潮汕平原全新世孢粉分析及古环境探讨

HOLOCENE POLLEN ANALYSIS AND ENVIRONMENTAL RESEARCH IN THE CHAOSHAN PLAIN

本文根据潮汕平原多个钻孔的孢粉分析结果,探讨了全新世以来的植被和气候演替以及沉积环境变迁。结论是:该区一万年来的气候波动小,地带性植被变化不大,海滩植被的消长则与沉积环境的改变密切相关。

Pollen analysis from several cores of the Hanjiang delta revealed a series of environmental changes since late Pleistocene. Among these sections, core SH5 is of particular biostratigraphic significance for the Holocene epoch. Based on the pollen diagram of SH5, five pollen zones were dissociated.The helophyte pollen, found abundantly in samples of Lower Holocene( Zone E), indicated the existence of fresh-water swamp. The appearance of mangrove pollen beyond 8600 yrs B.P. (Zone D) was consideredas an indication of sea transgression. The marine environment (marine bay) began about 7500 yrs B.P. (Zone C) was proved by either the richness of foraminiferas and marine shells, or the shaip fall in pollen influx values (grains of pollen per year on a cm2 surface). Sea regression occured about 4000 yrs B.P., resulting in the disappearance of mangrove elements. The monsoon evergreen broad-leaved forest, prevail-ing since Early Holocene, was strongly disturbed by human activities in these recent 3000 years, as was figured by the zone on top of the pollen diagrams.