广东东镇岩体微区^40Ar／^39Ar年龄及其意义

采用激光显微探针＾４０Ａｒ／＾３９Ａｒ测年技术（简称微区＾４０Ａｒ／＾３９Ａｒ法）对广东云开地区东镇岩体含眼球体的片麻状花岗质岩石中单矿物作了同位素年龄测定，获得眼球体内核中的巨晶状钾长石年龄（４１９．４０±４．３７）×１０＾６ａ。眼球体角缘中重结晶微粒状钾长石年龄（２７２．６３±３．１３）×１０＾６ａ，眼球体外壳中的强应变长条纹黑云母年龄（１７７．８４±２．２９）×１０＾ａ。暗色条带中的弱应变板     

高分辨10Be记录与黄土地层定年

利用Ｂ／Ｍ地磁极性倒转层位０．７３ＭａＢ．Ｐ．时间参考点，通过黄土剖面_１０Ｂｅ变化曲线与深海ＳＰＥＣＭＡＰδ_１８Ｏ变化曲线匹配拟合，求得洛川黄土剖面０．７５Ｍａ以来的相对连续时标。时标精度约５０００—１００００ａ。由于０．１５Ｍａ以来洛川剖面加密取样以及_１０Ｂｅ、δ_１８Ｏ两曲线之间更好的相关性，_１０Ｂｅ相对时标精度与ＳＰＥＣＭＡＰδ_１０Ｏ时标精度大体相同，即３０００—５０００ａ。各时期_１０Ｂｅ通量与黄土堆积速率之间存在十分好的线性相关关系，展示了一条崭新的地层定年途径。黄土_１０Ｂｅ记录３５０００ａＢ．Ｐ．处的Ｒａｉｓｂｅｃｋ峰可被用作地层时间参考点。黄土_１０Ｂｅ／(２６)Ａｌ值、黄土石英中“就地”成因_１０Ｂｅ／(２６)Ａｌ值以及“就地”成因_１０Ｂｅ浓度等均可望应用于黄土地层精确定年。     

广东徐闻早更新世古气候变化浅析

广东徐闻早更新世时期的气候曾发生多次冷,暖交替,徐闻前山ＺＫ１钻孔岩心显示,下更新统为连续沉积,孢粉含量丰富,可以划分为１３个孢粉带,代表热带－亚热带气候的植物面貌,据孢粉组分的分布规律及针,阔叶树种的含量比值,可将该区早更新世分为１２个气候期,其中有８次较大的冷暖交替,相对的冷期出现在２．４８×１０＾６～２．３８×１０＾６ａＢＰ,２．３３×１０＾６～２．２３×１０＾６,ａＢＰ,１．９２×１０＾６     

香港中生代火成岩U—Pb法年龄测定

香港中生代侵入岩和火山岩２２个锆石和独居石新的Ｕ－Ｐｂ年龄,揭示了中侏罗世至早白垩世火山－深成作用分为４期,（１６４．６±０．２）×１０＾６～（１５９．３±０．３）×１０＾６ａ,（１４６．６±０．２）×１０＾６～（１４６．２±０．２）×１０＾６ａ,（１４３．７±０．３）×１０＾６～（１４２．５±０．３）×１０＾６ａ,（１４０．９±０．２）×１０＾６～（１４０．４±０．２）×１０＾６ａ。从最早知道的     

渭南黄土剖面十五万年以来的主要地层界线和气候事件──年代学方面的证据

本文在渭南黄土剖面所测得的年龄结果和时间标尺研究的基础上，结合粒度、磁化率等气候曲线的分析，对该剖面十五万年以来一些主要地层界线和气候事件的年龄进行了初步讨论，结果如下：１）Ｓ１／Ｌ２界线位于剖面１１８０ｃｍ处，从时间标尺上可知其年龄为１２８８００ａＢ．ｐ．，同末次间冰期起始的年龄相一致；２）Ｌ１／Ｓ１的地层界线年龄为７４２２０ａＢ．Ｐ．，同ＳＰＥＣＭＡＰ曲线中末次间冰期的结束年龄相吻合；３）渭南剖面所指示的末次盛冰期约在２００００～１８０００ａＢ．Ｐ．之间；４）在２００００～１８０００ａＢ．Ｐ．之间的末次盛冰期，有一段不足１０００ａ的快速堆积期，其堆积速率是中国黄土平均堆积速率的１０倍以上。     

中国黄土10Be研究进展

８０年代中期，中国和瑞士科技工作者开始联合进行黄土＾１０Ｂｅ研究。建立了黄土＾１０ＢｅＡＭＳ测量的理想流程，发现了＾１０Ｂｅ在黄土地层良好保存性等重要地球化学行为特征，确认了黄土＾１０Ｂｅ研究具有重要意义。对洛川黄土部面０．４－１３８ｍ段６００多个样品进行了＾１０Ｂｅ测定，建立了２．５Ｍａ以来大陆堆积物同位素记录曲线。     

渭南黄土剖面十五万年以来的主要地层界线和气候事件──年代学方面的证据

本文在渭南黄土剖面所测得的年龄结果和时间标尺研究的基础上，结合粒度、磁化率等气候曲线的分析，对该剖面十五万年以来一些主要地层界线和气候事件的年龄进行了初步讨论，结果如下：１)Ｓ１／Ｌ２界线位于剖面１１８０ｃｍ处，从时间标尺上可知其年龄为１２８８００ａＢ．ｐ．，同末次间冰期起始的年龄相一致；２)Ｌ１／Ｓ１的地层界线年龄为７４２２０ａＢ．Ｐ．，同ＳＰＥＣＭＡＰ曲线中末次间冰期的结束年龄相吻合；３)渭南剖面所指示的末次盛冰期约在２００００～１８０００ａＢ．Ｐ．之间；４)在２００００～１８０００ａＢ．Ｐ．之间的末次盛冰期，有一段不足１０００ａ的快速堆积期，其堆积速率是中国黄土平均堆积速率的１０倍以上。     

华北地台钼（铜）矿床成矿年代学研究——辉钼矿铼-锇年龄及其地质意义

华北地台北缘的工产辽和南缘的东秦岭两个钼矿带闻名遐迩。本文用同位素稀释－等离子体质谱法，直接测定了燕辽钼矿带中兰家沟钼矿床的Ｒｅ－Ｏｓ等时线年龄为（１８６．５±０．７）×１０＾６ａ，杨家杖和肖家营子钼矿床的Ｒｅ－Ｏｓ模式年龄为（１８７±２）×１０＾６ｄ－（ｄ１９１±６）×ｄ１０＾６ａ和（１７７±５）×１０＾６ａ，小寺沟和寿王坟铜矿床的Ｒｅ－Ｏｓ模式为ＤＤ（１３４±３）×１０＾４ａ和（１４８±４）×     

氢化物发生原子荧光法和无火焰原子荧光法连续测定地球化学样品中…

建立了一种连续测定Ａｓ、Ｓｂ、Ｂｉ、Ｈｇ四元素的方法，对测汞用还原剂及几种测量体系进行了比较，采用对原子化器适当加温的无火焰原子荧光法测汞，以ＫＭｎＯ４消除Ｔｅ、Ｓｅ对汞测定的干扰。本方法Ａｓ、Ｓｂ、Ｂｉ、Ｈｇ四元素的检出限分别为２．０１×１０＾－１０ｇ／ｍｌ１．５６×１０＾－１０ｇ／ｍｌ、２．９８×１０６－１０ｇ／ｍｌ；４．２×１０＾－１１ｇ／ｍｌ；对ＧＳＳＩ平行测定１１欠，Ｈｇ的标准偏差为２．     

渭南黄土剖面的年龄测定及十五万年来高分辨时间序列的建立

作者对渭南黄土剖面连续采取的样品进行了系统的_１４Ｃ和ＴＬ年龄测定，测得的_１４Ｃ年龄做了δ_１３Ｃ校正和日历年龄校正，并与ＳＰＥＣＭＡＰ比较，取得了很好的结果。根据测得的年龄，Ｓ０底部１４３ｃｍ处的_１４Ｃ年龄为１０３００ａＢ．Ｐ，即全新世起始于１０３００ａＢ．Ｐ．；Ｌ１可划分五层，其中Ｌ(１－２)和Ｌ(１－４)为古土壤层，Ｌ(１－２)顶部_１４Ｃ年龄为２２０００ａＢ．Ｐ．，深度为３６１ｃｍ，Ｌ(１－４)．底部有一层明显的碳酸盐结核，其ＴＬ年龄为５１９１０ａＢ．Ｐ．，深度为６４０Ｃｍ；Ｌ１底部的ＴＬ年龄为７３０００ａＢ．Ｐ．，深度为８５５ｃｍ，这便是马兰黄土的起始年龄；Ｓ１底部为１３４５００ａＢ．Ｐ．，深度为１２１６ｃｍ。与深海沉积物氧同位素阶段对比，马兰黄土相当于１—４阶段，Ｓ１相当于５阶段。     

唐古拉山地区第四纪冰川作用与冰川特征

自中更新世以来,唐古拉山地区发生过3次更新世冰川作用(即昆仑冰期、倒数第二次冰期和末次错冰期)和2次全新世晚期冰进(即新冰期和小冰期冰进).昆仑冰期(最大冰期)发生在中更新世早期(0.80～0.60MaBP),不仅是本区最早的一次冰期,而且也是冰川规模最大的一次冰期,当时的冰川规模比现代冰川大16～18倍;倒数第二次冰期发生在中更新世晚期(0.30～0.135MaBP),比现代冰川大13～15倍;末次冰期发生在晚更新世晚期,应分为末次冰期早冰阶(75.0～58.0kaBP)和晚冰阶(32.0～15.0kaBP,23.0kaBP时达到极盛),但在唐古拉山地区截止目前还未找到早冰阶的冰川遗迹,因此,只对末次冰期的晚冰阶(LMG)进行了探讨.LMG时,冰川规模比现代冰川大10倍;新冰期发生在全新世高温期后,冰碛物的¹⁴C测年为(3540±160)aBP,冰川规模略大于现代冰川;小冰期发生在15～1世纪,冰川规模已接近于现代冰川.由于青藏高原的上升,对高原腹部地区引起的干旱化过程和水分严重不足,使唐古拉山地区的冰川自昆仑冰期以来,冰川规模一次比一次明显的减小.     

桂林地区水南洞14～25万年石笋的碳氧同位素记录和古气候重建

通过对桂林水南洞石笋进行高精度的热电离质谱(TIMS－U)测年和碳氧同位素分析,建立了桂林地区245.20 ka BP至147.90 ka BP间的古气候变化时间序列,确定了石笋记录的时段B与时段C分界的年龄为242.5±6.4 ka BP(相当于深海岩芯氧同位素标准曲线时段7与时段8分界的年龄)、时段A与时段B分界的年龄为 192.6±3.9 ka BP(相当于深海岩芯氧同位素标准曲线时段6与时段7分界的年龄)。桂林地区245.20～147.90 ka BP石笋记录的冷暖事件所反映出的古气候变化,大致可分为3个气候变化阶段:(1) 245.2～242.6 ka BP, 相当于深海岩芯氧同位素标准曲线阶段8的末期;(2) 242.5～192.6 ka BP,相当于深海岩芯氧同位素标准曲线时段7;(3)192.6～147.9 ka BP间的倒数第2次冰期, 相当于深海岩芯氧同位素标准曲线时段6的早中期。石笋的TIMS－U测年和碳氧同位素记录揭示,桂林地区245.2～147.9 ka BP的古气候演变历史与深海岩芯时段8末期、时段7和时段6的氧同位素,深海岩芯中记录的孢子花粉组合、CaCO3含量、海平面的升降变化以及与中国北方黄土、古土壤中记录的孢子花粉组合、成壤程度、全铁富集程度、磁化率变化、原生碎屑CaCO3含量和淋溶强度等所揭示的古气候和古季风变化具有极好的对应关系,表明桂林地区中更新世晚期以来的古气候演变既有全球性特征,又有着强烈的区域性特征。     

Glacial and environmental changes over the last 60 000 years in the Polar Ural Mountains,Arctic Russia,inferred from a high‐resolution lake record and other observations from adjacent areas

Our knowledge about the glaciation history in the Russian Arctic has to a large extent been based on geomorphological mapping supplemented by studies of short stratigraphical sequences found in exposed sections. Here we present new geochronological data from the Polar Ural Mountains along with a high‐resolution sediment record from Bolshoye Shchuchye, the largest and deepest lake in the mountain range. Seismic profiles show that the lake contains a 160‐m‐thick sequence of unconsolidated lacustrine sediments. A well‐dated 24‐m‐long core from the southern end of the lake spans the last 24 cal. ka. From downward extrapolation of sedimentation rates we estimate that sedimentation started about 50–60 ka ago, most likely just after a large glacier had eroded older sediments from the basin. Terrestrial cosmogenic nuclide (TCN) exposure dating (¹⁰Be) of boulders and Optically Stimulated Luminescence (OSL) dating of sediments indicate that this part of the Ural Mountains was last covered by a coherent ice‐field complex during Marine Isotope Stage (MIS) 4. A regrowth of the glaciers took place during a late stage of MIS 3, but the central valleys remained ice free until the present. The presence of small‐ and medium‐sized glaciers during MIS 2 is reflected by a sequence of glacial varves and a high sedimentation rate in the lake basin and likewise from ¹⁰Be dating of glacial boulders. The maximum extent of the mountain glaciers during MIS 2 was attained prior to 24 cal. ka BP. Some small present‐day glaciers, which are now disappearing completely due to climate warming, were only slightly larger during the Last Glacial Maximum (LGM) as compared to AD 1953. A marked decrease in sedimentation rate around 18–17 cal. ka BP indicates that the glaciers then became smaller and probably disappeared altogether around 15–14 cal. ka BP.     

西藏阿里阿伊拉日居山脉第四纪冰川作用

在西藏阿里阿伊拉日居山脉南北两麓及切割山脉的各沟谷中,分布着4套早更新世以来的冰川沉积物。根据这些冰川沉积物的地层层序和冰川沉积物的电子自旋共振(ESR)年龄测定结果,将阿伊拉日居山脉南北两麓所发生的4次早更新世以来的冰川作用,分别命名为札达冰期(1161-952 ka BP)、阿伊拉日居冰期(762-730 ka BP)、学朗冰期(336-211 ka BP)和弄穷冰期(105-15 ka BP),并与青藏高原及其他地区冰期进行了对比。各次冰期的冰川性质分别为大型山岳冰川、冰帽、山麓冰川和中小型山谷冰川。全新世时期,现代冰川有过冰川推进。近期冰川则发生了明显的后退。     

Correlating Alpine glaciation with Adriatic sea‐level changes through lake and alluvial stratigraphy

We compare lake and alluvial stratigraphy along a frame connecting the southern Alpine foothills and the Adriatic Sea, with the aim of matching the effects of Alpine glaciation and sea‐level changes on sedimentation during the last glacial cycle. The palynostratigraphy of Lake Fimon provided proxies for regional vegetation and climate change and was coupled with sediment petrography, loss on ignition and magnetic susceptibility, disentangling alluvial phases from fluvioglacial activity related to culminations of the southeastern Alpine glaciers. The Fimon area was not reached by alluvial fans during the penultimate glacial maximum, nor by the sea transgression during the last interglacial, but a closed lake soon developed at the Eemian onset due to enhanced rainfall. Sea‐level fall at glacial inception triggered the entrenchment of the drainage network in the plain reaching the outer Fimon Basin. Slow aggradation, but no sign of fluvioglacial activity, lasted to 38.2 ± 1.45 cal. ka BP, when a major forest withdrawal took place, coeval to the spread of alluvial fans. By 27.5 ± 0.5 cal. ka BP the Fimon Basin was dammed by the Brenta outwash system. The main step of of forest recovery commenced at around (15.8) cal. ka BP, when apex trenching of the outwash fans was triggered by the glacier's decay. Copyright © 2011 John Wiley & Sons, Ltd.     

中国第四纪冰期划分改进建议

由刘东生主持1位研究者提出的"以气候变化为标志的中国第四纪地层对比表"一文发表已近2a,其中由施雅风执笔第四纪冰期与海洋同位素对比部分.由于新情况的出现,需作适当改进:1)周尚哲等应用ESR测年确定祁连山北坡摆浪河源中梁赣海拔299m,高出现代河床500m处冰碛年代为42.9ka BP,天山乌鲁木齐河上游高出河床200～300m的高望峰阶地冰碛样品ESR测年为477.1ka BP和459.7ka BP,均相当于MIS 12阶段,该阶段国际上对应Kansan-Mindel冰期,与MIS 2、MIS和MIS 1都是100ka周期δ¹⁸O值特低时期;2)古里雅冰芯记录中相当于MIS3b阶段,δ¹⁸O值折算温度比现代低5℃左右,已经发现台湾雪山山庄期冰碛TL年代为(44.25±3.72)ka BP,天山乌鲁木齐河谷一处冰碛ESR年代45.9ka BP,喜马拉雅山、喀喇昆仑山和兴都库什南坡测定对应此时段冰川前进更为显著,初步检查亚、欧、北美、南美和澳洲12个地区23个地点相应于MIS 3b冷期冰川前进规模均超过MIS 2阶段,即常说LGM时,推测MIS 3b的降温值虽不及MIS 2,但降水较多,有利于冰川发展;3)MIS 3a暖期,不仅青藏高原异常暖湿,而且中国全境的降水量普遍高于现代,并有较大范围的海侵与仅低于现代海面8～10m的高海面,气候环境实际达到间冰期程度.上述3点应补充入中国冰期划分表.     

祁连山北缘—河西走廊西段晚新生代逆冲推覆断裂发育模式

祁连山北缘—河西走廊西段地处青藏高原东北缘,是我国新构造活动最强烈的地区之一。通过野外对研究区主要活动断裂的调查研究、结合年代学测试和综合分析,认为祁连山北缘—河西走廊西段地区的旱峡—大黄沟断裂、玉门断裂、新民堡断裂和阴洼山断裂都是晚更新世至全新世活动断裂。旱峡—大黄沟断裂形成于中新世晚期,一直活动至今;玉门断裂形成于上新世早期,在距今7.6ka左右和3.2ka左右发生过2次强烈的新构造活动(古地震),也是2002年玉门地震的发震断裂;阴洼山断裂形成于上新世晚期(3.0Ma左右),在距今19.9～21.0ka、8.6～10.0ka、4.1～5.0ka发生过3次强烈的新构造活动,也可能是1785年惠民堡(现新民堡)地震的发震断裂;但是位于近盆地中心的新民堡断裂形成时代明显晚的多,起始于中更新世晚期(0.17Ma左右),在距今28.3ka、4.4ka和1.2ka左右发生过强烈的3次新构造活动。在运动形式上,上述4条断裂均为自南南西向北北东的逆冲推覆。在变形性质上,新民堡断裂以非地震性的蠕滑为主,其他3条断裂主要为地震性的粘滑变形。在祁连山北缘—河西走廊西段的北北东剖面上,逆冲推覆断裂表现为前展-后展复合发育模式,即形成时代最新的是位于酒西盆地中心的新民堡断裂,在酒西盆地中心以南部分的剖面中断裂发育为前展式,由祁连山腹地向河西走廊盆地中心断裂形成时代越来越新,而酒西盆地中心以北部分的剖面中断裂发育为后展式,即从盆地中心到盆地北缘断裂形成时代越来越老。     

青藏高原东北部泥炭沉积粒度与元素记录的全新世千年尺度的气候变化

通过对青藏高原东北部共和盆地泥炭沉积的粒度与地球化学元素分析, 重建了区域全新世千年尺度的气候变化过程. 结果显示: 10.0~8.6 cal ka BP区域暖湿程度逐渐增加, 但在8.6~7.1 cal ka BP气候相对寒冷干燥, 7.1~3.8 cal ka BP 暖湿程度总体上为全新世最佳, 但也出现明显的气候波动, 3.8~0.5 cal ka BP气候向冷干方向发展, 0.5 cal ka BP以来气候又逐渐转向暖湿. 这一特征与中国东部季风区的气候变化有很好的一致性. 此外, 区域全新世气候变化过程中存在10次千年尺度的寒冷事件, 并与高原冰芯、 湖泊、 泥炭和风成沉积记录的古气候变化, 甚至与北半球高低纬度的气候变化都具有良好的可比性. 因此, 认为区域全新世气候变化具有"季风模式"与"千年尺度震荡"的双重特点.     

Last Interglacial palaeovegetation,palaeoenvironments and chronology: a new record from Lago Grande di Monticchio,southern Italy

The sediments of Lago Grande di Monticchio, southern Italy, extend continuously from the present back to the penultimate glacial stage and have an independent lamination-based chronology of high precision and accuracy. Results are presented here from a detailed palynological investigation of that part of the sediment sequence that extends from the last millennia of the penultimate glacial stage to the first stadial following the Last Interglacial (LI). Quantitative palaeovegetation and palaeoclimate reconstructions made from the palynological data are also presented. The onset of the LI is dated to 127.20 ka BP, a date that is consistent with other recent estimates; the duration of the LI is estimated to have been 17.70 ka. The palaeovegetation record indicates a transition period of 3.35 ka at the end of the penultimate glacial stage prior to the onset of the LI; no Younger Dryas-like oscillation is recorded, although the transition was interrupted by a brief event, lasting ca 250 years, during which pollen of woody taxa was reduced in abundance. Steppe vegetation dominated during the latter part of the penultimate full-glacial stage, but was replaced progressively by wooded steppe during the transition. Although the development of forest cover marked the onset of the LI, the forests were relatively open or discontinuous during the first 2.65 ka, closing progressively thereafter and generally dominating between 123.00 and 109.50 ka BP. The end of the LI is dated to 109.50 ka BP, after which date forest cover became discontinuous and wooded steppe or steppe dominated during the 1.90 ka of the subsequent stadial. As might be expected, given the location of the lake, the composition of the LI forests differs markedly from those recorded from northern Europe, as well as from those recorded at other localities in southern Europe. The palaeoclimate reconstructions reveal complex changes in seasonality, the maximum coldest month mean temperatures being between 125.70 ka BP and 123.00 ka BP, whereas maxima for both annual temperature sum and the ratio of actual to potential evapotranspiration were between 120.60 ka BP and 115.80 ka BP. Reconstructed zonal mean values for all three climatic variables in the zones in which they peak exceed values at the locality today. Comparison with other palaeovegetation records of the LI from Europe reveals that forest cover generally opened up north of the Alpine region probably ca 115 ka BP, coinciding with a marked decrease in sea surface temperatures in the Nordic Seas; this probably corresponds to a marked shift in forest composition at Lago Grande di Monticchio at 115.80 ka BP with an associated reconstructed decrease of ca 5 °C in coldest month mean temperature. Nonetheless, forest continued to dominate at Lago Grande di Monticchio until 109.50 ka BP. Such comparisons also reveal considerable complexity in the geographical and altitudinal patterns of change in palaeovegetation during the LI; such complexity is to be expected given the parallel complexity of Holocene changes. Systematic comparisons between reconstructions of palaeoclimate are hampered by a lack of consistency in approach and in the variables reconstructed. Further insight into this complexity of palaeoclimate development during the LI requires a synthesis of the available data and application of a consistent reconstruction approach that also provides robust estimates of the uncertainty in the reconstructed values.     

青藏高原唐古拉山口第四纪冰碛层划分及其地质环境意义

在对唐古拉山口现代冰川和古冰川考察研究的基础上，结合定位观测资料和TL、^10B-^26Al-^21Ne及^14C测年数据，对区内第四纪冰川遗迹进行了深入讨论，划分出二次冰期(即中更新世晚期的倒数第二次冰期、晚更新世中一晚期的末次冰期)和二次全新世冰进(即新冰期和小冰期)。提出在早更新世时，由于山体未达到当时冰川发育的雪线高度，所以未发育冰川。但在唐古拉山口地区，截止目前还未找到中更新世早期的倒数第三次冰期的冰川遗迹，由于高原隆升的滞后性和冰川发育的延滞效应及“亚洲干极”的耦合，推测仍只发育局部冰川作用。进一步研究表明，古今雪线由高原边缘向腹地升高，唐古拉山地区高出边缘1500m左右，生动表现了“亚洲干极”的作用；广泛分布的湖群说明羌塘地区是一个大江大河尚未伸入的内流地区，意味着青藏高原是个年青的高原。由于青藏高原的隆升，对高原腹地引起的干旱化过程和水分严重不足，使唐古拉山地区的冰川自倒数第二次冰期以来，冰川规模一次比一次明显地减小。