陕南降水变化时空差异分析

陕南地处南水北调中线工程水源地,降水量变化对该区域以及调水工程和受水区影响深刻.利用陕南及周边气象站点近30年的降水资料,运用经验正交函数法,分析获得陕南降水变化的空间分布特征和时间系数.结果表明:(1)陕南降水变化的特点主要表现出南北差异、东西差异和相对一致性的特点;(2)陕南降水变化的时间系数表现出明显的年内变化.     

济南市南部山区生态环境分析及对策

在分析了济南市南部山区西部区域生态环境现状的基础上，指出该区主要存在植被覆盖率低下、分布不均匀、林地质量差、水土流失严重、水资源短缺、水质恶化、景观破坏等生态问题，并结合当地实际情况提出了改善生态环境的对策，为保护其生态环境提供依据。     

Formate and acetate as recorded in a mid－latitude glacier in west China

Formic (HCOOH) and acetic (CH3COOH) acids are the chief carboxylic compounds in the troposphere[1]. Although weak acids, they contribute significantly to the free acidity, ionic balance of precipitation and the chemical reactions in the atmosphere, especially in the remote areas[2—4]. General sources for formate and acetate have been identified in the past 3 decades although a satisfactory source attribution is lacking to explain atmospheric observations[5]. Possible sources include veget…     

Quaternary folding in the south piedmont of central segment of Tianshan Mountains

The Tianshan Mountains are an important active structural belt in the interior of Eurasia. By integrated methods of surface geology survey and interpretation of seismic profiles, we distinguish fold scarps located at the south limb of the Kuqatawu anticline and the north limb of the Dongqiulitag anticline in the Kuqa rejuvenation foreland thrust belt, south piedmont of central segment of the Tianshan Mountains. Fold scarp is a newly found structural phenomenon. Because of the bend of thrust plane and the movement of hanging wall above the thrust plane, the original horizontal deposits of hanging wall and their surface become a monocline structure, resulting from the separating and migration of the active and fixed axial surfaces. Measuring the geometry of fold scarp and using the data of age of the deformed deposits, the crustal shortening rate resulting from the deeply seated subsurface thrust is calculated. The crustal shortening rate reflected by the fold scarp located at the north limb of the Dngqiulitag anticline is (1±0.1) mm/a. The fold scarps of the Dongqiulitag anticline and the Kuqatawu anticline identify that the deformation process of the crustal compressive structures in the Kuqa area extends into the Late Quaternary.     

贵州省独山南部岩溶地下水评价模型和管理模型

本文运用运筹学中的有关理论和方法,给出了贵州独山南部岩溶水资源系统的评价模型和管理模型。模拟和再现了岩溶水系统的若干重要特征,求出了重要的参数。根据该地区工农业生产的发展和水资源的时空分布特征,给出了2000年前三个时期的科学配水方案。     

Climate change over southern Qinghai Plateau in the past 500 years recorded in Sabina tibetica tree rings

Two tree ring-width chronologies of Sabina tibetica were developed based on cores sampled in Qumalal and Zhiduo, southern Qinghai Plateau. The response function analysis showed that the chronologies were sensitive to temperature and precipitation from April to June in the plateau. Moisture index (MI) was defined, reconstructed and extended back to AD 1550. The cross-validation method was used to check the stability of the calibration equation, and the result indicated that the equation was stable. Six severe dry periods were found in this region in the past 453-year reconstruction, which were 1592 to 1610, 1649 to 1665, 1687 to 1697, 1740 to 1750, 1818 to 1829 and 1918 to 1933. Five severe wetting periods were 1669 to 1682, 1700 to 1709, 1800 to 1814, 1898 to 1909 and 1935 to 1950. Spectrum analysis indicated that there existed long-term cycles of 60.4 and 53.4 a, solar cycle of 11 a and short-term cycles of 8, 6 and 4 a in the reconstructed series.     

Discovery and geological implication of rodingites derived from eclogites of ophiolites at Changawuzi, western Tianshan, China

We here report the first case of rodingites that were formed at the expense of eclogite enclosed in the ultramafic rocks of Changawuzi ophiolites. The rodingites contain a mineral assemblage of grossular, diopside, prehnite, chlorite, and relict omphacite and Fe-Mg-Al garnets. The presented data indicate that the formation of the rodingites resulted from a phase of secondary serpentinization during exhumation of the subducted oceanic plate. The rodingitization started at 370～410 ℃/6.5～8.5 kbar, while pervasive rodingitization took place under the condition of 200～350 ℃/4～6 kbar. The established PT path shows a retrograde track from eclogites to rodingites. We conclude that the process of rodingitization could also take place under subduction conditions in addition to its more common occurrence under ocean-floor metamorphic conditions.