西藏扎布耶湖区128～1.4ka BP的微体古生物与环境气候变化

本文主要根据西藏扎布耶湖区SZK02孔所揭露的近84m剖面的沉积物特征与其产的介形类6属20种,轮藻类2属3种,结合14C、ESR、U-series地层测年等,初步认为该区128～1.4ka至少存在5个较明显的气候变化时期。①在128～76.7ka(83.63～57.0m)处于我国末次间冰期时段,气候凉湿,湖盆扩展,在90～81ka期间湖面最高,水质最淡。②76.7～58.6ka(57.0～38.13m)为我国末次冰期早冰阶时期,湖盆收缩,水温低,早期76.7～69.7ka(57.0～47.5m)偏冷湿,中期69.7～65.0ka(47.52～42.64m)气候温干,正逢早冰阶时期;晚期65.0～58.6ka(42.64～38.13m)气候干燥度下降。③58.6～29.1ka(38.13～13.75m)处于我国末次冰期间冰阶时段,早期58.6～51.6ka(38.13～33.07m)偏温湿,为3c暖期;中期51.6～42.5ka(33.07～26.13m)气候干冷,为3b冷期,正临末次冰期中冰阶时;晚期42.5～36.0ka(26.13～20.16m)偏凉湿,湿度更大,再次出现高湖面,为3a暖期;末期36.0～29.1ka(20.16～13.75m),趋向温干。④29.1～11.8Cal.ka(13.75～4.83m),气候趋向干冷,处于末次盛冰期(LGM)、末次晚冰阶时期,湖盆萎缩,水温低。早期29.1～16.6Cal.ka(13.75～6.98m)偏温湿;晚期16.6～13.1Cal.ka(6.98～5.76m)寒冷干燥;至末期13.1～11.7Cal.ka(5.76～4.83m),进一步干燥寒冷,全球新仙女木事件在本区发生。⑤11.7～1.4Cal.ka(4.83～0.65m),大致进入全新世气候期,气候波动大,凉湿与干冷交替频繁发生。在11.7～10.7Cal.ka(4.83～4.42m)时较温湿;10.7～9.5Cal.ka(4.42～4.07m)转向干冷;9.5～9.1Cal.ka(4.07～3.7m)更干冷,湖盆进一步萎缩;9.1～6.3Cal.ka(3.7～2.86m)向温干过渡;6.3～3.6Cal.ka(2.86～1.77m)干冷,湖泊已成盐湖;3.6～1.4Cal.ka(1.77～0.65m),气候趋向冷湿。     

澜沧江云南德钦古水一带第四纪堰塞湖的沉积特征及其环境意义

在云南省西北部德钦县古水一带深切的澜沧江河谷中,发现了一套第四纪湖相沉积物,以纹层状粘土、粉砂质粘土和粉砂的互层组合为特征,构成了第三和第四级阶地的基座.笔者对该湖相剖面进行了U系、孢粉和若干地球化学指标的分析测试,并以这些结果讨论了古湖的形成时代和成因,以及古湖堆积时期的古植被和古气候.剖面顶部、中部和中下部粘土的U系法年龄测定结果分别为52.3±3.4 ka、64.2±5.6 ka和81.9±6.5 ka,说明古水古湖形成于晚更新世早中期的末次间冰期晚期和末次冰期的早冰阶与间冰阶早期,很可能是大型冰川(如下游的明永冰川等)或巨量的冰水沉积物堰塞了澜沧江河谷而造成的结果.     

萨拉乌苏河酒坊台剖面末次间冰阶以来的气候环境演化

酒坊台剖面位于萨拉乌苏河流域下游,其中末次间冰阶以来主要为风成砂沉积,间夹砂质古土壤和湖沼相粘土层等,对环境信息有良好的记录。OSL年龄结果表明该剖面顶部记录了末次冰期间冰阶(约52 ka B.P.)以来的气候演化历史。通过对剖面高精度的粒度和磁化率分析,结合Rb、Sr元素含量及其比值综合分析,表明末次冰期间冰阶以来该剖面自上而下可划分为3个主要层段,对应了深海氧同位素MIS 1~3。同时在MIS 3阶段呈现出明显的MIS 3a、3b、3c亚段,结合区域研究资料,表明萨拉乌苏河流域在中—长时间尺度上,对全球性和区域性气候事件有良好的沉积响应。     

季风的发展与冰川的消失——从台湾高山末次冰期冰川发育特征说起

台湾高山有无第四纪冰川之争,经历60a后终于得到澄清．此次查明台湾雪山主峰区有3套 不同时期的冰川遗迹．如冰斗湖、冰坎、大型磨光面和擦痕以及冰碛垄等,分别命名为山庄冰阶(末 次冰期早期．44.25±3.72ka BP)、黑森林冰阶(末次冰期最盛,18.26±1.52 ka BP)、雪山冰阶(末次冰 期晚期,10.68±0.84 ka BP)尤其以早期冰川规模大为特征．澄清了地学界近65a来的怀疑,将为 全球变化研究增添新内容．     

唐古拉山垭口地区的第四纪冰川测年新研究

在野外综合考察的基础上,对唐古拉山垭口地区末次冰期的冰碛漂砾(或有冰川擦痕的露头)进行了宇生核素10Be暴露年龄的测定,得到(16.1±1.7)ka BP、(31.9±3.4)ka BP、(41.4±4.3)kaBP和(66.8±4.3)ka BP 4个测年数据.结合前人对本地区研究和测年的资料,确定该区更新世经历了4次较大规模的冰川作用:中更新世晚期的倒数第二次冰期、晚更新世中晚期的末次冰期早冰阶、间冰阶和晚冰阶,依次与MIS6、MIS4、MIS3和MIS2阶段对应;全新世经历了2次小的冰进:新冰期和小冰期,它们的时代与青藏高原其它地区新冰期和小冰期的时代基本一致.末次盛冰期的冰川范围十分有限,并且MIS3阶段的冰进规模远远超过了末次盛冰期.早期考察中所命名的唐古拉冰期和巴斯错冰期的时代是中更新世晚期(MIS6)和末次冰期早冰阶(MIS4),扎加藏布冰期的冰碛可能是末次冰期的冰碛叠加在倒数第二次冰期的冰碛物之上,而又经过后期作用改造而形成的一套冰碛.在该区老的冰碛物上没有测定出MIS6阶段之前的年代数据,可能是由后期的破坏或采集的样品不够充分所致,因此对本区最早冰川作用的时代还有待于进一步深入研究.     

苏北盆地末次间冰期以来的气候变化记录

通过对苏北盆地 XH1 钻孔上部 25 m 沉积岩心的研究,重建了苏北盆地末次问冰期以来的气侯环境变化.根据对苏北盆地 XH1 钻孔岩心地层年代、质量磁化率、孢粉的研究,可以较为清晰地划分出末次间冰期--深海氧同位素 5 阶段(25.0～16.5 m)、末次冰期早冰阶--深海氧同位素 4 阶段(16.5～12.5 m)、末次冰期间冰阶--深海氧同位素 3 阶段(12.5～9.5m)、末次冰期冰盛期--深海氧同位素 2 阶段(9.5～5.8 m)、冰后期--深海氧同位素 1 阶段(5.8～0 m).XH1 钻孔记录与深海沉积物氧同位素和古里雅冰心氧同位素的对比研究表明,它们之间有着较好的一致性,但苏北盆地 XH1 钻孔记录与我国西部古里雅冰心记录更为相似,这可能揭示了气候环境变化在全球背景下的区域性特征.     

非洲南部赞比西河流域距今30～5 ka的孢粉组合及古气候变化

非洲东南部晚更新世植被重建及对比研究有助于理解区域气候变化过程和驱动机制。本研究依托国际大洋发现计划IODP361航次科学任务所获取的U1477B海洋钻孔,对其上部4～37 m的沉积岩芯的79个样品进行了孢粉分析,重建了30～5 ka B. P.的区域植被和气候变化历史。研究结果显示,钻孔岩芯整体以草本植物禾本科(Poaceae)和莎草科(Cyperaceae)花粉为主,平均约占75.5%;木本植物花粉较少,以罗汉松科(Podocarpaceae)、豆科(Fabaceae)、使君子科(Combretaceae)和红树科(Rhizophoraceae)等为主;孢粉组合记录了钻孔孢粉源区赞比西河流域的植被特征。在时间演化序列上,钻孔沉积物孢粉组合变化反映出明显的冰期-间冰期(全新世)的植被变化特征：末次冰期(30～17 ka B. P.)以禾本科、莎草科等草本花粉为主,平均约占82.2%,以草原/草甸植被占优势,推测在流域低海拔平原开阔草原广泛发育;罗汉松科为代表的山地森林在冰期也相对发育,指示了相对凉爽潮湿的气候环境;冰消期(17.0～10.5 ka B. P.)禾本科花粉保持稳定平均约...     

阿尔泰山喀纳斯河流域末次冰期OSL年代学新证

布尔津河支流喀纳斯河源于中俄蒙三国交界处友谊峰的南坡,为额尔齐斯河的重要源区.友谊峰连同奎屯峰等高峰形成了阿尔泰山最大的现代冰川作用中心.在第四纪期间,这些冰川都发生了规模较大的进退,在河谷中留下了形态较为清晰的冰川地形.应用OSL单片再生剂量测定技术对采自主U型谷两侧的高大侧碛垄进行了定年,测年结果分别为(27.2±2.0)ka(K-1)与(16.1±1.5)ka(K-2).基于地貌地层学原理、并结合已有的年代学资料(OSL与14 C)与古气候研究资料,末次冰期以来喀纳斯河流域共有5次规模较大的冰进,分别为小冰期、新冰期、末次冰期晚冰阶(MIS 2)、末次冰期中冰阶(MIS 3中期)与末次冰期早冰阶(MIS 4).     

德令哈盆地尕海湖DG03孔岩芯矿物组合与古环境变化

对气候敏感区德令哈盆地尕海湖DG03孔岩芯的矿物学分析表明,DG03孔岩芯的矿物主要包括石英、斜长石、微斜长石、绿泥石、伊利石、方解石、文石、白云石、石膏及石盐等。岩芯记录了尕海湖约11 ka以来（AMS 14C年龄）的古环境变化。根据矿物、碳酸盐含量及岩性的变化,整个岩芯可划分为三个部分:Ⅰ. 约11 ka～10 ka BP,晚冰期末期;Ⅱ. 10 ka～4 ka BP,全新世早中期;Ⅲ.4 ka至今,全新世晚期。矿物组合表明,自晚冰期以来,尕海湖先后经历了湖泊演化的逆向和正向演化阶段,即尕海湖先后经历了晚冰期的干冷气候,早全新世的暖干气候,中全新世的暖湿气候以及晚全新世以来的逐渐干冷的气候。岩性分析还表明,尕海湖沉积环境复杂,存在多种微相沉积。     

西藏纳木错末次盛冰期以来的古植被、古气候和湖面变化

西藏纳木错湖相沉积的U系、14C年龄和孢粉分析结果表明,纳木错沿岸的拔湖约1.5～8.3m和8.3～15.6m的T1和T2分别形成于末次盛冰期以来约(11.81±0.10)～(4.22±0.09)kaB.P.期间和(28.2±2.8)kaB.P.左右.该套湖相层的孢粉组合、地层和湖岸堤的分布表明,在末次盛冰期期间,纳木错湖面主要波动于拔湖12～20 m之间,但湖面最低可达拔湖约8m.区域植被主要为以蒿和莎草科为主、含松和桦的草原.在约11.8～4.2ka B.P.期间,湖面波动于拔湖2～9m之间,区域气候整体较为暖湿.其中全新世大暖期出现在约8.4～4.2 ka B.P.期间,气候温暖湿润,区域出现针叶林或针阔叶混交林,气温可能比现今高约5℃,降水量可能比现今多100～200mm,湖面扩张并升高,最高可达拔湖约10m.     

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.     

硅酸盐类样品中硅、铁、铝、钛、锰、钙、镁、钾、钠和磷的x射线荧光光谱测定

本文拟定了一种以熔融法制备样片,用X射线荧光光谱测定硅酸盐类样品中Si、Fe、Al、Tj、Mn、Ca、Mg、K、Na、P等元素的分析方法。在对不同靶材X光管和分光晶体实验对比的基础上,选择了最佳的测量条件。该法具有快速、准确,测量范围广,检测限低,价格便宜等优点。经过近百个各种类型标样或管理样品的分析对比表明,本法不仅适用于硅酸盐类岩石样品的分析,还适用于铁矿、铝土矿、碳酸盐类岩矿样品以及水泥、耐火材料等样品的分析。     

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     

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.     

Viscous, cohesive, non-Newtonian, depositing, radial slurry flow

Mining induced subsidence can significantly affect mining costs where major surface facilities and natural environment need to be protected. Overburden grout injection is a technology used to control coal mine subsidence by injecting the mine waste material extracted from the coal back into the inter-burden rock during longwall mining. The flowing slurry is here categorised as a nonlinear viscous cohesive (Bingham plastic) fluid. During longwall mining the grout slurry is pumped into the separated beds of the rock mass through a central vertical borehole, which is drilled deep into the inter-burden rock strata above the coal seam. However, a blockage can occur in the injection system when the slurry velocity falls below a certain critical threshold velocity, indicating a material phase change from cohesive-viscous to cohesive-frictional. In situ field injection tests through boreholes have been simulated at a smaller scale at the CSIRO laboratory in Brisbane by pumping the slurry through a radial disk (gap = 4 mm) from its centre. Laboratory experiments indicate a general, nonlinear, cohesive, viscous, frictional model for shear behaviour of the slurry, in which the material shear parameters are functions of the disk radial distance. Complete dimensional and dimensionless analytical solutions have been developed based on an approach related to Bingham–Herschel–Bulkley fluid mechanics. The derived formulae include relations for minimum pump pressure, local pressure and pressure gradient, wall shear stress, volume rate, velocity and velocity gradient. The theoretical results match the experimental measurements. The experiments covered slurries with maximum particle sizes of 0.5 to 2 mm with about 50% being larger than 100 µm. The viscosities at the various solids concentrations were measured with a standard torsion viscometer. This study differs from the previous research in several distinct aspects, namely, consideration of the variable shear parameters rather than fixed values, inclusion of total nonlinear behaviour, and implementation of a friction function to mimic behaviour of the deposited and consolidating stiff slurry, which can cause a significant pressure rise as a result of the increased shear resistance.     

硅酸盐中铁、锰、钛、钙、钾、磷、硅、铝、镁、钠、锶、铷、钡的X-射线荧光光谱定量测定

本文介绍样品经四硼酸锂熔融制成玻璃小饼。采用Lachance模式和理论a系数来校正元素间的效应,由3080E型X-射线荧光谱仪和DF-350B数据处理系统完成硅酸盐中十三个项目的测定。     

Bellechester,Minnesota, USA,lagoon collapses

Bellechester, Minnesota, is a small community of approximately 155 residents located on the county line between Goodhue and Wabasha counties in southeast Minnesota's karst region. Bellechester is served by a 21-year-old wastewater treatment facility (WWTF) consisting of three waste-stabilization ponds. On 28 April 1992 six sinkholes were discovered to have drained cell 2 of the WWTF resulting in the loss of approximately 8.7×10⁶ 1 of partially treated effluent and about 600 m³ of soil into previously undetected subsurface voids of unknown dimensions. In the week following the collapse, approximately 200 water wells located within a 5-km radius of the WWTF were sampled in an after-the-fact, emergency sampling program. Twelve samples with elevated fecal coliform levels, 18 samples with nitrate-nitrogen greater than the 10 mg/1 standard, and no samples with elevated chlorides were found. However, the elevated levels could not be unambiguously attributed to the WWTF collapse. This is the third WWTF to fail by sinkhole collapse in southeast Minnesota since 1974. All three collapsed lagoons have been located in similar geomorphic and stratigraphic settings. However, at least two lagoons have collapsed in the adjacent area in northeast Iowa, and these lagoons are located at different stratigraphic positions. Twenty-two WWTFs constructed in southeast Minnesota's karst region in the last 25 years have been identified as subject to potential sinkhole collapse. An unknown but significant number of manure storage lagoons, flood control structures, etc., have also been constructed in the karst region and are at risk. Public agencies are beginning to develop plans to deal with the risk associated with existing and future waste lagoons in this environment. The critical hydrogeologic parameters that can be used to prioritize the risk of collapse at existing facilities include: (1) the lithology of the first bedrock beneath each lagoon, (2) the thickness of surficial materials between the lagoon and the bedrock surface, (3) the presence and construction of liners (seepage rate), and (4) the proximity to existing sinkholes.     

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.     

滇东南花岗岩与锡、银、铜、铅、锌多金属矿床的成因关系

滇东南锡、银、铅、锌多金属矿床主要分布在个旧、白牛厂、都龙3个矿区,而滇东南较大的3个花岗岩体又分别出露在3个矿区或附近.花岗岩体均形成于燕山晚期,岩石化学、矿物成分相似,富含锡、银、铅、锌、钨、铜等成矿元素.矿床主金属元素组合与岩体之间的距离由远而近出现由锡、钨、(铍、铌、钽)→锡、钨、(铁)、铜、铟→锡、铅、锌、银、铟、(锑)有规律的变化.花岗岩浆是成矿物质来源和成矿热源.岩浆侵入初期使上覆地层隆起产生背斜(凹陷部位成向斜);同时使地层产生一系列裂隙、压性断层或层间断裂;岩浆侵入晚期,这些断层再次活动,表现为张性,岩浆产生的含矿热液沿由其活动所造成的断裂迁移、充填、交代、沉淀而形成矿床.     

岩石密度和超高压岩石折返速率

在常温常压条件下对中国大陆科学钻CCSD主孔100-3000米岩心样品进行了密度测量,建立了密度连续剖面,并界定了不同超高压岩石的密度值。通过对比高温高压物性实验资料,岩石密度随着退变程度增强而降低,榴辉岩密度变化序列为3.52g/cm3→3.49g/cm3→3.07g/cm3→2.93g/cm3。超高压长英质岩石密度变化序列为3.00g/cm→2.80g/cm3→2.65g/cm3。上述实验资料是讨论不同折返阶段岩石所受浮力的基础,为研究折返速率大小提供了基本参数。本文通过折返板块运动平衡时,上浮力与粘滞力平衡这一关系式,定量研究了大陆俯冲板块的折返速率,认为密度差产生上浮力从而引起折返,温度对板块折返速率的影响最为显著;密度差大小、折返角度、折返板块大小对折返速率也有直接的影响。定量模拟分析表明,在温度高于850℃时,板块的折返速率可以超过100mm/a;当温度降至700℃时,折返速率则低于1.5mm/a。作者认为在折返早期,温度较高,板块快速折返至60-70km榴辉岩相深度;随着传导散热,温度降低,板块以较慢的速率折返至中下地壳。折返速率的估算表明,浮力是板块折返第一阶段(从>100km深部折返至<40km的中下地壳)的主要驱动力。