Morphology of Molar-Tooth Structures in Neoproterozoic and Its Indication Significance for the Depositional Environment of Jinshitan Area in Dalian, Eastern Liaoning Province
Exemplified by “molar tooth” (MT) from Neoproterozoic Xingmincun Formation of Jinshitan in Dalian, this paper studied its morphological characteristics and analyzed its indication significance for sedimentary environment. A series of MT with complicated morphologies are developed in limestone of Upper Xingmingcun Formation. On the basis of a detailed observation, molar teeth are divided into ribbon, short-straight bar, worm, filamentous, dotted and detritus forms, with the ribbon form being dominant. Some sedimentary rhythms composed of silt-carbonates, micrite-carbonates, laminated carbonates and mud-carbonates were identified. Molar teeth were formed in the lower part of shallow subtidal-intertidal microfacies. It is thus concluded that different sets of morphology represent different lithofacies or rhythmic units, showing the indication significance for the morphology of MT.