A new Euprox from the Late Miocene of Yuanmou,Yunnan Province,China,with interpretation of its paleoenvironment

The Yuanmou Basin of Yunnan Province is a hotspot for the research of early homind evolution and its environmental background.During the implementation of the Program“Research of the Origin and Evolution of Early Man and Its Environmental Baqckground” from 1998 to 2001,a huge quantity of hominoid and mammal fossils were collected.The present report systematically describes an Euprox robustus sp.nov.identified during the recent laboratory work on the collected material.Euprox is a group of earliest cervids with true antlers.The new species is the third one of the genus discovered in China.Judged by its morphologic characteristics,the new species feed on juicy and tender leaves of dicotyledon.It implies that the vegetation of its epoch in the Yuanmou Basin is a kind of southern subtropical evergreen forest and the climate is humid and temperate with evident seasonality.The latter is mostly influenced by the monsoon and secondly by the latitude.     

元谋干热河谷区民营水土保持效益评价

民营水土保持是当今水土保持生态建设中出现的一种新模式,是水土保持走向市场的重要标志。本文以农户调查数据为基础,运用层次分析法,对元谋干热河谷区民营水土保持效益进行评价。研究显示,目前民营水土保持是以经济效益为主导,兼顾生态效益和社会效益;农户的思想开放程度、经营模式和理念、技术水平、市场等因素是影响效益的主要因素,提出政府应建立完善的制度体系,支持鼓励民营水土保持的发展。     

Taxonomy, age and environment status of the Yuanmou hominoids

When, where and from which hominoid the human originated has been one of the key subjects in the study of human natural history. It is therefore very important to learn the chronological, geographical and taxonomic distribution of all hominoids. Yunnan Pr…     

Selection of judging indicators for surface morphology of soil crack under different development degrees in Yuanmou arid-hot valley region

Quantification of complicated surface morphology of soil crack is a prerequisite and key to soil crack study. This paper takes soil crack quads in Yuanmou arid-hot valley region as examples, selecting several morphological indicators, and analyzes the soil crack＇s morphological features under various development degrees. By statistic analysis, three quantitative indicators for surface morphology are selected, namely soil crack area density, area weighted mean fractal dimension and connectivity index R, which can not only express the development intensity of soil cracks, but also effectively describe its morphological complexity and connectivity. The research results set a good base for the establishment of soil crack assessment system in Yuanmou arid-hot valley region.     

晚新生代元谋盆地演化与河谷发育研究

元谋盆地是在晚新生代青藏高原与云南高原隆起过程中形成的众多断陷盆地之一,流经元度盆地的龙川江和金沙江。其河谷发育与盆地演化具有密切关系,通过对元谋盆地及其邻区的层次地貌与相关沉积的分析研究,认为,始新世晚期￣中新世晚期是夷平面形成时期,中新世晚期￣３．４０ＭａＢＰ前后是第一级剥蚀面形成时期;元谋盆地形成于３．４０ＭａＢＰ前后第一级剥蚀面解体过程中,其后盆地经历了３．４０￣１．７８ＭａＢＰ的古湖形成     

元谋古猿的生活环境与年代

元谋古猿化石主要发现于云南元谋县小河村地区的小河组中。通过对小河组的沉积特征、粘土矿物分析、古植物孢粉和哺乳动物群的研究及地貌和新构造运动研究,可以认为,在元谋古猿生活时期,元谋盆地已开始断陷;盆地中河流、湖泊发育;植物群落为稀树林—草原型;气候温干,降水量年变幅大,年平均温度１０℃左右。通过对小河组磁性地层研究,得出小河组年代约为距今３．８～５．５Ｍａ,含元谋古猿化石层年代约为距今３．９～５．２Ｍａ,所以,可以说元谋古猿的年代为距今４～５Ｍａ。     

Soil crevice formation and erosion in Yuanmou dry-hot valley, Yunnan Province, China

The basic characteristics, X-ray analysis and micromorphology of soil developed from the parent ruified soil had been probed, results showed that there were similarities among different types of the rubified soils. The soil clay (D<0.002 mm) contents (C _c ) were relative higher as between 29.16% and 80.03%. In addition, organic matter contents were lower as between 2.2–6.6 g/kg. The clay minerals in the rubified soils had high content of 2:1 type swelling minerals, e.g., smectite and vermiculite, which were the basic causes of formation of soil cracks and crevices. Soil micromorphology characteristics showed that microcosmic crevices universally distributed within the tight and compact soil microstructure were the microcosmic characteristics of crevices formation. The soil cracks and crevices changed the erosion process. Obviously, well developed soil crevice carries a significant connection with strong soil erosion in Yuanmou, Yunnan province, China. The term “soil crevice erosion” was coincided with the viewpoint put forward that soil crevice erosion played a dominant role in regional and violent soil erosion in this area. Foundation item: Supported by the Knowledge Innovation Program of the Chinese Academy of Sciences(KZCX2-YW-409) and the National Key Technology R&D Program of China (2006BAC01A11)     

Rock magnetic studies on the hominoid-bearing sediments at Zhupeng, Yuanmou Basin, southwestern China and its paleoclimatic significance

It has been proposed that paleoclimatic changes and tectonic events strongly affect hominoid evolution. The Zhupeng section at Yuanmou Basin, southwestern China, with the hominoid-bearing fluvial-lacustrine sediments, is an ideal natural laboratory to test this hypothesis. This study provided an integrated magnetic study, including low-frequency susceptibility, the anisotropy of magnetic susceptibility, temperature-dependent susceptibility, hysteresis loops, isothermal remanent magnetization, and anhysteretic remanent magnetization, on samples from the Baozidongqing section at Zhupeng. Results show that the dominant mag- netic carrier is hematite, with minor amount of magnetite. Both the composition and concentration of magnetic miner- als strongly correlate with the lithostratigraphy. At least eight short-term events defined by higher concentrations of magnetite were identified. These short events reflect that the subtropical dry-hot climate is similar to today＇s climate. Basing on the lithostratigraphic and rock magnetic results, we suggest that Yuanmou Basin was in a steady deposition environment from about 11 to 7 Ma, which is characterized by alternating of long-term torrid-humid climate and short-term dry-hot climate. Our study provides invaluable environment information for understanding the climate shift and the relationship between paleoenvironment and hominoid evolution in southwestern China during late Miocene.     

元谋断裂带砂脉及其与断裂活动的关系

依据元谋断裂带砂脉发育的层位、成份、形态、围岩变形特征、区域构造背景和古气候环境, 以及断裂带晚第四纪活动特征, 结合释光年代学测试结果, 讨论砂脉的成因机理及其与断裂带的关系。结果表明, 元谋断裂带地表或近地表发育的砂脉较多, 产状近直立, 延伸较长, 沿断裂中?北段构造面平行展布。综合分析砂脉形态、内部结构以及与围岩和断层的空间关系, 揭示砂脉的形成应是断裂带强烈运动或地震活动引起的断层带上、次级断裂面上以及构造面附近局部节理面砂土液化的结果, 或为伸展构造面裂隙充填物, 且可能为同一期地质事件所为, 形成时间约为7 kaBP。这些砂脉构造对断裂活动的时限具有重要指示意义, 是元谋断裂晚第四纪一次强烈活动的伴生产物。     

Statistical analyses of metric data of hominoid teeth found in Yuanmou of China

Mesial-distal and buccal-lingual dimensions of 1 266 hominoid teeth found in Yuanmou of Yunnan Province during the period of 1986 and 1988 have been measured. The statistical analyses of the metric data show that the tooth sizes of Yuanmou hominoid can be divided into big and small two types, and most tooth dimensions display obvious bimodalities in both histograms and 2 dimensional plots. The coefficients of variance (CV) reveal that the CVs of Yuanmou hominoid tooth sizes are within or close to the CV ranges ofLufengpithecus and extant great apes. The comparisons of tooth sizes and their proportions indicate that Yuanmou hominoids have close affinities with Lefeng and Kaiyuan hominoids, and have obvious differences with Gorilla, Chimpanzee and Orangutan. The authors believe that the hominoid fossils found in Yuanmou in the past 10 years represent a single species with highly sexual dimorphism in morphology and this species may have a close evolutionary relationship with the hominoids found in Kaiyuan and Lufeng.