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91.
The strong 14C increase in the year AD 774/5 detected in one German and two Japanese trees was recently suggested to have been caused by an impact of a comet onto Earth and a deposition of large amounts of 14C into the atmosphere (Liu et al. 2014). The authors supported their claim using a report of a historic Chinese observation of a comet ostensibly colliding with Earth's atmosphere in AD 773 January. We show here that the Chinese text presented by those authors is not an original historic text, but that it is comprised of several different sources. Moreover, the translation presented in Liu et al. is misleading and inaccurate. We give the exact Chinese wordings and our English translations. According to the original sources, the Chinese observed a comet in mid January 773, but they report neither a collision nor a large coma, just a long tail. Also, there is no report in any of the source texts about “dust rain in the daytime” as claimed by Liu et al. (2014), but simply a normal dust storm. Ho (1962) reports sightings of this comet in China on AD 773 Jan 15 and/or 17 and in Japan on AD 773 Jan 20 (Ho 1962). At the relevant historic time, the Chinese held that comets were produced within the Earth's atmosphere, so that it would have been impossible for them to report a “collision” of a comet with Earth's atmosphere. The translation and conclusions made by Liu et al. (2014) are not supported by the historical record. Therefore, postulating a sudden increase in 14C in corals off the Chinese coast precisely in mid January 773 (Liu et al. 2014) is not justified given just the 230Th dating for AD 783 ± 14. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
92.
Georges Matheron (1930–2000) and John Tukey (1915–2000) were among the most prominent mathematical statisticians of the 20th century. Both men produced numerous important new theoretical and practical results. This personal appreciation of their work concentrates on contributions to mineral-resources research and describes their influence on my work in mineral-resource evaluation studies at the Geological Survey of Canada (1966–1983). 相似文献
93.
A.R.Mermut 《山地科学学报》2009,6(2):107-112
The book "micropedolog" by Kubieana and a large number of publications has induced many people to practice soil micromorphology. Quantification of the soil fabric and its components was a major challenge. The use of the image analyses in soil science was a breakthrough. Attempts to make soil thin sections go back to the beginning of the 2oth century. Microscopic techniques and recently high resolution electron microscope and use of computer assisted imaging techniques enabled the in vitro study of soils in three dimensional levels. It is now possible to store and process massive amounts of data. Micro- morphological concepts and techniques are applied in paleopedological, ecological, and archaeological studies. The aim of this work was to examine soil micromorphological imaging in historical perspective. 相似文献
94.
北祁连山作为青藏高原隆升与扩展的最前缘,一直以来都是研究的热点。本研究为弥补活动构造与热年代学方法时间尺度上难以链接的不足及提供青藏高原扩展隆升机制相关证据,利用河流水力侵蚀模型的方法模拟得出北祁连山河道陡峭指数与部分河流地质隆升历史。结果揭示出北祁连山河道陡峭指数与距断裂的距离存在显著关系,且具有从中间向东西两侧减小的特征,表现出北祁连山隆升速率大致也呈现自中向两侧减慢的特征;并通过分析处于北祁连山非沉积区白杨河、洪水坝河、丰乐河、马营河、大渚马河及洪水河这6条流域的地质隆升历史,发现在4 Ma左右,北祁连山隆升速率逐渐增加,且隆升速率大致在0.20~0.38 mm/a之间。直到0.6~1.0 Ma,隆升速率迅速加快,呈现陡增的趋势。因此,北祁连山的构造隆升并不是均匀的,而是随时间发生变化的。
相似文献95.
张应斌 《广东海洋大学学报》2012,(2):36-40
雷州雷祖神话文本《雷祖志》定型在明清时期。它的直接源头是北宋《雷庙记》,初源是《古雷庙记》。经考证,《古雷庙记》是唐房千里《投荒杂录》中的《陈义》,它记载了雷神及雷州12豪族诞生的神话。在宋代《雷庙记》和明清《雷祖志》中,12族神话消失,雷神神话也变成真实的历史。认清《雷祖志》文本的真相,对于研究雷祖神话有重要意义。 相似文献
96.
V. Trimble 《Astronomische Nachrichten》2009,330(7):761-769
More than 2000 years ago, Epicurus taught that there are an infinite number of other worlds, both like and unlike ours, and Aristotle taught that there are none. Neither hypothesis can currently be falsified, and some versions of current multiverses perhaps never can be, which has contributed to occasional claims that “this isn't science!” (a common complaint about cosmology for centuries). Define “cosmos”, or “world”, or “universe” to mean the largest structure of which you and the majority of knowledgeable contemporaries will admit to being a part. This begins with the small, earth‐centered worlds of ancient Egyptian paintings, Greek mythology, and Genesis, which a god could circumnavigate in a day and humans in a generation. These tend to expand and become helio‐rather than geo‐centric (not quite monotonically in time) and are succeeded by various assemblages of sun‐like stars with planets of their own. Finite vs. infinite assemblages are debated and then the issue of whether the Milky Way is unique (so that “island universes” made sense, even if you were against the idea) for a couple of centuries. Today one thinks as a rule of the entire 4‐dimensional space‐time we might in principle communicate with and all its contents. Beyond are the modern multi‐verses, sequential (cyclic or oscillating), hierarchical, or non‐communicating entities in more than four dimensions. Each of these has older analogues, and, in every milieu where the ideas have been discussed, there have been firm supporters and firm opponents, some of whose ideas are explored here. Because astronomical observations have firmly settled some earlier disputes in favor of very many galaxies and very many stars with planets, “other worlds” can now refer only to other planets like Earth or to other universes. The focus is on the latter (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
97.
Cesar N. Caviedes 《The Professional geographer》1984,36(4):428-436
Recognized for years as a major environmental disruption, El Niño generated intense public interest in 1982–1983. During its last occurrence, this phenomenon, which develops in the tropical Pacific and usually affects rimlands of the Pacific basin, exceeded its boundaries and its effects were transmitted to continental North America, Europe, Africa and East Asia. Notwithstanding its vast areal extent, the interest of geographers in El Niño events, past and recent, has been comparatively less than that demonstrated by natural scientists and ecologists: little has been accomplished to place these climatic-ecological crises within global perspective. Lessons from El Niño include the acknowledgement of new concepts of climatic transitivity, ocean dynamics and energy exchanges that must find a place within the conceptual wealth of geography if this science intends to keep up with the rapid progress of other geosciences. 相似文献
98.
储层孔隙度预测与孔隙演化史模拟方法探讨——以辽河拗陷双清地区为例 总被引:2,自引:1,他引:2
在成岩作用数值模拟的基础上,通过建立辽河拗陷双清地区不同沉积微相成岩指数ID与储层平均有效孔隙度的相关模型,预测了该地区古近系Es3下储层的孔隙度,恢复了孔隙演化史,确定了有效油、气储层的分布范围。孔隙度预测的结果表明,有效油、气储层分布于孔隙度大于8.5%和5.8%的斜坡区。储层预测平均孔隙度与实测孔隙度之间的绝对误差为2.8%,而研究区储层的填隙物含量在1.2%~45.0%之间,平均为16.9%。由此可见,这种模型可用于填隙物含量较高储层的钻前孔隙度预测和孔隙演化史模拟。孔隙演化史的模拟结果表明,储层孔隙度在埋藏早期主要受沉积相的影响,而在晚期则主要受成岩作用的控制。 相似文献
99.
Wu Chonglong Zhou Jiangyu Wang Gengfa Li ShaohuFaculty of Earth Resources China University of Geosciencex Wuhan Liu Pide Beijing High School Beijing 《中国地质大学学报(英文版)》1995,(2)
According to the ideas and concepts of systems dynamic of continent structure, using previous information related to the study area, combining analyses on orogenic belt, basin and magmatic rock, the present paper synthesizes the tectono-sedimentary development of southeastern coast region, China, with special emphasis on the mountain making, basining and magmafc activity. The tectonic evolution after Late Caledonian orogeny was dominated by alternating rifting and converging, subsiding and uplifting, mountain making and basining in central and southern parts of southeastern China and the adjacent regions to the east and west. Seventeen geologic events, nine events of plate or terrain convergence , and continental crust accretion, as well as eight events of intracontinental rifting and basin faulting , are closely related to the tectonic and sedimentary evolution of the study area. The accompanied intense and frequent sedimentation , folding , faulting , magmatism and ore-forming process allowed huge coal 相似文献
100.
Deformation History of the Kunavaram Complex, Eastern Ghats Belt, India: Implications for Alkaline Magmatism Along the Indo-Antarctica Suture 总被引:1,自引:0,他引:1
The Kunavaram alkaline complex is a NE-SW trending elongate body located along a major lineament, the Sileru Shear Zone (SSZ) that is regarded as a Proterozoic suture related to Indo-Antarctica collision. The complex is hosted within migmatitic quartzofeldspathic gneisses, mafic granulites retrogressed to amphibolites, and quartzites. The structural evolution of the country rocks and the alkaline complex are similar. The first phase of deformation, D1, produces a pervasive segregation banding (S1) in all rock units within and outside the complex. A second deformation phase D2 isoclinally folded S1 along subvertical axial planes with shallow plunging axes. F2 isoclinal folds are ubiquitous in the country rocks and the eastern extremity of the complex. In the interior of the alkaline body, D2 strain decreases and S1 is commonly subhorizontal. While amphibolite to granulite facies conditions prevailed during deformation, post-D2 annealing textures testify to persisting high grade conditions. In the west, a NNE-SSW trending dextral shear zone with strike-slip sense (D3) truncates the complex. Within this shear zone, quartzofeldspathic country rocks are plastically deformed, while hornblende-K-feldspar assemblages of the complex are retrogressed to biotite and plagioclase. Warping related to D3 shears also resulted in fold interference patterns on the subhorizontal S1 foliation in low D2 strain domains. Based on its steep dip, north-easterly trend, and non-coaxial nature with dextral strike-slip sense, the D3 shear zone can be correlated with the SSZ. Since this shear zone, i.e., the SSZ, is not associated with primary igneous fabrics and resulted in solid state deformation of the complex, it cannot be considered as a conduit for alkaline magmatism, but is probably responsible for the post-tectonic disposition of the pluton. 相似文献