There are Holocene beachrocks exposed on the sandy beach of the mid-intertidal zone in thirteen coves between rock headlands along the coast in Zhejiang Province. Except for Lianyungang beachrock, Zhejiang beachrocks are the northernmost ones found in China, located in the middle subtropic.The age from data of 14C is from 2 705 a±160 a BP to 6 485 a±210 a BP. Its basic features and palaeogeo-graphic significance were discussed. Results of the study indicate that the grains ( shells and their frag-ments of in tertidal-neritic bivalves, gastropods, foraminiferas and ostracods, and clasts of granite, etc.) which are produced by marine processes,grain-supported texture and aragonite as the cement are the most important features of the beachrocks. Favourable geomorphologic landscape, such as in a cove with sandy beach, sufficient supplies of grains including terrigenous detritus, quartz, feldspar, and a large amount of bioclasts, moderate grain size and hydrodynamic conditions , stable sea level and high temperature influ-ence the formation of the beachrocks. During formation of the beachrocks, the coast-line of the middle-northern part of Zhejiang Province was basically stable, and Donghai Sea longshore current was not the low temperature current like the present.Its temperature was about 5-6°(at least 2°C)higher than the pr-esent, whereas it was the low salinity current like the present. Zhejiang Province belonged to the tropical climate zone,or climatic zonation was not distinct at that time.
Journal of Palaeogeography