导致古森林沉没于海的福建深沪湾古地震研究  

RESEARCH OF PALEO-EARTHQUAKE THAT CAUSED THE SUBSIDENCE OF PALEO-FOREST ON THE SEAFLOOR IN SHENHUWAN BAY, FUJIAN PROVINCE

作　　者：徐起浩[1] 冯炎基[2] 施建生 

机构地区：[1]广东省地震局,广州5100702 [2]广州地理研究所,广州5100703 [3]福建省晋江市科学技术委员会,晋江362200

出　　处：《地震地质》2001年第3期367-380,T001,T002,共16页Seismology and Geology

基　　金：地震科学联合基金资助 (1970 96)

摘　　要：福建深沪湾海底古森林是强古地震遗迹。研究结果表明 ,全新世早期该处海底古森林生长在由松散的晚更新世含砾砂粘土构成的低凹洼地内。距今 70 0 0a左右的强古地震导致古森林沉没于海并形成泻湖环境 ,约距今 2 0 0 0a的又一次强古地震使海底古森林沉没到更深的海底 ,推测这两次古地震的震级都超过 7级。The submerged paleo forest in Shenhuwan Bay, Fujian Province, is accepted to be the vestige of strong paleo earthquake. The fossil trees were formerly growing in low lying land filled with late Pleistocene gravel bearing sandy clay during Holocene. A strong earthquake occurred 7000 years B.P. had caused the subsidence of the trees onto the seafloor and the development of lagoon environment, while another strong earthquake occurred 2,000 years B.P. had given rise to the further subsidence of the trees to a greater depth. The evidences of these two events are as follows: 1. Earthquake landform composed of loose sediments was buried by littoral facies deposits on the seafloor, and its remnants were left on the beach. This may indicate that the land was subsided rapidly below the sea level during the earthquake, while several island like highlands composed of red and yellow gravel bearing sandy clays of late Pleistocene age remained above the sea level after the earthquake. After long period erosion by sea water, red brown and yellow land spots were left on tidal zone or shoal, while isolated blocky highlands surrounded by marine and eolian deposits were remained on the coast. 2. Many paleo trees had killed simultaneously, some of which were collapsed and broken. Some broken trunks laid down on the sea floor, and some broken branches were still connected with the trunks. All these may indicate a sudden subsidence caused by strong earthquake, which had given rise to the rapid burying of the paleo trees. 3. Evidence from seismic facies sediments. The ZK 1 and ZK 2 drill holes on the shoal have revealed that the Holocene sediments contains a 20～30m thick bed of carbonized, half carbonized and un carbonized broken wood chips with a little amount of gravels. This bed has not been eroded and transported by the sea water, containing marine facies sands of fine to medium size and small yellow clay balls. The formation of this bed seems to closely related to the sudden subsidence caused by strong earth

关 键 词：海底古森林 全新世 强古地震 福建 深沪湾 地质环境 

分 类 号：P316.2[天文地球—地震学]