中国气象局兰州干旱气象研究所

中国气象局兰州干旱气象研究所（简称干旱所）是经国家科技部、财政部、中央编制办公室批准同意成立的国家级公益性研究机构，其主要任务是根据国民经济、社会发展、西部大开发和气象业务现代化的需要，围绕我国干旱气象与生态环境问题，开展相关的应用基础研究、应用研究和技术开发工作。干旱所前身是成立于1974年的甘肃省气象科学研究所，2001年作为中国气象局“一院八所”之一，开始进行科研体制改革，实行理事会领导下的所长负责制，建立起“开放、流动、竞争、协作”的新型管理模式和运行机制，2004年通过了国家科技部首批改革试点单位的改革目标验收。     

干旱地区河流扇三角洲-河流扇演替模式:来自黄羊泉扇的启示

通过地表实地踏勘和浅层探槽解释，结合卫星照片解译，参考第四纪和历史地理研究结果，对准噶尔盆地西北缘黄羊泉扇的沉积特征及其第四纪以来的演变进行了分析.黄羊泉扇是一个发育在内陆干旱地区、以河流沉积为主的河流扇，扇体平面上呈上细下粗的“葫芦型”，可以划分为上扇、中扇和扇缘3个相带，沉积物具有由上扇向扇缘变细的趋势.扇上沉积动力以河流为主，缺乏泥石流沉积，但扇面活动水道不发育，大多数河道为偶尔才有径流通过的暂时性河道，风对扇表面的沉积物有明显的改造作用.黄羊泉扇扇缘发育4种不同的终止方式，一部分进入艾里克湖，一部分终止在沼泽地带，一部分在小型湖泊边缘消失，一部分受地形阻挡终止，与经典冲积扇和扇三角洲都不完全相同.结合前人历史地理研究成果认为第四纪以来黄羊泉扇所在的古玛纳斯湖出现过6次高湖平面，在30 ka以前，黄羊泉扇体一直处于古玛纳斯湖包围中，形成黄羊泉扇三角洲.直到30~10 ka期间才由于湖泊水位下降，扇体逐步出露形成河流扇.研究建立了黄羊泉扇随着湖平面升降从河流扇三角洲不断演化为河流扇的沉积模式，表明黄羊泉扇目前正处于河流扇三角洲沉积体系向河流扇沉积体系演变的过渡阶段.      

缅怀恩师任美锷、杨怀仁、施雅风和高由禧先生——兼谈老师对我国地理学、地貌与第四纪地质学、海洋学、冰冻圈学和冰川气象气候学的杰出贡献

正缅怀恩师任美锷先生1*任师地理学泰斗,学识渊博冠神州;精通经济、自然地理学,通晓地貌、古地理领域;提出"准热带"科学概念,首著"中国自然地理纲要";指导三角洲、海涂利用,引导海洋学研究;运用"沉积圈闭"理论,论述陆相盆地储油.教学科研很严谨,贡献颇多人称颂;培养数代地理学院士,桃李满园遍五洲.而今仙逝精神在,激励后生永探索.     

《地质论评》、《地质学报》、《地质学报(英文版)》网上投稿、审稿、稿件处理状况查询系统开通启事

为了更高效率地办刊,《地质论评》、《地质学报》、《地质学报(英文版)》开通了网上投稿、审稿、稿件处理状况查询系统。欢迎各位作者、专家、读者登陆、使用。《地质论评》的网址为:http://www.geojournals.cn/ georev。本系统中,作者可以网上投稿、查询稿件处理进度,专家可以网上审稿。     

兰州地区黄土的冻结温度

兰州东岗镇剖面下部黄土的冻结温度T_f与土含水量W和Na~+与Cl~-含量(mmol/100g)有以下的相关关系:T_f=-4.27W~(-1.03)[Na~+]~(0.54)[Cl~-]~(0.48)。在冻结开始瞬间,可认为W等于未冻水含量W_u,T_f等于土温T,于是此式可改变为Anderson-Tice公式的形式:W_u=40.53|T|~(-0.98),据Tice等人的实验资料,对兰州九洲台剖面黄土,有W_u=30.21|T|~(-0.97);而对于兰州白塔山剖面黄土,有W_u=26.47|T|~(-0.98),这些来源不同而结果相近的式子,说明含盐量与第一个系数的关系比之它与T的指数的关系更为密切。     

Sources and vertical distribution of 137Cs, 238Pu, 239+240Pu and 241Am in peat profiles from southwest Spitsbergen

This paper presents a detailed survey of the activities of selected man-made radionuclides in peat deposits located in SW Spitsbergen. Peat cores from the High Arctic (SW Spitsbergen) were analyzed by gamma spectrometry (¹³⁷Cs), alpha spectrometry (²³⁸Pu, ^239,240Pu, ²⁴¹Am activities) and by ICPMS (²⁴⁰Pu/²³⁹Pu atom ratios). Maximum activities evident in the peats correspond to the 1963/1964 global maximum fallout from atmospheric testing of nuclear weapons; some of the activity profiles have been altered post-deposition by water infiltration. Activity ratios of ²³⁸Pu/^239+240Pu, ²⁴¹Am/^239+240Pu, ^239+240Pu/¹³⁷Cs and ²⁴⁰Pu/²³⁹Pu atom ratios indicate mixing between global (stratospheric) and regional (tropospheric) sources of these radionuclides in the Svalbard area. The ²³⁸Pu/^239+240Pu activity ratios varied from 0.02 ± 0.01 to 0.09 ± 0.03, suggesting global fallout as the dominant source of Pu. The ^239+240Pu/¹³⁷Cs activity ratios varied from 0.01 ± 0.01 to 0.42 ± 0.11, which apparently arises from the post-depositional mobility of ¹³⁷Cs. The ²⁴¹Am/^239+240Pu activity ratios ranged between 0.10 ± 0.02 and 1.5 ± 0.3 and exceed the published global fallout ratio for Svalbard of 0.37 due to the relatively higher geochemical mobility of Pu vs. Am and/or ingrowth of Am from the decay of ²⁴¹Pu. The atom ratio ²⁴⁰Pu/²³⁹Pu ranged from 0.142 ± 0.006 to 0.241 ± 0.027; however, the vast majority of peat samples exhibited ²⁴⁰Pu/²³⁹Pu atom ratios similar to the stratospheric fallout (∼0.18).     

Abstracts of Acta Geologica Sinica (Chinese Edition): Vol. 73, No. 4, 1999

The Reservior Characteristics of Lower Ordovician Dolomites Below Pre-Mesozoic Unconformity in Yakela Fault-convex, Tarim Basin The Blueschist Belt in the Shuanghu Region, Central-Northern Tibet and Its Tectonic Implications Reef Palaeopool and Prediction of Buried Reefs in the Lower Permian Series from Shiwandashan Basin of Guangri Province Geochemistry of Rare Earth Elements in Late Paleozoic Coals in the North China Phase Transition and Composition Change of Minerals from Melting Experiment of Two Kinds of Metamorphics in Fuping Group, Pingshan, Hebei Province, China Palaeoecology and Palaeoenvironment of the Jehol Biota — A Palaeoecological and Palaeoenvironmental Reconstruction of Conchostracan Palaeocommunities in the Northern Hebei-Western Liaoning Area Research on Micro-FT.IR of Macerals of C-P Coals in the Bohal Bay Basin Self-similar Texture of the Mid—Longling—Ruili Strike-Slip System and the Location of Hydrothermal Deposits Metamorphism of the Eclogites from the ZK703 drillhole in Donghai, South Sulu (Jiangsu-Shandong) Ultrahigh-pressure Metamorphic Belt, Eastern China     

A recent turbidity current event, Hueneme Fan, California: reconstruction of flow properties

A recent (100 yr old) turbidite is described from Hueneme Fan, California Continental Borderland. Dense sampling over the fan surface has allowed excellent delineation of the characteristics of this deposit. It exhibits Bouna DE sequences and has a distinctly bimodal, sandy silt grain size distribution. Through the use of generalized fluid dynamics equations, it is possible to reconstruct original flow properties of the current which deposited this material. The calculated velocities ranged from 10–90 cm s^-1 and excess density (above ambient seawater) from 0·001–0·005 g cm^-3 in the lower midfan and upper fan channel regions, respectively. Height of the current ranged from 5–15 m, on slopes from 1·5 to 0·15°. A total of 10⁷ m³ of sediment was deposited during 10 days. The turbidity current is conjectured to have originated from direct river input during the floods of 1884. An older event is also described, which has distinctly different properties and origins. The grain sizes of this older deposit are much coarser, and sedimentary structures suggest higher flow regimes. This turbidite is conjectured to have been deposited from a higher density, faster current thought to have been generated by slumping. The need for a better understanding of the controls on the characteristics of turbidity currents and their effect on fan morphology is emphasized.     

华北克拉通对前寒武纪超大陆旋回的基本制约

全球大陆克拉通在前寒武纪至少记录了3次超大陆聚合－裂解的构造旋回。不同大陆前寒武纪地质的研究证明，板块的构造模式可以前推至新太古代。超大陆的聚合表现为大规模造山带的穿时性发育，而裂解则表现为大陆裂谷系、非造山花岗岩及巨型基性岩浆岩省的同期快速发育。广泛的区域地质研究揭示华北克拉通前寒武纪地质构造演化具有明显的阶段性差异特征，克拉通主体形成于新太古代陆壳增生与碰撞造山过程。华北克拉通在太古宙末期首次经历强烈的裂解作用，在古元古代晚期涉及强烈的陆缘再造作用。在古元古代末期发生第二次大规模的裂解活动，随后以中元古代末期的造山带拼合为Rodinia超大陆的组成部分。详细的区域构造对比证明，华北克拉通长期以来与波罗的地质、东南极克拉通、印度南部克拉通、巴西克拉通等具有构造亲缘关系。