中国全新世海平面变化周期与世界未来海平面变化规律

A STUDY ON PERIODICITY OF HOLOCENE SEA-LEVEL CHANGES IN CHINA AND FUTURE SEA-LEVEL CHANGES IN THE WORLD

从发现海滩岩断代序列模式后,通过多学科综合研究又发现气候变化周期、闽粤海岸升降周期和海平面变化周期等皆为500a 左右。在13000aB.P.前中国气候变暖,海平面为以上升为主的升降期;近6000多年海平面以周期性上下波动为特征;而近3100年寒冷气候以每1000年7个纬度的速度南移,海平面向上波动幅度变小。按气候变化周期,现阶段为变寒期,将抵消一部分“温室效应”,世界未来50—100年的海面可能与今持平或有所下降。按照冰期和间冰期的时间规律,未来6000—7000年的海平面将下降几十米。

Only a very rough outline knowledge is obtained at present for the study on the climatein historic times and the study on Holocene sea-level changes is also in a stage of extensivedespute with various opinions.Through the research on the Holocene beachrocks of China,the authors have discoveredthat the formation and depositional break periods of beachrocks,the warming and coolingperiods of climate,the rise and fall periods of sea-level and so on are characterized by asynchronous period of about 500 years.The authors,therefore,have revealed and advancedthe dynastic sequential model of the Holocene climatic strata and on this basis the periodsof climatic changes in historic times,the periods of Holocene climatic changes and sea-levelchanges,and other related natural phenomena have been discovered.Beachrocks are formed on the coast of tropical zones with an average temperature higherthan 26.5℃ a year,and at present they are formed in the tropical area to the south of the XishaIslands.The area of China from the Liaodong Peninsula to the Nansha Islands are located atthe middle and low latitude up to 38 latitude zones in the Northern Hemisphere,China hasthe exceptional advantages of geological geography to find the dynastic sequential model ofHolocene beachrocks,and the rock-forming regularities of “northward advance” and “south-ward movement”.The beachrocks discovered so far are mostly the relic bodies formed at different stages for6850 a B.P.,a complete dynastic sequential model can be established through a comprehensivestudy on a variety of nature factors.This pattern is also the staff to test and verify the climateand sea-level changes.By the rise and fall features the periods of the Holocene sea-level changes can be distin-guished into two major stages:the rise and fall stage dominated by rising before 6500 a B.P.and the stage of fluctuation round the present sea-level later.For the future variations of climate and sea-level in the world a number of scientists havepredicted that temperature and sea-level would be raised at a large range after scores of yearsbecause of “greenhouse effect”,and the others hold that the climate during a glacial period isabout to come round.In fact,the future climate and sea-level changes can only be deter- mined by the laws of nature.According to the studying by Bloom,there is,on an average,a long period of 2×10~4 yearsfor the sea-le(?) changes in the past 14×10~4 a B.P.During the period of Holocene in China,it began to warm 13000 a B.P.and after 10000 years it has been dominated by cooling in thepast 3100 years.A cold clima(?)e moves southward at a velocity of 7 latitudes every 1000 years;and the amplitude of sea-level fluctuation has also gradually decreased.This is the normallaw of nature.Therefore,the sea-level after 6000—7000 years will fall some dozens of me-ters.As the “greenhouse effect” can be partly offsetted by the normal cooling law,it is im-possible for sea-level to rise largely within the coming 50—100 years,but similar to thepresent one or even somewhat fall.