珠江口盆地惠州地区新生界珠海组和珠江组重力流沉积特征*

通过2口井的岩心观察，在珠江口盆地惠州地区新生界珠海组和珠江组，发现有重力流沉积。该地区重力流沉积的主要特征是：滑塌构造发育广泛，是本区最主要的重力流沉积；液化沉积中泄水构造发育；浊流沉积中鲍马序列不完整。惠州地区的重力流沉积是三角洲前缘砂体垮塌再搬运沉积而形成的。在重力流沉积中还发现有潮汐作用的存在，潮汐作用和重力流沉积伴生。通过对惠州地区重力流沉积特征的研究，认为不能简单地将重力流沉积等同于浊流沉积；重力流沉积不仅局限在深水地区，在相对浅水地区也会发育。建议正确理解鲍马序列并予以合理使用。

Feature of gravity flow deposit of the Zhuhai and Zhujiang Formations of Cenozoic in Huizhou area,Pearl River Mouth Basin

Gravity flow deposits were identified from the cores of Zhuhai and Zhujiang Formations of Cenozoic in Huizhou area, Pearl River Mouth Basin.Three types of the gravity flow deposits are classified in the study area，including slump deposits，liquefaction deposits and turbidity flow.Slump deposit is the most important one；water-escape structures are abundant in liquefaction deposits；turbidity flow deposit is characterized by incomplete Bouma sequences.The gravity flow deposits in Huizhou area are formed by slumping，transporting and depositing of the sandbody in delta front.Meanwhile，tidal influenced sediments are also presented in the gravity flow deposits.Tidal deposits are associated with gravity flow sediments.It is realized that there are some misunderstanding about gravity flow，such as equal the gravity flow to the turbidity flow simply，limit gravity flow in deep water area，abuse the Bouma sequence，and so on.So a new understanding about gravity flow is needed.