The classification of sedimentary basins and discussion on relevant issues

The classification of sedimentary basins is fundamental for research on basins and related fields.Although there are a variety of basin classification schemes with different emphases and advantages,the study of the classification of intracontinental basins is still weak.A sedimentary basin represents a typical giant system and its classification is a complicated system engineering.The excellent classification for basins should reflect integrality,hierarchy,relevancy,typicality(representativeness)and comparability(predictability)of the basin system.The classification of basin types is mainly based on the factors,including tectonic position,lithospheric type,subsidence mechanism and dynamic environment,basinal texture and structure,basement property,sedimentary environment and filling feature,etc.,during the formation and development of the basin.The forces which led to basin subsidence were mainly originated from the deep Earth and can be divided into four types:thermal,stress,gravity and combination of all the three.The basin formed by asteroid impact is a special case and could be classified into the gravity-originated type.Another noteworthy basin type is the basin generated by landform genesis;the basin did not result from endogenic processes but caused by sediments and water body accumulating in lowland;this type of basin has been observed in different tectonic environments;their occurrence conditions of mineral deposits and geodynamic implications are quite different from those basins having endogenic genesis;therefore,the basin is separately treated as a basin type with distinctive origin.Based on previous classification schemes and studies of sedimentary basins and considering plate tectonics dynamic setting,independence and initiative of intracontinental internal dynamics,and main forces leading to basin subsidence,this paper divides the regional tectonic environment of basin development into 6types:within oceanic plate,within continental plate,divergent,subduction,collision,and transform continental(plate)margin,plus newly-added asteroid-impact and reformed composite types.Among the former 6 types,44 sub-types of sedimentary basins are further classified according to their dynamic environments and major mechanical properties(stresses),respectively.We further discussed and explained about the newly-added types and newly-defined types of basins and the terms which have been changed;these basins include backland basins,side continental basins,transform-compensation basins,pull-rift basins,landform genesis basins,asteroid-impact basins,intermediate massif basins,intracontinental foreland basins,reformed basins and so on.This basin classification scheme is a rational and comprehensive induction based on the same or similar tectonic environment of the basins in various regions;it is relatively systematic and complete.In the geological history and today,a certain type of basin may have been absent or incompletely developed in somewhere having the same tectonic environment because of the differentiated geologicalconditions and changing of development processes.Every sedimentary basin classification scheme,from its birth,must be under test,controversy and construction.By doing this,it gradually becomes perfect.