THE DISCOVERY AND GEOLOGICAL IMPLICATIONS OF THE DEEPER SHALLOW-MARINE SEDIMENT TYPES IN THE LIANTUO FORMATION,NORTHWESTERN JIANGXI

The small-scale gravity-flow deposits considered as the event sediments at the upper-most part of the Liantuo Formation,north western Jiangxi indicate a progressively increas-ing depth of sedimentary environments rather than a simple terrestrial-marine transition. The retrogradational sediments from continent to foreshore to shelf produced by increasing expansion of transgressions in the early and middle stages of the deposition of the Liantuo Formation show a gradually deepening of sea water,whereas the intercalations of the sea-ward progradational small-scale gravity flow sediments and thick massive non-gravity flow sediments generated during the late stage of it represent relatively complicated sediments. The small-scale gravity-flow sediments in the study area may not only play an impor-tant part in facies analysis,sequence stratigraphic analysis and genetic analysis of the grav-el-bearing tillites overlying the Nantuo Formation,but also serve as good indicators for the reconstruction of tectono-palaeogeography and plate tectonics.