Variations of alkenone temperature in the Sea of Japan during the last 170 ka and its paleoceanographic implications

Two sediment cores, KCES1 and ODP797, which were recovered from the Sea of Japan （JS）, were measured for alkenone-derived sea surface temperatures （U37-SSTs）. Our results revealed that the SSTs closely follow the glacial-interglacial cycles during the last 170 ka, except in the last glacial maximum （LGM）, during which the SST was higher than in the Holocene. The anomalous high temperature in the LGM is considered as an effect of the intrusion of a low salinity water mass into the JS when the sea level was almost below 130 m. On the glacial- K interglacial to orbital timescale, the U37-SSTs record in the JS correlated well with the benthic foraminiferal SO record and solar insolation, which suggests the dominant control of solar insolation and its related sea ice develop- ment on the SST in the JS. On the sub-orbital/millennial timescale, reduced SST corresponds to an enhanced east asian winter monsoon （EAWM） during the last glacial period （MIS3 and MIS4）, indicating the dominant control of sea ice expansion due to the enhanced EAWM on the SST in the JS. In contrast, during the last interglacial period （MIS5）, the SST in the JS was controlled by variations in the east Asian summer monsoon. These results highlight the key role of solar insolation and associated glacial-interglacial conditions in the variations of the SST in the JS since the last 170 ka.     

大厂凹陷MIS3阶段以来沉积物地球化学特征分析

深海氧同位素3-1阶段是指深海沉积物有孔虫氧同位素记录的第四纪末次冰期至冰后期的一个时期,期间气候表现为间冰阶、极端寒冷、多次千年尺度气候事件至最后转暖多个变化特征,相关气候变化沉积响应及影响因素等科学问题一直以来备受关注。然而,该时期相关千年尺度气候事件的记录及讨论在华北平原地区仍有争议,为探讨华北平原西北地区在该阶段的气候特征,本研究在大厂凹陷区天然剖面进行高密度碳14断代样品测试,并开展常量和微量元素地球化学含量分析,获得地球化学数据变化趋势特征,结果表明,该剖面年代从32.5ka至8.2 ka,处于深海氧同位素3阶段末期至深海氧同位素1阶段早期。在该时段,主量元素氧化物TFe2O3、Al2O3、SiO2、MgO、CaO、Na2O与K2O与微量元素Sr、V、Ni、Co、Ga、Cu、Ba、Cr和Zn均呈现一致的变化趋势;在MIS2末次冰盛期和MIS1早期中的B?lling-Aller?d暖期和新仙女木冷期,K/Na、Al/Na、化学蚀变指数 、化学风化指数 和古温度等指标与东亚季风区气候呈现一致的变化,同时与全球尺度的事件具有同步性,因此认为晚更新世晚期华北平原的气候变化可归因于全球气候系统下东亚季风区的演化。     

A 60 000-year loess-paleosol record of millennial-scale summer monsoon instability from Lanzhou, China

The 28-m high-resolution Shajinping loess section in Lanzhou on the Chinese western Loess Plateau records a detailed history of millennial Asian summer monsoon change since the earlier last glaciation. Summer monsoon proxies of soil magnetic susceptibility, carbonate content and soil color show that Asian summer monsoon experienced a series of rapid episodic pulse enhancements spanning only ca. 1-2 ka and have sub-Milankovitch cycles of progressive weakening in low frequency domain since ca. 60 kaBP. Soil formation responds to these by deepening colors, accumulating organic matter, increasing biological channels and leaching certain carbonates. The pedogenic degree generally increases with the degree of enhancement of summer monsoon. These may reflect the impact of the last glacial fast climatic change in the North Atlantic region on Asian summer monsoon.     

Variations of organic carbon isotopic composition and its environmental significance during the last glacial on western Chinese Loess Plateau

The last glacial period is characterized by a cold and dry climate with low atmospheric CO2 concentration. The relatively arid climate and low CO2 concentration are favorable to the growth of C4 plants, but the low temperature limits the development of th…     

广东平远花岗岩风化壳及其稀土成矿特征

以竹细塘和神背岩体为例，研究燕山晚期黑云母花岗岩的风化壳及其稀土成太特征。结果表明：风化壳剖面发育层状结构，自下而上，碎屑矿物减少，粘土矿物含量增加，活动组分（Ｋ２Ｏ，Ｎａ２Ｏ，ＣａＯ）减少，稳定组分（Ａｌ２Ｏ３，Ｆｅ２Ｏ３，ＴｉＯ２）增加，风化壳中稀土分布总体上保持原岩特征，但各风化壳层中铈负异常均增加，铕和负异常消失乃至出现正异常；全风化壳的中下部稀土最为富集，稀土分布型式也变化最大；在全风化     

川东北宋家洞石笋氧碳同位素及锶含量突变分析

通过对宋家洞石笋SJ3的氧碳同位素及锶含量进行Mann-Kendall test突变分析,得出以下结论:(1)氧同位素值记录了末次冰盛期向Heinrich Event 1时期的转变;(2)碳同位素值和锶含量记录了由H1冷期向BФlling-AllerФd暖期的转变;(3)碳同位素值和锶含量指示了在19.8～15.3ka时当地的东亚夏季风和冬季风呈正相关关系,在15.3～14.8 ka呈负相关关系,表明石笋SJ3记录了古气候环境的冷干、暖湿变化,且不同气候指标对环境变化的敏感度不同。     

助催化剂在醋酐催化法制备氯乙酸中的作用

考察了几种助催化剂(SO4^2-／Fe2O3，活性炭负载SO4^2-／Fe2O3和活性炭＋发烟硫酸)对醋酐催化醋酸氯化反应的影响。研究发现，活性炭负载＋助催化剂对该反应的活性最高，在一定程度上既提高了反应速率和氯乙酸的产率，又较好地抑制了副产物二氯乙酸的生成。     

High-resolution multi-proxy records of Asian monsoon activities from terrestrial sediments over the last 75,000 years

Our research group have investigated chronology and sedimentology of terrestrial sediments including loess-paleosols sediments over the last 75 ka at Lanzhou, northwestern China, and over the last 45ka at Tokyo, central Japan. Based on chronology of high resolution dating of ESR, TL, and IRSL and tephrochronology in these sediments, we investigated to reconstruct activities of Asian summer and winter paleomonsoons by using magnetic susceptibility, color reflectance and eolian dust concentrations over the last 75ka. Relations between standard curves of delta ~(18)O in GISP2 and color reflectance in loess-paleosol sediments of Linxia over last 140 ka shows that color reflectances are good proxy records indicating Asian summer paleomonsoon activity in time and are closely related to standard curve of delta ~(18)O in GRIP since the last interglacial. Also, relations between standard curve of delta ~(18)O in GISP2 and eolian dust concentrations over the last 75 ka at Lanzhou shows the Asian winter paleomonsoon activities have coincided with climatic changes in North Atlantic by GISP2 ice cores, and suggests that response of winter monsoon was rapid in global cooling stages, but slow in warming stage. Other results of our research in terrestrial sediments show as follows; 1) Horizons of Heinrich events from H1 to H4 in loess-paleosol sequences at Lanzhou. 2) Magnetic susceptibility and MS frequency dependent are possible to be available as proxy records for pedogenesis of tile Kanto Loam in Japan. 3) 8.2ka cooling event was recognized in Holocene loess-paleosol sequences at Lanzhou.     

贵州荔波42.0kaB.P.~65.0kaB.P.气候变化的石笋记录

对贵州荔波董哥洞D42石笋进行TIMS-U测年和碳、氧同位素分析,建立末次冰期42．0ka B．P．～65．0ka B．P．的古气候变化时间序列。研究结果表明,荔波地区在65．0ka B．P．～42．0ka B．P．石笋记录的冷暖事件所反映出的季风气候变化,大致可分为3个气候阶段;65．0ka B．P．～60．6ka B．P．相当于海洋氧同位素MIS4晚期,反映本阶段东亚冬季风强盛,气温降低,表现为干旱寒冷的气候环境;60．6ka B．P．～48．4ka B．P．相当于海洋氧同位素MIS3早期,反映东亚夏季风相对增强,气温升高,有效降水相对较少,表现为温暖半干旱的气候环境;48．4ka B．P．～42．0ka B．P．相当于海洋氧同位素MIS3中期,显示东亚夏季风由强变弱,东亚冬季风相对增强,表现为干旱冷凉的气候环境。石笋记录揭示的2次寒冷事件在各类沉积物中均有记录,反映为全球变化的气候事件,相当于北大西洋沉积物中的Heinrich5和Heinrich 6冷事件,可以进行全球对比,显示荔波地区与北极地区存在着古气候的遥相关。     

Millennial- and orbital-scale changes in the East Asian monsoon over the past 224,000 years

High-resolution speleothem records from China have provided insights into the factors that control the strength of the East Asian monsoon. Our understanding of these factors remains incomplete, however, owing to gaps in the record of monsoon history over the past two interglacial-glacial cycles. In particular, missing sections have hampered our ability to test ideas about orbital-scale controls on the monsoon, the causes of millennial-scale events and relationships between changes in the monsoon and climate in other regions. Here we present an absolute-dated oxygen isotope record from Sanbao cave, central China, that completes a Chinese-cave-based record of the strength of the East Asian monsoon that covers the past 224,000 years. The record is dominated by 23,000-year-long cycles that are synchronous within dating errors with summer insolation at 65 degrees N (ref. 10), supporting the idea that tropical/subtropical monsoons respond dominantly and directly to changes in Northern Hemisphere summer insolation on orbital timescales. The cycles are punctuated by millennial-scale strong-summer-monsoon events (Chinese interstadials), and the new record allows us to identify the complete series of these events over the past two interglacial-glacial cycles. Their duration decreases and their frequency increases during glacial build-up in both the last and penultimate glacial periods, indicating that ice sheet size affects their character and pacing. The ages of the events are exceptionally well constrained and may thus serve as benchmarks for correlating and calibrating climate records.     

Long-term trend and abrupt events of the Holocene Asian monsoon inferred from a stalagmite δ18O record from Shennongjia in Central China

The middle-Holocene was a period of profound cul- ture transitions: the Neolithic culture around Central China[1], Mesopotamia[2] and India[3] all mysteriously collapsed around 4 ka . It is plausible that this civiliza-tion collapse can be contributed to …     

轮古西地区奥陶系碳酸盐岩古岩溶储层碳、氧同位素地球化学特征

中—下奥陶统鹰山组碳酸盐岩古岩溶储层是塔里木盆地轮古西地区的主要油气产层 .为了弄清储层的成因类型、储层古岩溶过程中的流体性质和古水文条件 ,为预测和评价此类储层提供有关的地球化学信息 ,讨论了储层形成过程中记录的碳、氧稳定同位素特征 .结果表明 :轮古西地区奥陶系鹰山组碳酸盐岩古岩溶储层中的δ13C和δ18O值的变化范围较大 ,δ13C值为 -0 .70‰～ -6.5 0‰ ,平均值 -1 .76‰ ;δ18O值为 -3 .75‰～ -1 7.1 0‰ ,平均值 -9.42‰ .碳酸盐岩基质、冲积岩和方解石胶结物的δ13C和δ18O分布具有一定的差异 .三类样品的δ18O值均具有明显偏负特征 ,表明在碳酸盐岩成岩过程中受到大气成因的淡水影响 ,反映了当时的风化壳岩溶成岩环境 .冲积岩样品的δ13C值的偏负程度较高 ,其物源可能来自石炭—二叠系地层     

Millennial-scale monsoonal climatic change from paleosol sequences on the Chinese western Loess Plateau and Tibetan Plateau: a brief summary and review

This paper summarizes the work from the INQUA 1997 Project "Response of soil formation to short-warm-episodes of Asian summer monsoon" and its seeded related international and domestic grants. It reviews the effects of the millennial monsoonal changes on the loess- paleosols of the Chinese Loess and Tibetan Plateaus. High-resolution proxy records of pedogenesis and monsoons demonstrate that both Asian winter and summer monsoons were unstable and synchronously and inversely coupled during the last glaciation. During that time rapid episodic cycles of cold surges and warm enhancements spanned only ca. 1-2 ka in high- frequency domain. Sub-Milankovitch cycles (6-8 ka) of progressive cooling or weakening in low- frequency domain generally resembled the pattern of the North Atlantic climatic change. However, during the last interglacial, Asian winter and summer monsoons seemed to vary independently, the former being stable and the later unstable. Soil formation seems to occur in surprisingly fast response to the summer monsoon warm enhancements, resulting in weakly or moderately developed paleosol sequences. North Atlantic and polar cold air surges though the westerlies and other paths, and the north-south swing of the westerlies beside the Tibetan Plateau, may be the alternative mechanisms for the rapid monsoonal changes during the last glacial. But in the last interglacial, the summer monsoons worked largely independently.     

Reconstructed index of summer monsoon dry-wet modes in East Asia for the last millennium

Monthly precipitation datasets collected at 160 stations in China as well as the monthly winds and humidity data derived from the US National Centers for Environmental Prediction (NCEP) were used to construct the relationship between six summer dry-wet modes in eastern China and the summer monsoon airflow northward advance in East Asia. A millennial series of the monsoon dry-wet index (MDWI) was reconstructed based on Wang??s six summer dry-wet modes in eastern China since 950 AD. A high (low) index indicates that the strong (weak) East Asian summer monsoon airflow can reach northern (southern) China and cause above (below) normal precipitation. Interdecadal periodic variations, such as the approximate 70-year oscillation, can be found in the MDWI series. In the last millennium, northern China has experienced persistent decadal wet periods and persistent decadal dry periods. At present, the MDWI is a low period on the interdecadal time scale so above-normal precipitation is observed in southern China and below-normal precipitation in northern China.     

天山乌鲁木齐河源1号冰川雪冰中δ18O的演化过程

2002年9月14日-2005年3月7日,在天山乌鲁小齐河源1号冰川积累区雪坑中连续观测取样,频率为1次/周,分析了其巾的部分表层雪样品和粒雪坑样品中的δ18O.结果表明:表层雪样品的δ18O具有明显的季节变化,且与月平均温度关系密切.粒雪坑样品中的δ18O在9月底至次年6月初变化较小,升华对雪坑1 m以下雪冰中δ18O的影响不超过-2‰,整个雪坑都较好地保持了δ18O的季节变化特征.但6月初-9月底融水对雪冰中δ18O的影响巨大,冬季形成的δ18O低于-30%的中、细粒雪层,经过夏季融水的改造,可成为δ18O-11.6‰的粗粒雪和冰片层.融水可使雩冰中δ18O的改变最>60%.在全球变暖背景下,冬季形成的低δ18O雪层经过夏季融水的改造,其内的δ18O可以完全被平滑.     

Orbital- and millennial-scale variability of the Asian monsoon during MIS8 from Sanbao Cave at Mount Shennongjia,central China

One stalagmite oxygen isotope record from Sanbao Cave, China, established with 7 230Th ages and 355 oxygen isotope data, pro- vides a continuous history of the East Asian Monsoon (EAM) intensity for the period from 284 to 240 thousand years before present (ka BP) with typical errors of 3―4 ka. This new record extends the previously published stalagmite δ18O record back to the marine oxygen isotope stage (MIS) 8. The MIS8 EAM record broadly follows orbitally-induced insolation variations and is punctuated by...     

纳米级Fe3O4粉体的研制

采用化学沉淀法制备了Fe3O4微粒,用溶剂置换等方法进行了干燥,获得了平均粒径Dv为50～70 nm,饱和磁化强度为(75～80)kA/m的超细Fe3O4粉体.考察了工艺条件和干燥条件对Fe3O4粉体性能的影响.     

An ice-core record of vegetation and climate changes in the central Tibetan Plateau during the last 550 years

We present a 550-year ice-core pollen record with a 5-year resolution from the Puruogangri ice field in the central Tibetan Plateau.Analysis of the relationship between pollen record and instrumental observations suggests that the sum of the steppe and meadow pollen taxa is a good indicator of summer (June-August) temperature,whereas the ratios of Cyperaceae/(Gramineae+Artemisia) [Cy/(G+A)] as well as M/S (meadow to steppe percentages) are indicative of humidity changes in this region.Together with δ18O and...     

An erosional hiatus in Chinese loess sequences revealed by closely spaced optical dating

1 Introduction Loess deposits in China are the thickest and most extensively distributed in the world. Investigations overthe past around one century have significantly im- proved our understanding of the origin, transportation, deposition and evolution o…     

五道沟试验场降雨径流中的氢氧稳定同位素特征分析

在淮北平原区五道沟水文水资源试验场,对降雨径流中的氢氧稳定同位素组成变化的特点及控制平原区河道径流组分划分的一些流域水文因素进行了同位素示踪实验研究.结果表明,实验期间降雨中的δ(18O)(-0.918%～-0.518%)及δ(2H)(-5.064%～-2.310%)的变幅较大,并随雨强的降低而增大;1,3,6号测井地下水的δ(18O)(或δ(2H))主要与补给区水源及降雨的δ(18O)(或δ(2H))有关,其对降雨入渗补给的响应较慢,有明显的滞后效应;IR自记井及S4抽水井由于受抽水灌溉等人类活动的持续影响,δ(18O)(或δ(2H))明显偏负,表明有来自深部潜水的补给.此外,流域出口断面河水的δ(18O)(或δ(2H))受平原型流域较强均化作用的影响,其变幅远远小于降雨的δ(18O)(或δ(2H))变幅,在使用同位素方法划分河道径流组分时,需要考虑降雨到形成河道径流的传输时间.