Origin, evolution and extinction of Cathaysia flora

Recent research results showed that the Cathaysia flora originated and developed from the global uniformLepidodendropsis flora of the Early Carboniferous, which had already become an independent flora in the early Late Carboniferous (Namurian B to C). The center of origin of the Cathaysia flora is restricted to the North China Plate. On the basis of the successional characteristics of the Cathaysia flora in different geological ages, it may be divided into seven evolutionary stages. The evolutionary trend of the Cathaysia flora, as a whole, was characterized by the gradual increase of the typical Cathaysian elements in the sequence from the early Late Carboniferous to the early Late Permian, which began to decline during the late Late Permian. The climatic differentiation, tectonic movement, oceanic circulation, palaeogeographical environment, extraterrestrial event and plant evolution caused the mass extinction of the Cathaysia flora on a large scale by the end of the Permian.     

内蒙古小孤山锡锌多金属矿的矿床地质特征与找矿意义

内蒙小孤山锡锌多金属矿是产于燕山期花岗斑岩与下二叠统大石寨组含碳质岩石接触带的热液成因矿床。该矿床没有地表露头．完全依靠大比例尺的地球化学土壤测量结合激电中梯、电阻率测量发现异常后进行钻探验证查明的。该矿床的查明为在大面积第四系覆盖区和地台区寻找隐伏矿体提供了有益帮助。     

Flabellariopteris,a new aquatic fern leaf from the Late Triassic of western Liaoning,China

An aquatic fern leaf, Flabellariopteris mii Sun gen. et sp. nov. from the Late Triassic of Western Liaoning, China, is described and proposed as the type species of the new morphortaxon of the Marsileaceae. The fossil leaves are preserved as impression. No fertile and rhizomatic materials are found. The leaves attached at a common point on the top of the petiole are composed of two leaflets joined basally in an opposite arrangement. The petiole is slender. The leaflet is fan-shaped or semi-circular, and commonly divided into four wedge-shaped lobes. Terminal margin of lobes is usually incised, incisions shallow or deep, with bluntly rounded or notched apex. The veins are conspicu- ously dichotomous, but anastomoses and marginal vein are absent. The unique morphological features, including two- parted thin leaflets, size, shape, veins and slender petiole, indicate that the present specimen represents an aquatic fern, which is the oldest fossil record and the first megafossil evidence assignable to Marsileaceae from the Triassic floras.     

Paleoclimate change recorded in the red earth and brown-yellow sediment of Late Quaternary for northeastern part of Guangdong Province, south to the Nanling Mountains, China

The paleoenvironment indicated by the geochronology, major oxides SiO2, Al2O3 and TOFE （Fe2O3 ＋ FeO）, and CIA （Chemical Index of Alteration） value of the red earth and brown-yellow silt primarily characterized by the Linjiang stratigraphic section, based on the geological investigation of Late Quaternary along the river banks of northeastern part of China＇s Guangdong Province, south to the Nanling Mountains, allow us to hypothesize that the red earth on the first terrace in northeastern part of Guangdong belongs to reticulated red clay developed in a hot-wet environment of the last interglacial period （132-73 ka BP）, similar to the monsoon environment in the northern margin of modern tropical zone, while the overlying brown-yellow silt layer mainly accumulated in a monsoon environment of warm temperate zone in the last glacial period （73-11 ka BP）, with the aeolian sand LJ3 representing an extreme period of worsening climate. Such a hypothesis corresponds well with predecessors＇ research on the paleoenvironment indicated by abundant fossils in both south and east to the Nanling Mountains. Hence, it follows that the bioclimatic zone did experience a large and rapid vicissitude in northeastern part of China＇s Guangdong Province, and even in the full extent of the region south to the Nanling Mountains from the last interglacial period to the last glacial period, with the red earth being replaced by the brown-yellow silty sediment, and even maybe with the Ailuropoda-Stegodon Fauna being replaced by the Penghu Fauna. This study may provide an important geological demonstration for the environmental response to global change in China＇s low latitudes on a 10 ka scale.     

晚新生代元谋盆地演化与河谷发育研究

元谋盆地是在晚新生代青藏高原与云南高原隆起过程中形成的众多断陷盆地之一,流经元度盆地的龙川江和金沙江。其河谷发育与盆地演化具有密切关系,通过对元谋盆地及其邻区的层次地貌与相关沉积的分析研究,认为,始新世晚期￣中新世晚期是夷平面形成时期,中新世晚期￣３．４０ＭａＢＰ前后是第一级剥蚀面形成时期;元谋盆地形成于３．４０ＭａＢＰ前后第一级剥蚀面解体过程中,其后盆地经历了３．４０￣１．７８ＭａＢＰ的古湖形成     

"诗史"精神重放光辉--论宋末诗人对杜诗的接受

南宋末年,在文天祥以身殉国、忠义存诗存史的影响下,一大批南宋遗民、诗人奋起直笔,模仿杜诗,以诗存史,而且往往在诗前另以序言辅以记史.     

钟乳石铀系年龄与洞穴遗址年代测定

中、晚更新世洞穴古人类遗址中,多有与遗物有明确层位关系的钙板或其它形式的钟乳石类碳酸岩,是测定铀系年龄的理想材料。本文在简单介绍钟乳石铀系年龄原理后,着重讨论了其可信度。铀系年代计算需引入二个主要假设:“零点假设”及封闭体系假设,还有若干同位素和地层学的标准,可用来判断数据是否异常而应被舍去。已有实验证据表明,对纯净致密、结晶良好的钟乳石样来说,上述基本假设可以成立,也尚未发现与地层顺序相矛盾及同位素比异常的例子,这表明了钟乳石铀系年龄的良好可信度。文中给出了法国Arago、希腊Petralona、周口店第一地点、贵州黔西观音洞等重要古人类遗址的应用实例,并讨论了其存在问题及发展前景。     

论晚明来华耶稣会士的公关艺术——以利玛窦为中心的考察

晚明以利玛窦为首的耶稣会士来华传教,很好地运用了现代公关艺术。他们在组织内部统一传教思想,推行适应策略;对外改装易服、结交士人、传播学术,最终获得在华传教的成功;同时也成就了中西文化交流的一段美丽佳话。     

中国北方晚新生代红粘土研究之若干问题

对于中国北方地区晚第三纪以来沉积的红粘土的成因,近年来不少学者通过对其粒度、地球化学及古生物等替代性指标的研究,认为该套沉积物为风尘沉积.通过大量野外考察、理论与室内分析测定,认为粒度、地球化学等指标存有多解性,而古生物证据与所谓风成的干旱化环境不相一致,上述指标并不足以成为红粘土风成的确凿证据因此,进一步深入研究相关替代性指标的研究是今后努力的方向,对红粘土成因的确认不能仅局限于青藏高原的可能影响,全球环境的变化才有可能是解决问题的关键途径.参17.     

东北地区晚泥盆世岩相古地理研究

利用野外实测剖面和区域地质资料,在地层划分和对比、构造格局研究以及早中泥盆世研究基础上,从点—线—面的沉积相分析入手,将晚泥盆世的弗拉斯期和法门期作为一个编图单元进行岩相古地理编图,恢复了东北地区晚泥盆世的岩相古地理面貌。研究表明,晚泥盆世东北地区主要发育浅海陆棚沉积体系(浅海陆棚相)、无障壁海岸沉积体系(滨海相)、三角洲沉积体系(三角洲相)、碳酸盐台地沉积体系(局限台地、开阔台地相、台缘斜坡相)和障壁海岸沉积体系(潟湖、潮坪相);存在额尔古纳和松辽两个主要古陆区,其余地区以滨、浅海相沉积为主。黑龙江小河里河、内蒙古卧都河地区发育三角洲相沉积;苏尼特左旗西南部受到海侵影响,海侵方向由西向东,发育滨海相沉积;沿贺根山-扎兰屯一线仍为陆间洋盆俯冲形成的蛇绿混杂岩带。