共查询到18条相似文献，搜索用时 125 毫秒
1.
《中国科学:地球科学》2016,(2)
过去温度变化的定量记录对于深入探讨气候变化机制非常重要,不仅有助于检验并改善气候模式模拟的准确性,也可以为全球变化背景下的气候变化幅度提供参考.青藏高原由于其特殊的地理位置影响着大气环流格局,研究青藏高原气候变化有助于理解高原对全球气候变化的响应及其与全球气候系统之间的关系.生物标志化合物代用指标在气候变化研究中的应用为定量重建高原过去温度变化提供了可能.湖泊沉积物中甘油二烷基甘油四醚类化合物(GDGTs)来源相对复杂,其分布特征受多种气候与环境因素影响.本文对青藏高原27个湖泊表层沉积物及部分湖泊流域表土样品GDGTs进行分析,探讨湖泊表层沉积物中GDGTs分布特征的影响因素,并建立其与气候要素的定量关系.结果显示:(1)绝大多数湖泊表层沉积物GDGTs以b GDGTs为主,crenarchaeol和GDGT-0含量较低;(2)高原多数湖泊表层沉积物与表土GDGTs分布没有显著差异,表明i GDGTs可能同时来源于湖泊环境和陆源输入;(3)湖泊表层沉积物i GDGTs分布主要受湖水水化学要素(p H和盐度)及近地表大气年均温的影响,对于青藏高原小型湖泊,TEX86可能反映湖水p H的变化;(4)湖泊表层沉积物b GDGTs分布主要受气候要素(温度和降水)控制;(5)利用已发表的转换方程重建高原同一地区温度差异明显,因此利用GDGTs定量重建青藏高原过去气候前必须开展GDGTs的现代过程调查.本研究基于湖泊表层沉积物b GDGTs分布,分别利用代用指标(MBT,CBT)及不同b GDGTs化合物组分丰度(fabun)与湖泊所在地的年均气温(MAAT)建立了适用于青藏高原湖泊古气候研究的转换方程,为高原古气候定量重建提供研究基础. 相似文献
2.
甘油二烷基甘油四醚脂(GDGTs)是目前生物地球化学研究的热点之一.与GDGTs有关的指标已成功地应用在海洋环境中有关来源判识和古环境古气候重建的研究,但是在湖泊环境中的应用目前还比较有限.通过开展巢湖柱状沉积物中GDGTs的组成测定,为GDGTs类脂分子标志物在湖泊系统中的应用提供依据.研究表明由柱状沉积物中支链GDGTs参数计算得到的量化结果与巢湖周围流域的环境温度、pH等历史记录能较好地吻合;柱状沉积物中类异戊二烯类GDGTs来源的不确定性可能是造成TEX_(86)指标的量化结果和实际的水体温度出现较大偏差的重要原因.另外,沉积物中GDGTs指标和TOC、C/N、δ~(13)C_(org)、δ~(15)N等传统湖泊总体有机质参数以及其它分子标志物指标相比,具有高分辨性和抗干扰等特点.因此,湖泊中GDGTs有望成为湖泊古气候和古环境重建的重要指标. 相似文献
3.
《中国科学:地球科学》2016,(2)
湖泊沉积物中甘油二烷基甘油四醚化合物(GDGTs)在记录陆地古气候方面有着重要作用.然而,这些化合物,尤其是细菌支链GDGTs(bGDGTs)异构体(5-,6-甲基bGDGTs)在中国不同酸碱性湖泊中的分布及其影响因素仍未可知.本文通过对碱酸度不同的湖泊进行对比,并结合其他环境变量,调查了GDGTs各类化合物在中国中东部湖泊系统和西南酸性青海中的分布特征及其影响因素.结果表明,湖水含氧量能够影响湖泊古菌群落结构,从而影响古菌iGDGTs的分布.GDGT-0/crenarchaeol比值随着含氧量降低而增高,表明厌氧的产甲烷古菌或混杂型泉古菌(MCG)与奇古菌相对含量受控于湖水含氧量.含氧量较低的湖泊奇古菌贡献GDGTs化合物比例较小,四醚指数TEX_(86)不能用来重建表层湖水温度.与土壤不同的是,湖水pH并不会影响古菌iGDGTs和细菌bGDGTs的相对含量,但在单一湖泊,如腾冲青海中,古菌与细菌的相对含量(R_(ilb))与水深相关.虽然这些湖泊中细菌bGDGTs的甲基化指数(MBT')与年均大气温度(MAT)和pH(或年均降雨量)相关,环化指数(CBT)仅与pH相关,但基于5-甲基bGDGTs的MBT'_(5ME)与MAT的关系并不明显,反而是表征6-甲基bGDGTs甲基化程度的MBT'_(6ME)与MAT更相关.与全球土壤相似,湖泊中5-,6-甲基bGDGTs的相对含量也主要受pH影响.因此,6-甲基bGDGTs的相对含量(IR)或CBT'可以作为潜在的湖泊pH计.但在较小pH梯度下,IR和CBT'两个指标可能受其他环境因子,如温度等的影响. 相似文献
4.
青藏高原东北部青海湖距今12ka以来的四醚指标BIT记录:对古环境重建的启示 总被引：1，自引：0，他引：1
《中国科学:地球科学》2016,(2)
早期的研究认为湖泊沉积物中的支链GDGTs(b GDGTs)主要来自陆地土壤细菌,而奇古菌醇由水生奇古菌产生,因此湖泊中表示b GDGTs与奇古菌醇比值的BIT指标可用于衡量陆源有机质的输入程度.然而越来越多的研究表明,湖泊环境中普遍存在着自生的b GDGTs,这样,湖泊沉积物中的BIT指标可能不能用来指示陆源物质输入.尽管如此,最近对非洲Challa湖的研究表明BIT仍可作为一个有效的古水文指标,但是在不同的湖泊中BIT对古水文变化的响应可能有所不同.本文调查了距今12 ka以来青海湖沉积物中的BIT及其相关GDGTs含量的变化.结合已发表的表层样品数据发现,青海湖沉积物中BIT的变化主要反映了奇古菌醇含量的变化,而不是细菌b GDGTs含量的变化.在青海湖中,由于奇古菌醇含量与水深正相关,因此BIT与水深负相关.这与Challa湖BIT与湖面或降雨正相关的情况相反,表明不同湖泊中BIT对水文变化的响应有所差异.因而在应用BIT重建特定湖泊古水文变化时,需要先确定控制其沉积物BIT值的主要因素. 相似文献
5.
目前,甘油二烷基甘油四醚(GDGTs)组成和分布特征已被成功应用于古气候古环境重建中。然而,越来越多的研究表明除温度和pH值外,GDGTs也受其他环境因素影响,这导致了在同一地区运用多种温度和pH校准公式得到的结果差异较大,特别是在干旱地区尤为显著。因此,有必要开展现代过程GDGTs分布及其影响因素的调查,以提高温度和pH校准公式的适用性。为此,我们以北方察汗淖尔湖泊为中心,分析流域内24个湖泊沉积物和土壤GDGTs组成和分布。结果显示,所有样品GDGTs分布模式相似,其中古菌类异戊二烯GDGTs(简称isoGDGTs)以crenarchaeol为主,GDGT-0次之,crenarchaeol’含量较低,指示GroupⅠ.1b型奇古菌输入较多;细菌支链GDGTs(简称brGDGTs)中五甲基化brGDGTs丰度最高,其次是六甲基化和四甲基化brGDGTs。群落指数(community index,CI)表明,产brGDGTs的细菌群落属于冷簇,且冗余分析显示pH值对brGDGTs分布影响显著,二者可能共同导致了应用多种校准公式计算结果与器测记录之间的差异。通过该项工作我们认为在利用GD... 相似文献
6.
甘油二烷基甘油四醚化合物(GDGTs)是陆地和海洋环境中古环境和生态定量重建的重要工具.目前对陆地土壤GDGTs的研究主要集中在相对暖湿和冷干气候区,冷湿条件下GDGTs对环境的响应尚不清晰.基于此,本文选取具有冷湿气候条件的长白山作为主要研究对象,探究长白山不同海拔土壤GDGTs的分布特征及相关指标对环境的响应.结果表明,长白山冷湿气候条件下,由古菌iso GDGTs分布反映的长白山不同海拔土壤古菌群落结构发生了显著变化,古菌群落结构对温度指标TEX_(86)产生影响;此外,温度季节性对TEX_(86)的影响也较为显著.细菌5-甲基br GDGTs的甲基化指数MBT′_(5me)及MBT_(5/6)与土壤含水量具有一定的相关性而与温度关系不显著,说明MBT′_(5me)及MBT_(5/6)指标可能并不适用于冷湿环境下的温度和海拔重建.6-甲基br GDGTs甲基化指数MBT′_(6me)、环化指数(CBT、CBT_(5me)、CBT_(6me))与甲基位置异构化指数(IR_(IIa′)、IR_(IIIa′))都与p H呈现显著相关性,表明这些指标在冷湿条件下仍具有反映土壤p H的潜力.不同地区的MBT′_(5me),MBT′_(6me)组合与典型气候型(冷干、暖湿、冷湿和暖干)存在较好的对应关系,冷湿条件下MBT′_(5me)值较小(0.65),而MBT′_(6me)值较大(0.55),表明MBT′_(5me)-MBT′_(6me)联合具有指示古气候型的潜力. 相似文献
7.
《中国科学:地球科学》2016,(4)
甘油二烷基甘油四醚(glycerol dialkyl glycerol tetraethers,GDGTs)作为古菌和细菌的生物标志物,广泛存在于陆地(土壤、泥炭、石笋、湖泊、河流和热泉等)和海洋环境中.近年来,基于这些化合物的环境指标(如表层海水温度指标TEX_(86),陆源输入指标BIT,平均大气温度指标MBT/CBT)已经被广泛应用于大洋和陆相环境,成为研究古环境和生物地球化学过程强有力的工具.相对而言,这些指标在边缘海尚未得到充分应用,主要是由于边缘海沉积环境复杂、物源多样且受人类活动影响.本文总结了已发表的关于中国边缘海(南海、东海和黄海)及主要大河河口(珠江口和长江口)的GDGTs研究结果,以更好地理解GDGTs及相关环境指标在中国边缘海的分布特征和应用潜力. 相似文献
8.
《中国科学:地球科学》2016,(6)
土壤环境中广泛存在的支链甘油二烷基甘油四醚脂化合物(br GDGTs),为古气候与古环境重建研究提供了新的指标.br GDGTs的甲基化指数与环化指数分别用MBT和CBT表示,被认为主要受到年平均大气温度(MAAT)和土壤p H的控制.然而在综合不同环境样品的条件下,br GDGTs指标重建的温度和土壤p H与真实值之间存在着较大的偏差.本文报道了分别代表湿润气候(西双版纳、广州、上海)、半干旱气候(东营)以及干旱气候(兰州、青藏高原)环境下超过300个土壤样品中br GDGTs化合物随中国气候带的变化特征.总体数据表明,在湿润与非碱性环境下MBT/CBT指标重建的温度与真实温度的吻合比干旱/半干旱(MAP500mm/a)及碱性环境下(p H7.0~7.5)表现得更好.同样地,CBT指标在湿润与非碱性环境中可以较好地反映土壤p H的变化.与此相反的是,在干旱/半干旱与碱性环境下,CBT指标与p H之间趋于正相关关系.本文的结果表明了土壤p H、年均大气温度及降水量是控制br GDGTs在不同气候带分布的主要环境因素,并且土壤电导率、总有机碳、总有机氮与含水率在区域环境中同样起着重要作用.通过在CBT指标计算中去除br GDGT-II化合物得到了一个新的CBT指标.该指标可以提供更准确的p H估算,特别是在干旱/半干旱与碱性环境下.本文大量的中国土壤数据表明br GDGTs指标恢复的陆地大气温度与真实值之间可能存在较大偏差,因此在应用这一指标重建古气候或古环境时应相当谨慎. 相似文献
9.
东亚夏季风北边界的湖泊水位记录所指示的区域全新世夏季风演化历史备受争议.文章以中国北方一个封闭湖泊过去15000年来甘油二烷基甘油四醚(GDGTs)的记录来探讨此问题.湖泊表层和岩芯沉积物数据结果显示,GDGT-0和brGDGTs均来源于湖泊内部自生.从湖岸到湖中心,表层沉积物中GDGT-0和brGDGTs含量随着水深... 相似文献
10.
在全球变化的背景下,厘清湖泊生态系统对气候环境以及人类活动的响应机制对制定社会的适应政策非常重要.目前的研究手段如现场观测和围隔实验等可以很好地揭示湖泊生态系统在有观测记录以来的演替和变化过程,但是不能提供历史时期湖泊生态系统的变化及其对气候环境变化和人类活动的响应.古湖沼学可以为探讨湖泊生态系统的长期变化及其对气候环境变化的响应提供重要信息.本文以青藏高原中部无鱼湖泊达则错为研究对象,利用沉积物岩芯西藏拟溞（Daphnia tibetana）残体丰度和总烯酮含量重建该区过去1000年的浮游生物记录;利用总氮、总磷以及总有机碳含量重建过去1000年湖泊营养盐以及有机质变化记录;结合烯酮不饱和度重建的古温度记录,探讨达则错过去1000年生态系统变化及其对气候环境演变的响应机制.研究发现达则错湖泊生态系统尤其是生产力在自然状况和人类活动影响下存在显著变化.在自然状况下,较高的湖泊初级和次级生产力发生在温度较低和湖水营养盐浓度较高时;而在过去150年,达则错湖泊环境受到人类活动影响显著,湖泊生产力发生相应变化,较高的湖泊生产力发生在温度较高时期,其主要受由人类活动带来的营养盐元素浓度控制.研究结果表明达则错湖泊生态系统在人类活动影响下发生了显著的改变. 相似文献
11.
Quantitative paleotemperature records are vital not only for verifying and improving the accuracy of climate model simulations, but also for estimating the amplitude of temperature variability under global warming scenarios. The Tibetan Plateau (TP) affects atmospheric circulation patterns due to its unique geographical location and high elevation, and studies of the mechanisms of climate change on the TP are potentially extremely valuable for understanding the relationship of the region with the global climate system. With the development of biomarker-based proxies, it is possible to use lake sediments to quantitatively reconstruct past temperature variability. The source of Glycerol Dialkyl Glycerol Tetraethers (GDGTs) in lake sediments is complex, and their distribution is controlled by both climatic and environmental factors. In this work, we sampled the surface sediments of 27 lakes on the TP and in addition obtained surface soil samples from six of the lake catchments. We analyzed the factors that influence GDGT distribution in the lake sediments, and established quantitative relationship between GDGTs and Mean Annual Air Temperature (MAAT). Our principal findings are as follows: the majority of GDGTs in the lake sediments are bGDGTs, followed by crenarchaeol and GDGT-0. In most of the lakes there were no significant differences between the GDGT distribution within the lake sediments and the soils in the same catchment, which indicates that the contribution of terrestrial material is important. iGDGTs in lake sediments are mainly influenced by water chemistry parameters (pH and salinity), and that in small lakes on the TP, TEX86 may act as a potential proxy for lake pH; however, in contrast bGDGTs in the lake sediments are mainly controlled by climatic factors. Based on the GDGT distribution in the lake sediments, we used proxies (MBT, CBT) and the fractional abundance of bGDGTs (fabun) to establish calibrations between GDGTs and MAAT, respectively, which potentially provide the basis for paleoclimatic reconstruction on the TP. 相似文献
12.
Yue Li Shijin Zhao Hongye Pei Shi Qian Jingjie Zang Xinyue Dang Huan Yang 《中国科学:地球科学(英文版)》2018,61(7):925-939
Glycerol Dialkyl Glycerol Tetraethers(GDGTs)serve as important tools for the quantitative reconstruction of paleoclimate and paleoecology in both continental and marine environments.Previous studies of GDGTs in the terrestrial environments focused primarily on the soils from the relatively warm-humid or cold-dry regions.However,it is still unclear how GDGTs respond to environmental variables in the cold-humid regions.Here,we collected soils along an altitudinal transect of Mountain(Mt.)Changbai,which has a typical cold-humid climate,to investigate the distribution of GDGTs and the response of GDGT-based proxies to changes in climate along the transect.The shift in the distribution of archaeal isoprenoidal GDGTs(iso GDGTs)revealed that the archaeal community varied significantly along the transect,which can affect the relationship between TEX_(86)and mean annual air temperature(MAT).In addition,the increased temperature seasonality at higher altitudes exerted a significant impact on TEX_(86).We proposed a global calibration of TEX_(86)for the growing season temperature reconstruction in the soil environments:T=85.19×TEX_(86)-46.30(R~2=0.84,p0.001).The methylation indices for 5-methyl branched GDGTs(br GDGTs)including MBT′_(5me)and MBT_(5/6),showed correlation with soil water content but no relationship with MAT,indicating that MBT′_(5me)and MBT_(5/6)from cold-humid environments may be not suitable for temperature and altitude reconstruction.In contrast,the recently developed p H proxies,including MBT′_(6me)(the methylation index for 6-methyl br GDGTs),CBT(Cyclisation index of Branched Tetraethers),IR_(IIa’)(Isomer ratio of IIa′)and IR_(IIIa′)(Isomer ratio of IIIa′)exhibited significant correlations with soil p H,suggesting these proxies can still be used for soil p H reconstruction in the coldhumid regions.The combination of MBT′_(5me)and MBT′_(6me)was strongly related to different types of climate(cold-dry,warmhumid,cold-humid,and warm-dry).For example,MBT′_(5me)0.65 and MBT′_(6me)0.55 are diagnostic for the cold-humid climate.Thus,the combination of MBT′_(5me)and MBT′_(6me)has the potential as a tool for the identification of different types of paleoclimate. 相似文献
13.
Glycerol dialkyl glycerol tetraethers(GDGTs) in lake sediments are useful biomarkers for the continental paleoclimatic reconstruction. However, the environmental controls on the distribution of these compounds, in particular the 6-methyl isomers of bacterial branched GDGTs(bGDGTs), in the lakes with contrasting pH, are still unknown, hindering their application for paleo-reconstructions. Here, we investigated the environmental impacts on the distribution of GDGTs in 17 alkaline lakes and 1 acid lake in China. It was found that the dissolved oxygen content in water column may have an impact on the distribution of archaeal isoprenoid GDGTs(iGDGTs) by causing the change in archaeal communities. The ratio of GDGT-0/crenarchaeol increases with decreasing oxygen content, indicating that the relative abundance of anaerobic methanogenic archaea or Miscellaneous Crenarchaeotic Group(MCG) vs. aerobic Thaumarchaeota is controlled by the oxygen content dissolved in water of these lakes. Thaumarchaeota are likely to contribute only a small proportion of iGDGTs in the relatively oxygen-depleted lakes, and thus TEX_(86) is not suitable for the reconstruction of the surface temperature of these lakes. The abundance ratio of iGDGTs to bGDGTs(R_(i/b)) appears to show no relationship with water pH in all the lakes, but exhibits a significant positive correlation with the water depth of the acid Lake Qinghai in Tengchong. As expected, the methylation degree of bGDGTs(MBT′) was found to correlate with both mean annual air temperature(MAT) and water pH, and the cyclization degree of bGDGTs(CBT) correlates only with water pH in these lakes. However, the MBT′_(5ME), an index to measure the methylation degree of 5-methyl bGDGTs, exhibits no relationship with MAT, whereas MBT′_(6ME), the methylation degree of 6-methyl bGDGTs, was found to correlate significantly with MAT. This is opposite to the situation observed in the global soils, pointing to a different adaptation of b GDGT-producing bacteria to environmental variables or different microbial sources of bGDGTs in these lakes. The relative abundance of 6- vs. 5-methyl bGDGTs is controlled by pH in these lakes, similar to that observed in worldwide soils. Hence, the isomer ratio(IR) of 6-methyl bGDGTs or CBT′ can be used as a proxy for water pH, although they might be influenced by other environmental factors including temperature in the lakes with a narrow range of pH. 相似文献
14.
Archaeal and bacterial glycerol dialkyl glycerol tetraethers (GDGTs) play a unique role in discerning the biogeochemical processes and climate change in terrestrial (e.g. soil, peat, stalagmites, lakes, rivers, hot springs) and marine environments. Organic proxies based on GDGTs (e.g. TEX86, MBT/CBT and BIT) have made impressive applications in the open ocean and terrestrial environments. However, the applicability of these proxies in marginal seas has not been thoroughly evaluated, which is necessary given the complexity and dynamics of these systems, such as organic matter (OM) flux, hydrodynamic conditions, and human impact. This review aims to summarize recent studies of GDGTs and GDGT-based proxies in the Chinese marginal seas (CMS), which are characterized by diverse gradient in terrigenous supplies and ocean productivity and hold rich information on climate and sea level changes, ocean current dynamics, sedimentary evolution and biogeochemical processes. 相似文献
15.
HuanYe Wang HaiLiang Dong ChuanLun Zhang HongChen Jiang WeiGuo Liu 《中国科学:地球科学(英文版)》2016,59(5):951-960
Branched and Isoprenoid Tetraether (BIT) index was considered as a proxy for terrestrial organic matter input in lake sediments, based on the assumption that branched glycerol dialkyl glycerol tetraethers (bGDGTs) are mainly derived from terrestrial soils. However, mounting evidences have showed that the in situ production of bGDGTs is widespread in lakes, challenging BIT as a reliable terrestrial input proxy. Recently, BIT has been proven to be a reliable proxy for paleohydrology in a small crater lake (Lake Challa) in accordance with a different mechanism. However, the response of BIT to paleohydrology variation may differ for different lakes. In this study, we investigate the variations in the BIT index and the concentrations of its related GDGTs in a 12-ka sediment core from Lake Qinghai, in combination with our previous results for surface sediments. We find that variations in BIT strongly depend on the concentration of crenarchaeol in both surface and ancient sediments of this lake, whereas bGDGT concentration varies much less remarkably. Considering that crenarchaeol production is positively correlated with water depth in Lake Qinghai, water depth may exert negative control on the BIT index in this lake. This case is inconsistent with the positive relationship between BIT and lake levels or rainfall intensity reported for Lake Challa, suggesting that the response of BIT to local paleohydrology is site specific in lacustrine systems. Hence, the application of sedimentary BIT as a paleohydrological proxy in a specific lake requires caution before confirming the environmental controls on BIT in that lake. 相似文献
16.
Molybdenum(Mo) proxies, including bulk concentration and isotopic composition, have been increasingly used to reconstruct ancient ocean redox states. This study systematically reviews Mo cycles and their accompanying isotopic fractionations in modern ocean as well as their application in paleo-ocean redox reconstruction. Our review indicates that Mo enrichment in sediments mainly records the adsorption of Fe-Mn oxides/hydroxides and chemical bonding of H2 S. Thus, Mo enrichment in anoxic sediments generally reflects the presence of H2 S in the water column or pore waters. In addition to the effect of euxinia, sedimentary Mo enrichment is related to the size of the oceanic Mo reservoir. Given these primary mechanisms for oceanic Mo cycling, Mo abundance data and Mo/TOC ratios acquired from euxinic sediments in geological times show that fluctuations of the oceanic Mo reservoir are well correlated with oxygenation of the atmosphere and oceans and suggest that oxygenation occurred in phases. Mo proxies suggest that Mo isotopes in strongly euxinic sediments reflect the contemporaneous Mo isotopic composition of seawater, but other processes such as iron-manganese(Fe-Mn) adsorption and weak euxinia can result in different fractionations. Diagenesis may complicate Mo enrichment and its isotopic fractionation in sediments. With appropriate constraints on the Mo isotopic composition of seawater and various outputs, a Mo isotope mass-balance model can quantitatively reconstruct global redox conditions over geological history. In summary, Mo proxies can be effectively used to reconstruct oceanic redox conditions on various timescales due to their sensitivity to both local and global marine redox conditions. However, given the complexity of geochemical processes, particularly the effects of diagenesis, further work is required to apply Mo proxies to ancient oceans. 相似文献
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18.
地下水补给型湖泊表层沉积物矿物组成及其形成机制——以巴丹吉林沙漠湖泊群为例 总被引：1，自引：0，他引：1
盐湖中的矿物沉积记录着丰富的环境气候变化信息,是古环境研究的重要对象.在无地表径流补给的盐湖中,其矿物组成及沉积特征与有地表径流补给的湖泊相比是否有一定的特殊性,是值得探讨的问题.采集巴丹吉林沙漠33个不同矿化度地下水补给型湖泊的表层沉积物和10个地表风积砂样品,通过X衍射的方法,分析样品的矿物组成.结果显示:湖泊表层沉积物主要为石英、长石、辉石、云母等碎屑矿物,部分湖泊含有少量的碳酸盐和氯化物盐类矿物.湖泊沉积物的矿物组成与湖水矿化度的关系较为密切,淡水湖仅分布碎屑矿物,微咸水湖含有碎屑矿物和碳酸盐类矿物,盐湖含有碎屑矿物、碳酸盐类矿物和氯化物.风积砂样品中主要为碎屑矿物,占总矿物含量的90%,对湖泊沉积物的矿物组成影响较大,但对湖泊沉积物中的盐类矿物没有贡献,表明湖泊表层沉积物中盐类矿物主要是自生作用形成的.虽然本地区湖泊边缘的沉积物中盐类矿物种类相对较少并且含量较低,但其盐类矿物组成与分布能够响应湖水矿化度的变化,其环境指示意义与有径流补给的盐湖相同,可以指示其湖水的盐度.因此,可以从巴丹吉林沙漠地下水补给型湖泊沉积的盐类矿物中提取相应的古环境信息,用于恢复古气候和古环境的研究. 相似文献