山西襄汾县赵店动物群的发现及初步研究

赵店动物是作者近年来的一个新发现，本文对赵店动物群的化石类型，沉积特征、生态环境和地层时代等进行了初步研究，提出这一动物群生态于中更新世晚期（相当于大洋氧同位素阶段６）。赵店动物群的发现对研究这一时期生物演化及环境变化具有重要价值。     

秦岭北麓黄土沉积环境

秦岭北麓黄土最早形成于2.45Ma.区内各地质时代的黄土层中几乎都发现了大量哺乳动物化石和人类化石.黄土颜色深,颗粒细,粘化重;古土壤色鲜艳,层数多,底部钙质结核常联结成钙板;黄土中的原生碳酸钙几乎全部被淋溶,光性方位粘土较显著.这些说明本区黄土物质沉积后经受了比较强烈的淋滤作用和成土作用,反映出第四纪期间秦岭北麓黄土沉积环境要比黄土高原西北部温暖而湿润。     

辽宁省北二十家子镇第四纪肿骨鹿化石的研究

初步对辽宁省建平县北二十家子镇附近出土的第四纪哺乳动物化石进行分析,结果为形成于新生代中更新世的温暖潮湿的草原生态系统的肿骨鹿鹿角化石.鹿角化石硅化较强,通过区域地层与化石对比,研究区内的鹿角化石时代形成于中更新统早期.鹿角化石埋藏于黄土地层中,黄土为干燥寒冷的草原环境产物,分析得出研究区出现过温暖潮湿的气候环境,此后长期以干燥寒冷的气候环境为主,进而推测哺乳动物受气候影响变化较大,乃至灭绝.     

黄土物理性质变化规律研究

研究了黄土孔隙度和湿陷性在垂向上变化的规律和原因 .结果表明 ,孔隙度高和湿陷强的层位是风化成壤弱的黄土层 ,孔隙度低和湿陷弱的层位是红色古土壤或风化成壤强的黄土层 .第四纪冷干与温湿气候的交替和由此产生的成壤过程的变化是造成黄土地层孔隙度和湿陷性波动变化的根本原因 .黄土湿陷性是在干旱与半干旱地区弱的成壤过程中产生的 ,是草原地带灰黄色土壤具有的特征 .     

黄土物理性质变化规律研究

研究了黄土孔隙度和湿陷性在垂向上变化的规律和原因。结果表明,孔隙度高和湿陷强的层位是层位是风化成壤弱的黄土层,孔隙度低和湿陷弱的层位是红色古土壤或风化成熟强的黄土层。     

临夏盆地晚新生代哺乳动物群

临夏盆地位于甘肃省东南部，是青藏高原东北缘的一个山前凹陷盆地。其晚新生代地层非常发育，蕴藏着丰富的哺乳动物化石。中国科学院古脊椎动物与古人类研究所已在临夏盆地从晚渐新世至早更新世的各个层位中，发现和征集了大量的哺乳动物化石，其中以距今１５００～１２００万年的中中新世铲齿象动物群、１０００～７００万年的晚中新世三趾马动物群和约２００万年的早更新世真马动物群的材料和种类最为丰富。已有的化石标本产自近５０个化石地点，约１７００多件哺乳动物头骨，以及大量牙齿和肢骨，代表了１００多种哺乳动物；另有陆龟化石…     

河南孟津地区中全新世环境变化及其对人类活动的影响

在河南孟津地区发现全新世古土壤－黄土沉积剖面和湖沼相沉积剖面。作者对这2个剖面之间进行了野外调查,绘制了其间的地层图,并在古土壤-黄土沉积剖面采样,对样品做了粒度、磁化率以及CaCO₃含量分析。通过古土壤－黄土沉积剖面与湖沼相沉积剖面的对比,研究了中全新世孟津地区环境变化及其对人类活动的影响。结果表明孟津地区在7020～5660aBP和4610～3755aBP是古湖泊形成和古土壤发育的时期,气候温暖湿润;在5660～4610aBP孟津地区经历了一次气候波动,湖泊缩小为零星湖沼, 古土壤发育中断;3755～3055aBP湖泊萎缩干涸,黄土开始沉积,气候转向冷干。河南龙山文化时代晚期,湖面水位较高,人类在古土壤上活动;二里头文化时期湖泊萎缩,人类活动向低处转移,湖泊完全干涸时人类开始在干涸的湖相沉积层上活动。     

甘肃环县楼房子晚更新世孢粉组合

一九六三年初夏,我系黄土科研组,在环县楼房子附近,环河一级支流合道川柏林沟二级阶地沉积物中,发现了丰富的哺乳动物化石,经薜祥煦同志鉴定有:披毛犀(Coelodonta antiguitatis)、赤鹿(Cervus elaphus)、原始牛(Bos primigenius)、盘羊(Ovis ammon)等喜寒动物群。这个动物辟除缺象类化石外,其余与萨拉乌苏动物群相同,时代当属晚更新世。孢粉取样直接来自埋藏该动物群的剖面中。本文试图通过孢粉分析,了解当时的植被,再现古气候、古地理,不但具有一定的科学价值,也是寻找各种沉积矿产的一种值得注意的方法。     

辽西又出价值极高的远古化石——三燕丽蟾堪称世界第二

继中华龙鸟、尾羽鸟、北票龙、孔子鸟等轰动世界的远古化石之后,辽西地区化石出土和考古又有重大发现,被命名为“三燕丽蟾”的远古蛙化石,堪称世界第二。 中国科学院古脊椎人类研究所侯连海教授,在古鸟类化石的研究中意外地发现了一块蛙化石。经过两年多野外地质工作和室内研究,研究人员逐步了解了该化石的产出起点、层位及相关的地质占生物信息。它出土于辽宁省北票市四合屯村村西的中生代中期的硅质页岩层中,其时代是距今至少1亿2千多万年前。因为辽西地区的古地名是“三燕”,且该化石保存了完整而精美的骨     

咸阳市区晚更新世黄土微结构特征及其环境意义

目的揭示咸阳市区晚更新世黄土的微结构特征,探讨黄土微结构特征与其形成环境的关系,为区域环境提供科学依据。方法应用粒度分析和扫描电子显微镜对咸阳市区晚更新世黄土．古土壤系列的微结构进行分析研究。结果粒度小于0．005 mm的黏粒级含量在黄土与古土壤中差异最大,S1古土壤高达39．7％,而L1黄土仅24％;S1古土壤黏粒中大量铁质黏粒胶膜呈流胶状出现并有次生伊利石的产出,结构密实;L1黄土微骨架颗粒相互支架,黏粒胶结物含量较少,胶结程度差,土质疏松。结论咸阳市区晚更新世S1古土壤形成在湿热的森林环境,L1黄土形成于干冷的草原环境,S0黑垆土形成于凉湿气候环境。     

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.     

The summer monsoon evolution recorded by carbon isotope of organic matter from the Yuanbao loess section during the Last Interglaciation

Based on the carbon isotope record of organic matter from the Yuanbao loess section, northwestern China, five enhanced summer monsoon events were observed at this area during the Last Interglaciation. Such events were also recorded by the paleosol layers, pollen assemblage and magnetic susceptibility. It is suggested that the enhanced summer monsoon leads to the shift of vegetation type, which results in the change of δ¹³C value of organic matter in the paleosol layer. It appears that the δ¹³C of organic matter is a good indicator for the summer monsoon variation. Among these five events, the first, second and the fifth reached their maximum smoothly, but the other two had experienced a less cold stage before reaching their peaks, which suggests that the mechanisms of such events may be different.     

Comparisons of grain size characteristics of red earth from southern China with that of loess and dune sand from Beijing region

The comparisons of grain size distributions among eolian deposits along the monsoon wind trajectory are a fundamental task for the reconstruction of the past wind regimes. Here the authors sampled the dune sands in Hunsandak desert, loess deposits in Beijing region and red earth in southern China. Grain size analyses show that the distribution models of the loess and dune sand samples are unimodal whereas the red earth and paleosol are polymodal. The red earth, paleosol, loess and dune samples are distinguished and closely related to one another in grain size parameter diagrams. Moreover, the grain size distributions and parameters of the red earth and paleosol are similar, implying that the red earth in southern China and the paleosol in northern China had the same origin.     

Comparisons of grain size characteristics of red earth from southern China with that of loess and dune sand from Bering region

The comparisons of grain size distributions among eolian deposits along the monsoon wind trajectory are a fundamental task for the reconstruction of the past wind regimes. Here the authors sampled the dune sands in Hunsandak desert, loess deposits in Beijing region and red earth in southern China. Grain size analyses show that the distribution models of the loess and dune sand samples are unimodal whereas the red earth and paleosol are polymodal. The red earth, paleosol, loess and dune samples are distinguished and closely related to one another in grain size parameter diagrams. Moreover, the grain size distributions and parameters of the red earth and paleosol are similar, implying that the red earth in southern China and the paleosol in northern China had the same origin.     

黄土高原黄土地层分区及其地层结构

黄土地层序列同黄土地貌分区有成因上的联系,不同成因的地貌环境其黄土地层结构不同.依据地貌区划结合黄土地层特征可将黄土高原黄土地层划分为以下四个主要分区:1.梁峁地层区.该区又可分为六盘山以西及以东两个亚区;2.源地层区.又可细分为塬亚区.台塬亚区及山麓塬亚区;3.山间盆地地层区;4.河谷地层区。     

Reconstruction of the spatial patterns of desert/loess boundary belt in North China during the Holocene

The desert/loess boundary belt is the transi-tional region between desert and loess, where aeolian sandand loess interlock in space and alternate in time. It, being seriously unstable in space-time, sensitive to climatic changes and with fragile ecological environment, is an ideal region for studying the global climate change. There are deposi-tional sequences of paleosol with sub-horizontal interbedded aeolian sand and loess, and the stratigraphical evidences show that there widely exist 3—4 layers paleosol in sand lands of northeastern China, 4—5 layers in Mu Us Sandy Land and Hunshandake Sandy Land, more than 4 layers in the Qinghai Lake region and the Gonghe Basin of Qinghai Province during the Holocene. These indicate that the desert has experienced several times of extending and compacting, along with which the desert/loess boundary belt vibrated. It possesses good coherence with global climate change and eustasy. The coherence shows that the monsoon change in East Asia is the primary driving factor for the swing of desert/loess boundary belt. Besides, human influence con-stantly intensified the swing of the belt, especially in the south of Mu Us Sandy Land during the 2000—3000 aBP.     

末次间冰期陇西黄土记录与气候不稳定性问题的初步研究

陕西黄土高原黄土记录的分辩率较高，Ｓ１古土壤厚达８．５ｍ，主要由两个古土壤组和其间黄土层组成。临夏塬堡剖面上可分为５个古土壤层，主要黄土层记录了末次间冰期内的较干冷高粉尘堆积时期。     

采用沉积地貌学方法分析"丁村组"的年代

自1954年发现“丁村组”化石至今，“丁村组”的年代长期存在很大争论。作者通过对S5以来临汾盆地地貌和沉积环境演化过程的研究，揭示出“丁村组”的堆积是在S1早期的一次区域构造抬升引起盆地湖退后才开始发生的，时间距今大约13万年。结合上覆“丁村组”的黄土古土壤分析，发现其堆积结束于距今约5.3万年。“丁村组”的堆积与气下S1古土壤的发育和L1黄土下半段的堆积几乎的同期的。     

砂土夹层的阻水减渗机制及合理埋深

土壤中设置砂层将起到阻水减渗的作用,使大部分土壤水分滞留在砂层在上的细质土层中,这是近年来提出的较为有前途的建筑减渗防渗措施。从物理角度和土壤能量观点分析了砂层在土壤中的阻水减渗性;同时从建筑防渗角度对砂层最优埋深作了分析,给出了表层土壤的水分分布的解析解。     

陕北及鄂尔多斯地区降水变化与沙漠化

本文根据1959～1984年降水记录,讨论了陕北及鄂尔多斯地区沙漠化和草场退化的主要原因.由于沙漠化范围扩展阶段与降水量减少阶段的影响范围具有一致性,所以认为主要原因是自然过程。因1980年以来本区降水出现增加趋势,本区自然环境向沙漠化的发展将受到抑制。