摘要
胶莱盆地是一白垩系发育较为完整的陆相含火山地层沉积盆地。白垩系中发现有大量恐龙骨骼、恐龙蛋,以及其它动植物化石,是研究陆相白垩纪古环境演变的重要地区。本文通过对胶莱盆地莱阳洼陷Albian阶林家庄组—辛格庄组地层沉积特征、碳酸盐碳氧同位素组成(δ^(13)C,δ^(18)O)、色度(L^(*),a^(*),b^(*))、碳酸盐含量、TOC含量,以及风化指数(CIA)、古气候指数(C)等古环境指标的综合分析,反映出Albian阶古气候从早期偏冷干逐渐过渡到半干旱-半湿润状态。古气候总体上温暖湿润,但也存在多次气候波动特征。偏重的碳同位素组成与OAEs事件有较好的对应关系,表明胶莱盆地在白垩纪时期陆相地层与海相地层之间存在一定的对比关系。碳酸盐碳、氧同位素组成特征表明,高浓度大气CO_(2)可能是这两者之间联系的纽带。林家庄组—辛格庄组地层碳同位素组成显示,陆相地层中OAE1c至少由3次次级旋回组成,代表了气候的不稳定性和复杂性。
Jiaolai Basin is a Cretaceous terrestrial sediment basin with complete strata from the early to late period and includes magmatites among the sediment layers.Lots of dinosaur bone fossils and egg fossils,and even other animal bone and plant fossils were buried in the Cretaceous sediment layers.It is a key region to research the terrestrial paleoenvironmental change during the Cretaceous period.In this study,we surveyed the PM301 section of Linjiazhuang and Xingezhuang Formations in the Laiyang depression,which belongs to the Jiaolai Basin at Albian Stage in the field.Carbon and oxygen isotopes of carbonates(δ^(13)C,δ^(18)O),chromaticness(L^(*),a^(*),b^(*)),carbonate content,TOC,and chemical index of alteration(CIA),paleoclimate index(C)had been done for the sediment samples collected from these two Formations.Based on these geochemical proxies,paleoclimate was reconstructed from the cold and dry early Albian Stage to semi-dry and semi-wet gradually,but on the whole,paleoclimate at Albian Stage was warm and wet with several climate oscillation.From the PM301section,we can find that the heavier carbon isotope at Albian stage had a high correlation with ocean OAEs events,indicating a similarity between the terrestrial and ocean sediment environments.High atmospheric CO_(2)from volcano emissions may be a linkage between the terrestrial and ocean teleconnection.Based on the heavier carbon isotope excursion,OAE 1c can be divided into at least three sub-cycle stages,and it is inferred that the paleoclimate at Albian stage was unstable and complex.
作者
陶有兵
任天龙
黄永波
王丽娟
姚金娇
张成君
TAO You-bing;REN Tian-long;HUNAG Yong-bo;WANG Li-juan;YAO Jin-jiao;ZHANG Cheng-jun(Shandong Institute of Geological Survey,Jinan,Shandong 250013;School of Earth Sciences&Key Laboratory of Mineral Resources in Western China(Gansu Province),Lanzhou University,Lanzhou,Gansu 730000)
出处
《地球学报》
CAS
CSCD
北大核心
2022年第1期38-48,共11页
Acta Geoscientica Sinica
基金
山东省地勘项目“胶莱盆地中部白垩纪古生物化石调查研究及保护”(编号:鲁勘字(2019)54号)资助~~。
