retrograding sequence meaning in English

退积层序

Moreover , the system tracts in sequence are characterized by dualistic structure , namely transgressive - highstand system tracts , and tst > hst . the parasequences are divided into three types , which is respectively dominated by sandstones , mudstones , and shallowing - upward tidal flat system . and prograding sequence and retrograding sequence are composed of stacking parasequence set
层序中体系域具有二元结构特征，即海侵?高水位体系域，且tst hst ，准层序类型有三种，分别是以砂岩为主的准层序、以泥岩为主的准层序和以潮坪体系向上变浅的准层序。