SEQUENCE STRATIGRAPHY AND SEA LEVEL CHANGES IN SOUTHERN CHINA DURING THE TRIASSIC

The Triassic strata and sedimentary facies are of widespread occurrence in southern China. The stratigraphic division and correlation are accurate as a result of the detailed sedimentological studies of the Triassic strata by the previous workers. The emphasis in this paper will be on sequence stratigraphy and sea level changes in southern China during the Triassic. Two types of sequence boundaries have been distinguished for the Triassic strata:Type Ⅰ sequence boundary including Indian-Olenekian, Oienekian-Anisian, Anisian-Ladinian and early Ladinian-late Ladinian, and Type Ⅱ sequence boundary including Permian-Indian on the basis of which two types of the depositional sequences have been correspondingly recognized for the Triassic strata in southern China. The Indian is involved in Type Ⅱ depositional sequence composed of shelf margin systems tract, transgressive systems tract and highstand systems tract. In the Olenekian, there are three depositional sequences (belonging to Type Ⅰ depositional sequence), i. e. T₁f⁴-T₁j², T₁j²-T₁j⁴ and T₁j⁴-T₁j⁵, composed of lowstand systems tract, transgressive systems tract and highstand systems tract, whereas in the Anisian-Ladinian, there are two depositional sequences, i. e. T₁j⁵-T₂l² and T₂l²-T₂l⁴, composed of lowstand systems tract, transgressive systems tract and highstand systems tract. According to the relationship between the systems tracts cited above and sea level changes, the curves showing the sea level changes in southern China during the Indian-Ladinian (Triassic) are also established by the authors in the present paper.