甘肃玉门下白垩统下沟组植物木化石及其古气候意义  

THE FOSSIL WOODS OF LOWER CRETACEOUS XIAGOU FORMATION IN YUMEN OF GANSU PROVINCE AND THEIR PALEOCLIMATE SIGNIFICANCE

作　　者：马杰林 杨国林 邓鹏 彭措 MA Jie-lin;YANG Guo-lin;DENG Peng;PENG Cuo(BaiLie School of Petroleum Engineering,Lanzhou City University,Lanzhou 730070,China;Gansu Geological Museum,Lanzhou 730000,China)

机构地区：[1]兰州城市学院培黎石油工程学院,甘肃兰州730070 [2]甘肃地质博物馆,甘肃兰州730000

出　　处：《甘肃地质》2024年第2期13-21,共9页Gansu Geology

基　　金：甘肃省教育厅创新基金项目(2022A-143);兰州城市学院博士科研启动基金项目(LZCU-BS2018-11);甘肃省古生物化石调查研究及数据库建设项目。

摘　　要：甘肃玉门早白垩世下沟组保存有较完好的木化石。统计了玉门木化石树桩直径,采用Mosbrugger方法和Niklas方法定量推测玉门松柏类木化石的树高约为26~33 m,表明在早白垩世甘肃玉门地区曾发育有高大的松柏类乔木。计算木化石生长轮早材与晚材的比率,表明植物生长季时间较短。年敏感度和平均敏感度表明玉门早白垩世的气候存在波动。另外,对木化石进行解剖学研究发现有假轮、年轮扭曲和创伤树脂道存在,说明玉门地区早白垩世气候存在异常,并且树木生长时风力较大。统计玉门盆地下白垩统下沟组植物化石共计8属8种,该植物群以松柏类(75%)繁盛,银杏类(25%)占一定比例为特征。综合定性分析等证据,推断甘肃玉门地区早白垩世为潮湿、温暖的气候,并表现出季节性的特点。Numerous petrified woods with well-preserved anatomical details have been found in the Lower Cretaceous Xiagou Formation in Yumen City,Gansu Province.The stump diameter of fossil wood in Yumen were calculated by Mosbrugger et al.and Niklas methods.Annual sensitivity and mean sensitivity were used to reconstruct the Early Cretaceous climate in Yumen.The tree height of fossil wood in Yumen were estimated to be 26~33 m indicating that tall conifer trees were developed in Yumen area of Gansu province during the Early Cretaceous.The ratio of early wood to late wood of fossilized wood rings was calculated,indicating that the plant growing season was short.Analyses on annual sensitivity and mean sensitivity indicated that the climate fluctuated in Yumen during the Early Cretaceous.In addition,the anatomical study of wood fossils revealed the existence of false rings,tree ring distortion and wound resin channel,indicating that the Early Cretaceous climate in Yumen area was abnormal,and the wind was strong when the trees grew.The results show that the flora of the Lower Cretaceous Xiagou Formation in the Yumen Basin is composed of 8 species in 8 genera.The flora is characterized by the abundance of conifers(75%)and the proportion of ginkgoales(25%).Based on qualitative analysis and other evidences,it is concluded that the Yumen area in Gansu province had a humid and warm climate during the Early Cretaceous,with seasonal characteristics.In addition,the climate in Yumen area fluctuated during the Early Cretaceous.

关 键 词：玉门市 下沟组 早白垩世 木化石 古气候 

分 类 号：P534.52[天文地球—古生物学与地层学] Q914.2[天文地球—地质学]