宁夏清水河盆地晚更新世中晚期孢粉记录及古气候意义

亚洲内陆荒漠化和干旱化与中国西部人类生存环境和社会可持续发展密切相关。中国西部地区的气候自晚更新世以来经历了多次冷暖、干湿变化，研究其晚更新世古气候变化，有助于预测未来气候的变化趋势。文章分析了宁夏南部清水河盆地晚更新世中晚期的孢粉记录，结果显示孢粉序列可从下至上划分为4个组合带，反映了该地区晚更新世中晚期植被和气候变化规律。研究表明研究区晚更新世中期(75～50 ka B.P.)是植被以蒿属为主的干草原，气候温凉偏干；晚更新世晚期(25～15 ka B.P.)由荒漠草原-干草原和疏林草原交替出现逐渐过渡到荒漠草原，该时期冬季风呈现逐渐增强的趋势，致使气候逐渐变冷变干，气候类型由温凉偏湿过渡到冷干。宁夏南部清水河盆地晚更新世中晚期孢粉记录的深入研究对于正确认识黄土高原自然环境历史演变和黄土高原治理决策的制定具有重要指导意义。     

西藏札达盆地托林剖面孢粉组合特征及其古气候意义

西藏札达盆地托林剖面的孢粉分析显示，该地区在5．4-5．05MaBP时期，气候环境由温凉干旱转变为温暖稍湿，植被相应地经历了疏林草原植被-森林草原植被的演变过程；到了5．05-4．40MaBP时期，转变为温暖潮湿的气候。植被亦相应地经历了由森林草原-暖温带针阔叶混交林-亚热带针阔叶混交林的演变过程。总地来说，当时该地区的植被是乔木植物（松属）和草本植物（蒿属、藜科）占主导地位，气候总体表现为温暖湿润。     

阳原西堡剖面的孢粉分析

通过对阳原西堡剖面的孢粉分析,得到16000年以来该地区植被与环境发展的历史。约16000~11000aBP期间,植被是以蒿和藜为主的干旱草原景观,气候寒冷而干燥;约11000~9000aBP期间,植被有一定的增长,气候变得温凉稍湿;约9000~4800aBP期间,气温上升湿度下降,植被呈现疏林草原景观;距今4800aBP以来,植被虽然仍以草原为主,但低花粉浓度指示环境条件又趋于恶劣,气候进一步向暖干方向发展。      

神农架大九湖晚更新世与全新世之交的气候变化——来自孢粉的信息

对神农架大九湖泥炭地层进行了孢粉分析,建立了晚更新世与全新世之交(14 031～9 625 aBP)高分辨率的孢粉组合带.根据孢粉植被反映的气候信息推断大九湖地区在晚更新世与全新世之交的气候大致以冷湿为特点,同时气候变化剧烈,表现为冷暖干湿波动频繁,可划分为3个气候旋回:第一旋回(14 031～12 581 aBP)气候变化经历了由温凉偏干-温凉湿润-温暖偏干的过程;第二旋回(12 581～11 046 aBP)气候变化经历了由寒冷偏干-温凉湿润-温凉偏干的过程;第三旋回(11 406～9 625 aBP)气候变化经历了由温凉偏干-寒冷湿润-温凉偏干的过程.     

西藏佩枯错盆地晚更新世以来的孢粉组合特征及其古气候意义

西藏佩枯错盆地晚更新世以来河湖相沉积剖面的孢粉分析显示,该地区在晚更新世早期的127—72kaB.P.时期,气候温和湿润,植被以针阔叶混交林为主;至66—56kaB.P.时期,气候转变为温凉略干,植被转为疏林草原;在56—49kaB.P.时期,气候温凉潮湿,植被又转为针阔叶混交林为主的森林草原;而在49—46kaB.P.时期,气候温和偏干,植被转为疏林草原;在46—31kaB.P.时期,气候寒凉湿润,植被表现为温度进一步下降的疏林草原;在31—15kaB.P.时期,环境向寒冷方向发展,植被转为高寒草原;自11kaB.P.(全新世初期)开始,气候由温暖偏干转变为温凉偏湿,植被由灌丛草原转变为森林灌丛草原。这表明自晚更新世以来,该区气候环境是在逐渐变干的总趋势上,经历了多次明显的冷暖与干湿波动。     

MIS3阶段以来沙漠/黄土过渡区植被演替及其对气候变化的响应

选择沙漠/黄土过渡带姬塬、和林格尔两个地点的黄土-古土壤剖面开展较高分辨率花粉记录研究,重建MIS 3以来植被演替及其对气候变化的响应.黄土高原北部MIS 3阶段以来植被经历了4个主要阶段:MIS 3阶段早-中期气候较温湿,植被为疏林草原类型;MIS 3晚期-末次盛冰期为荒漠草原植被类型;末次冰消期为干草原植被类型;全...     

西藏札达盆地上新世托林组剖面环境变化记录

对西藏札达盆地上新世托林组的孢粉、沉积物粒度、磁化率、碳酸盐、易溶盐和ESR年代等测试数据的综合分析,得到5.40～4.40 Ma时期环境变化的丰富信息.5.24～4.72 Ma时期,气候温凉干旱,属于针阔叶疏林草原环境特征;4.72～4.67 Ma时期,河流水量增多,气候湿润,孢粉组合表现出温带森林草原环境特征;4.67～4.40 Ma时期,气候进一步向温暖湿润方向发展,属于暖温带针阔叶混交林环境特征.     

邯郸地区晚更新世以来植被波动特征及其对气候变化的响应

对河北邯郸HZ S孔沉积物进行孢粉分析,结果表明该地区晚更新世以来的气候演变形式既有与全球同步的特点,也有本区域独自的特征。古气候与古植被演变过程如下:（1）晚更新世末次间冰期气候温暖湿润(130～75 kaBP),植被为森林草原;末次冰期气候演化经历了寒冷干燥(75～55 kaBP)→温暖湿润(40～30 kaBP)→寒冷干燥(30～10 kaBP)的过程,植被演替过程相应为草原→森林草原→草原。（2）全新世气候演化经历了温凉略干(10～8 kaBP)→温暖湿润(8～3 kaBP)→温凉偏干(3～0 kaBP)的过程,植被演替过程相应为疏林草原→森林草原→疏林草原。（3）发生在25 kaBP左右,16 kaBP左右和11～10 kaBP的冷事件可能是Heinrich事件3、1和Younger Dryas事件在中国东部季风区的响应。     

天津北部4.00 Ma BP以来古植被与古气候

依据CQJ1孔275块孢粉样品分析结果,结合岩性特征和测年资料,建立了天津北部4.00 Ma BP以 来古植被与古气候变化序列。大约在3.60-4.00Ma BP, 天津北部植被以荒漠草原为主, 气候冷干;3.44- 3.60Ma BP植被为疏林草原, 气候温和湿润;3.18-3.44Ma BP植被为荒漠草原, 气候冷干;2.58-3.18Ma BP植被以针阔叶混交林草原为主,气候温暖湿润;1.90-2.58Ma BP植被以疏林草原为主,气候温凉偏干; 1.74-1.90Ma BP植被为荒漠草原,气候冷干;1.30-1.74Ma BP植被以针阔叶混交林为主,气候温暖潮湿; 0.78-1.30Ma BP植被为以针叶树种为主的针阔叶混交林草原,气候温和湿润;0.15-0.78Ma BP植被以针阔叶 混交林为主,气候温暖潮湿;0.15Ma BP以来,孢粉丰度呈现有规律的变化,3个高丰度层段分别相当于MIS（海洋氧同位素） １、３、５阶段,与河北平原东部具有可比性。     

北京天竺晚上新世以来植被演替与气候变迁

研究了北京天竺TZ01钻孔岩心孢粉样品239块，孢粉组合反映了北京天竺晚上新世以来(约3.580 Ma BP)植被演替和气候变迁大致经历了10个发展阶段：(1) 3.580～3.050 Ma BP：以针叶林植被为主，气候寒冷偏湿；(2) 3.050～2.555 Ma BP：植被为落叶阔叶和常绿阔叶混交林-草原类型，该阶段开始升温，但气候较为温暖湿润；(3)2.555～2.300 Ma BP：植被为温凉偏干的疏林草原，湿度开始下降；(4) 2.300～1770 Ma BP：植被类型仍为疏林草原，该阶段温度上升，但幅度并不大，湿度基本不变，气候温凉干爽；(5) 1.770～1.070 Ma BP：植被类型为针阔混交林-草原，气候温暖湿润；(6) 1.070～0.922 Ma BP：植被演替为较暖湿略干的针阔混交林-草原；(7)0.922～0.800 Ma BP：植被为较寒冷干燥的疏林草原，温度降低，降水减少；(8) 0.800～0.650 Ma BP：植被为温暖偏干的以松为主的疏林草原，温度有所上升，但湿度变化较小；(9)0.650～0.160 Ma BP：植被为温凉湿润的针阔叶混交林-草原；(10) 0.160 Ma BP至今：植被以针阔叶混交林-草原为主，前期气候冷湿，后期较为温暖湿润。     

Isotopic systematics of He,Ar, S,Cu, Ni,Re, Os,Pb, U,Sm, Nd,Rb, Sr,Lu, and Hf in the rocks and ores of the Norilsk deposits

This paper reports the first results of a study of 11 isotope systems (³He/⁴He, ⁴⁰Ar/³⁶Ar, ³⁴S/³²S, ⁶⁵Cu/⁶³Cu, ⁶²Ni/⁶⁰Ni, ⁸⁷Sr/⁸⁶Sr, ¹⁴³Nd/¹⁴⁴Nd, ^206–208Pb/²⁰⁴Pb, Hf–Nd, U–Pb, and Re–Os) in the rocks and ores of the Cu–Ni–PGE deposits of the Norilsk ore district. Almost all the results were obtained at the Center of Isotopic Research of the Karpinskii All-Russia Research Institute of Geology. The use of a number of independent genetic isotopic signatures and comprehensive isotopic knowledge provided a methodic basis for the interpretation of approximately 5000 isotopic analyses of various elements. The presence of materials from two sources, crust and mantle, was detected in the composition of the rocks and ores. The contribution of the crustal source is especially significant in the paleofluids (gas–liquid microinclusions) of the ore-forming medium. Crustal solutions were probably a transport medium during ore formation. Air argon is dominant in the ores, which indicates a connection between the paleofluids and the atmosphere. This suggests intense groundwater circulation during the crystallization of ore minerals. The age of the rocks and ores of the Norilsk deposits was determined. The stage of orebody formation is restricted to a narrow age interval of 250 ± 10 Ma. An isotopic criterion was proposed for the ore-bearing potential of mafic intrusions in the Norilsk–Taimyr region. It includes several interrelated isotopic ratios of various elements: He, Ar, S, and others.     

高压微波消解法测定醋酸纤维过滤器采集的微尘粒子中的砷镉钴铬铜铁锰镍铅钒锌

最新的流行病学研究表明,空气中较高浓度的悬浮细颗粒可能对人类的健康有不利的影响。根据该项研究显示,由于心脏病、慢性呼吸问题和肺功能指标恶化而导致死亡率的升高与细尘粒子有关。这些研究结果已经促使欧盟于1999年4月出台了限制空气中二氧化硫、二氧化氮、氧化氮、铅和颗粒物含量的法案(1999/30/EC),对各项指标包括对可吸入PM10颗粒的浓度提出了新的限制性指标。PM10颗粒是指可以通过预分级器分离采集的气体动力学直径小于10μm的细颗粒。目前研究的兴趣重点逐步偏向PM2.5这些更细微颗粒物,PM2.5这种颗粒物对健康有明显的不利影响。在欧盟指令2008/50/EC中,对PM10和PM2.5都提     

Wavelength-dispersive X-ray fluorescence spectrometric determination of Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in komatiites

Komatiites are mantle-derived ultramafic volcanic rocks. Komatiites have been discovered in several States of India, notably in Karnataka. Studies on the distribution of trace-elements in the komatiites of India are very few. This paper proposes a simple, accurate, precise, rapid, and non-destructive wavelength-dispersive x-ray fluorescence (WDXRF) spectrometric technique for determining Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in komatiites, and discusses the accuracy, precision, limits of detection, x-ray spectral-line interferences, inter-element effects, speed, advantages, and limitations of the technique. The accuracy of the technique is excellent (within 3%) for Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Zr, Nb, Ba, Pb, and Th and very good (within 4%) for Y. The precision is also excellent (within 3%) for Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th. The limits of detection are: 1 ppm for Sc and V; 2 ppm for Cr, Co, and Ni; 3 ppm for Cu, Zn, Rb, and Sr; 4 ppm for Y and Zr; 6 ppm for Nb; 10 ppm for Ba; 13 ppm for Pb; and 14 ppm for Th. The time taken for determining Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in a batch of 24 samples of komatiites, for a replication of four analyses per sample, by one operator, using a manual WDXRF spectrometer, is only 60 hours.     

Mercury,arsenic, antimony,and selenium contents of sediment from the Kuskokwim River,Bethel, Alaska,USA

The Kuskokwim River at Bethel, Alaska, drains a major mercury-antimony metallogenic province in its upper reaches and tributaries. Bethel (population 4000) is situated on the Kuskokwim floodplain and also draws its water supply from wells located in river-deposited sediment. A boring through overbank and floodplain sediment has provided material to establish a baseline datum for sediment-hosted heavy metals. Mercury (total), arsenic, antimony, and selenium contents were determined; aluminum was also determined and used as normalizing factor. The contents of the heavy metals were relatively constant with depth and do not reflect any potential enrichment from upstream contaminant sources.     

Roles of xenomelts,xenoliths, xenocrysts,xenovolatiles, residues,and skarns in the genesis,transport, and localization of magmatic Fe-Ni-Cu-PGE sulfides and chromite

Most sulfide-rich magmatic Ni-Cu-(PGE) deposits form in dynamic magmatic systems by partial melting S-bearing wall rocks with variable degrees of assimilation of miscible silicate and volatile components, and generation of barren to weakly-mineralized immiscible Fe sulfide xenomelts into which Ni-Cu-Co-PGE partition from the magma. Some exceptionally-thick magmatic Cr deposits may form by partial melting oxide-bearing wall rocks with variable degrees of assimilation of the miscible silicate and volatile components, and generation of barren Fe ± Ti oxide xenocrysts into which Cr-Mg-V ± Ti partition from the magma. The products of these processes are variably preserved as skarns, residues, xenoliths, xenocrysts, xenomelts, and xenovolatiles, which play important to critical roles in ore genesis, transport, localization, and/or modification. Incorporation of barren xenoliths/autoliths may induce small amounts of sulfide/chromite to segregate, but incorporation of sulfide xenomelts or oxide xenocrysts with dynamic upgrading of metal tenors (PGE > Cu > Ni > Co and Cr > V > Ti, respectively) is required to make significant ore deposits. Silicate xenomelts are only rarely preserved, but will be variably depleted in chalcophile and ferrous metals. Less dense felsic xenoliths may aid upward sulfide transport by increasing the effective viscosity and decreasing the bulk density of the magma. Denser mafic or metamorphosed xenoliths may also increase the effective viscosity of the magma, but may aid downward sulfide transport by increasing the bulk density of the magma. Sulfide wets olivine, so olivine xenocrysts may act as filter beds to collect advected finely dispersed sulfide droplets, but other silicates and xenoliths may not be wetted by sulfides. Xenovolatiles may retard settling of – or in some cases float – dense sulfide droplets. Reactions of sulfide melts with felsic country rocks may generate Fe-rich skarns that may allow sulfide melts to fractionate to more extreme Cu-Ni-rich compositions. Xenoliths, xenocrysts, xenomelts, and xenovolatiles are more likely to be preserved in cooler basaltic magmas than in hotter komatiitic magmas, and are more likely to be preserved in less dynamic (less turbulent) systems/domain/phases than in more dynamic (more turbulent) systems/domains/phases. Massive to semi-massive Ni-Cu-PGE and Cr mineralization and xenoliths are often localized within footwall embayments, dilations/jogs in dikes, throats of magma conduits, and the horizontal segments of dike-chonolith and dike-sill complexes, which represent fluid dynamic traps for both ascending and descending sulfides/oxides. If skarns, residues, xenoliths, xenocrysts, xenomelts, and/or xenovolatiles are present, they provide important constraints on ore genesis and they are valuable exploration indicators, but they must be included in elemental and isotopic mass balance calculations.     

Regional distribution of Al,B, Ba,Ca, K,La, Mg,Mn, Na,P, Rb,Si, Sr,Th, U and Y in terrestrial moss within a 188,000 km2 area of the central Barents region: influence of geology,seaspray and human activity

Five hundred and ninety-eight samples of terrestrial moss (Hylocomium splendens and Pleurozium schreberi) collected from a 188,000 km² area of the central Barents region (NE Norway, N Finland, NW Russia) were analysed by ICP-AES and ICP-MS. Analytical results for Al, B, Ba, Ca, K, La, Mg, Mn, Na, P, Rb, Si, Sr, Th, U and Y concentrations are reported here. Graphical methods of data analysis, such as geochemical maps, cumulative frequency diagrams, boxplots and scatterplots, are used to interpret the origin of the patterns for these elements. None of the elements reported here are emitted in significant amounts from the smelting industry on the Kola Peninsula. Despite the conventional view that moss chemistry reflects atmospheric element input, the nature of the underlying mineral substrate (regolith or bedrock) is found to have a considerable influence on moss composition for several elements. This influence of the chemistry of the mineral substrate can take place in a variety of ways. (1) It can be completely natural, reflecting the ability of higher plants to take up elements from deep soil horizons and shed them with litterfall onto the surface. (2) It can result from naturally increased soil dust input where vegetation is scarce due to harsh climatic conditions for instance. Alternatively, substrate influence can be enhanced by human activity, such as open-cast mining, creation of ‘technogenic deserts’, or handling, transport and storage of ore and ore products, all of which magnify the natural elemental flux from bedrock to ground vegetation. Seaspray is another natural process affecting moss composition in the area (Mg, Na), and this is most visible in the Norwegian part of the study area. Presence or absence of some plant species, e.g., lichens, seems to influence moss chemistry. This is shown by the low concentrations of B or K in moss on the Finnish and Norwegian side of the (fenced) border with Russia, contrasting with high concentrations on the other side (intensive reindeer husbandry west of the border has selectively depleted the lichen population).     

Petrographic, mineralogy, and geochemistry of coals of Pabedana, Kerman Province, Central Iran

This paper discusses the result of the detailed investigations carried out on the coal characteristics, including coal petrography and its geochemistry of the Pabedana region. A total of 16 samples were collected from four coal seams d2, d4, d5, and d6 of the Pabedana underground mine which is located in the central part of the Central-East Iranian Microcontinent. These samples were reduced to four samples through composite sampling of each seam and were analyzed for their petrographic, mineralogical, and geochemical compositions. Proximate analysis data of the Pabedana coals indicate no major variations in the moisture, ash, volatile matter, and fixed carbon contents in the coals of different seams. Based on sulfur content, the Pabedana coals may be classified as low-sulfur coals. The low-sulfur contents in the Pabedana coal and relatively low proportion of pyritic sulfur suggest a possible fresh water environment during the deposition of the peat of the Pabedana coal. X-ray diffraction and petrographic analyses indicate the presence of pyrite in coal samples. The Pabedana coals have been classified as a high volatile, bituminous coal in accordance with the vitrinite reflectance values (58.75–74.32 %) and other rank parameters (carbon, calorific value, and volatile matter content). The maceral analysis and reflectance study suggest that the coals in all the four seams are of good quality with low maceral matter association. Mineralogical investigations indicate that the inorganic fraction in the Pabedana coal samples is dominated by carbonates; thus, constituting the major inorganic fraction of the coal samples. Illite, kaolinite, muscovite, quartz, feldspar, apatite, and hematite occur as minor or trace phases. The variation in major elements content is relatively narrow between different coal seams. Elements Sc,, Zr, Ga, Ge, La, As, W, Ce, Sb, Nb, Th, Pb, Se, Tl, Bi, Hg, Re, Li, Zn, Mo, and Ba show varying negative correlation with ash yield. These elements possibly have an organic affinity and may be present as primary biological concentrations either with tissues in living condition and/or through sorption and formation of organometallic compounds.     

Alkaline rocks of Samchampi-Samteran, District Karbi-Anglong, Assam, India

The Samchampi-Samteran alkaline igneous complex (SAC) is a near circular, plug-like body approximately 12 km² area and is emplaced into the Precambrian gneissic terrain of the Karbi Anglong district of Assam. The host rocks, which are exposed in immediate vicinity of the intrusion, comprise granite gneiss, migmatite, granodiorite, amphibolite, pegmatite and quartz veins. The SAC is composed of a wide variety of lithologies identified as syenitic fenite, magnetite ± perovskite ± apatite rock, alkali pyroxenite, ijolite-melteigite, carbonatite, nepheline syenite with leucocratic and mesocratic variants, phonolite, volcanic tuff, phosphatic rock and chert breccia. The magnetite ± perovskite ± apatite rock was generated as a cumulus phase owing to the partitioning of Ti, Fe at a shallow level magma chamber (not evolved DI = O1). The highly alkaline hydrous fluid activity indicated by the presence of strongly alkalic minerals in carbonatites and associated alkaline rocks suggests that the composition of original melt was more alkalic than those now found and represent a silica undersaturated ultramafic rock of carbonated olivine-poor nephelinite which splits with falling temperature into two immiscible fractions—one ultimately crystallises as alkali pyroxenite/ijolite and the other as carbonatite. The spatial distribution of varied lithotypes of SAC and their genetic relationships suggests that the silicate and carbonate melts, produced through liquid immiscibility, during ascent generated into an array of lithotypes and also reaction with the country rocks by alkali emanations produced fenitic aureoles (nephelinisation process). Isotopic studies (δ¹⁸O and δ¹³C) on carbonatites of Samchampi have indicated that the δ¹³C of the source magma is related to contamination from recycled carbon.