新元古代地球气候研究进展

新元古代曾发生过强烈的全球性冰川作用,本文回顾了新元古代晚期全球性冰川作用存在的证据及其特点,论述了新元古代冰期产生的原因,综述了一些代表性的“雪球地球”模型并探讨了“雪球地球”对早期生物演化的影响,最后对未来“雪球地球”研究趋势进行了展望.     

武汉重力固体潮长周期潮汐参数的确定

基于武汉国际重力潮汐基准台GWR-C032型超导重力仪记录的1997年到2002年的重力潮汐数据,研究了重力固体潮长周期潮汐波的潮汐参数特征。引进一种新的VAV重力固体潮汐分析方法,设计了有效的漂移模型,考虑台站气压、极移和日长变化对重力的影响,得到非潮汐变化量为22．54nms^-2／a。     

川主寺尕里台滑坡形成机制分析

尕里台滑坡位于松潘县北西约39km,在哲波河上游尕里台支沟右岸Ⅰ级阶地边缘谷坡中下部,为体积约10×10^4m^3的中型滑坡。滑坡体在天然或暴雨状态下处于不稳定状态,现根据所掌握的资料,对滑坡形成机制进行分析。     

松辽盆地西部斜坡北段油气成藏特征分析

松辽盆地西部斜坡北段油气主要来自齐家-古龙生油凹陷青山口组烃源岩,油气沿着高台子油层和萨尔图二-三油层砂体以狭窄的路径侧向西运.共发育3条运移路径,侧向运移的油气受低幅度构造、断层和地层尖灭遮挡富集成藏.西部斜坡构造幅度较低,断层规模小,平面延伸的距离短,不利于油气大规模聚集成藏,盆地边部的地层超覆带是寻找大规模地层尖灭油气藏和油砂矿的有利地区.斜坡区普遍受大气降水淋滤作用,原油受喜氧细菌的降解作用普遍稠化,沿着大气水下渗方向,原油稠化的程度越米越低,造成自西而东原油性质呈现规律性变化：地层超覆带为严重降解的稠油和油砂,断层遮挡油气聚集带为中等降解的稠油,构造-岩性油气聚集带为轻度降解的稠油和正常原油.     

贵州锦屏新元古界青白口系下江群稀土、微量元素分布特征——探讨金的来源问题

贵州东南地区的新元古界下江群产大量的石英脉型金矿,有关金的矿源一直是争议的问题。通过对下江群逐层采样,进行微量、稀土元素测试,结果表明金主要在变余砂岩中富集,特别是在变余砂岩透镜体或板岩封闭的变余砂岩顶部是含金石英脉形成的部位。Au与Mn、Sr、Cu等成正相关,特别是Au与Mn呈显著的正相关,可能是Mn胶体对金具有显著的吸附作用,Mn含量高的层位金含量高。而Au与Hg、Ba、W、As呈弱的负相关性,Ti、Co与Au呈负相关性,说明Au与陆源物质没有关系。下江群中稀土配分非常类似,表明地层被后期热液充分混合作用,金往往在稀土含量较低的层位富集,说明流体运移到砂岩内,而砂岩中的石英对稀土有稀释作用。富含金的pq-15样品具有与下江群完全不同的稀土配分,其表明金的成矿物质可能除来源于下江群外,还有深部流体参与成矿。     

A Holocene climatic record denoted by geochemical indicators from Barkol Lake in the northeastern Xinjiang,NW China

The Barkol Lake, as a closed inland lake, is located at the northeast Xinjiang in northwest China. A combination of geochemical indicators including δ¹⁸O and δ¹³C of carbonate, TOC, carbonate contents, as well as grain size proxies and magnetic susceptibility of sediments obtained from a newly recovered section at this lake, provides a high-resolution history of climatic change in the past 9400 years. Multi-indicators reflect that Holocene climatic change in the study region generally follows the Westerly Wind pattern of Holocene, and three climatic periods can be identified. Between 9400 and 7500 cal a B.P., climate was characterized by relatively drier and colder condition. From 7500 to 5800 cal a B.P., a relatively warmer and moister climate prevailed, but between 5800 and 3500 cal a B.P., climate shifted towards warmer and drier conditions. A relatively colder and wetter climate prevailed during 3500∼1000 cal a B.P., then it changed towards cold and dry between 1000 and 500 cal a B.P.; after 500 cal a B.P., climate changed towards warm and dry conditions again. This study reflects that during the Middle Holocene (from ca 7000 to 3500 cal a B.P.), variations of carbonate δ¹⁸O of sediments from several lakes in the northern Xinjiang were synchronous with that of Qinghai Lake, where was strongly influenced by the South Asian monsoon; however, after 3500 cal a B.P. this consistency was interrupted, possibly resulting from a re-domination of the Westerly Wind and the retreat of South Asian monsoon in the northern Xinjiang.     

Damage assessment of tunnels caused by the 2004 Mid Niigata Prefecture Earthquake using Hayashi’s quantification theory type II

Mountain tunnels, being underground structures and situated deep within rock layers, are generally considered to suffer appreciably less damage from earthquakes than surface structures. However, it has been reported that many tunnels were damaged by the 1923 Great Kantou earthquake, the 1995 Great Hanshin Earthquake, the 1999 Taiwan Chi-Chi Earthquake, the 2004 Mid Niigata Prefecture Earthquake and the May 2008 Great Wenchuan Earthquake in China. In this study, the damaged tunnels resulted of the 2004 Mid Niigata Prefecture Earthquake are the study objects. The damage patterns are analyzed, and the information which is considered to be of influence, such as the distance to epicenter, the completion time, the geological conditions, etc., are collected. A database of the damaged tunnels has been created using a Geographic Information System (GIS). The influence ranking for these factors has been analyzed using Hayashi’s quantification theory II. The degree of the tunnel damage has also been assessed using GIS and Hayashi’s quantification theory II. The field investigation is in close agreement with the assessment results following Hayashi’s quantification theory II.     

Hydrocarbon Generation Evolution of Permo-Carboniferous Rocks of the Bohai Bay Basin in China

<正>The Bohai Bay Basin is a Mesozoic subsidence and Cenozoic rift basin in the North China Craton.Since the deposition of the Permo-Carboniferous hydrocarbon source rock,the basin has undergone many tectonic events.The source rocks have undergone non-uniform uplift,twisting,deep burying,and magmatism and that led to an interrupted or stepwise during the evolution of hydrocarbon source rocks.We have investigated the Permo-Carboniferous hydrocarbon source rocks history of burying,heating,and hydrocarbon generation,not only on the basis of tectonic disturbance and deeply buried but also with new studies on apatite fission track analysis,fluid inclusion measurements,and the application of the numerical simulation of EASY%R_o.The heating temperature of the source rocks continued to rise from the Indosinian to Himalayan stage and reached a maximum at the Late Himalayan.This led to the stepwise increases during organic maturation and multiple stages of hydrocarbon generation.The study delineated the tectonic stages, the intensity of hydrocarbon generation and spatial and temporal distribution of hydrocarbon generations.The hydrocarbon generation occurred during the Indosinian,Yanshanian,and particularly Late Himalayan.The hydrocarbon generation during the late Himalayan stage is the most important one for the Permo-Carboniferous source rocks of the Bohai Bay Basin in China.     

New Species of Enantiornithes (Aves: Ornithothoraces) from the Qiaotou Formation in Northern Hebei,China

<正>We report on a new species of enantiornithine bird from the Lower Cretaceous Qiaotou Formation of northern Hebei,China.The new taxon,Shenqiornis mengi gen.et sp.nov.,possesses several enantiornithine synapomorphies but is unique from other known species.The specimen has a well-preserved skull that reveals new information about enantiornithine cranial morphology.The new taxon possesses a large postorbital with a long tapering jugal process indicating that some enantiornithines may have had a fully diapsid skull,as in Confuciusornis.The tooth morphology of the specimen is unique and likely represents a previously unknown trophic specialization within Enantiornithes.     

基于eSuperMap的自然地理实习数据采集与导航系统

针对传统自然地理实习技术手段落后、效率低下、数据采集困难等问题,利用eSuperMap嵌入式开发技术,结合自然地理实习的实际情况,开发出运行于智能终端的自然地理实习数据采集与导航系统,为自然地理实习中的数据采集与导航提供有效的辅助手段。应用实践表明,该系统能够提高实习质量,具有应用推广价值。