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1.
自然界中ＣＯ＿２主要来自有机质、大气和碳酸盐岩石，因同位素分馏作用，其稳定碳同位素组成在这三种物质中的分配不尽相同。本文根据地下水实测ＨＣ，的δ￣（１３）Ｃ￣２值，利用热力学及同位素平衡计算与之相平衡的ＣＯ＿２气体的δ￣（１３）Ｃ值，确定了ＣＯ＿２气体来源，进而确定了的有机来源。 相似文献
2.
大气中CO2浓度的全球监测现状 总被引：2，自引：0，他引：2
较系统地介绍了大气中ＣＯ＿２浓度（主要是ＣＯ＿２大气背景浓度）的全球监测进展现状。重点阐述了ＣＯ＿２浓度的全球监测网、监测方法、ＣＯ＿２同位素监测、监测质量控制以及ＣＯ＿２监测资料管理等问题的进展状况，分析讨论了当前ＣＯ＿２浓度全球监测中存在的问题和发展前景。 相似文献
3.
关于CO_2若干问题的讨论 总被引：23，自引：5，他引：23
文章论述了地球内部成因ＣＯ２研究的一些新进展，并立足于地质宏观观察、矿物及元素共生组合、地球化学模拟及稳定同位素等探讨了地质历史时期大气ＣＯ２含量的变化及其与古气候的关系。最后，扼要地讨论了ＣＯ２与成矿作用的关系。 相似文献
4.
碳酸盐岩在全球碳循环过程中的作用 总被引：22，自引：3，他引：22
碳酸盐岩是地球上最主要的碳库，开展全球变化研究应重视碳酸盐岩在岩溶作用过程中的地球化学动力学研究。这方面的科学问题有二个。第一是关于全球碳酸盐岩的碳库容量问题，尚须利用全球沉积岩和碳酸盐岩数据库，根据全球地质历史时期碳酸盐岩的分布面积、厚度和岩石成分等进行重新计算。其次是关于碳酸盐岩在岩溶作用过程中对全球碳循环的动力学贡献问题。一方面碳酸盐岩的溶蚀作用不仅关系到海洋ＣａＣＯ＿３的供给量而影响海洋中碳通量的平衡，而且还可直接回收大气圈中的ＣＯ＿２；另一方面由于钙华的沉积又可向大气圈释放ＣＯ＿２，而影响温空气体的变化。它们构成了大气温室气体源汇关系中不可忽视的一项。 相似文献
5.
地质学家重视研究深部（变质）CO_2对古气候的影响 总被引：5，自引：0，他引：5
地质学家重视研究深部（变质）ＣＯ２对古气候的影响贾跃明（中国地质矿产信息研究院，北京，１０００３７）近几年来，随着过去全球变化研究的兴起，地质学家越来越重视地质历史时期影响大气ＣＯ２浓度的因素的调查。不少人认为，变质作用和火山活动可能是过去大气中ＣＯ... 相似文献
6.
川东南脉状萤石－重晶石矿床流体包裹体研究 总被引：2，自引：0，他引：2
川东南脉状萤石──重晶石矿床主要产于下奥陶统碳酸盐岩中，其成矿与岩浆活动无明显联系．成矿温度较低，成矿流体富含ＮａＣｌ和Ｈ＿２Ｏ，ＣＯ＿２和ＣＨ＿４的含量较低，Ｎ＿２，Ｏ＿２及Ｈ＿２的含量甚微。成矿介质水主要来源于地层水（如封存的海水、盆地压实脱水等）及大气降水，成矿温度、δ￣Ｄ值、盐度、Ｎａ￣＋／Ｋ￣＋比值以及矿石中有机包裹体的在在均表明本区萤石和重晶石的成矿流体类似于密西西比河谷型矿床的成矿热卤水，其形成与介质水溶滤本区寒武系蒸发岩有关。 相似文献
7.
8.
对Ｐ５０７萃淋树脂分离稀土元素的条件进行了实验，拟定了以Ｐ５０７萃淋树脂为固定相，ＨＣｌ为流动相分离４Ｎ级荧光材料Ｅｕ＿２Ｏ＿３中１４种稀土杂质元素的流程，使被测杂质与基体Ｅｕ＿２Ｏ＿３达到了较好的分离；再用阳离子交换树脂分离被测液中非稀土杂质元素。选择了端视ＩＣＰ－ＡＥＳ测量稀土杂质元素的最佳条件。称样量５０ｍｇ时各杂质组分的测定下限（ｕｇ／ｇ）为：ＣｅＯ＿２、Ｐｒ＿６Ｏ＿（１１）、Ｎｄ＿２Ｏ＿３、Ｓｍ＿２Ｏ＿３、Ｔｂ＿４Ｏ＿７、Ｈｏ＿２Ｏ＿３、Ｅｒ＿２Ｏ＿３，Ｔｍ＿２Ｏ＿３、Ｌｕ＿２Ｏ＿３０．４，Ｌａ＿２Ｏ＿３、Ｇｄ＿２Ｏ＿３、０．２，Ｄｙ＿２Ｏ＿３、Ｙ＿２Ｏ＿３０．０４，Ｙｂ＿２Ｏ＿３０．０２。６次取样分析，各杂质组分加入量为１０ｕｇ／ｇ（ＣｅＯ＿２为２ｕｇ／ｇ），加入回收率在８４％～１１２％；ＲＳＤ＜１３％。方法可用于纯度在９９．９９％～９９．９９９５％Ｅｕ＿２Ｏ＿３中１４种稀土杂质元素的测定。 相似文献
9.
摘要：古气候模拟已经成为白垩纪古气候研究中不可替代的技术手段。但是目前中国白垩纪陆相古气候模拟的一些关键边界条件尚未完全确定。通过白垩纪沉积记录对中国大陆白垩纪古海陆边界和古地形做出约束。早白垩世,新疆西南部喀喇昆仑地区可能存在喀喇昆仑海湾,在东北松辽盆地东侧有乌苏里湾;晚白垩世,受全球海平面上升的影响, 特提斯海向北延伸,新疆西部地区存在塔西南海湾和喀喇昆仑海湾;而受燕山运动的影响,乌苏里湾向东退出松辽盆地,影响变小。在古地形方面,认为东北大兴安岭,西北天山、祁连山、昆仑山等山脉,西南云贵高原、川西高原、横断山,秦岭-大别山在白垩纪时均已形成并隆升到一定高度;指出“东部高原”和“沿岸山脉”的存在与否可能对白垩纪古气候状况产生深远的影响。此外, 还讨论了沉积记录与古气候模拟结果的对比、验证对中国大陆白垩纪古气候重建的重要作用。 相似文献
10.
黄山东镁铁超镁铁杂岩中的辉石化学成分研究 总被引：7，自引：0，他引：7
通过对黄山东镁铁超镁铁杂岩的辉石化学成分研究，证明辉石的化学成分受寄主岩石类型的制约，从超镁铁岩相到角闪辉长岩相斜方辉石的化学成分由富ＭｇＯ、ＳｉＯ＿２、Ａｌ＿２Ｏ＿３、Ｃｒ＿２Ｏ＿３到富ＦｅＯ、ＴｉＯ＿２、ＣａＯ、ＭｎＯ；单斜辉石化学成分由富Ａｌ＿２Ｏ＿３、Ｃｒ＿２Ｏ＿３、Ｎａ＿２Ｏ、ＭｇＯ到富ＦｅＯ、ＭｎＯ、ＣｏＯ。在同一寄主岩石中，单斜辉石比斜方辉石富ＴｉＯ＿２、Ａｌ＿２Ｏ＿３、Ｃｒ＿２Ｏ＿３、ＣａＯ和Ｎａ＿２Ｏ，贫ＭｇＯ、ＳｉＯ＿２、ＭｎＯ和ＦｅＯ。根据辉石化学成分特征得出黄山东杂岩形成于岛弧环境，为上地幔石榴二辉檄榄岩部分熔融形成的拉斑玄武岩岩浆结晶分异作用的产物。 相似文献
11.
为探讨柴达木盆地晚更新世的环境变迁,同时为青藏高原隆升对气候变化的影响提供基础资料,对柴达木盆地昆特依地区ZK1404钻孔沉积物中的正构烷烃分布特征以及ASM~(14)C测年数据进行了分析。结果显示,昆特依地区晚更新世沉积物的正构烷烃总体上呈现以高碳数为主的分布特征,多数样品以nC_(27)、nC_(29)为主峰,部分以nC_(31)为主峰,呈现出显著的奇碳优势。少数样品中低于nC_(21)的短链正构烷烃相对丰度较高,主要以nC_(17)、nC_(20)为主峰碳数,无明显的奇偶优势。根据正构烷烃分布特征、AMS~(14)C测年数据、区域地质调查资料及沉积环境判断,柴达木盆地昆特依地区晚更新世(33600～26370a B.P.)气候环境以温凉干旱与温凉干旱偏湿交替出现为特征,与现代大陆性干旱荒漠气候截然不同。 相似文献
12.
利用X射线衍射等分析方法,对贵州威宁麻窝山岩溶盆地沉积物中粘土矿物进行研究,获得了粘土矿物的组成、相对含量、结晶度指数、化学指数以及相对含量比值等方面的信息,探讨该盆地的沉积环境演化特征。研究表明,粘土矿物以伊/蒙混层矿物(30%~75%)和绿泥石(10%~45%)为主,高岭石(5%~20%)和伊利石(10%)次之,基本不含蒙脱石。伊/蒙混层矿物和绿泥石含量呈负相关性。高岭石含量在剖面底部较稳定,在484cm上部出现较大的波动。伊利石结晶度和化学指数与伊/蒙混层矿物含量具有较好的正相关性,且在第Ⅰ阶段相对于其它指标较敏感,出现波动。通过综合对比分析,将研究区剖面划分为4个阶段,其是3个冷暖干湿的大循环和若干个小循环气候环境的物质记录。 相似文献
13.
七十三万年来柴达木盆地察尔汗盐湖古气候波动的形式 总被引：21，自引：2，他引：21
本文采用14C、230Th和古地磁法,测定了察尔汗盐湖CK-6孔岩芯的年龄,并根据对该孔有机碳含量变化的研究,讨论了0.73Ma以来古气候波动的形式。初步结果表明,CK-6孔可与洛川黄土及深海沉积钻孔的气候曲线进行对比,认为全球性气候事件在青藏高原内部同样有明显的反映。 相似文献
14.
柴达木盆地第四纪古气候变化在物理测井自然伽玛曲线上的记录 总被引：7，自引：2，他引：7
利用物理测井曲线分析古气候变化，是近年发展起来的新领域。本文在对取芯井涩中6井多种气候指标分析的基础上，建立了涩中6井GR曲线古气候反演模式，将该模式引进到盆地东部唯一贯穿第四纪的钻孔---达参1井，利用该井高分辨率自然伽玛曲线建立了盆地东部地区2.85Ma以来的时间标尺，据此讨论盆地东部地区2.85Ma以来的古气候变化，表明盆地气候变化在大阶段上明显受到天文轨道周期的控制，但也具有明显的区域性特征。此外还与盆地西部大浪滩ZK-336孔进行了对比。表明柴达木盆地同时包含了高原隆升与全球性气候变化的信息，是古环境变迁的良好的信息载体。也证明了自然伽玛曲线是反映内陆干旱盆地气候与环境变化良好的代用指标。 相似文献
15.
Palaeoclimatic cycles, global environmental changes and new glacial periods induced by the impact of extraterrestrial bodies 总被引：1，自引：1，他引：0
In terms of Earth-Sun geometry, the Milankovitch theory has successfully explained most of the cyclic palaeoclimatic variations
during the history of the Earth, especially in the Quaternary. In this paper, the authors suggest that the impact of extraterrestrial
bodies on the Earth may be another mechanism to cause palaeoclimatic cycles, global environmental changes and new glacial
periods. Based on geological and geochemical records in the boundary layers produced by six huge Cenozoic bolide-impact events
(65, 34, 15, 2.4, 1.1, 0.73 Ma B.P.), including those at 34, 15, 1.1 and 0.73 Ma B. P. which are represented by four famous
tektite-strewn fields, the process and mechanics of palaeoclimatic cycles and global environmental catastrophes induced by
extraterrestrial impact are discussed in detail. Impact-generated dust, soot and aerosol floating in the stratosphere could
result in short-term (<1 year), rapid drop in temperature immediately after impact. Through self-regulation of the Earth’s
climate system, the temperature at the surface slowly went up within 100a and maintained stable for a long time at 250K. If
there were no other factors leading to the break-down of the newly-established equilibrium, a new glacial pound would be initiated.
Estimating from the thickness of δ13C and δ18O anomalies in sediments across the impact boundary layer and deposition rate, the duration of two stages of the palaeoclimate
cycle in the form of cold weather—greenhouse effect—normal weather was 104 – 105a, respectively. The conclusion deduced from the above model is supported by palaeotemperature change recorded by oxygen isotope
in sediments across the impact boundary layer.
The study was granted by the Scientific and Technological Bureau of Resources and Environment, Chinese Academy of Sciences
(KZ952-J1-031) and the National Natural Science Foundation of China. 相似文献
16.
Pierre Antoine Sylvie Coutard Jean-Jacques Bahain Jean-Luc Locht David Hérisson Emilie Goval 《第四纪科学杂志》2021,36(8):1293-1310
This study presents an overview of Middle Pleistocene loess–palaeosol sequences (LPS) in northern France and discusses the palaeoclimatic significance of the pedosedimentary record in the context of western European LPS and of global climatic cycles for the last 750 ka. In this area, the oldest loess deposits (early Middle Pleistocene) are preserved in sedimentary traps (leeward scarps of fluvial terraces and dissolution sinkholes). They result from local deflation processes reworking Pleistocene sandy fluvial deposits or relicts of Tertiary sands. A large extension of typical calcareous loess over the landscape, the Loess Revolution, is then observed during MIS 6, with heavy mineral assemblages testifying to long-distance transport from the polar desert area of the dried eastern Channel. A correlation scheme is proposed between the global records of northern France in continental environments and both global palaeoclimatic records and other main western European LPS. After 30 years of research, northern France LPS stand as a fundamental archive of the impact of interglacial–glacial climatic cycles as well as millennial events. Finally, these works provide a robust chronoclimatic framework for the study of the western European Late Acheulean and Middle Palaeolithic and for the relative dating of the various fluvial terraces that they fossilise. 相似文献
17.
Laminated sediments in a core from Alberca de Tacámbaro, western central Mexico, provide a high-resolution record of palaeoclimatic variability for most of the Holocene. Using compositional and textural characteristics we identified 14 facies classified in biogenic, clastic and volcaniclastic groups, in which diatoms and other algal remains are the most common components. In addition to facies analysis, high-resolution geochemical data from continuous core scanning XRF and the analysis of discrete samples for organic and inorganic carbon content, provide the basis for palaeoclimatic reconstruction. The age model indicates that the record spans from 9.4 cal ka bp toad 1760. Three main phases in the sequence are identified, controlled by millennial-scale variability. During the period between 9.4 and 5.7 cal kabp , the lake is dominated by siliceous organisms. Drier conditions between 8.2 and 6.3 cal kabp are linked to decreases in summer insolation and solar irradiance. By 5.7 cal kabp , the change in sedimentation is related to the increase in El Niño Southern Oscillation frequency. Evidence of the occurrence of dry conditions during the archaeological Late Classic period (ad 600–900) and historical droughts are also documented in the Alberca de Tacámbaro record. Unprecedented changes in the landscape are recorded afterad 1520. 相似文献
18.
G. H. F. Young R. J. Bale N. J. Loader D. Mccarroll N. Nayling N. Vousden 《第四纪科学杂志》2012,27(6):606-614
In regions with seasonal temperate climatic regimes, tree growth is rarely controlled by any single environmental factor. As a consequence, the development of robust palaeoclimate reconstructions has proved challenging. Tree‐ring stable carbon isotope ratios (δ13C), however, are controlled primarily by photosynthetic rate, not by net growth. Therefore, at sites where climatic controls on tree‐ring growth are not strongly expressed, a robust (isotopic) palaeoclimate signal may still potentially be preserved. This hypothesis was tested using a 160‐year record of δ13C measured from the pooled latewood cellulose of six Quercus petraea L. (sessile oak) trees from Allt Lan‐las in West Wales, UK. Raw δ13C values were corrected for changes in the isotopic ratio of atmospheric carbon dioxide and for changes in the behaviour of trees due to the increasing availability of atmospheric CO2 since AD 1850. Strong correlations with local summer temperature and sunshine are reported, and also with the Central England Temperature record over the full length of the isotopic chronology (AD 1850–2010) (r = 0.69, P < 0.001). We conclude that tree‐ring stable isotopes can be used to extract strong palaeoclimate signals even from oak trees growing in a temperate maritime climate. This demonstrates the potential for extracting robust palaeoclimatic information from the very long and well‐replicated oak chronologies which have been developed in western and central Europe primarily for dating rather than palaeoclimatic research purposes. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
19.
碳酸盐岩台地多旋回沉积小层精细划分对比方法研究——以川中磨溪构造嘉二段为例 总被引：4，自引：0，他引：4
以四川盆地川中磨溪构造下三叠系嘉陵江组二段为研究对象,研究海相碳酸盐岩台地多旋回小层精细划分与对比方法。通过对海水咸化旋回、相对海平面变化旋回、古气候变化旋回沉积特征与成因的分析,磨溪地区嘉二段沉积期主要发育潮下型碳酸盐米级旋回层序,沉积界面特征明显并具有一定的成因联系,这种高频沉积旋回具多成因机制特征。在此基础阐明了高频米级旋回的划分原则,提出了一种多旋回沉积界面优选的依据与方法,据此,重新厘定了川中磨溪构造嘉二段小层划分方案。通过精细对比,建立了近于等时的地层格架。该方法有效地避免了单纯运用岩电特征进行地层划分对比时带来的多解性问题,并使各亚段和小层接近于等时的沉积体,为沉积微相及储层的成因和分布研究奠定了可靠的地层学基础。 相似文献
20.
Palaeoenvironmental records in Holocene Spanish tufas: a stable isotope approach in search of reliable climatic archives 总被引：3，自引：0，他引：3
Tufa deposits are potential terrestrial archives of palaeoenvironmental and palaeoclimatic information. This study assesses the potential of stable isotopic archives from two closely juxtaposed Holocene tufa sites in SE Spain. The Ruidera site contains deep‐water lacustrine micrites and tufas, whereas the nearby Alcaraz site represents a shallow barrage tufa. Understanding site characteristics is critical to interpreting the stable isotopic variations. These Holocene lacustrine micrites have isotopic compositions consistent with modern European lake shore microbial carbonates, where the isotopic chemistry is strongly influenced by hydrological and residence time effects. All the lacustrine micrite δ13C values were influenced by microenvironmental microbial effects to some degree. Because of these effects, stable isotope data from lacustrine microbial micrites and tufas will not normally yield precise information on the isotopic composition of palaeoprecipitation, temperature or vegetation composition of an area. In contrast, Holocene tufas that formed in shallow, fast‐flowing riverine settings may contain valuable palaeoclimatic archives. The tufa deposits must be largely autochthonous, as at Alcaraz, where in situ reed stem encrustations are present. Records of relative change in air temperature and changes in the source of airmasses are potentially resolvable in the δ18O data. These interpretations can be verified by other independent climatic data where chronology is constrained. Variations in riverine tufa δ13C values probably record changes in local vegetation and/or soil respiration. Covariation between δ18O and δ13C values may be intrinsically linked to climatic factors such as aridity. Tentative palaeoclimatic interpretations for the middle Holocene at Alcaraz based on the isotope data suggest warming (or increasing influence of Mediterranean‐sourced precipitation) between approximately 5000–3000 radiocarbon years BP, accompanied by increased aridity. These interpretations are consistent with the sparse independent palaeoclimatic data and climate modelling results for the Holocene of SE Spain. This study supports the growing evidence that well‐chosen tufa sites could yield valuable palaeoclimatic information. 相似文献