南海西北部莺歌海盆地晚更新世三角洲地震地层反射特征

SEISMIC STRATIGRAPHIC FEATURES OF THE LATE PLEISTOCENE DELTA OF THE YINGGEHAI BASIN, NORTHWEST OF SOUTH CHINA SEA

摘要: 利用南海西北部莺歌海盆地高分率单道地震资料,在海南岛西南海域发现了一套晚更新世埋藏古三角洲,命名为琼西南三角洲。根据钻井资料的AMS¹⁴C与OSL光释光测年结果,初步确定琼西南三角洲顶、底界面的年龄分别约为33.2 ka和45.9 ka。经粗略估算,该三角洲分布面积约2.5万km²。根据区域地质背景和地震资料等综合分析,推断该三角洲沉积物主要来自海南岛西部并向外推进。该成果对研究南海西北部晚第四纪气候及沉积环境具有重要意义,亦可为油气勘探等提供基础资料。

Abstract: A late Pleistocene paleo-delta, which is named the Southwest Hainan Delta by the authors, has been found in the offshore region southwest to the Hainan Island by the interpretation of single channel seismic data. The delta was developed in the period from 45.9 ka to 33.2 ka according to AMS¹⁴C and OSL dating of the Core HDQ2. A preliminary estimation suggests that the delta covers an area of around 25 000 km². Analysis of geological background and interpretation of seismic profiles indicate that the Island of Hainan was the main provenance of the deltaic sediments.