辽宁北部地区下白垩统木化石及其古气候意义  

THE LOWER CRETACEOUS PETRIFIED WOOD IN NORTHERN LIAONING:Paleoclimatic Significance

作　　者：丁秋红[1] 李晓海[1] 李文博[1] 张志斌[1] 陈树旺[1] 张健[1] 孙守亮[1] 张渝金[1] DING Qiu-hong;LI Xiao-hai;LI Wen-bo;ZHANG Zhi-bin;CHEN Shu-wang;ZHANG Jian;SUN Shou-liang;ZHANG Yu-jin(Shenyang Center of China Geological Survey,Shenyang 110034,China)

机构地区：[1]中国地质调查局沈阳地质调查中心,辽宁沈阳110034

出　　处：《地质与资源》2022年第1期13-20,12,共9页Geology and Resources

基　　金：国家自然科学基金项目“松辽盆地及邻区早白垩世陆相地层高精度年代格架”(编号41790451),“大兴安岭中南部中侏罗世植物群及地层新探”(编号42172024);中国地质调查局项目“松辽盆地北部及外围石炭-二叠系油气地质调查”(编号DD20190097).

摘　　要：对辽宁北部地区下白垩统沙海组木化石进行的木材解剖学及系统分类学研究显示,木化石均为硅化保存的松柏类裸子植物次生木质部,分别属于Protocupressinoxylon、Protopiceoxylon和Xenoxylon等3个分类群.当前木化石新材料生长轮清晰,早晚材比率在0.84~64之间,年平均敏感度在0.23~0.3之间,表明气候具有明显的季节性变化;树木生长的晚材时间短,早材跨度时间长,即在生长季管胞分裂旺盛,水分、温度、湿度、光照等因素较为适宜的时间较长.连续生长轮宽度不均匀以及假轮的存在,表明当时气候变化频繁,年均降水量可能存在较大差异,从生长特征整体推断,辽宁北部地区沙海组沉积时期整体较为湿润,但可能存在一定的干旱—半干旱的气候波动.木化石中存在假轮、创伤树脂道、生长轮扭曲、虫孔等特殊解剖构造,揭示当时的生态环境中可能存在旱灾、风灾以及虫害等短时间内不利于树木生长的影响因素.The wood anatomy and systematics study of petrified woods from the Lower Cretaceous Shahai Formation in northern Liaoning show that the petrified woods are all silicified secondary xylem of conifer gymnosperms,belonging to the taxonomic groups of Protocupressinoxylon,Protopiceoxylon and Xenoxylon respectively.The growth rings of novel materials of the current petrified woods are clear,with the early wood to late wood ratio of 0.84-64,and the annual average sensitivity of 0.23-0.3,indicating that the climate has obvious seasonal variation.The trees have a short late-wood growth time and long early-wood time span,that is,the tracheid division is strong in the growing season,and the suitable time for factors such as moisture,temperature,humidity and light last longer.The uneven width of continuous growth rings and existence of false rings reflect that the climate changed frequently at that time,and the average annual precipitation may have a great difference.It can be inferred from the growth characteristics that the Shahai Formation in northern Liaoning was generally humid during the sedimentary period,but there might be some arid-semiarid climate fluctuations.The special anatomical structures in petrified woods such as false ring,traumatic resin canal,twisted growth ring and insect hole reveal that there may be drought,wind disaster and insect pests in the then eco-environment,which are unfavorable for the growth of trees in a short time.

关 键 词：木化石 古气候 下白垩统 沙海组 生长轮 辽宁北部 

分 类 号：P534.53[天文地球—古生物学与地层学] Q914.2[天文地球—地质学]