共查询到20条相似文献，搜索用时 27 毫秒
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晚中生代,太平洋板块对欧亚板块的俯冲,使得中国东南沿海岩浆活动十分强烈,引发大规模火山喷发,形成遍布浙闽赣粤的火山-侵入岩带,并发育了大量火山岩山岳景观。位于浙江定海南部的摘箬山岛就是其中的一个代表。作者通过野外实地考察,结合有关地质资料,对摘箬山岛的地形地貌、地质构造、火山岩相特征进行了分析,研究摘箬山岛的火山形成及其演化历史,并对摘箬山岛地质旅游资源进行初步研究,赋予海岛旅游新的地学意义。 相似文献
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Jie Yuan Zhenyu Yang Chenglong Deng Wout Krijgsman Xiumian Hu Shihu Li Zhongshan Shen Huafeng Qin Wei An Huaiyu He Lin Ding Zhengtang Guo Rixiang Zhu 《国家科学评论(英文版)》2021,8(7)
The India-Asia collision is an outstanding smoking gun in the study of continental collision dynamics. How and when the continental collision occurred remains a long-standing controversy. Here we present two new paleomagnetic data sets from rocks deposited on the distal part of the Indian passive margin, which indicate that the Tethyan Himalaya terrane was situated at a paleolatitude of ∼19.4°S at ∼75 Ma and moved rapidly northward to reach a paleolatitude of ∼13.7°N at ∼61 Ma. This implies that the Tethyan Himalaya terrane rifted from India after ∼75 Ma, generating the North India Sea. We document a new two-stage continental collision, first at ∼61 Ma between the Lhasa and Tethyan Himalaya terranes, and subsequently at ∼53−48 Ma between the Tethyan Himalaya terrane and India, diachronously closing the North India Sea from west to east. Our scenario matches the history of India-Asia convergence rates and reconciles multiple lines of geologic evidence for the collision. 相似文献
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羌塘与拉萨地块处于青藏高原的核心位置。青藏高原北羌塘及拉萨地块的年代学及古地磁学研究表明,北羌塘地块在距今约3亿年前位于南半球(21.9o±4.7oS)冈瓦纳大陆附近,因而不支持北羌塘地块来自北方劳亚大陆。北羌塘随后开始其持续的北向漂移过程,在约2.1亿年前到达当前纬度位置(34oN),形象地表明其是一只"冈瓦纳大陆的早飞鸟"。拉萨地块从冈瓦纳大陆裂离后的漂移演化史则与北羌塘地块差别明显。自晚古生代—中生代(石炭纪—三叠纪)拉萨地块从冈瓦纳大陆北缘裂离后,其运动学演化过程更显得"犹豫不决"。最新的古地磁研究表明拉萨地块自冈瓦纳大陆裂离后并未显示出明显的快速北向漂移趋势,而是呈现出较为慢速的漂移,直到距今约1.8亿年前(早侏罗世)到达位于南半球赤道附近(3.7o±3.4oS),随后与北面的羌塘地块在晚侏罗世首先从东部发生碰撞,随后于早白垩世时期两个地块完成拼贴。之后的印度次大陆快速向北漂移并在早新生代(距今6 500万年前)发生印度-亚洲大陆碰撞,继而对新生代时期欧亚大陆地形地貌格局产生了深远影响。 相似文献
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Four new species of the genus Aristolochia (Aristolochiaceae) are described as
new from China. They are Aristolochia austrochinensis C. Y. Cheng & J. S. Ma, A. caulialata
C. Y. Wu, A. salweenensis C. Y. Cheng & J. S. Ma, and A. kunmingensis C. Y. Cheng &J. S. Ma. A naturalized species, A. ringens Vahl is also reported. 相似文献
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Qun-Ke Xia Jia Liu Istvn Kovcs Yan-Tao Hao Pei Li Xiao-Zhi Yang Huan Chen Ying-Ming Sheng 《国家科学评论(英文版)》2019,6(1):125
Understanding the concentration and distribution of water in the Earth''s mantle plays a substantial role in studying its chemical, physical and dynamic processes. After a decade of research, a comprehensive dataset of water content in upper-mantle samples has been built for eastern China, which is now the only place with water-content data from such diverse types of natural samples, and provides an integrated picture of the water content and its distribution in the upper mantle at a continental scale. The main findings include the following: (i) the temporal heterogeneity of the water content in the lithospheric mantle from early Cretaceous (∼120 Ma) to Cenozoic (<40 Ma) was tightly connected with the stability of the North China Craton (from its destruction to its consolidation); (ii) the heterogeneous water content in the Cenozoic lithospheric mantle beneath different blocks of eastern China was not only inherited from tectonic settings from which they came, but was also affected later by geological processes they experienced; (iii) the distinct water content between the lowermost crust and lithospheric mantle of eastern China and its induced rheological contrast at the base of the crust indicate that the continental crust–mantle boundary could behave either in a coupled or decoupled manner beneath different areas and/or at different stages; (iv) the alkali basalts of eastern China demonstrate a heterogeneous distribution of water content in the mantle; local and regional comparisons of the water content between the lithospheric mantle and basalts'' source indicate that the Cenozoic alkali basalts in eastern China were not sourced from the lithospheric mantle. Instead, the inferred high water contents in the mantle sources suggest that the Cenozoic eastern China basalts were likely sourced from the mantle transition zone (MTZ); and (v) both oceanic and continental crusts may carry a certain amount of water back into the deep mantle of eastern China by plate subduction. Such recycled crustal materials have not only created a local water-rich zone, but have also introduced crustal geochemical signatures into the mantle, both accounting for crustal geochemical imprints in the intra-plate magmatic rocks of eastern China. 相似文献
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Tingting Wang Dong Wei Xien Chang Zhiyong Yu Xinyu Zhang Changsui Wang Yaowu Hu Benjamin T Fuller 《国家科学评论(英文版)》2019,6(5):1024
The westward expansion of human millet consumption from north China has important implications for understanding early interactions between the East and West. However, few studies have focused on the Xinjiang Uyghur Autonomous Region, the vast geographical area directly linking the ancient cultures of the Eurasian Steppe and the Gansu Corridor of China. In this study, we present the largest isotopic investigation of Bronze Age China (n = 110) on material from the key site of Tianshanbeilu, in eastern Xinjiang. The large range of δ13C values (–17.6‰ to –7.2‰; –15.5 ± 1.2‰) provides direct evidence of unique dietary diversity and consumption of significant C4 resources (millets). The high δ15N results (10.3‰ to 16.7‰; 14.7 ± 0.8‰) likely reflect sheep/goat and wild game consumption and the arid climate of the Taklamakan Desert. Radiocarbon dates from four individuals indicate Tianshanbeilu was in use between 1940 and 1215 cal bc. The Tianshanbeilu results are then analysed with respect to 52 Bronze Age sites from across Eurasia, to investigate the spread and chronology of significant human millet consumption and human migration. This isotopic survey finds novel evidence that the second millennium bc was a dynamic period, with significant dietary interconnectivity occurring between north China, Central Asia and Siberia. Further, we argue that this ‘Isotopic Millet Road’ extended all the way to the Mediterranean and Central Europe, and conclude that these C4 dietary signatures of millet consumption reflect early links (migration and/or resource transfer) between the Bronze Age inhabitants of modern-day China and Europe. 相似文献
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