cal．kaBP期间的喷发有关。
In this paper, the mineralogical and geochermical characteristics of sediments in Core CSH1 from the northern Okinawa Trough are analyzed, and it is shown from the analysis results that two large-scale volcanic eruption activities occurred in the Kyushu Island area of Japan during the Holocene epoch, and a large amount of volcanic materials were deposited in the northern Okinawa Trough. Two layers of tephra deposits can be identified from the upper sediments in Core CSH1 and are characterized by coarser particle, higher SiO2 and Na2O contents and lower contents of clay minerals, volatiles, Fe2O3, MgO, CaO and Sr. It is shown from the analysis results of grain size data that the sediments from the northern Okinawa Trough are mixture of terrigenous materials and volcanic ash during the Holocene epoch. The grain size distributions of sediments in two tephra layers show a bimodal partern with modal grain sizes of 74.3μm and 7.81 μm. It is shown from the AMS^14C dating results and 10 870 cal. aBP are related with the eruption event of K-Ah volcano （7 300 cal. aBP） and the eruption event of Kuju Volcano（12 to 10 cal. aBP） ,respectively.
出处
《海洋科学进展》
CAS
CSCD
北大核心
2007年第1期34-45,共12页
Advances in Marine Science
基金
中丹国际合作研究项目--东海晚第四纪高分辨率的古环境和古气候演变序列研究(2002DFG00034)
国家自然科学基金重点项目--末次冰期以来西北太平洋边缘海关键断面古环境演化记录(40431002)
国家自然科学基金项目--末次冰期以来日本海表层海水温度变化与东海的对比研究(40606016)
