琼东南盆地南部中新统生物礁的识别

Identification of reef in Miocene,south of Qiongdongnan Basin

琼东南盆地南部地区在新近纪中新世梅山组沉积时期具有适合生物礁发育的古地理条件。近来在该区域采集的地震资料发现在梅山组地层存在典型的丘状反射,主要分布在古隆起上,底平顶凸,顶底界面清晰,反射能量强,内部具前积或杂乱反射,两翼见上超,顶部为披覆沉积,波阻抗值为（8~10）×106kg/（m2.s）,目前初步研究认为该套地层为生物礁建造。文章还从区域沉积背景、丘状体发育部位以及地震反射特征等方面对生物礁和泥构造两类地震反射异常体加以分析和对比,排除梅山组发育泥底劈的可能性。

The southern part of the Qiongdongnan Basin was suitable for reef generation when the Meishan Formation deposited during Miocene.Seismic data collected in this region during the past few years have indicated that the Meishan Formation is characterized by typical mound reflection,mainly on ancient uplifts.The formation is flat at the bottom and convex at the top.There is clear boundary between top and bottom.The reflection is strong.Progradational or random reflection exists in the formation,while on the 2 flanks there is onlapping,and on the top there is drape.The wave impendence value is（8-10）×106 kg/（m2·s）.The formation is regarded as reef according to present studies.Comparisons between reef and mud structure have been carried out based on the studies of regional sedimentary background,mound structure generation location and seismic reflection characteristics,indicating that it is impossible for shale diapire generation in the formation.