浙江宁海下南山组晚中新世古海拔与古气候定量重建

QUANTITATIVE RECONSTRUCTION ON PALEOELEVATION AND PALEOCLIMATE OF MIOCENE XIANANSHAN FORMATION IN NINGHAI,ZHEJIANG PROVINCE

通过对浙江宁海晚中新世下南山组已准确鉴定23属植物大化石的现存属共存分析表明,它们的共存区间为:26°—30°N,107°—115°E,海拔为500—1200m。依据共存分布区间的常年气候资料,获得宁海晚中新世古气候参数定量数值为:年平均气温9.91—19.74℃;年较差18.31—30.68℃;最冷月均温-3.20—5.19℃;最热月均温16.73—26.44℃;年极端最高气温27.99—37.41℃;年极端最低气温-6.56—-20.16℃,年降雨量为1117.7—1546.4mm。推测晚中新世浙江宁海地区为亚热带山地气候,古湖海拔为500—1200m。

The Xiananshan flora in the Upper Miocene from Ninghai County,Zhejiang Province is consisted of 23 genera based on megafossils plants. The coexistent region of their extant equivalent genera ranges from the altitude of 500 m to 1 200 m within the latitudes from 26°N to 30°N and longitudes from 107°E to 115°E. The concept of the nearest living relatives （NLR） is adopted and applied in this paper by using the assumption that the fossil and its nearest living relative have similar ecological requirements. Based on extant data of above coexist region derived from climatic data of China,the Miocene paleoclimate data in Ninghai,Zhejiang Province are estimated as the mean annual tempe-rature （MAT） 9.91—19.74 ℃,the difference in temperature between the coldest and warmest month （DT） 18.31 —30.68 ℃,the mean temperature of the coldest month （TCM） -3.20—5.19 ℃,the mean temperature of the warmest month （TWM） 16.73—26.44 ℃,annual extremely warmest temperature （EWT） 27.99—37.41 ℃,annual extremely coldest temperature （ECT） -6.56—-20.16℃,the meaning annual precipitation （MAP） 1 117.7 ？ ？ 546.4 mm ,showing a subtropical mountainous climate. The elevation of Ninghai in the Miocene ranges from 500 m to 1 200 m.