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The article makes a research of the calcareous concretions in the surface sediments of the northern East China Sea. Based on the isotopic composition of carbon and oxygen, chemical composition, radiometric dating and distribution pattern of the concretions, we infer that they are chiefly formed in the area of the fossil delta of the Changjiang River under a fresh water environment. Therefore, the calcareous concretion can act as a facies indicator, showing that the sea bottom of the area once exposed above the sea water.
The article makes a research of the calcareous concretions in the surface sediments of the northern East China Sea. Based on the isotopic composition of carbon and oxygen, chemical composition, radiometric dating and distribution pattern of the concretions, we infer that they are chiefly formed in the area of the fossil delta of the Changjiang River under a fresh water environment. Therefore, the calcareous concretion can act as a facies indicator, showing that the sea bottom of the area once exposed above the sea water.