初论古文化类型演替与传承模式的区域分异——以西拉沐沦河流域和汶泗流域为例   总被引：6，自引：0，他引：6       下载免费PDF全文

崔之久  杨晓燕  夏正楷 《第四纪研究》2002,22(5):434-441

西拉沐沦河流域地处中国地貌大势三大台阶之中台阶与低台阶的过渡区。该区的中度抬升和下切,造成了西拉沐沦河流域考古文化遗址在空间上的垂向迁移;频繁的迁移也导致了考古遗址在堆积形态上主要表现为单一型,体现了不同考古文化之间“间断”的,不稳定的传承方式。位于中国地貌大势之低台阶上的汶泗流域,属自下古生代以来就十分稳定的剥蚀区,这些自然条件造成了汶泗流域遗址在堆积形态上主要表现为叠置型,考古文化在时空上,很少随着时间做空间上的改变,基本上在同一水平空间稳定不动,体现了不同考古文化之间“连续”、稳定的传承方式。两个流域的对比研究说明,不同地域、不同的自然条件,可以造成考古文化演替与传承模式的区域分异  相似文献   

呼伦西白金矿点外围区化异常查证方法及找矿效果     

曹金虎  张玉宝  钟仁  刘还林 《内蒙古地质》2002,(4)

呼伦西白金矿点外围异常查证工作中,采用围山短水系沉积物测量为主,土壤测量为辅的方法,圈定以金为主的综合异常8处,发现金矿脉4条(III～VI号)、锑矿化带1处,取得了较为明显的地质找矿效果。该方法可供同类地区开展异常查证时参考。  相似文献   

Study and review on crust-mantle velocity structure in Bohai Bay and its vicinity   总被引：3，自引：0，他引：3  

张成科  张先康  赵金仁  任青芳  张建狮  海燕 《地震学报(英文版)》2002,15(4):447-455

Introduction Bohai Bay, along with its adjacent areas, is one of the seismically active areas in North China. Understanding its crust/upper-mantle structural characteristics and lateral heterogeneity of the medium in this area is of great significance to the study of seismogenic environment, thus improvimg the level of earthquake prediction. For years, scientists have studied the area by gravity and magnetic methods (FENG, et al, 1989), geothermal field (WU, et al, 1988; TIAN, ZHANG, 19…  相似文献   

Determining Q of near-surface materials from Rayleigh waves     

Jianghai Xia  Richard D. Miller  Choon B. Park  Gang Tian 《Journal of Applied Geophysics》2002,51(2-4)

High-frequency (≥2 Hz) Rayleigh wave phase velocities can be inverted to shear (S)-wave velocities for a layered earth model up to 30 m below the ground surface in many settings. Given S-wave velocity (V_S), compressional (P)-wave velocity (V_P), and Rayleigh wave phase velocities, it is feasible to solve for P-wave quality factor Q_P and S-wave quality factor Q_S in a layered earth model by inverting Rayleigh wave attenuation coefficients. Model results demonstrate the plausibility of inverting Q_S from Rayleigh wave attenuation coefficients. Contributions to the Rayleigh wave attenuation coefficients from Q_P cannot be ignored when Vs/V_P reaches 0.45, which is not uncommon in near-surface settings. It is possible to invert Q_P from Rayleigh wave attenuation coefficients in some geological setting, a concept that differs from the common perception that Rayleigh wave attenuation coefficients are always far less sensitive to Q_P than to Q_S. Sixty-channel surface wave data were acquired in an Arizona desert. For a 10-layer model with a thickness of over 20 m, the data were first inverted to obtain S-wave velocities by the multichannel analysis of surface waves (MASW) method and then quality factors were determined by inverting attenuation coefficients.  相似文献   

Utilization of water resources,ecological balance and land desertification in the Tarim Basin,Xinjiang     

Zili Fan  Xuncheng Xia  Yuling Shen  Kurban Alishir  Ranghui Wang  Shengyu Li  Yingjun Ma 《中国科学D辑(英文版)》2002,45(1):102-108

Because of the human exploitation and utilization of water resources in the Tarim Basin, the water resources consumption has changed from mainly natural ecosystem to artificial oasis ecosystem, and the environment has changed correspondingly. The basic changes are: desertification and oasis development coexist, both “the human being advance and the desert retreat” and “the desert advance and the human being retreat” coexist, but the latter is dominant. In the upper reaches, water volume drawing to irrigated agricultural areas has increased, artificial oases have been enlarging and moving from the deltas in the lower reaches of many rivers to the piedmont plains. In the middle and lower reaches of the Tarim River, the stream flow has decreased, old oases have declined, natural vegetations have been degenerating, desertification has been enlarging, and the environment has deteriorated. The transition regions, which consist of forestlands, grasslands and waters between the desert and the oases, have been decreasing continuously, their shelter function to the oases has been weakened, and the desert is threatening the oases seriously.  相似文献   

ARTIFICIAL NEURAL NETWORK CORRECTION OF ROUGH ERRORS OF OBSERVATIONS^*          下载免费PDF全文

JIANG Guorong  ZHANG Ren  SHA Wenyu  YAN Junyue  YAO Huadong 《Acta Meteorologica Sinica》2002,16(1):123-132

In the context of tower measured radiation datasets.following the correction principle meeting a diagnostic equation in data quality control and in terms of a technique for model construction on data and ANN (artificial neural network) retrieval for BP correction of radiation measurements with rough errors available,a BP model is presented.Evidence suggests that the developed model works well and is superior to a convenient multivariate linear regression model,indicating its wide applications.  相似文献   

河流水质风险评价的灰色-随机风险率方法   总被引：3，自引：2，他引：3  

胡国华  夏军  赵沛伦 《地理科学》2002,22(2):249-252

提出了量化影响河流水质的随机不确定性与灰色不确定性的水质超标灰色－随机风险率概念，建立了水质超标灰色－随机风险率评价模型。在水质单项参数评价模型中，将河流污染物浓度变量的分布处理成灰色概率分布，将污染物浓度超过水质类别标准值的风险率处理成灰色概率，即水质超标灰色－随机风险率。在水质综合评价模型中，河流水环境系统被考虑为担任某一使用可能的可靠性系统，而任意一种水质参数超标意味着河流水体使用功能不能得到应有的保证，也即表明水体综合评价超标，最后借鉴系统可靠性分析的理论和方法计算水质综合超标率。该方法应用于黄河花园口断面重金属污染风险评价。  相似文献   

Research progress of socio-economic water cycle in China   总被引：3，自引：0，他引：3  

Jia Shao-feng  Wang Guo  Zhang Shi-feng  Yu Gui-rui  Wang Jin-xia  Xia Jun 《地理学报(英文版)》2002,12(1):114-120

China has made great progress in the study of socio-economic water cycle. She has completed national water resources appraisement and medium to long-term water supply planning. She has been engaging in study on water-deficient regions in North China and Northwest China for about half a century. For solving water shortage problem in northern China, she has put forward the famous South-to-North Water Transferring Projects, which has been set as one of the four biggest national projects in the Tenth Five-Year-Plan period although there are still debates. For promoting water use efficiency, China has been reforming her water management system, including water right system and water price system. There has already been a case of water right purchase. China has also done a lot of research on the interaction between human activity, water and ecosystem. For meeting the need of sustainability and coordinating water resources development and environmental protection, the study of ecological water requirement became very hot in recent years. There are three focuses of socio-economic water cycle study now in China: water transfer projects from the south to the north, water resources management and ecological water requirement.  相似文献   

Tectonique transpressive en terre Adélie au Paléoprotérozoı̈que (Est Antarctique)Palaeoproterozoic transpression in Terre Adélie (East Antarctica)     

Anne Pelletier  Denis Gapais  René-Pierre Ménot  Jean-Jacques Peucat 《Comptes Rendus Geoscience》2002,334(7):505-511

The Palaeoproterozoic units of Terre Adélie show two types of structural domains associated with HT–LP metamorphic conditions: domes and NS–N340° striking vertical shear zones. Shear zones reflect dextral transpressive motions. Domes reflect sub-vertical shortening and principal stretching subparallel to shear zones. They could partly result from longitudinal flow coeval with transpression. Deformations are comparable to those described along the eastern and western boundaries of the Archean Gawler Craton (South-East Australia), which underlines the continuity between these two areas before opening of the Austral Ocean. To cite this article: A. Pelletier et al., C. R. Geoscience 334 (2002) 505–511.  相似文献   

基于农用地价格体系的征用地价应用研究   总被引：5，自引：0，他引：5  

李强  马仁会  王秋香 《地理与地理信息科学》2003,19(6):56-59

农用地价格体系和估价成果应用是当前农用地定级估价工作的难点和争论焦点，该文提出了农用地价格体系应以资源基准地价为基础，通过一系列修正，得出分级分区的征用基准地价、不转变用途的农地流转价、转变用途的农地转用价；以佛山市南海区的农用地估价成果为例，就其与现行征地补偿标准进行了比较，并与南海城区、广州市区城镇建设用地基准地价的相互衔接性进行了验算，应用成本逆推法，从城镇基准地价导出建设用地生地地价，在内涵一致的条件下相互比较。结果表明，按此地价体系建立的农用地征用价能够与城镇地价相衔接，可为城乡地价一体化的建立提供实证。  相似文献