Abstract:

Rifting basin is usually developed of grabens and/or halfgrabens, so that the basin configuration and structural styles  are  distinctly impressed by different patterns of composition and superimposition. This paper named the sag controlled by multipieces and multiperiods of normal faults as “complex faulted sag”. By the configuration of basin compounded by contemporaneous faulted sag, the “complex faulted sags” in the HalaerTamsag Basin could be categorized into 4 types of composition models which are named respectively as serial, parallel, diagonal and interlaced, and by the superposed style of sequel basin, “complex faulted sags” could be divided into 3 types of superimposition models which  are named respectively as inherited, imposed and neonatal. HalaerTamsag Basin develops large quantities of relatively separate minifaulted sags in the early stage of Early Cretaceous, but the synchronous minisags was compositing into larger faulted sag along with the progressive  crustal extension. HalaerTamsag Basin develops some of relatively separate large sags in the middle of Early Cretaceous, and they superposed upon   the preexisting faulted sag in different patterns.  The  newly developed faulted sags superimposed upon  the previously formed  sags  and  finally there are  17 complex faulted sags developed. The processes of compositing and superposing of complex faulted sags during Early Cretaceous in HailarTamsag Basin  directly effect the conditions of oil accumulation in the sedimentary basin. The composition in parallel, diagonal and interlaced patterns and   the superposition in inherited, imposed styles, are in favor of the development of high quality hydrocarbon source sequence. The transfer zones in the process of structural compositioning are in favor of the development of high quality reservoir. The basement involved fault zone and related structures are in favor of developing petroliferous structure zone.

Key words: normal fault, complex faulted sag, rifting basin, HailarTamsag Basin