北京市延庆县崖居探秘

中华第一迷宫中国最大的崖居华夏最迷人的景观古崖居,位于延庆县西部约20公里处的张山营镇东门营村北的峡谷中。是由一支不见史志记载的古代先民在陡峭的岩壁上开凿的,我国已发现的规模最大的崖居遗址。是华北地区目前发现规模最大的崖居遗址,被称之为"中华第一迷宫"。1984年,延庆县文物管理所前任所长程金龙在走访北山周围的村子时,第一次听老人们提起"洞沟"。在村民的带     

驾石飞梁尽一虹 水从碧玉环中过 人在苍龙背上行——赵州桥以中国古代“四大”名桥之一“天下第一桥”“国际土木工程里程碑”的名声响誉天下

赵州桥,义名安济桥,位干河北省石家庄市东南45公里：赵县城南2．5公甩处的大石桥村,南北飞跨。因赵县占时曾为赵州,所以一般称为赵州桥。被誉为“天下第一桥”、“世界奇迹”。赵州桥全长644米,拱顶宽9米,跨径37．02米,拱矢7．23米。桥的结构十分巧妙,从整体来看,是一座单孔弧形桥。但它却是由28道拱纵向并列构成的。特别是在大拱的拱肩上各建造了两个小拱,即敞肩拱,     

雷击不焚强震不倒的山西应县木塔之谜

精工的技术内涵世界木结构建筑的典范精湛的建筑构造中国古代建筑的瑰宝精美的文化价值华夏艺术博物馆     

中国古代的环境地质观念

在中国北方发现的石器时代文化遗址,多位于河谷两侧的阶地上。这种地方取水近而又不卑湿,较适于人类居住,因此这些遗址的分布,明显地受到地质条件的控制。当文明社会兴起后,中国人就开始把这些经验整理起来,记入典籍。成书于两千多年前的《管子》一书中,就有了这样的概括:"凡立国都,非于大山之下,必于广川之上。高勿近旱,而水用足;下勿近水,而沟防省"。     

加强理论方法研究提高学科基础水平

地理学是一门古老而又年轻的科学。古代地理学思想内涵丰富;而近现代地理社会应用广泛。100年前,随着西方科技文化的传人和渗透,以及与中国传统地理学发生碰撞、融合,逐渐形成了中国近代地理学。100年来,中国地理学逐渐建立起了比较完整的学科体系,从教育到研究都展现了欣欣向荣的景象。尤其是近30年来,随着中国改革开放以及经济社会的快速发展,地理学的社会需求十分旺盛,地理学研究成果数不胜数,地理学和地理学家的社会知名度快速攀升。     

《秦代政区地理》评介

历史政区地理研究是中国传统舆地学的核心内容之一,也是现代历史地理学研究的重要内容之一。作为我国历史上第一个封建大一统王朝,秦代的郡县设置问题一直是中国古代史研究中的一个热点、难点问题,由于秦祚短促,加之文献记载的阙如、歧异,秦代的郡县设置问题一直未能得到真正解决。后晓荣博士著《秦代政区地理》一书,所针对的正是这一历史地理学界的重大问题。该书作为东方历史学术文库丛书之一,已于2009年由社会科学文献出版社出版。书中作者利用新材料和新研究手段重新审视秦代历史地理,特别是秦代政区地理中郡县设置的重大问题,得出了仅靠传统文献无法得出的新的结论,提出了秦置54郡的见解,又考证落实了近700个秦置县,从而促进了秦代历史地理问题的研究。     

Environmental Redox Changes of the Ancient Sea in the Yangtze Area during the Ordo-Silurian Transition

Extensive organic-matter （OM） rich facies （black shales） occur in the Ordo-Silurian boundary successions in the Yangtze area, South China. To investigate the redox changes of the Yangtze Sea during the Ordo-Silurian transition, two OM sections （Wangjiawan in Yichang, Hubei Province, and Sanjiaguan in Zhangjiajie, Hunan Province） straddling the Ordo-Silurian boundary are studied. The measurements finished in this study include contents of the total organic carbon （TOC）, pyrite sulphur, and different species of Fe, including dithionite-extractable Fe （FED）, pyrite Fe （FeP）, HCl-extractable Fe （FeH）, and total Fe （FeT）, in black shales, as well as other redox proxies, such as the SIC ratio, the ratio between highly reactive Fe （FeHR = FeD ＋ FeP） and FeT, and the FeP/（FeP ＋ FeH） ratio, known as the degree of pyritization （DOP）. In the Wangjiawan section, the Middle Ashgill sediments have high FeHR/FeT ratios （0.20-0.77; avg. 0.45）, high DOP values （0.21-0.72; avg. 0.54）, and a relatively constant sulfur content independent of the organic carbon content. By the contrast, the mid-early Hirnantian deposits generally have low FeHR/FeT ratios （0.10-0.35; avg. 0.21）, low DOP values （0.11- 0.40; avg. 0.28）, and SIC values are clustering on the normal marine value （SIC = 0.36）. The late Hirnantian and early Rhuddanian deposits, similar to those of the Middle Ashgill deposits, are characterized by high FeHR/FeT ratios （0.32-0.49; avg. 0.41）, high DOP values （0.46-0.68; avg. 0.53） and fairly constant sulfur contents. These data suggest the occurrences of marine anoxia on the Yangtze Sea shelf during intervals of the Mid Ashgill, Late Hirnantian and Early Rhuddanian, and ventilated and oxygenated marine conditions during the mid-early Hirnantian time. The mid-early Hirnantian ventilated event was concomitant with the global glacial period, likely resulted from the glacio-eustatic sea-level fall and subsequent circulation of cold, dense oxygenated waters     

Mineralogical and Petrological Characteristics of the Neoproterozoic Orthoamphibolite and Orthogneisses in the Mutki Area, the Bitlis Massif, Southeast Turkey

<正>The rocks form as amphibolite±garnet±epidote and orthogneisses in the Pan-African basement of the Bitlis Massif.The petrochemical data of the studied metamorphic rocks suggest different igneous protoliths ranging from calcalkaline basalt to andesite in composition. Petrochemically,the rocks can be classified as group 1(low Zr and La) and group 2(high Zr and La), all showing various enrichments in large ion lithophiles and light rare earth elements,and a depletion in high-field strength elements,suggestive of a destructive plate margin setting.The protoliths of the all samples might have formed mostly by the partial melting of an enriched source,possibly coupled with the fractional crystallization of plagioclase,apatite,and titaniferous magnetite±olivine±clinopyroxene±amphibole in relation with subduction-related magmatism neighboring the Andeantype active margins of Gondwana.The group 2 samples could,however,be generated by a relatively lower degree of the partial melting of an inhomogeneous source with a preponderance of a high-level, fractional crystallization process in comparison to group 1.The protoliths of the samples were metamorphosed up to amphibolite facies conditions,which destroys original igneous texture and mineral assemblages.Geothermobarometric calculations show that the metamorphic rocks are finally equilibrated between 540 and 610℃and～5 kbars,following a clockwise P-T-t path.     

康定杂岩锆石SHRIMP U-Pb定年及其地质意义

康定杂岩在扬子地块西缘呈南北向带状分布,这套岩石岩性变化很大(从基性到中性、酸性),中性、酸性岩是组成该杂岩的主体。岩石类型有变辉长岩、闪长质片麻岩、石英闪长质片麻岩和花岗质片麻岩。康定杂岩以往被认为是扬子地块太古宇的基底,但近年来的同位素年龄测定结果表明其并不是形成于太古宙。本研究样品采自康定-泸定地区,挑选有代表性的两个样(样号71704.2、71501.1),对其进行岩石化学与微量元素分析及SHRIMP U-Pb测年。分析得出样品为钙碱性;原始地幔标准化微量元素分布型式显示相对富集大离子亲石元素K、Rb等,亏损高场强元素Nb、Ta、Ti、P等;稀土元素具有略向右倾的配分型式,且铕异常不明显,显示其具有与消减作用有关的岛弧火成岩的特征。锆石U-Pb分析给出的结晶年龄为765～771 Ma,w(Th)/w(U)大于0.1,具示岩浆成因特征。个别年轻的锆石颗粒,如71704.2中的12.1测点年龄为(430±8)Ma,可能是在后期构造、岩浆、变质作用中新形成的锆石,该年龄可解释为后期变质热事件的年龄。这些充分说明康定杂岩形成于新元古代,而非太古宙。此外,康定杂岩可能形成于岛弧环境,其岩浆主要起源于俯冲洋壳的熔融,结合其形成年龄说明扬子地块西缘新元古代岩浆活动可能是Rodinia超大陆裂解后的产物。