The Napo-Qinzhou Tectonic Belt （NQTB） lies at the junction of the Yangtze, Cathaysia and Indochina （North Vietnam） Blocks, which is composed of five major lithotectonic subunits： the Qinzhou-Fangcheng Suture Zone...The Napo-Qinzhou Tectonic Belt （NQTB） lies at the junction of the Yangtze, Cathaysia and Indochina （North Vietnam） Blocks, which is composed of five major lithotectonic subunits： the Qinzhou-Fangcheng Suture Zone （QFSZ）, the Shiwandashan Basin （SB）, the Pingxiang-Nanning Suture Zone （PNSZ）, the Damingshan Block （DB） and the Babu-Lingma Suture Zone （BLSZ）. On the basis of geochemical compositions, the Permian mafic igneous rocks can be divided into three distinct groups： （1） mafic igneous rocks （Group 1） from the Longjing region in the PNSZ and Hurun region in the BLSZ, which are characterized by intermediate Ti, P and Zr with low Ni and Cr contents; （2） mafic igneous rocks （Group 2） from the Naxiao and Chongzuo region in the DB, characterized by low-intermediate Ti, P and Zr with high Ni and Cr concentrations; and （3） mafic igneous rocks （Group 3） from the Siming region in the Jingxi carbonate platform of the northwestern margin of the NQTB, with intermediate-high Ti, P and Zr and low Ni and Cr contents. The Group 1 rocks yield a weighted mean 206 Pb/ 238 U age of 250.5±2.8 Ma and are geochemically similar to basalts occurring in back-arc basin settings. The Group 2 rocks exhibit geochemical features to those basalts in island arcs, whereas the Group 3 rocks show geochemical similarity to that of ocean island basalts. All three groups are characterized by relatively low ε Nd （t） values （-2.61 to ＋1.10） and high initial 87 Sr/ 86 Sr isotopic ratios （0.705309-0.707434）, indicating that they were derived from a subduction-modified lithospheric mantle and experienced assimilation, fractional crystallization, and crustal contamination or mixing during magmatic evolution. Accordingly, we propose the existence of an arc-back arc basin system that developed along the NQTB at the border of SW Guangxi Province （SW China） and northern Vietnam, and it was formed by continued northwestward subduction of the Cathaysian （or Yunkai） Block under the Yangtze Block, and northeastward subduction of the Indochina Block beneath the Yangtze Block during Permian time.展开更多
目的探索案例教学法(Case Based Learning,CBL)和问题学习教学法(Problem Based Learning,PBL)在“分子遗传学实验技术和分析方法”课程中的应用效果。方法2017年2月至2019年2月选择“分子遗传学实验技术和分析方法”中表观遗传学DNA甲...目的探索案例教学法(Case Based Learning,CBL)和问题学习教学法(Problem Based Learning,PBL)在“分子遗传学实验技术和分析方法”课程中的应用效果。方法2017年2月至2019年2月选择“分子遗传学实验技术和分析方法”中表观遗传学DNA甲基化内容进行教学改革,将安徽医科大学90名医学研究生随机分为三组,实验组30人,案例学习教学法结合问题学习教学法教学;CBL组30人,单独案例学习教学法教学;PBL组30人,单独问题学习教学法教学。考核包括理论考核和综合能力考核两部分,使用统一的试卷进行理论考核,通过现场回答问题及操作进行综合能力考核,正确率>90%为优秀、80%~90%为合格、<80%为不合格。结果实验组研究生的理论考核成绩均优于CBL组(χ^2=11.57,P=0.002)及PBL组(χ^2=14.32,P=0.001),实验组研究生的综合能力考核成绩均优于CBL组(χ^2=13.63,P=0.001)及PBL组(χ^2=16.54,P=0.0002),差异有统计学意义;CBL组及PBL组理论考核及综合能力考核成绩之间差异无统计学意义。结论案例学习方法与问题学习方法相结合,以生动的案例为基础,结合精心设计的问题,突出重点和难点,培养思维和能力,两者综合运用,可以在“分子遗传学实验技术和分析方法”教学中取得满意的教学效果。展开更多
基金Financial support for this study was jointly provided by the Hundred Talents Project of Ministry of Land and Resources of China, the Ten-Hundred-Thousand Talent Project of Guangxi (Grant No. 2006218)Guangxi Science Foundation (Grant No.0728089)+1 种基金Institute of Mineral Resources, Chinese Academy of Geological Sciences (Grant No. K0914)China Geological Survey (Grant No. 201111020 and1212010510805)
文摘The Napo-Qinzhou Tectonic Belt （NQTB） lies at the junction of the Yangtze, Cathaysia and Indochina （North Vietnam） Blocks, which is composed of five major lithotectonic subunits： the Qinzhou-Fangcheng Suture Zone （QFSZ）, the Shiwandashan Basin （SB）, the Pingxiang-Nanning Suture Zone （PNSZ）, the Damingshan Block （DB） and the Babu-Lingma Suture Zone （BLSZ）. On the basis of geochemical compositions, the Permian mafic igneous rocks can be divided into three distinct groups： （1） mafic igneous rocks （Group 1） from the Longjing region in the PNSZ and Hurun region in the BLSZ, which are characterized by intermediate Ti, P and Zr with low Ni and Cr contents; （2） mafic igneous rocks （Group 2） from the Naxiao and Chongzuo region in the DB, characterized by low-intermediate Ti, P and Zr with high Ni and Cr concentrations; and （3） mafic igneous rocks （Group 3） from the Siming region in the Jingxi carbonate platform of the northwestern margin of the NQTB, with intermediate-high Ti, P and Zr and low Ni and Cr contents. The Group 1 rocks yield a weighted mean 206 Pb/ 238 U age of 250.5±2.8 Ma and are geochemically similar to basalts occurring in back-arc basin settings. The Group 2 rocks exhibit geochemical features to those basalts in island arcs, whereas the Group 3 rocks show geochemical similarity to that of ocean island basalts. All three groups are characterized by relatively low ε Nd （t） values （-2.61 to ＋1.10） and high initial 87 Sr/ 86 Sr isotopic ratios （0.705309-0.707434）, indicating that they were derived from a subduction-modified lithospheric mantle and experienced assimilation, fractional crystallization, and crustal contamination or mixing during magmatic evolution. Accordingly, we propose the existence of an arc-back arc basin system that developed along the NQTB at the border of SW Guangxi Province （SW China） and northern Vietnam, and it was formed by continued northwestward subduction of the Cathaysian （or Yunkai） Block under the Yangtze Block, and northeastward subduction of the Indochina Block beneath the Yangtze Block during Permian time.
文摘目的探索案例教学法(Case Based Learning,CBL)和问题学习教学法(Problem Based Learning,PBL)在“分子遗传学实验技术和分析方法”课程中的应用效果。方法2017年2月至2019年2月选择“分子遗传学实验技术和分析方法”中表观遗传学DNA甲基化内容进行教学改革,将安徽医科大学90名医学研究生随机分为三组,实验组30人,案例学习教学法结合问题学习教学法教学;CBL组30人,单独案例学习教学法教学;PBL组30人,单独问题学习教学法教学。考核包括理论考核和综合能力考核两部分,使用统一的试卷进行理论考核,通过现场回答问题及操作进行综合能力考核,正确率>90%为优秀、80%~90%为合格、<80%为不合格。结果实验组研究生的理论考核成绩均优于CBL组(χ^2=11.57,P=0.002)及PBL组(χ^2=14.32,P=0.001),实验组研究生的综合能力考核成绩均优于CBL组(χ^2=13.63,P=0.001)及PBL组(χ^2=16.54,P=0.0002),差异有统计学意义;CBL组及PBL组理论考核及综合能力考核成绩之间差异无统计学意义。结论案例学习方法与问题学习方法相结合,以生动的案例为基础,结合精心设计的问题,突出重点和难点,培养思维和能力,两者综合运用,可以在“分子遗传学实验技术和分析方法”教学中取得满意的教学效果。
