关键词: 层序地层, 岩相古地理, 雷口坡组, 四川盆地

Abstract: The inconsistence in different mining areas of the stratigraphic division schemes of Leikoupo Formation，Sichuan
Basin，and the fact that on the karst zone strata sloughed off effected by Early Indosinian movement，brings about a problem
of stratigraphic classification and lithofacies paleographic reconstitution. Guided by sequence stratigraphy theories and
methods，this paper collates and stipulates the stratigraphic division schemes of Leikoupo Formation on the basin interior and
reconstructs stratic lithofacies paleography by using quarternary bedding as constructive units. High precision lithofacies paleographic
study demonstrates that Sichuan Basin of Leikoupo stage was in restricted-evaporated sea environment and that
platform edge developed near Songpan-Ganzi oceanic trough in northwest Sichuan，where the grain bank of platform internal
and fringe constitutes the main prospecting parts of Leikoupo Formation. The evolution of lithofacies paleography indicates
that the bed form of basin transformed from dipping eastward to westward by the way of“seesaw”in the period of Leikoupo
Formation deposition. Even in the early stage of sequence Ideposition，it still remained what the topographic configuration took
on as in early Triassic，which was high westward and low eastward，while the eastward dipping trend disappeared gradually in
sequenceIII depositional period. Yet，after that period there presented a miniature of uplift-hollow framework in the sequence
IV—V depositional period on the basin interior. From sequence VI on，the bed form uplift-hollow framework differentiated
intensively accompany with the intensity of the tectonic compression movement，forming macro-thick gypsolyte basin，whose
depocencer had an apparent westward dipping trend in the depositional period of sequence VI—X.

Key words: sequence strata, lithofacies paleography, Leikoupo Formation, Sichuan Basin