Chemostratigrphil characteristics of Mg, Ca, Sr, δ13C and δ18O can clearly quantify lithofacies of Middle Devonian

strata along the Liujing section. Within the biostratigraphic framework, these characteristics make possible the highresolution

partition and regional highresolution correlation of the Middle Devonian strata. The sedimentary environment of Middle Devonian

Najiao Formation is characterized by three times of alternate shoalrear lagoon and vaporizing foreshore, and that of Mintang

Formation and Lower Gubi Formation is the reefrear slope. These chemostratigrphic characteristics are consistent perfectly with

those of sedimentary facies and biofacies. Chemostratigraphic data of Najiao Formation also show that dolomite should not be hastily

excluded from the chemostratigraphic study. The finegrained dolomite and powder crystal dolomite, especially the thinlayered and

laminated dolomite, deserve further proper studies.