地球科学进展, 2021, 36(1): 45-57 DOI: 10.11867/j.issn.1001-8166.2021.011

综述与评述

风成沉积物叶蜡氢同位素在揭示东亚季风区干湿变化中的原理及应用

梁承弘,, 鹿化煜,

南京大学地理与海洋科学学院自然地理学系,南京大学关键地球物质循环前沿科学中心,江苏 南京 210043

The Application of Leaf Wax n-alkanes δD in Aeolian Sediments as a Proxy for Reconstructing Quaternary Humidity Variations in the Monsoonal East Asia

LIANG Chenghong,, LU Huayu,

Department of Physical Geography,School of Geography and Ocean Science,Frontiers Science Center for Critical Earth Material Cycling,Nanjing University,Nanjing 210043,China

通讯作者: 鹿化煜(1968-),男,陕西西安人,教授,主要从事自然地理和环境演变研究. E-mail:huayulu@nju.edu.cn

收稿日期: 2020-11-28   修回日期: 2020-12-24   网络出版日期: 2021-03-19

基金资助: 国家自然科学基金项目“北半球中纬度黄土沉积与最近四个冰期旋回气候—植被变化”.  41920104005
“气候变化对长江和湄公河流域水文水资源的影响”.  42011530119

Corresponding authors: LU Huayu (1968-), male, Xi'an City, Shaanxi Province, Professor. Research areas include physical geography and paleoenvironment study. E-mail:huayulu@nju.edu.cn

Received: 2020-11-28   Revised: 2020-12-24   Online: 2021-03-19

作者简介 About authors

梁承弘(1996-),男,湖北十堰人,硕士研究生,主要从事生物地球化学与古气候研究.E-mail:MG1727005@smail.nju.edu.cn

LIANGChenghong(1996-),male,ShiyanCity,HubeiProvince,Masterstudent.Researchareasincludebiogeochemistryandpaleoclimatestudy.E-mail:MG1727005@smail.nju.edu.cn

摘要

沉积物叶蜡正构烷烃氢同位素是指示气候和环境变化的一种新的生物地球化学指标,由于其存在广泛、成因机制清晰、易于保存等特点,被认为是具有很大潜力的重建古环境的替代指标。分析了正构烷烃的形成过程与其氢同位素的分馏机制,讨论了叶蜡正构烷烃氢同位素在不同气候区指示湿度变化的能力,总结了在东亚季风区半干旱区的一些应用案例。相比于风成黄土中其他气候代用指标,沉积物正构烷烃氢同位素更直接地指示了区域干湿变化,对区域气候和环境变化响应敏感,在长时间尺度上记录了水汽变化过程,并存在显著的太阳辐射岁差周期。正构烷烃氢同位素是一种理想的东亚季风区干旱半干旱地区湿度重建的代用指标,未来需要进一步研究大气降水同位素和本地分馏过程对其变化的控制规律,加强其在古气候定量重建中的研究应用。

关键词: 正构烷烃氢同位素 ; 湿度重建 ; 黄土 ; 半干旱区 ; 东亚季风

Abstract

Leaf wax n-alkanes are widely distributed in sediments; they have a clear formation process, and they are resistance to environment change. δD composition of leaf wax n-alkanes is a newly developed biogeochemistry proxy with great potential in paleoenvironment reconstruction. In this paper, we reviewed the formation process of leaf wax n-alkanes and their hydrogen isotopic fraction, evaluated the relationship between leaf wax n-alkanes δD and regional humidity, and summarized recent applications of them to paleoclimate reconstruction. Based on the studies of n-alkanes δD of surface sediments, we find n-alkanes δD is a good proxy indicator of humidity in semiarid and arid climate region in monsoonal East Asia. Compared with other proxies from loess-paleosol sequences, the n-alkanes δD is a direct indicator of humidity variations; it shows direct response to environment change, and it reveals precession signal of solar insolation variations in orbital timescales paleoclimate record. In this case, the n-alkanes δD is a good proxy for humidity variations in sedimentary records in East Asia monsoon region, and, further research on the influence of the variations of precipitation isotope and local isotope fraction process to the n-alkanes δD is compulsively needed.

Keywords: n-alkanes δD ; Paleo-humidity reconstruction ; Loess ; Semi-arid regions ; Asia monsoon

PDF (5550KB) 元数据 多维度评价 相关文章 导出 EndNote| Ris| Bibtex  收藏本文

本文引用格式

梁承弘, 鹿化煜. 风成沉积物叶蜡氢同位素在揭示东亚季风区干湿变化中的原理及应用. 地球科学进展[J], 2021, 36(1): 45-57 DOI:10.11867/j.issn.1001-8166.2021.011

LIANG Chenghong, LU Huayu. The Application of Leaf Wax n-alkanes δD in Aeolian Sediments as a Proxy for Reconstructing Quaternary Humidity Variations in the Monsoonal East Asia. Advances in Earth Science[J], 2021, 36(1): 45-57 DOI:10.11867/j.issn.1001-8166.2021.011

1 引 言

在我国干旱半干旱地区,生态环境脆弱且受干湿变化影响显著,水分和湿度变化是重要的环境控制因素。近50年来器测的降水记录显示,大气降水变化地区差异和年代际差异大,理解其干湿变化的规律和机制需要古气候研究的支持12;从数值模拟结果看,在全球变暖的背景下,蒸发与降水均会增强,由于气候模式中的反馈机制仍有待改进,数值模拟对湿度变化的预测具有很大的不确定性34。因此,长时间尺度上的气候记录研究,对于认识干旱半干旱区气候变化具有重要意义。

风成黄土沉积在东亚半干旱地区广泛存在,由于其连续而稳定的沉积过程,是进行古气候研究的良好材料。在前人的研究中,已有一系列物理、化学和生物的代用指标,但由于不少古气候替代指标作用机制的不确定性,其指示意义需要深入研究。例如,磁化率记录了第四纪冰期—间冰期旋回,被广泛用作指示气候干湿程度的代用指标,但磁性矿物生成、转换、保存机制有不确定性,定量化程度低5。孢粉和植硅体等生物指标在沉积物中的保存差异大,且在半干旱区环境条件不利于孢粉保存,往往难以获得足够的统计数量6。近年来,叶蜡正构烷烃以其明确的高等植物的来源与化学稳定性,被认为是一种良好的指示过去气候和环境变化的生物标志物7~10。本文归纳分析了前人研究成果,总结了正构烷烃合成的生物学过程与控制其氢同位素分馏的机制因素,讨论了东亚季风区风成沉积物中的应用案例,对正构烷烃氢同位素揭示湿度变化的潜力进行了总结。

2 叶蜡正构烷烃氢同位素的气候指示意义

2.1 叶蜡正构烷烃的合成、保存及其氢同位素的分馏与受控的环境因素

正构烷烃指直链的饱和烷烃化合物。在自然环境下,长链正构烷烃(碳数大于22)主要来自于高等植物叶蜡11。正构烷烃具有良好的化学稳定性,在沉积物中可以长久保存,是土壤有机质中最为稳定的成分之一12。叶蜡正构烷烃来自于高等植物非木质部分表面正角质层(即一般所说的植物蜡质层)的外层蜡质(Epicuticular wax)。外层蜡质主要由多种长链脂肪酸及其衍生的正构烷烃等物质组成,通过自组装形成微米级的片状、管状、针状、簇状等多种形态的晶体结构1314。外层蜡质是植物与外界接触的第一层屏障,起到了抵御不良环境的作用,其主要功能在于维持水分、防止辐射损伤、抵抗低温、防止虫害病菌15。植物体内正构烷烃的合成主要在植物的表皮细胞中进行,其合成过程分为两步,首先表皮细胞通过脂肪酸合成酶系统合成长链脂肪酸(碳数在18以上的饱和直链脂肪酸)碳骨架,随后表皮细胞在内质网中将碳骨架进一步延长与修饰,最终表皮细胞将形成的正构烷烃化合物送至外层蜡质中131617。由于正构烷烃不同碳数含量在不同植物种属间存在差异18,正构烷烃含量指标及其碳同位素在古植物重建中得到广泛的应用91920

陆生高等植物产生的长链正构烷烃的含量峰值碳数一般为29或3118。现有研究中,一般使用这两种化合物的氢同位素组成代指叶蜡正构烷烃氢同位素组成。为方便讨论,下文使用碳数为29的正构烷烃氢同位素组成代表陆生高等植物产生的正构烷烃氢同位素,以δDwax进行指代。氢同位素组成常用与标准样品的差异值δD表示,降水与正构烷烃之间的氢同位素分馏系数称为表观分馏值Ɛapp,其计算公式如下:

δD=(R样品-R标准样品)/R标准样品
Ɛapp=[(δD正构烷烃+1)/(δD降水+1)]-1,

式中:R样品R标准样品分别指代测样品与标准样品的氢同位素丰度。一般使用维也纳标准平均海水(Vienna Standard Mean Ocean Water,VSMOW)作为标准样品。影响δDwax组成的分馏过程可分为外部环境过程与内部生理过程两大类。外部环境的分馏过程主要是大气降水和土壤蒸发,内部生理过程的分馏包括叶片蒸腾作用、植物合成正构烷烃。大气降水过程中的同位素分馏由水汽输送过程、降水过程的气象因素决定,呈现较大的地域和季节差异,但在长时间尺度上表现出与降水量、温度和水汽来源等因素的相关性21

土壤蒸发过程指降水进入土壤后被植物吸收前水分的蒸发,较轻的同位素体(isotopologue)在蒸发中更容易离开、使得水分的δD值偏正,分馏程度与当地的温度、湿度相关1022。对土壤水分同位素的观测显示,土壤蒸发作用引发的同位素动力分馏,在温带地区,主要发生在土壤剖面的顶部0.2~0.3 m;在地中海的干旱地区,作用深度达到了3 m23。另一方面,降水的补充也会弥补蒸发作用的分馏23,因此土壤蒸发过程的同位素分馏、δD值偏正,受到降水与蒸发的共同控制,体现着环境干旱程度的影响。

一般认为,在植物根系吸收水分、韧皮部传输水分的过程中,并不会发生水分同位素的分馏102324。植物体内水分同位素的分馏,主要发生在叶片蒸腾作用的过程中。由于植物强烈的蒸腾作用,被叶片细胞利用的水分δD值会进一步偏正,分馏程度受到外部环境的温度、湿度、气压与不同植物种属叶片结构差异的影响102425。在环境湿度增大的情况下,植物蒸腾作用引发的水分δD值偏正也会减弱24

植物合成正构烷烃过程中的氢同位素分馏主要源自于合成过程中与水分和还原性辅酶Ⅰ、Ⅱ(NADH和NADPH)的氢原子交换,其中,由于前文所述的过程,叶片水分δD值较大气降水已偏正,而植物光合作用产生的还原性辅酶δD值却强烈偏负,最终使得生成的正构烷烃δD值也显著偏负1026,不同种属的植物其生理合成过程的同位素分馏可能存在较大差异27~29。由此,最终植物叶蜡正构烷烃与降水同位素之间表现为平均约-110‰的表观分馏系数,表土沉积物中保存的正构烷烃与本地降水之间的分馏系数与此接近30

由于不同种属、生理形态(草本/木本)的植物在叶片结构、光合作用途径、生理合成作用途径的差异,对现代植物叶片正构烷烃氢同位素组成的观测显示,其与本地降水氢同位素之间的表观分馏值Ɛapp存在一定的差异10。例如,有统计显示,C3光合作用途径的单子叶植物与双子叶植物之间,存在约36‰的表观分馏值的差异10,且这种差异在高纬地区更加明显30;在C3、C4途径的禾本科草本植物之间,也存在约15‰的表观分馏值的差异10。这种差异可能来自于不同植物的蒸腾、正构烷烃生理合成过程的差异10,例如,不同叶片结构导致叶片水分δD值偏正程度的差异24,光合作用、呼吸作用生产还原性辅酶氢同位素差异等26

在正构烷烃进入土壤后,也有研究认为,土壤细菌对正构烷烃同位素组成可能存在一定程度的改造31,但从周转周期看,正构烷烃进入土壤后可以在百年甚至更长的时间尺度上稳定的保存12,这也符合正构烷烃自身的化学惰性的特点。因此,一般认为次生改造作用对进入沉积物中的正构烷烃氢同位素值的影响较小。

从正构烷烃的生成与氢同位素分馏机制可以看出,对沉积物正构烷烃δD值起到决定性影响的因素主要有3点:大气降水本身的δD值,水分在植物外和叶片蒸腾中蒸发产生的分馏,植物生理合成过程中分馏。其中,大气降水δD值与水分蒸发均与环境湿度的变化密切相关,这也预示着正构烷烃氢同位素是一种良好的湿度指标。

2.2 现代地表沉积物正构烷烃氢同位素与环境因素的相关分析

目前,在全球范围内,已有不少地表沉积物正构烷烃氢同位素的研究成果32~46。但是,一方面,现有的研究缺乏对不同气候背景样点的综合对比,难以确定现代地表沉积物正构烷烃氢同位素与环境因素的精确关系;另一方面,区域之间的大气环流、水汽输送引起的降水同位素的差异,以及干湿程度等环境因素引起的局地分馏过程的差异,对正构烷烃氢同位素值变化的贡献也不清楚。因此,本文聚焦于东亚季风区的研究成果3335373841~45,着重分析了现代地表沉积物正构烷烃氢同位素与环境因素关系的空间特点,从而评价正构烷烃氢同位素对环境因素的指示能力。

本文收集整理东亚季风区现有表层沉积物δDwax分析数据,根据样点经纬度、高程信息补充降水同位素数据、多年平均气象数据(表层沉积物样点降水同位素使用在线降水同位素计算器获得47,多年平均气象数据包括年均降水量和干旱指数48),并去除缺失数据,获得土壤、湖泊表层沉积物、表层泥炭样点数据共332个,文献引用情况如表1所列。统计样点沉积物类型、纬度分布与气候类型(以干旱指数划分48)分布,可以看到,样点以表层土壤与湖泊表层沉积物为主,在各个纬度地带和气候区域均有分布(图1),可以用以分析宏观上正构烷烃氢同位素与环境因素的相关性。此外,收集中国大气降水同位素观测数据[数据引用自IAEA/WMO (current Year). Global Network of Isotopes in Precipitation. The GNIP Database. Accessible at:https://nucleus.iaea.org/wiser],计算其逐年年均降水氢同位素值,去除缺失年份数据,获得数据239条,用于分析大气降水同位素规律。

表1   东亚季风区表层沉积物正构烷烃氢同位素数据汇总清单

Table 1  Summary of the studies in δDwax of surface sediments in east Asia monsoon regions

序号表层沉积物有效样本数/个参考文献
1土壤41[33]
2湖泊12[35]
3泥炭7[37]
4土壤34[38]
5湖泊21[41]
6湖泊22[42]
7土壤54[43]
8土壤61[44]
9土壤38[45]

新窗口打开| 下载CSV


图1

图1   东亚季风区表层沉积物正构烷烃氢同位素数据年均降水量分布(a)和干旱区分布(b)统计图

Fig.1   Histogram of the local climate condition (a) annual precipitation and (b) distribution of Aridity Index of δDwax of surface sediments in east Asia monsoon regions


分析样点正构烷烃氢同位素值与年均降水氢同位素值的相关性如图2a所示,可以看出,两者之间呈现出较好的相关性(相关系数r=0.6468,p<0.05),且这种线性相关在各个降水梯度上均有体现。这与前人的研究结果一致1030。计算样点拟合残差ei=δDpi-δDp-regression,iδDpi指样点降水同位素观测值,δDp-regression,i指依据正构烷烃氢同位素值与降水氢同位素值拟合关系的计算值),统计拟合残差与本地干旱指数的的分布,从统计箱式图(图2b)可以看出,拟合残差在不同干旱条件下的差异主要集中在湿润区与干旱区之间。使用单因素非参数方差分析及事后检验(K-W检验、Dunnett's t检验)对分析不同气候区样点回归残差值的差异性,同样观察到湿润区、半湿润区与干旱区、半干旱区的明显差别(图2c),而干旱区和半干旱区之间,或湿润区和半湿润区之间,未表现出按干旱程度划分的差别(p<0.05)。因此在下文中,将对总体样本/干旱区、半干旱区样本分别进行分析。

图2

图2   正构烷烃氢同位素—年均大气降水氢同位素回归分析(a)及不同气候区间差异分析(b,c

(a)正构烷烃氢同位素值—降水氢同位素值相关分析(显著性水平为0.05);(b)不同气候区回归残差箱式图(中心线为中位数,中心点为平均值,箱体为四分位距,箱外线为1.5倍中位距,箱外点为异常值);(c)不同气候区回归残差组间K-W及Dunnett’s t差异检验

Fig.2   Correlation analysis of δDwax and δDp (a) and their variations in different climate zone (b,c)

(a) Correlation analysis of δDwax and δDp (significant level: p< 0.05);(b) Box plot of ei in different climate zone (middle line is the median,middle point is the mean value,the box is the interquartile range,the line outside the box is the 1.5 times interquartile range,and the point outside the box is the abnormal value);(c) K-W & Dunnett's t test of ei in different climate zone


分析全样本与非湿润区样本,其各自的正构烷烃氢同位素值、表观分馏值与本地干旱指数的关系。由图3可以看出,无论是全样本数据或干旱半干旱区样本数据,在0.05的显著性水平下,表观分馏值与年均降水量(全样本r=0.54,干旱区r=0.32)、干旱指数(全样本r=0.50,干旱区r=0.31)的关系均较为明显;但正构烷烃氢同位素与年均降水量、干旱指数的关系则有所不同:对于全样本数据,表土正构烷烃的氢同位素值,与年均降水量(r=0.13)、干旱指数(r=0.17)的相关性都较低(图3b,d);而在干旱区和半干旱区样点,正构烷烃氢同位素值与年均降水量(r=0.32)、干旱指数(r=0.28)的相关性均比全样本数据更高(图3a,c)。与正构烷烃氢同位素类似,大气降水氢同位素年均观测值与年均降水量、干旱指数的相关性,也表现出在全样本与干旱半干旱区样本之间的差异(图3)。这可能指示,正构烷烃氢同位素对气候的指示意义具有空间差异,在非湿润区对环境湿度具有较好的指示意义。对此将在下一节进行更详细的讨论。

图3

图3   大气降水氢同位素值、正构烷烃氢同位素值、表观分馏值与年均降水量、干旱指数的干旱半干旱区样本(a,c)、全样本(b,d)相关分析图(*表示p< 0.05

Fig.3   Correlation analysis of δDpδDwax and εapp of precipitation (P) and Aridity Index (AI) in arid-semiarid regions (a,c) and all regions (b,d) (* indicates p< 0.05


2.3 正构烷烃氢同位素的气候指示意义

如前文所述,决定δDwax值的主要因素,包括大气降水同位素值、土壤水分蒸发与植物蒸腾作用,以及植物种属或生理合成作用。因此,需要从正构烷烃氢同位素对降水同位素的指示、对蒸发作用的指示以及对植被组成和植物生理合成作用的指示三方面评判正构烷烃氢同位素的环境指示意义。

首先,从图3a可以看到,降水同位素值与正构烷烃氢同位素值之间具有显著的相关性。这与前人的结论一致,即降水同位素值是影响正构烷烃氢同位素值的最主要因素10293049。基于现代降水同位素观测、石笋等降水同位素的代用指标以及耦合同位素气候模式的研究结果显示,在东亚季风区,降水同位素值的偏负/偏正在大空间尺度上指示着季风强度的增强/减弱,其与局地干湿程度变化的关系可能存在空间的差异50~53。例如,在太阳辐射增强或大西洋翻转流活动增强的背景下,由于海陆热力差异的增强、大气能量增加,季风活动增强、西风急流北抬5354;伴随着这种大气环流的变化,东亚季风的主要水汽源区印度季风区降水增加、水汽同位素值偏负,引发泛亚州季风区整体的同位素值偏负,并表现出同位素值变化与本地降水变化之间关系的空间差异性53。在我国,在位于季风边缘地带的北方地区,处于水汽输送的末端,大气降水的氢氧同位素的偏负程度与季风强度、本地降水量相关52~55;而在南方地区,本地降水量/湿度与降水同位素的关系并不清晰5152。这解释了季风主导的湿润半湿润区—干旱半干旱区在正构烷烃氢同位素值—降水同位素值拟合关系上的差异,指示着在季风控制的干旱半干旱区正构烷烃氢同位素对区域湿度的指示意义更强(图3a和c)。

其次,干旱程度的增加会增强蒸发作用,使得植物利用水分的δD值更加偏正,最终使得正构烷烃δD值偏正10。从图3可以看出,无论在湿润区或非湿润区,正构烷烃氢同位素与降水同位素之间的表观分馏值均表现出与年均降水量、干旱指数之间的相关性,这表明了蒸发作用的影响并未表现出明显的湿润区/非湿润的差别。在前人的研究中,蒸发作用对正构烷烃氢同位素的影响存在争议。有研究认为,在某些地区,降水同位素的变化不能解释正构烷烃氢同位素值的变化,蒸发作用是控制正构烷烃氢同位素值的主要因素22,这种效应,可能在干旱地区尤为显著46。但从本文的汇总分析看,蒸发作用的影响并未改变正构烷烃氢同位素对降水同位素的指示。在干旱半干旱区,蒸发作用与降水同位素变化的影响,对于正构烷烃氢同位素值变化的影响可能是同向的;使得最终在干旱半干旱,正构烷烃氢同位素值与年降水量、干旱指数表现出比全样本更高的相关性(图3a和c)。

最后,现代植物观测研究显示,不同植物类型的表观分馏值具有一定的差异,植被组成可能对正构烷烃氢同位素具有重要影响103056。例如,灌木与乔木间存在约50‰的表观分馏值差异,而乔木与非禾本草类之间表观分馏值差异并不明显;禾本草类中,按照光合作用途径的不同,C3途径与C4途径植物存在约15‰的表观分馏值差异1030。也有对表层沉积物的研究认为,在某些研究区,C3/C4禾本科植物比例的变化,是正构烷烃氢同位素变化的主要影响因素47。但对表土数据综合分析的结果看,相比于降水同位素或本地蒸发作用,植被组成对正构烷烃氢同位素的影响比较有限29

综上所述,正构烷烃氢同位素值直接指示着降水同位素。东亚季风区中,在湿润半湿润区,由于降水同位素与本地降水量的复杂关系,正构烷烃氢同位素对环境湿度的指示意义并不显著;在干旱半干旱区,湿度变化与降水氢同位素值、蒸发作用的变化可能是同向的,即正构烷烃δD值的偏正,指示着本地降水的减少、干旱程度的增加,正构烷烃δD值的偏负,指示着本地降水的增加、干旱程度的减弱。

3 叶蜡正构烷烃氢同位素在半干旱区古环境研究中的应用

在我国,叶蜡正构烷烃氢同位素在泥炭57~60、湖泊沉积物61~67、海洋沉积物6869中已有较多研究,而对半干旱区风成黄土的研究数量较少、时间尺度较短870~72。现有的黄土正构烷烃氢同位素序列研究,从植被演替角度、区域蒸发等角度讨论了正构烷烃氢同位素的指示意义870~72,缺少指标间的检验与区域上的长序列对比。本文从东亚季风区代表性剖面的多指标对比结果、正构烷烃氢同位素长序列记录两方面,分析了正构烷烃氢同位素在不同时间尺度上对半干旱区区域湿度的指示意义。

3.1 区域指标的对比检验

在长时间尺度环境变化研究中,不同指标间的对比检验可以明确其指示意义。在位于陕北榆林的镇北台黄土剖面,处于沙漠—黄土的交接地带、东亚季风边缘地带,对气候变化的响应十分敏感,是开展多指标古气候分析的良好地点。镇北台剖面已有全新世正构烷烃氢同位素、有机碳同位素、有机碳含量、环境磁学、粒度等多种指标的变化序列对比73,可以看到,磁化率、粒度、有机碳含量、有机碳同位素、环境磁学指标(非磁滞剩磁与饱和等温剩磁的比值,χarm/SIRM)指示着4 ka前的湿润期,而正构烷烃氢同位素记录着6 ka以来气候逐渐干旱化的过程(图4)。指标间的差异来自于其受环境影响的机制的差异。例如,磁化率和χarm/SIRM,其强度变化与土壤发育过程中磁性矿物的生成、转化、保存有关,在成土过程中磁性的增强,主要由于成土母质通过化学、生物过程生成强磁性的磁铁矿、磁赤铁矿的增强,而难以将成土过程中气候的影响与母质、排水性、生物活动等因素的影响区分开575。黄土中粒径组成包括2 μm左右的细粒物质与63 μm左右的粗颗粒物质,前者来自于土壤发育过程或是高层气流搬运的物质,后者来自于冬季风下低空搬运的粉尘,因此粒度反映了冬季风/夏季风的综合影响,与区域气候间接相关7677。而土壤有机质含量与碳同位素,直接反映着植被有机质的输入量和植被类型,高有机质含量指示植物丰度的增加,而碳同位素的变化在不同纬度、C3/C4植被类型下对温度、降水的响应不同78,在镇北台剖面,较小的碳同位素波动可能并非气候驱动的植被类型变化,而是植物对温度变化的响应79

图4

图4   黄土—沙漠交错带镇北台剖面黄土序列多指标互检结果

磁化率、粒度、有机碳含量、碳同位素数据来自参考文献[73],正构烷烃氢同位素、χarm/SIRM数据来自梁承弘等未发表数据,沙丘固定概率来自参考文献[74]

Fig.4   Comparison of multiple proxies results in ZBT section which is located in the desert-loess transition zone,North China

MS, grain size, TOC, and δ13CTOC are cited from reference [73]. Leaf wax n-alkanes δD and χarm/SIRM are Liang Chenghong, Thesis of Master Degree, Nanjing University (2020). The probability of sand dune stabilization is cited from reference [74]


因此,以上传统指标所呈现的4 ka前后的气候转型,与区域风沙活动在6 ka前后开始增强、沙丘固化减弱74的结论并不一致,可能的原因在于传统指标未能区分环境演化中的温度与降水信号,对本地湿度变化的指示意义不强。而本地正构烷烃氢同位素表现出6 ka后快速偏正的趋势,指示着本地湿度的减弱,与本地风沙活动的记录更加一致。其原因在于,如前文分析的,正构烷烃氢同位素在非湿润区主要受降水同位素变化与蒸发作用的强度影响,且两者的影响具有同向性;正构烷烃氢同位素的偏正/偏负,直接指示着降水同位素的偏正/偏负、蒸发作用的增强/减弱,与本地湿度具有直接关联。因此,相比于其他传统指标,正构烷烃氢同位素对区域湿度变化具有更明确的指示意义。

3.2 对长尺度气候旋回上湿度变化的指示

风成黄土是第四纪气候变化的重要记录,黄土—古土壤序列磁化率变化与深海氧同位素记录具有一致性,且指示着第四纪的冰期—间冰期季风气候交替80。目前,现有的半干旱区正构烷烃氢同位素研究,集中在末次冰盛期以来的湖泊记录646567和全新世的泥炭565859、黄土记录871,在中国黄土高原、中亚黄土地区已有一些轨道尺度的正构烷烃氢同位素研究结果707281。不同于传统指标记录的显著的10万年太阳辐射偏心率周期,新的正构烷烃氢同位素研究结果表现出明显的2万年岁差周期(图5)。正构烷烃氢同位素表现为对太阳辐射变化的直接响应,在太阳辐射较强的时期,正构烷烃氢同位素更加偏负,指示着区域湿度的增大。这种与石笋氧同位素记录的相似的特性,指示着太阳辐射驱动对季风演化的重要作用8384。传统的米兰科维奇理论认为,北半球高纬辐射量控制着陆地冰量,进而通过大洋环流影响全球气候。因此,在深海氧同位素、黄土—古土壤磁化率中,均表现出明显的高纬辐射的偏心率10万年周期8586。但是,相比于偏心率周期,2万年的岁差周期具有更大幅度的辐射量波动、在低纬地区表现更加显著,且岁差周期通过远日点/近日点的变化影响太阳辐射的季节性差异,与低纬地区大气、季风活动关系更加密切8788。而从变幅上看,正构烷烃氢同位素记录均表现出约30‰的变幅,石笋氧同位素记录表现出约4‰的变幅,两者符合现代大气降水线的比例关系(δD=8δ18O+1089),这说明两者一致指示着太阳辐射通过季风活动控制区域湿度的变化。

图5

图5   东亚季风区半干旱区轨道尺度正构烷烃氢同位素记录

(a)35°N7月太阳辐射[82];(b)黄土高原西峰剖面正构烷烃氢同位素记录[72];(c)黄土高原蓝田、渭南剖面叶蜡脂肪酸氢同位素记录[70](叶蜡脂肪酸与叶蜡正构烷烃合成过程、氢同位素分馏机制基本一致);(d)三宝洞石笋氧同位素记录[83]

Fig.5   Examples of orbital timescales n-alkanes δD records in semiarid regions of east Asia monsoon regions

(a) The July insolation of north hemisphere 35°[82]; (b) n-alkanes δD of Xifeng loess section in Chinese Loess Plateau[72]; (c) n-fatty acid δD of Lantian and Weinan loess section in Chinese Loess Plateau[70] (the production and isotope fraction of n-fatty acid are similar to n-alkanes); (d) Speleothem δ18O of Sanbao Cave[83]


4 结 语

本文总结了正构烷烃氢同位素作为区域湿度替代指标的原理与机制,并梳理了其在东亚季风半干旱区风成黄土记录中的应用。可以看到,由于正构烷烃氢同位素相对明确的合成过程与分馏机制,相比于其他传统古气候替代指标具有更明确的气候指示意义。另一方面,将正构烷烃氢同位素记录与其他记录结合,依据水循环过程中的同位素分馏方程建立模型,可以定量重建区域相对湿度变化,进而为气候模式提供重要参照9091。因此,沉积物正构烷烃氢同位素是极具潜力的古气候、古环境重建代用指标,在干旱半干旱区环境演变中将发挥重要作用。

本文的研究也指出,正构烷烃氢同位素对环境湿度的指示效果,存在明显的区域差异,这反映了对降水同位素指示意义、本地蒸发过程的、植被演化与生物分馏的机制三方面问题认识不足。在未来,需要从这三方面出发,加强对现代过程的研究,以进一步明确不同气候背景下沉积物正构烷烃氢同位素的指示意义。

参考文献

DING YihuiREN GuoyuSHI Guangyuet al.

National assessment report of climate change (Ⅰ): Climate change in China and its future trend

[J]. Advance in Climate Change Research,20061): 3-8.

[本文引用: 1]

丁一汇任国玉石广玉.

气候变化国家评估报告(Ⅰ):中国气候变化的历史和未来趋势

[J]. 气候变化研究进展,20061): 3-8.

[本文引用: 1]

HUANG JianpingCHEN WenWEN Zhipinget al.

Review of chinese atmospheric science research over the past 70 years: Climate and climate change

[J]. Science China Earth Sciences,2019491 607-1 640. DOI:10.1360/SSTe-2019-0125.

[本文引用: 1]

黄建平陈文温之平.

新中国成立70年以来的中国大气科学研究: 气候与气候变化篇

[J]. 中国科学:地球科学,2019491 607-1 640. DOI:10.1360/SSTe-2019-0125.

[本文引用: 1]

LUAN YihuaYU YongqiangZHENG Weipeng.

Review of development and application of high resolution global climate system model

[J]. Advances in Earth Science,2016313): 258-268.

[本文引用: 1]

栾贻花俞永强郑伟鹏.

全球高分辨率气候系统模式研究进展

[J]. 地球科学进展,2016313): 258-268.

[本文引用: 1]

TAPIADOR F JNAVARRO ALEVIZZANI Vet al.

Global precipitation measurements for validating climate models

[J]. Atmospheric Research,20171971-20.

[本文引用: 1]

DENG ChenglongLIU QingsongPAN Yongxinet al.

Environmental magnetism of chinese loess-paleosol sequences

[J]. Quaternary Research,20072): 193-209.

[本文引用: 2]

邓成龙刘青松潘永信.

中国黄土环境磁学

[J]. 第四纪研究,20072): 193-209.

[本文引用: 2]

ZHANG WenchaoLU HuayuLI Chunhaiet al.

Pollen preservation and its potential influence on paleoenvironmental reconstruction in chinese loess deposits

[J]. Review of Palaeobotany and Palynology,20172401-10.

[本文引用: 1]

Eglinton T IEglinton G.

Molecular proxies for paleoclimatology

[J]. Earth and Planetary Science Letters,20082751): 1-16.

[本文引用: 1]

LIU WeiguoHUANG Yongsong.

Compound specific D/H ratios and molecular distributions of higher plant leaf waxes as novel paleoenvironmental indicators in the Chinese Loess Plateau

[J]. Organic Geochemistry,2005366): 851-860.

[本文引用: 3]

XIE ShuchengCHEN FahuWANG Zhiyuanet al.

Lipid distributions in loess-paleosol sequences from northwest China

[J]. Organic Geochemistry,2003348): 1 071-1 079.

[本文引用: 1]

SACHSE DBILLAULT IBOWEN G Jet al.

Molecular paleohydrology: Interpreting the hydrogen-isotopic composition of lipid biomarkers from photosynthesizing organisms

[J]. Annual Review of Earth and Planetary Sciences,2012401): 221-249.

[本文引用: 14]

EGLINTON GHAMILTON R J.

Leaf epicuticular waxes

[J]. Science,19671563 780): 1 322-1 346.

[本文引用: 1]

SCHMIDT M W ITORN M SABIVEN Set al.

Persistence of soil organic matter as an ecosystem property

[J]. Nature,20114787 367): 49-56.

[本文引用: 2]

MURPHY D J. Plant lipids: Biology,utilisation and manipulation[M]. United StatesJohn Wiley & Sons2005.

[本文引用: 2]

LI JingjingHUANG Junhua

XIE Shucheng. Plant wax and its response to environmental conditions: An overview

[J]. Acta Ecologica Sinica,2011312): 565-574.

[本文引用: 1]

李婧婧黄俊华谢树成.

植物蜡质及其与环境的关系

[J]. 生态学报,2011312): 565-574.

[本文引用: 1]

YEATS T HROSE J K C.

The formation and function of plant cuticles

[J]. Plant Physiology,20131631): 5-20.

[本文引用: 1]

WANG DongyangSHAO ShujunJI Nanaet al.

Research advances on genes related to plant cuticular wax synthesis and secretion

[J]. Plant Physiology Journal,2016526): 789-798.

[本文引用: 1]

王东阳邵淑君季娜娜.

植物表皮蜡质合成与分泌基因研究进展

[J]. 植物生理学报,2016526): 789-798.

[本文引用: 1]

DENG Caixia. Plant physiology[M]. BeijingChinese Forestry Publishing Press2013.

[本文引用: 1]

邓彩霞. 植物生理学[M]. 北京中国林业出版社2013.

[本文引用: 1]

BUSH R TMCINERNEY F A.

Leaf wax n-alkane distributions in and across modern plants: Implications for paleoecology and chemotaxonomy

[J]. Geochimica et Cosmochimica Acta,2013117161-179.

[本文引用: 2]

ZHANG ZhaohuiZHAO MeixunEglinton Get al.

Leaf wax lipids as paleovegetational and paleoenvironmental proxies for the Chinese Loess Plateau over the last 170kyr

[J]. Quaternary Science Reviews,2006255/6): 575-594.

[本文引用: 1]

ZHOU BinWali GPeterse Fet al.

Organic carbon isotope and molecular fossil records of vegetation evolution in central Loess Plateau since 450 kyr

[J]. Science China Earth Sciences,2016596): 1 206-1 215.

[本文引用: 1]

LIU JianrongSONG XianfangYUAN Guofuet al.

Stable isotopic compositions of precipitation in China

[J]. Tellus B: Chemical and Physical Meteorology,2014661): 22 517-22 567.

[本文引用: 1]

DOUGLAS P M JPAGANI MBRENNER Met al.

Aridity and vegetation composition are important determinants of leaf-wax δD values in southeastern Mexico and Central America

[J]. Geochimica et Cosmochimica Acta,20129724-45.

[本文引用: 2]

SPRENGER MLEISTERT HGIMBEL Ket al.

Illuminating hydrological processes at the soil-vegetation-atmosphere interface with water stable isotopes

[J]. Reviews of Geophysics,2016543): 674-704.

[本文引用: 3]

CERNUSAK L ABARBOUR M MARNDT S Ket al.

Stable isotopes in leaf water of terrestrial plants

[J]. Plant,Cell & Environment,2016395): 1 087-1 102.

[本文引用: 4]

GAO LiHUANG Yongsong.

Inverse gradients in leaf wax δD and δ13C values along grass blades of Miscanthus sinensis: Implications for leaf wax reproduction and plant physiology

[J]. Oecologia,20131722): 347-357.

[本文引用: 1]

CORMIER MWERNER R ASAUER P Eet al.

2H-fractionations during the biosynthesis of carbohydrates and lipids imprint a metabolic signal on the δ2H values of plant organic compounds

[J]. New Phytologist,20182182): 479-491.

[本文引用: 2]

GAMARRA BKAHMEN A.

Concentrations and δ2H values of cuticular n-alkanes vary significantly among plant organs,species and habitats in grasses from an alpine and a temperate European grassland

[J]. Oecologia,20151784): 981-998.

[本文引用: 1]

LIU JinzhaoLIU WeiguoAN Zhisheng.

Insight into the reasons of leaf wax δD n-alkane values between grasses and woods

[J]. Science Bulletin,2015605): 549-555.

LIU JinzhaoAN Zhisheng.

A hierarchical framework for disentangling different controls on leaf wax-alkane δD values in terrestrial higher plants

[J]. Quaternary Science Reviews,2018201409-417.

[本文引用: 3]

LIU JinzhaoAN Zhisheng.

Variations in hydrogen isotopic fractionation in higher plants and sediments across different latitudes: Implications for paleohydrological reconstruction

[J]. Science of the Total Environment,2019650470-478.

[本文引用: 6]

SARANGI VKUMAR ASANYAL P.

Effect of pedogenesis on the stable isotopic composition of calcretes and n-alkanes: Implications for palaeoenvironmental reconstruction

[J]. Sedimentology,2018665): 1 560-1 579.

[本文引用: 1]

SACHSE DRADKE JGLEIXNER G.

Hydrogen isotope ratios of recent lacustrine sedimentary n-alkanes record modern climate variability

[J]. Geochimica et Cosmochimica Acta,20046823): 4 877-4 889.

[本文引用: 1]

RAO ZhiguoZHU ZhaoyuJIA Guodonget al.

Compound specific δD values of long chain n-alkanes derived from terrestrial higher plants are indicative of the δD of meteoric waters: Evidence from surface soils in eastern China

[J]. Organic Geochemistry,2009408): 922-930.

[本文引用: 2]

POLISSAR P JFREEMAN K H.

Effects of aridity and vegetation on plant-wax δD in modern lake sediments

[J]. Geochimica et Cosmochimica Acta,20107420): 5 785-5 797.

AICHNER BHERZSCHUH UWILKES Het al.

δD values of n-alkanes in Tibetan lake sediments and aquatic macrophytes—A surface sediment study and application to a 16ka record from Lake Koucha

[J]. Organic Geochemistry,2010418): 779-790.

[本文引用: 2]

GARCIN YSCHWAB V FGLEIXNER Get al.

Hydrogen isotope ratios of lacustrine sedimentary n-alkanes as proxies of tropical African hydrology: Insights from a calibration transect across Cameroon

[J]. Geochimica et Cosmochimica Acta,201279106-126.

HUANG XianyuMEYERS P AXUE Jiantaoet al.

Paleoclimate significance of n-alkane molecular distributions and δ2H values in surface peats across the monsoon region of China

[J]. Palaeogeography,Palaeoclimatology,Palaeoecology,201646177-86.

[本文引用: 2]

WANG ChaoranHren M THoke G Det al.

Soil n-alkane δD and Glycerol Dialkyl Glycerol Tetraether (GDGT) distributions along an altitudinal transect from southwest China: Evaluating organic molecular proxies for paleoclimate and paleoelevation

[J]. Organic Geochemistry,201710721-32.

[本文引用: 2]

DANIELS W CRUSSELL J MGIBLIN A Eet al.

Hydrogen isotope fractionation in leaf waxes in the Alaskan Arctic tundra

[J]. Geochimica et Cosmochimica Acta,2017213216-236.

Herrmann NBoom ACarr A Set al.

Hydrogen isotope fractionation of leaf wax n-alkanes in southern African soils

[J]. Organic Geochemistry,20171091-13.

TIAN QianFANG XiaominWANG Mingda.

Sedimentary n-alkanes record of precipitation D/H ratios in arid regions of the Tibetan Plateau

[J]. Chinese Science Bulletin,2017627): 700-710.

[本文引用: 2]

田茜方小敏王明达.

青藏高原干旱区湖泊正构烷烃氢同位素记录降水同位素

[J]. 科学通报,2017627): 700-710.

[本文引用: 2]

HOU JuzhiTIAN QianWANG Mingda.

Variable apparent hydrogen isotopic fractionation between sedimentary n-alkanes and precipitation on the Tibetan Plateau

[J]. Organic Geochemistry,201812278-86.

[本文引用: 1]

LI YangyangYANG ShilingLUO Panet al.

Aridity-controlled hydrogen isotope fractionation between soil n-alkanes and precipitation in China

[J]. Organic Geochemistry,201913353-64.

[本文引用: 1]

LIU WeiguoWANG HuanyeLENG Qinet al.

Hydrogen isotopic compositions along a precipitation gradient of Chinese Loess Plateau: Critical roles of precipitation/evaporation and vegetation change as controls for leaf wax δD

[J]. Chemical Geology,2019528119278.

[本文引用: 1]

LU JiayiZANG JingjieMeyers Pet al.

Surface soil n-alkane molecular and δD distributions along a precipitation transect in northeastern China

[J]. Organic Geochemistry,2020. DOI:10.1016/j.orggeochem.2020.104015.

[本文引用: 2]

Struck JBliedtner MStrobel Pet al.

Leaf waxes and hemicelluloses in topsoils reflect the δ2H and δ18O isotopic composition of precipitation in mongolia

[J]. Frontiers in Earth Science,20208343. DOI:10.3389/feart.2020.00343.

[本文引用: 2]

Bowen G JRevenaugh J.

Interpolating the isotopic composition of modern meteoric precipitation

[J]. Water Resources Research,20033910). DOI: 10.1029/2003WR002086.

[本文引用: 2]

Zomer R JTrabucco ABossio D Aet al.

Climate change mitigation: A spatial analysis of global land suitability for clean development mechanism afforestation and reforestation

[J]. Agriculture,Ecosystems & Environment,20081261/2):67-80.

[本文引用: 2]

HOU JuzhiAndrea W J DHUANG Yongsong.

Can sedimentary leaf waxes record D/H ratios of continental precipitation? Field,model,and experimental assessments

[J]. Geochimica et Cosmochimica Acta,20087214): 3 503-3 517.

[本文引用: 1]

CHENG HaiAI SibenWANG Xianfenget al.

Oxygen isotope records of stalagmites from southern China

[J]. Quaternary Research,20052): 157-163.

[本文引用: 1]

程海艾思本王先锋.

中国南方石笋氧同位素记录的重要意义

[J]. 第四纪研究,20052): 157-163.

[本文引用: 1]

CHENG HaiZHANG HaiweiZHAO Jingyaoet al.

Chinese stalagmite paleoclimate researches: A review and perspective

[J]. Science China Earth Sciences,20194910): 1 565-1 589.

[本文引用: 1]

程海张海伟赵景耀.

中国石笋古气候研究的回顾与展望

[J]. 中国科学:地球科学,20194910): 1 565-1 589.

[本文引用: 1]

ZHANG HaiweiAit Brahim YLI Hanyinget al.

The Asian Summer Monsoon: Teleconnections and forcing mechanisms—A review from chinese speleothem δ18O Records

[J]. Quaternary,2019226.

[本文引用: 2]

HE ChengfeiLIU ZhenyuOtto-Bliesner B Let al.

Hydroclimate footprint of pan-Asian monsoon water isotope during the last deglaciation

[J]. Science Advances,202174): e2611. DOI:10.1126/sciadv.abe2611.

[本文引用: 3]

LIU ZhenyuWEN XinyuBrady E Cet al.

Chinese cave records and the East Asia summer monsoon

[J]. Quaternary Science Reviews,201483115-128.

[本文引用: 1]

TAN LiangchengLI YanzhenWANG Xiqianet al.

Holocene monsoon change and abrupt events on the western Chinese Loess Plateau as revealed by accurately dated stalagmites

[J]. Geophysical Research Letters,20204721). DOI:10.1029/2020GL090273.

[本文引用: 1]

HUANG XianyuMEYERS P A.

Assessing paleohydrologic controls on the hydrogen isotope compositions of leaf wax n-alkanes in chinese peat deposits

[J]. Palaeogeography,Palaeoclimatology,Palaeoecology,2019516354-363.

[本文引用: 2]

CHEN QingminZHOU WeijianWANG Zheet al.

Holocene precipitation records from Inner Mongolia derived from hydrogen isotope compositions of sediment fatty acids

[J]. Radiocarbon,2019611): 51-65.

[本文引用: 1]

HUANG XianyuPancost R DXUE Jiantaoet al.

Response of carbon cycle to drier conditions in the mid-Holocene in central China

[J]. Nature Communications,201891). DOI:10.1038/s41467-018-03804-w.

[本文引用: 1]

Seki OMeyers P AYamamoto Set al.

Plant-wax hydrogen isotopic evidence for postglacial variations in delivery of precipitation in the monsoon domain of China

[J]. Geology,2011399): 875-878.

[本文引用: 1]

WANG XinxinHUANG XianyuSachse Det al.

Molecular paleoclimate reconstructions over the last 9 ka from a peat sequence in south China

[J]. PLoS One,2016118): e160934. DOI:10.1371/journal.pone.0160934.

[本文引用: 1]

Aichner BFeakins S JLee J Eet al.

High-resolution leaf wax carbon and hydrogen isotopic record of the late Holocene paleoclimate in arid central Asia

[J]. Climate of the Past,2015114): 619-633.

[本文引用: 1]

Günther FWitt RSchouten Set al.

Quaternary ecological responses and impacts of the Indian ocean summer monsoon at Nam No,southern Tibetan Plateau

[J]. Quaternary Science Reviews,201511266-77.

HOU JuzhiD'Andrea W JWANG Mingdaet al.

Influence of the Indian monsoon and the subtropical jet on climate change on the Tibetan Plateau since the late Pleistocene

[J]. Quaternary Science Reviews,201716384-94.

RAO ZhiguoJIA GuodongLI Yunxiaet al.

Asynchronous evolution of the isotopic composition and amount of precipitation in north China during the Holocene revealed by a record of compound-specific carbon and hydrogen isotopes of long-chain n-alkanes from an alpine lake

[J]. Earth and Planetary Science Letters,201644668-76.

[本文引用: 1]

LIU WeiguoLIU HuWANG Zhenget al.

Hydrogen isotopic compositions of long-chain leaf wax n-alkanes in Lake Qinghai sediments record palaeohydrological variations during the past 12 ka

[J]. Quaternary International,201744967-74.

[本文引用: 1]

Thomas E KHUANG YongsongClemens S Cet al.

Changes in dominant moisture sources and the consequences for hydroclimate on the northeastern Tibetan Plateau during the past 32 kyr

[J]. Quaternary Science Reviews,2016131157-167.

ZHANG CanZHAO ChengYU Zichenget al.

Western Pacific Ocean influences on monsoon precipitation in the southwestern Chinese Loess Plateau since the mid-Holocene

[J]. Climate Dynamics,2020545): 3 121-3 134.

[本文引用: 2]

HUANG EnqingCHEN YunruSchefuß Eet al.

Precession and glacial-cycle controls of monsoon precipitation isotope changes over East Asia during the Pleistocene

[J]. Earth and Planetary Science Letters,20184941-11.

[本文引用: 1]

Thomas E KClemens S CPrell W Let al.

Temperature and leaf wax delta H-2 records demonstrate seasonal and regional controls on Asian monsoon proxies

[J]. Geology,20144212): 1 075-1 078.

[本文引用: 1]

Thomas E KClemens S CSUN Youbinet al.

Heterodynes dominate precipitation isotopes in the East Asian monsoon region,reflecting interaction of multiple climate factors

[J]. Earth and Planetary Science Letters,2016455196-206.

[本文引用: 5]

LI YangyangYANG ShilingXIAO Juleet al.

Hydrogen isotope ratios of leaf wax n-alkanes in loess and floodplain deposits in northern China since the Last Glacial Maximum and their paleoclimatic significance

[J]. Palaeogeography,Palaeoclimatology,Palaeoecology,201850991-97.

[本文引用: 1]

WANG ZhengAN ZhishengLIU Zhonghuiet al.

Hydroclimatic variability in loess δD wax records from the central Chinese Loess Plateau over the past 250 ka

[J]. Journal of Asian Earth Sciences,201815549-57.

[本文引用: 5]

LU HuayuYI ShuangwenLIU Zhenyuet al.

Variation of East Asian monsoon precipitation during the past 21 k.y. and potential CO2 forcing

[J]. Geology,2013419): 1 023-1 026.

[本文引用: 3]

XU ZhiweiMason J AXU Chiet al.

Critical transitions in chinese dunes during the past 12,000 years

[J]. Science Advances,202069): p.

eaay

8020. DOI:10.1126/sciadv.aay8020.

[本文引用: 3]

HU PengxiangLIU Qingsong.

The production and transformation of magnetic minerals during pedogenesis and its paleoclimate significance

[J]. Quaternary Sciences,2014343): 458-473.

[本文引用: 1]

胡鹏翔刘青松.

磁性矿物在成土过程中的生成转化机制及其气候意义

[J]. 第四纪研究,2014343): 458-473.

[本文引用: 1]

LU HuayuAN Zhisheng.

Paleoclimate significance of grain size distribution of loess in Chinese Loess Plateau

[J]. Science China Earth Sciences,19983): 278-283.

[本文引用: 1]

鹿化煜安芷生.

黄土高原黄土粒度组成的古气候意义

[J]. 中国科学:D辑,19983): 278-283.

[本文引用: 1]

SUN DonghuaiLU HuayuDavid Ret al.

Bimode grain -size distribution of chinese loess and its paleoclimate implication

[J]. Acta Sedimentologica Sinica, 2000183): 327-335.

[本文引用: 1]

孙东怀鹿化煜David R.

中国黄土粒度的双峰分布及其古气候意义

[J]. 沉积学报,2000183): 327-335.

[本文引用: 1]

RAO ZhiguoGUO WenkangCAO Jiantaoet al.

Relationship between the stable carbon isotopic composition of modern plants and surface soils and climate: A global review

[J]. Earth-Science Reviews,2017165110-119.

[本文引用: 1]

LU HuayuZHANG HongyanZENG Linet al.

Temperature forced vegetation variations in glacial-interglacial cycles in northeastern China revealed by loess-paleosol deposit

[J]. Quaternary Sciences,2015354): 828-836.

[本文引用: 1]

鹿化煜张红艳曾琳.

温度影响东北地区更新世植被变化的黄土记录

[J]. 第四纪研究,2015354): 828-836.

[本文引用: 1]

HELLER FLIU Dongsheng.

Palaeoclimatic and sedimentary history from magnetic susceptibility of loess in China

[J]. Geophysical Research Letters,19861311): 1 169-1 172.

[本文引用: 1]

HÄGGI CEGLINTON T IZECH Wet al.

A 250 ka leaf-wax δD record from a loess section in Darai Kalon,Southern Tajikistan

[J]. Quaternary Science Reviews,2019208118-128.

[本文引用: 1]

LASKAR JROBUTEL PJOUTEL Fet al.

A long-term numerical solution for the insolation quantities of the Earth

[J]. Astronomy & Astrophysics,20044281): 261-285.

[本文引用: 2]

CHENG HaiEDWARDS R LSINHA Aet al.

The Asian monsoon over the past 640,000 years and ice age terminations

[J]. Nature,2016534640-646.

[本文引用: 3]

WANG YongjinCHENG HaiEdwards R Let al.

The Holocene Asian Monsoon: Links to solar changes and North Atlantic climate

[J]. Science,20053085 723): 854-857.

[本文引用: 1]

LIU DongshengDING Zhongli.

Chinese loess and the paleomonsoon

[J]. Annual Review of Earth and Planetary Sciences,199826111-145.

[本文引用: 1]

LISIECKI L ERAYMO M E.

A Pliocene-Pleistocene stack of 57 globally distributed benthic δ18O records

[J]. Paleoceanography,2005201). DOI:10.1029/2004PA001071.

[本文引用: 1]

LU HuayuWANG Yao.

What caused the ice age?

[J]. Chinese Science Bulletin,20166111): 1 164-1 172.

[本文引用: 1]

鹿化煜王珧.

触发和驱动第四纪冰期的机制是什么?

[J]. 科学通报,20166111): 1 164-1 172.

[本文引用: 1]

WANG Pinxian.

Orbital forcing of the low-latitude processes

[J]. Quaternary Research,2006265): 694-701.

[本文引用: 1]

汪品先.

低纬过程的轨道驱动

[J]. 第四纪研究,2006265): 694-701.

[本文引用: 1]

CRAIG H.

Isotopic variations in meteoric waters

[J]. Science,19611333 465): 1 702-1 703.

[本文引用: 1]

RACH OKAHMEN ABRAUER Aet al.

A dual-biomarker approach for quantification of changes in relative humidity from sedimentary lipid D/H ratios

[J]. Climate of the Past,2017137): 741-757.

[本文引用: 1]

KONECKY BDEE S GNOONE D C.

WaxPSM: A forward model of leaf wax hydrogen isotope ratios to bridge proxy and model estimates of past climate

[J]. Journal of Geophysical Research: Biogeosciences,20191247): 2 107-2 125.

[本文引用: 1]

/