临汾盆地陶寺遗址附近全新世黄土剖面的环境指标分析

在对临汾盆地陶寺遗址北城墙外全新世黄土剖面粒度、磁化率、Rb/Sr值和CaCO₃含量等气候指标进行分析的基础上, 结合光释光测年结果和考古学资料, 探讨该剖面记录的环境信息及其与文化发展的相互关系。研究发现: 全新世早期(10.5~9.6 kaBP), 东亚冬季风较弱, 风化成壤作用增强, 气候由凉干转向暖湿; 全新世早中期(9.6~4.9 kaBP), 风化成壤作用最强, 气候最为暖湿; 全新世中后期(4.9~2.5 kaBP), 风化成壤作用较之前有所下降, 气候较之前温干, 但较现今暖湿; 全新世晚期(2.5 kaBP)以来, 东亚冬季风增强, 风化成壤作用较弱, 气候较为凉干。暖湿气候期与文化的繁荣发展时期有较好的对应关系, 凉干气候期植被的退化可能受气候和人类活动共同作用的影响。     

Abnormal overpressure distribution and natural gas accumulation in foreland basins,Western China

Shizitan in Jixian County, Shanxi Province, is a site of transitional period from Paleolithic to Neolithic. The dating and the sporopollen analysis show that the middle reaches of the Yellow River where the site is located had been maintaining a steppe environment during 35.1-9.4 kaBP, in which, 35.1-17 kaBP belonged to the last glacial. With cold and dry climate, this period featured a desert steppe environment. In the late of this period, the area had a cold and half-humid steppe environment. The 17.0-11.9 kaBP belonged to the early- and mid-period of the last deglaciation. Mild and half-arid steppe alternates with mild and half-arid steppe, with a small amount of deciduous broadleaf species. During the period of 11.9-10.5 kaBP, cold and dry glacial climate appeared once more, featuring a desert steppe environment. During 10.5-9.4 kaBP, it is mild and half-arid, and later transited toward warm and half-humid. The early phase of this period featured a steppe environment and the later transited into a steppe environment with fairly more deciduous broadleaf species. Microlith, a mark of a transitional period from Paleolithic to Neolithic, was distributed mainly in 17.0-11.9 kaBP. The relatively warm, half-arid and fluctuating steppe environment in the early and medium period of the last deglaciation made a contribution to the appearance and development of Microlithic culture.     

地质环境差异对中国摩崖石刻的影响机理分析

目的探究中国南北方不同地质环境背景下摩崖石刻风化病害的机理。方法采用野外调查、室内实验和检测分析岩石的地质特征、自然环境特征等进行对比分析。结果红石峡以风蚀打磨字迹消失、模糊或者字迹多处粗糙为主要病害,千佛崖以彩绘造像表面酥粉和粉化脱落为主;千佛崖岩石吸水率和饱水系数都高于红石峡;红石峡可溶盐主要为硫酸盐和碳酸盐,千佛崖可溶盐主要为硫酸盐和硝酸盐;千佛崖还存在NH4+,自然地理特征存在明显差异。结论中国南北摩崖石刻风化机理的共性表现为冷热风化、风蚀风化及水化水合作用,不同之处在于红石峡病害主要由风沙磨蚀、冰劈作用和碳酸化侵蚀造成,千佛崖病害主要由水化学作用下可溶盐离子表聚作用造成;文物的保护应采用各自独立的方法和手段。     

Progress in studies of the climate of humid period and the impacts of changing precession in early-mid Holocene

Studies on the climate of humid period and the impacts of changing precession in the early-mid Holocene are reviewed in this paper. High-resolution proxy data indicated that the African Humid Period, strong summer monsoon from the Arabian Sea to South Asia, northward migration of ITCZ （Intertropical Convergence Zone） over the northern South America, and the humid period of China appeared in 10.5-5.5 kaBP, 10.0--6.0 kaBP, 10.5-5.4 kaBP, and 11.0-8.0 kaBP, respectively. Modeling studies proved that summer insolation over the Northern Hemisphere increased following the changes of precession in the early Holocene, which increased the land-sea temperature contrasts, intensified the summer monsoon circulation over the area under the influence of summer monsoon. However, in the Northern Hemisphere, and finally induced a humid climate modeling results underestimated the increase of precipitation and the degree of northward extension of monsoon rain belt compared with palaeo-environmental data. These discrepancies between the modeling results and the palaeo-environmental data may be associated with the changes of North Atlantic circulation, sea ice and vegetation covers. Moreover, climate of the humid period was not stable, in which several droughts were inlaid on centennial scale. In this review, perspectives for further studies of the climate change of the humid period in the early-mid Holocene are also proposed. demy of Sciences. Published by Elsevier Limited and Science in China Press. All rights reserved.     

Youger Dryas and Heinrich events recorded by magnetic susceptibility of sediments from the central temperature area of Western Pacific Warm Pool

Three short geomagnetic excursions, the Go thenburg, Mono Lake and Mungo (or Maelifell) in the Brunhes Positive Polarity period, were revealed based on the studies of magnetostratigraphy, susceptibility (χ) and δ^18O of sediments in core WP 92-5 from the central temperature area of the Western Pacific Warm Pool (WPWP), and the ages of them are 12.1--11.3 kaBP, 25.0--24.0 kaBP, and 31.0--28.0 kaBP respectively. Furthermore, the Younger Dryas (YD) and Heinrich (H) cold events were also discovered in this core by the susceptibility record. The YD cold event occurred at the depth of 30--22 cm with an age of 11.5--10.6 kaBP; H1, H2 and H3 cold events occurred at depths of 51--39 cm, 108---91 cm and 140--126 cm with ages of 15.1--13.0 kaBP, 25.0--22.1 kaBP and 30.6---28.2 kaBP respectively, which well correspond to the HI, H2, H3 events recorded by susceptibility of core SU90-09 from middle Atlantic, indicating that the susceptibility change of marine sediments can be an important sign of climatic frequent fluctuations.     

戈壁地表野外风速脉动特征

【目的】探究戈壁地表野外风场不同高度风速脉动特征,为进一步湍流情况下风蚀研究奠定基础。【方法】2015年春季在新疆卡拉贝利工程区实测了戈壁地表不同高度瞬时风速,利用统计学方法(标准差、曲线估计等)从风速脉动和脉动强度、湍流度,以及三者与风速之间的关系等角度分析戈壁地表风速脉动特征。【结果】不同高度的瞬时风速和风速脉动在时间序列上变化非常复杂,但变化趋势一致。大风时段(0～50 min),风速脉动幅度非常大,最大接近6 m/s,但90%以上集中在Symbol|A@0～3Symbol|A@ m/s。风速脉动幅度随风速增强而增大,随距地表高度增加而增大。风速脉动概率分布符合高斯分布。不同高度的风速脉动强度与风速均呈一元线性关系,风速越大,风速脉动强度越大。风速脉动强度最大值2.41 m/s。在距地表0～2 m高度内,湍流度在0.14～0.21之间变化,平均约为0.17,湍流强度较高,此高度内湍流度与高度、平均风速无明显关系。【结论】戈壁地表风速脉动具有非平稳性,随风速增强而增大,尤其是大风天气下研究风蚀不能忽略风速的脉动性。     

Comparison of paleoclimatic characteristics between monsoon and westerly areas, China

For past decades there have been many studies on the climate features during the last interglacial and glacial periods. A comparison between the loess record of western China with that of monsoon areas shows some regional differences. ( i) Generally, the climate of the Yili region since the late Pleistocene was dry, with fluctuations. Late Pleistocene climate change in the study area can be divided into 5 stages, corresponding to 5 marine isotopic stages (MIS 1-MISS), (ii) Evidence from grain size composition, magnetic susceptibility, carbonate content, pollen assemblage and geochemistry shows that the climate during the last glacial period was instable. During MIS4 the westerly winds were strong and the humidity was relatively high. Compared with the early stage, MIS2 was dry. In MIS3, westerly winds were relatively weak; pedogenesis prevailed, forming paleo-sols. (iii) In contrast to the Loess Plateau the deposition rate of dust at the early stage was higher than at the late stage of the last galical in the Yili region. The strongest wind event occurred at about 24 kaBP instead of 18 kaBP. (iv) Variations in the grain size indicate that the westerly winds decreased since the deglaciation, but dust accumulation continued until the late Holocene. High carbonate contents, low ratio of Rb/Sr and lack of soil development imply that the climate was dry during the early and middle Holocene. Since the late Holocene the climate became relatively wet and the soil was developed.     

吉林省风蚀的影响因素及其治理途径

通过对吉林省风蚀图斑资料的分析,运用线性模型理论对该地区风蚀规律进行了研究,获得了影响风蚀的主导因素,阐述了吉林省的风蚀现状,同时提高了相应的防治对策。     

黑色页岩化学风化过程的微观机制及演化

针对黑色页岩化学风化系统的复杂系统演化问题,通过X射线衍射(XRD)试验、扫描电子显微镜和X射线能谱(SEM-EDS)试验,从风化过程的微观结构变化和非平衡热力学过程出发,对黑色页岩化学风化剖面中不同风化层的矿物成分和微观结构变化进行对比分析,探讨黑色页岩化学风化的微观机制,同时利用非平衡态热力学理论和耗散结构原理分析黑色页岩化学风化系统的耗散结构的形成过程及化学风化演化规律。研究表明:在黑色页岩化学风化过程中酸性水的侵蚀作用下,易溶性矿物溶解、次生矿物生成及离子交换吸附作用,促使矿物成分发生转变;同时矿物颗粒间的连接方式发生了改变,也促使岩石内部产生大量微孔隙。黏土矿物和含水硫酸盐矿物的吸水膨胀及失水收缩过程,使岩石内部产生不均匀应力,进一步改变岩石内部的微孔隙,促进化学风化进程。黑色页岩化学风化系统是一个开放的复杂系统,利用非平衡热力学计算认为该系统是不可逆过程,且经历了近平衡阶段和远离平衡阶段,最终可形成具有一定稳定性的耗散结构。     

高水速凝充填材料的风化特征和风化机理

高水速凝固化胶结充填材料在养护至６０ｄ左右时，开始出现风化现象，到９０ｄ时较严重。风化原因是空气中的二氧化碳侵蚀充填材料中的钙矾石晶体以及材料中含有的自由重力水的逸出等造成的。保持恒温恒湿的环境条件是防止这种充填材料风化的可行途径之一。     

Precise timing of lacustrine gypsum in Luobubo, Xinjiang using the thermal ionization mass spectrometry U-series method

Dating techniques including gypsum dissolution in water, iron hydroxide co-precipitation with uranium and thorium and mass spectrometric determination have been investigated in this note. The ages of the gypsum samples in a CK core from Luobubo lacustrine sediments are in the range of (12.85±0.21) kaBP (4 m distance from the top core) to (153.2±7.2) kaBP (49 m distance from the top core) with the relative errors of ±1.6%–±4.7%. It indicates that the sedimental environment of the CK core was situated in the middle-late Pleistocene and Holocene periods, corresponding to 1–6 stages of oxygen isotopes in the abyssal sediments and included much information from last interglacial to Holocene warm periods.     

Climatic changes documented by stable isotopes of sedimentary carbonate in Lake Sugan, northeastern Tibetan Plateau of China, since 2 kaBP

Lake Sugan at the northern edge of the Qaidam Basin was selected as the research object. The temporal sequence of sedimentary cores retrieved from Lake Sugan since 2 kaBP was reconstructed using the ^210Pb, AMS 14C and conventional 14C dating methods. Carbon and oxygen isotopes of carbonate in the fine-grained lake sediments were analysed. Combined with the changes of 8180 values of surface water and air temperature observation data in the study area, it might be thought that the δ^18O value of the carbonate indicates effective moisture, and the changes in δ^13C values are related to annual freeze-up duration of the lake and indirectly indicate air temperature changes in winter half year. From the above, the sequence of climatic changes in the region since 2 kaBP was established. The climatic changes experienced five stages： Warm-dry climate during 0-190 AD： cold-dry climate during 190-580 AD; warm-dry climate during 580-1200 AD （MWP）; cold-wet climate during 1200-1880 AD （LIA）; cold-dry climate during 1880-1950 AD： and climate warming since 1950s. The air temperature changes in winter half year reflected by carbon isotope since 2 kaBP are in good agreement with the historical literature records and other geologic records, which shows that the climate changes recorded by the stable isotopes from Lake Sugan since 2 kaBP are of universal significance.     

新疆巴里坤湖 9.0cal.ka BP来沉积物地球化学元素分布特征与古气候环境演化

根据中国西北干旱区巴里坤湖BLK-1剖面沉积物的地化元素分析,采用SPSS因子分析法提取了对沉积环境变化敏感的地化元素和氧化物组分. 在 R、Q 型因子分析的基础上,结合沉积物的硅铁铝率（SiO2/（Al2O3+Fe2O3））、淋失系数（SiO2/（MgO+K2O））、CaO/MgO以及腐殖化度等指标,提取出古气候环境信息. 初步研究结果表明:近9.0cal ka BP以来,巴里坤湖地区气候环境仍以干旱化为主,全新世期间出现过多次不同程度的干湿变化,经历了5个气候阶段:9.0～7.5cal kaBP期间,气候干旱;7.5～5.8cal kaBP期间,气候温暖湿润,为研究区全新世最佳适宜期;5.8～3.0cal kaBP期间,气候干旱;3.0～1.0cal kaBP期间,气候湿润;1.0～0cal kaBP期间,气候干旱.     

Evidence of a humid mid-Holocene in the western part of Chinese Loess Plateau

Field works show that the wetland/swamp layers were distributed ubiquitously in the western part of the Chinese Loess Plateau. Universality of the wetland/swampy layer and the consistency of the age reveal that the layer was developed under the humid climatic condition. Dated between 9 and 3.8 kaBP, the wetland/swampy layer is full of aquatic mollusks and has the highest tree and shrub pollen,indicating a humid mid-Holocene. Variations of grain size suggest that winter monsoon weakened during 9-3.8 kaBP while climate change to humid and vegetation cover increased from 9 kaBP onward. After 5.9 kaBP, the humidity declined gradually. In 3.8 kaBP, summer monsoon sharply retreated, and the climate changed to dry.     

A Cenozoic record of the equatorial Pacific carbonate compensation depth

Atmospheric carbon dioxide concentrations and climate are regulated on geological timescales by the balance between carbon input from volcanic and metamorphic outgassing and its removal by weathering feedbacks; these feedbacks involve the erosion of silicate rocks and organic-carbon-bearing rocks. The integrated effect of these processes is reflected in the calcium carbonate compensation depth, which is the oceanic depth at which calcium carbonate is dissolved. Here we present a carbonate accumulation record that covers the past 53 million years from a depth transect in the equatorial Pacific Ocean. The carbonate compensation depth tracks long-term ocean cooling, deepening from 3.0-3.5?kilometres during the early Cenozoic (approximately 55?million years ago) to 4.6 kilometres at present, consistent with an overall Cenozoic increase in weathering. We find large superimposed fluctuations in carbonate compensation depth during the middle and late Eocene. Using Earth system models, we identify changes in weathering and the mode of organic-carbon delivery as two key processes to explain these large-scale Eocene fluctuations of the carbonate compensation depth.     

A tropical paleosol at high elevation in the Yulong Mountains and its implication on the uplift of the Tibetan Plateau

A paleosol dated for about 500–700 kaBP and developed on a glacial deposit at ～3 000 m a.s.l. in the Yulong Mountains is studied using soil chemical, morphological and mineralogical methods. The analytical results indicate that this soil was formed under tropical and humid conditions and can be classified as red soil, which cannot be formed in the present alpine environment at the studied site. This implies that the southeast margin of the Tibetan Plateau has experienced intense uplift since the formation of the paleosol. According to the necessary conditions for the formation of the modern red soil in China, we estimate that the uplift height of the Plateau since 500–700 kaBP would have exceeded 800 m.     

河南省新石器遗址的时空特征及其环境背景

根据裴李岗、仰韶和龙山3个新石器文化遗址在不同地区分布的数量演变关系,将河南新石器遗址地理区分为3个类型:成长型,萎缩型,振荡型.尽管新石器时期河南地区历经干湿波动(8.5~7.0kaBP)、暖湿(6.8~5.3kaBP)、暖干(4.8~3.8kaBP)的气候过程,新石器遗址地理分布亦随之波动,但由于独特的水系网络和地貌环境,洛阳盆地和嵩山东南麓始终是河南新石器文化的核心区.     

Chronology of the stratum containing the skull of the Dali Man

The field investigations of geomorphology and Quaternary sediment sequences show that the sediment stratigraphic profile containing the skull of the Homo sapiens Daliensis (Dali Man) at Tianshuigou trench, Jiefang Village (109° 44′E, 34°52′N), Dali County, Shaanxi Province, is composed of the loess-paleosol sequence, 17.3 m thick, in the upper part, and the alluvial silts, fine sands and sandy gravels interbedded, 15.4 m thick, in the lower part. There are the well developed layers L₁, S₁, L₂ and S₂ in the loess-paleosol sequence of the profile, which are comparable; to those of the Luochuan loess section on the basis of magnetic succeptibility measurements and IRSL dating of the loess samples. An alluvial gravel layer, where the skull of the Dali Man was discovered, is in 13 m beneath the bottom of paleosol S₂, implying that, the age of the Dali Man must be older than about 247 kaBP when the paleosol S₂ began to be developed. The samples of mammal animal tooth and shell fossils from the gravel layer containing the skull of the Dali Man have been dated by uranium series and ESR methods respectively. Based on the multiple dating results and the stratigraphic chronology, the age of the Dali Man, therefore, would be estimated as older than 250 kaBP and younger than 350 kaBP, and reasonably estimated as 260–300 kaBP.     

中尺度天气预报模式边界层参数化方案以及近地层方案对苏州东山冬季近地层气象要素模拟的影响

运用WRF3. 9模式并选取四种常用的边界层参数化方案(YSU、ACM2、MYJ和BL)和两种近地层方案(Eta和MM5)模拟了2015年1月16～25日苏州东山的近地层气象要素,并与东山气象站观测实验数据进行对比,评估了四种边界层参数化方案对近地层气象要素的模拟能力。同时设置了边界层参数化方案与近地层方案耦合的敏感性试验,分析两类方案的耦合对近地层气象要素模拟的影响。结果表明:①白天四种边界层方案对2 m温度的模拟差异较小,两种近地层方案的模拟结果有差异,对流混合较弱时Eta方案模拟较好,对流混合较强时MM5方案较好;夜间四种边界层方案和近地层方案均有影响,但是整个观测期间四种方案的模拟结果统计量差异较小;②无论白天还是夜间,四种边界层参数化方案模拟的2 m相对湿度均高于观测值,BL方案的模拟效果最佳,MYJ方案的模拟偏差最大;③无论白天还是夜间,四种边界层参数化方案对10 m风速的模拟均存在一定程度的高估,MYJ方案的模拟效果最好,四种方案对风向的模拟均优于对风速的模拟,白天的模拟效果整体优于夜间;④选择不同的近地层方案对风速和风向的模拟结果没有明显影响,对2 m气温模拟结果的影响小于对2 m相对湿度模拟结果的影响,BL边界层方案与MM5近地层方案耦合对近地层气象要素2 m气温和2 m相对湿度的模拟效果最好。     

Discovery of Quaternary glacial evidence of Snow Mountain in Taiwan, China

There are glacial remains of three different periods on the main peak of Snow Mountain in Taiwan province, including cirque lake, crosswall, polished surface, striation, moraine etc. These three different periods were called, respectively, Shanzhuang ((44.25 ±3.72) kaBP), Shuiyuan ((18.26 ±1.52) kaBP), and Xueshan glacial stages (the late period of last glaciation). It is characterized by the earlier glacier broad in scale.