珠江口盆地21Ma和13.8Ma陆架边缘三角洲对比

Comparison between shelf-margin delta of 21 Ma and 13.8 Ma in Pearl River Mouth Basin

易雪斐 张昌民 李少华 杜家元 罗明 李向阳

Yi Xuefei Zhang Changmin Li Shaohua Du Jiayuan Luo Ming Li Xiangyang

陆架边缘三角洲是三角洲动态分类中一种比较重要的三角洲类型，已经成为科学研究和勘探开发的热点。根据驱动因素，可将陆架边缘三角洲分为物源供给驱动型和可容纳空间驱动型两类。珠江口盆地距今21 Ma和13.8 Ma时期具备发育陆架边缘三角洲的地质条件。通过对录井、测井曲线和地震资料的综合分析，从地形、相对海平面变化和沉积物供给三方面对21 Ma和13.8 Ma进行对比，对陆架边缘三角洲形成条件进行了分析，认为21 Ma时期为物源供给驱动型，而13.8 Ma时期为可容纳空间驱动型。虽然层序SQ2和SQ9在地形、相对海平面变化和沉积物供给三方面都存在较大差异，但它们都为典型的Ⅰ型层序，发育低位扇体、陆架边缘三角洲和三角洲前缘的滑塌体，均为稳定的陆架边缘三角洲。

Shelf-margin delta,an important type in the dynamic classification of delta,has become the focus of science researches and hot spot in oil & gas exploration.According to the driving factors,shelf-margin delta can be categorized into two types,namely sediment supply-driving delta and accommodation-driving delta.The Pearl River Mouth Basin had favorable geological condition for shelf-margin delta development at 21 Ma and 13.8 Ma.Shelf-margin deltas(21 Ma and 13.8 Ma)are analyzed in respects of topography,relative sea-level change and sediment supply through integration of well logging,logging curves and seismic data.The forming condition analysis shows that the delta at 21 Ma is of sediment supply-dri-ving type,while the delta at 13.8 Ma is of accommodation-driving type.Although SQ2 and SQ9 are obviously different in respects of topography,relative sea-level change and sediment supply,they both are type I sequences,and have well-developed lowstand fans,shelf-margin delta and delta-front slumping deposits,which belonging to stable shelf-margin deltas.

10.11743/ogg20140512