叶蜡单体氢同位素古高程计研究进展
Research Progress of Leaf-wax Hydrogen Isotope Paleoaltimetry
林杰 1庄广胜 2王成善 1戴紧根1
作者信息
- 1. 中国地质大学(北京)地球科学与资源学院,北京100083;中国地质大学(北京)生物与环境地质国家重点实验室,北京100083
- 2. 路易斯安那州立大学地质与地球物理系,路易斯安那州 巴吞鲁日 70803
- 折叠
摘要
高等植物类脂物广泛分布于土壤、河流和湖泊沉积物中,正构烷烃是植物类脂物的重要组成部分.高等陆生植物叶蜡正构烷烃具有较长的链长(nC27-nC33)以及明显的奇偶优势(CPI＞5),其氢同位素组成在一定程度上反映了大气降水的同位素特征,对古高程重建具有重要的指示意义.不同地区的现代土壤正构烷烃氢同位素随高程的递减率有所不同,说明地区性的校正是必要的.蒸散富集作用和生物合成作用过程也会影响正构烷烃氢同位素值.在利用长链正构烷烃重建古高程时,需结合古气候、古纬度、古植被等多方面资料综合分析.
Abstract
Leaf waxes/lipids which are derived from terrestrial higher plants are ubiquitous in fluvial,lake,and marine sediments.N-alkanes are an important component of leaf waxes.Modern leaf wax n-alkanes from terrestrial higher plants are characterized with long chains with 27 to 33 carbon atoms (nC27-nC31) and high carbon preference index (CPI) values (＞5).The hydrogen isotopes in n-alkanes are determined by meteoric water compositions,which makes them a potential proxy in paleoaltimetry studies.The lapse rates at which n-alkane hydrogen isotopes in modern soils change with altitude vary in different areas,implying that local calibration has to be conducted.The enrichment due to evapotranspiration and difference in fractionation during biosynthesis also influence nalkane hydrogen isotopes values.When using long-chain n-alkanes to reconstruct paleoaltitude,many factors such as paleoclimate,paleolatitude and paleobotany should be considered.
关键词
叶蜡正构烷烃/氢同位素/古高程/表观分馏系数Key words
Leaf wax n-alkanes/Hydrogen isotope composition/Paleoaltimetry/Apparent fractionation引用本文复制引用
基金项目
中国地质调查局项目(DD20160027)
出版年
2016
NETL
NSTL
维普
万方数据