摘要
南沙群岛永暑礁小■湖“南永3井”沉积柱样长5．90m，沉积物为泛灰黄的白色，岩性松散，未胶结，主要为粉砂质砂，少量为砂、砂质粉砂和粉砂－砂，常含小砾石。沉积物由珊瑚类为主的生物碎屑组成，分选性差，负偏态值和双峰态等均表明沉积物搬运距离不远、水动力条件较弱的特点。柱样底部 TIMS U系年龄为 1682±15 a B．P。对照有关文献，发现该井沉积跨越了小冰期D至现代气候最适宜期A等4个小气候期，其沉积物粒度百分含量变化趋势可以作为气候变化的替代性指标。
The sediment pillar from the core of Nanyong-3 well, which was drilled in thesmall lagoon of the Yongshu Atoll, Nansha Islands, is 5. 90 m long. The sediment iswhite with a little drab, composed of biological detritus dominated by coral. It has ho-mogenous and loose lithological characteristics, without cementation. Dominated bysilty sand, it has little sand, sandy silt and silt-sand. Small gravels are prevalent.Worse sorting, negative skewness value and two-kurtosis all show the features that thetransport distance of the sediment is not long and the hydrodynamic condition is bad.The age of the bottom pillar, dated by TIMS U system, is 1 682±15 a B. P. Comparedwith related references, this core sediment is found to cross 4 small climatic stages fromlittle ice stage D (60BC-AD600) to the most suitable stage A of modern climate (sinceAD1820). The change of the sediment granularity contents in this lagoon can be regar-ded as a proxy for the climate change.
出处
《热带海洋学报》
CAS
CSCD
北大核心
2001年第3期15-20,共6页
Journal of Tropical Oceanography
基金
"九五"国家科技专项"南沙群岛及其邻近海区综合科学考察"资助项目(97-926-03-01)
关键词
环礁ao湖沉积
粒度特征
环境演化
永暑礁
南沙群岛
沉积物
sedimentd atoll lagoon；granulometric characteristics；environmental evo-lution；Yongshu Atoll；Nansha Islands
