中国侏罗纪古气候分区与演变

The Jurassic palaeoclimate regionalization and evolution of China

以古生物学和沉积学资料为主,结合地球化学和植物化石气孔器参数等资料系统分析了中国侏罗纪的气候特征、气候分区及其演变过程。侏罗纪时期的气温明显比现代为高,但无论是温度还是湿度都经历了强烈的变化,可划分为早侏罗世早中期、晚期,中侏罗世早、晚期以及晚侏罗世等5个演化阶段,各阶段气候分区特征明显。其中,早侏罗世早中期(大致为埃唐日期—普林斯巴赫期)可划分为5个气候区,自北而南依次为黑龙江东部乌苏里温凉气候区、北方暖温带潮湿气候区、东南热带-亚热带潮湿气候区、西南热带-亚热带半干旱半潮湿气候区以及西藏—滇西热带海洋干旱气候区。其中,北方暖温带潮湿气候区范围最大,占据了昆仑—秦岭—大别山一线以北的广大地区。早侏罗世晚期(图阿尔期)总体升温并趋于干旱化,依然可以划分为5个气候区,但北方暖温带潮湿气候区由于南界的大幅度向北移而大为缩小,范围最广的是中部热带-亚热带半干旱-半潮湿气候区。中侏罗世早期(阿伦期—巴柔期)气温较早侏罗世晚期明显下降,北方暖温带潮湿气候区南界向南推移,基本恢复到了早侏罗世早中期的范围,东南地区为热带-亚热带半干旱-半潮湿气候。中侏罗世晚期(巴通期—卡洛维期)又复升温趋干,气候区界线再度北移,暖温带潮湿气候区范围再次大幅度缩小到燕辽及东北地区,热带-亚热带半潮湿-半干旱气候区范围扩大至整个华北与西北地区,南方则为热带-亚热带干旱气候区。晚侏罗世气温进一步升高,暖温带潮湿气候区退缩至东北一隅,除滇、藏热带海洋干旱气候区外,其他广大地区均为热带-亚热带干旱气候,且多地出现荒漠化。

The Jurassic climate of China was analysed mainly based on the data of palaeontology,sedimentology,geochemistry and stomatal index and stomatal ratio of fossil plants.Both the temperature and humidity of China experienced drastic alteration in the Jurassic,and the temperature was obviously higher than that of the present.There were five climatic evolution stages including the early-middle of Early Jurassic,the late Early Jurassic,the early of Middle Jurassic,the late of Middle Jurassic and the Late Jurassic.Each of them had distinct characteristic of regionalization.In the early-middle of Early Jurassic stage（HettangianPlinsbachian）there were five climate regions,namely, Wushuli warm-cool climatic region in Eastern Heilongjiang,North China warm-temperate humid climatic region,Southeast China tropic-subtropical humid climatic region,Southwest China tropic-subtropical semi-arid and semi-humid climatic region and Tibetwestern Yunnan tropical oceanic arid climatic region.Among these regions,the warm-temperate humid climatic region was the widest one,occupied the vast area north of the Kunlun Mountains-Qinling MountainsDabie Mountains.It was becoming warmer and tending to be dry in the late of Early Jurassic stage（Toarcian）,while there were still five climate zones.However,the warm temperate humid climate zone in North China was shrinking because the south boundary of which was dramatically moved northwards.The largest one was the tropical-subtropical zone in central China.The temperature had a dramatic decrease and becoming in the early of Middle Jurassic（Aalenian-Bajocian）.The area of the warm temperate humid climate zone in North was restored almost to that of the early-middle of Early Jurassic by extending southwards,and Southeast China was occupied by tropical-subtropical semi-arid and semi-humid climatic.It became hot and dry again in the lateof Middle Jurassic（Bathonian-Callovian）and the area of warm temperate humid climate zone in North was sharply reduced to restrict in the Yanliao（northern Hebei Province and western Liaoning Province）area and Northeast China.The subtropical semi-arid and semi-humid climate zone extended to the whole North and Northwest China.The temperature continued warming in the Late Jurassic（Oxfordian-Tithonian）.The warm temperate humid climate zone was shrunk away to a corner of Northeast China.It was hot and dry and appearing desertification in the vast area of China except the Tibet-western Yunnan region which belonged to tropical oceanic climate.