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Evolution and changes of permafrost on the Qinghai-Tibet Plateau during the Late Quaternary 被引量:3
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作者 xiaoli chang HuiJun Jin +2 位作者 RuiXia He LanZhi Lu StuartA.Harris 《Research in Cold and Arid Regions》 CSCD 2017年第1期1-19,共19页
Due to the uplift of Qinghai-Tibet Plateau (QTP), the cryosphere gradually developed on the higher mountain summits after the Neocene, becoming widespread during the Late Quaternary. During this time, permafrost on ... Due to the uplift of Qinghai-Tibet Plateau (QTP), the cryosphere gradually developed on the higher mountain summits after the Neocene, becoming widespread during the Late Quaternary. During this time, permafrost on the QTP experienced repeated expansion and degradation. Based on the remains and cross-correlation with other proxy records such as those from glacial landforms, ice-core and paleogeography, the evolution and changes of permafrost and environmental changes on the QTP during the past 150,000 years were deduced and are presented in this paper.At least four obvious cycles of the extensive and intensive development, expansion and decay of permafrost occurred during the periods of 150-130, 80-50, 30-14 and after 10.8 ka B.P.. Ehiring the Holocene, fluctuating climatic environ-ments affected the permafrost on the QTP, and the peripheral mountains experienced six periods of discernible permafrost changes: (1) Stable development of permafrost in the early Holocene (10.8 to 8.5-7.0 ka B.P.); (2) Intensive permafrost degradation during the Holocene Megathermal Period (HMP, from 8.5-7.0 to 4.0-3.0 ka B.P.); (3) Permafrost expansion during the early Neoglacial period (ca. 4,000-3,000 to 1,000 a B.P.); (4) Relative degradation during the Medieval Warm Period (MWP,from 1,000 to 500 a B.R); (5) Expansion of permafrost during the Little Ice Age (LIA,from 500 to 10.a B.P.); (6) Observed and predicted degradation of permafrost during the 20th and 21st century. Each period differed greatly in paleoclimate, paleoenvironment, and permafrost distribution, thickness, areal extent, and ground temperatures, as well as in the development of periglacial phenomena. Statistically, closer dating of the onset permafrost formation, more identi-fication of permafrost remains with richer proxy information about paleoenvironment, and more dating information enable higher resolution for paleo-permafrost reconstruction. Based on the scenarios of persistent climate warming of 2 2 -2 .6 °C 展开更多
关键词 Qinghai-Tibet Plateau (QTP) PLEISTOCENE Holocene permafrost expansion and degradation periglacial remains paleo-reconstruction environmental impacts
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初高中衔接阶段英语词汇教学研究 被引量:2
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作者 沈小力 《基础教育外语教学研究》 2018年第4期56-58,共3页
词汇是英语学习的基础.本文基于对高一新生英语词汇学习观念和学习策略的调查分析,对初高中衔接阶段词汇教学方面提出建议, 指出教师应该培养学生形成良好的词汇学习习惯, 补充一定的语音知识, 了解单词构词法等, 从而提高学生学习英语... 词汇是英语学习的基础.本文基于对高一新生英语词汇学习观念和学习策略的调查分析,对初高中衔接阶段词汇教学方面提出建议, 指出教师应该培养学生形成良好的词汇学习习惯, 补充一定的语音知识, 了解单词构词法等, 从而提高学生学习英语词汇的效率. 展开更多
关键词 初高中衔接 词汇教学 学习策略
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