短语词组短語progressive offlap 漸進退覆;前進退覆offlap sequence 退覆層序marine offlap 海上退覆offlap p 退複staggered offlap 堦段退覆regressive offlap 退覆simple offlap 簡單退覆offlap fault 平移斷層offlap slope facies 退覆斜坡相 返回 offlap