大多数内生金属矿床成矿作用与花岗岩关系密切(Chen et al.,1989;洪大卫,1994),尤其是稀土元素、铀矿床等均与复式岩体晚期岩体(包括浅色花岗岩与伟晶岩)成岩作用关系密切。因此,厘清花岗岩复式岩体演化过程中的稀土元素演化,对认识花...大多数内生金属矿床成矿作用与花岗岩关系密切(Chen et al.,1989;洪大卫,1994),尤其是稀土元素、铀矿床等均与复式岩体晚期岩体(包括浅色花岗岩与伟晶岩)成岩作用关系密切。因此,厘清花岗岩复式岩体演化过程中的稀土元素演化,对认识花岗岩类演化过程中相应金属矿床的成矿作用等方面具有重要的理论意义。根据岩石熔化实验结果,在岩石熔化过程中。展开更多
Continental crust rocks can be grouped into three petrochemical, systems, i.e.,oxygen-poor, transitional, and oxygen-rich system, which are intimately related to the intensity of crustal movement. Stable areas in the ...Continental crust rocks can be grouped into three petrochemical, systems, i.e.,oxygen-poor, transitional, and oxygen-rich system, which are intimately related to the intensity of crustal movement. Stable areas in the crust are characterized by rocks of oxygen-poor system, while rocks of oxygen-rich system are typical of active regions.Rocks of the transitional system form all gradations between the two systems Parallel to the orogenic cycle in crustal movement an evolutionary cycle from low to high oxygen content can always be recognized with respect to rocks in each system. On the other hand, with regard to rocks of the same type in the same petrochemical system, apart from the influence of crustal movement intensity, a tendency of increasing oxygen content with decreasing orogenic age is noticeable. As a region changes from active into gradational geologically, oxygen content is found decreasing for rocks of the same type,or vice versa. In this context, new implications may be attached to studies on petrochemical system : (1) A“family tree” can be established for rocks, thus sheding light on their evolutionary hlstoryand geneses (2)To provide information on the intensity of crustal movement, i.e., the tectonic nature for the studied area at the time of magma generation, and (3) To aid in determining petrogenetie age of magmatic rocks and in making geological divisions.展开更多
恒星氦燃烧阶段3α反应和^(12)C(α,γ)^(16)O反应相互竞争,两者的反应率共同决定了氦燃烧结束后^(12)C与^(16)O的丰度比,该比值是大质量恒星后继演化以及伴随的元素核合成过程的初始条件。目前,氦燃烧^(12)C(α,γ)^(16)O反应起始T_9=...恒星氦燃烧阶段3α反应和^(12)C(α,γ)^(16)O反应相互竞争,两者的反应率共同决定了氦燃烧结束后^(12)C与^(16)O的丰度比,该比值是大质量恒星后继演化以及伴随的元素核合成过程的初始条件。目前,氦燃烧^(12)C(α,γ)^(16)O反应起始T_9=0.2处,天体物理模型要求的反应率的精确度要低于10%,然而尚未有实验或理论给出满足要求的结果。最为直接和可靠地获取^(12)C(α,γ)^(16)O反应率的方法,就是尽可能往低能区测量其天体物理S因子,然后通过理论外推到感兴趣的能区。为此基于经典的R-矩阵理论,建立了适用于低能核反应的多道、多能级的约化R-矩阵理论来拟合几乎所有可用的^(16)O系统的实验数据。配合使用协方差统计和误差传播理论,拟合外推得到了客观的、内部自恰的和唯一性好的^(12)C(α,γ)^(16)O反应天体物理S因子。总的外推S因子STOT(0.3 Me V)=162.7±7.3 keV·b,理论上首次给出达到恒星演化与元素核合成模型的最低要求的S因子。基于计算给出的全能区的S因子,数值积分给出了温度位于0.04≤T_9≤10的^(12)C(α,γ)^(16)O天体物理反应率。在T_9=0.2处,推荐的反应率为(7.83±0.35)×10^(-15)cm^3mol^(-1)s^(-1)。展开更多
文摘大多数内生金属矿床成矿作用与花岗岩关系密切(Chen et al.,1989;洪大卫,1994),尤其是稀土元素、铀矿床等均与复式岩体晚期岩体(包括浅色花岗岩与伟晶岩)成岩作用关系密切。因此,厘清花岗岩复式岩体演化过程中的稀土元素演化,对认识花岗岩类演化过程中相应金属矿床的成矿作用等方面具有重要的理论意义。根据岩石熔化实验结果,在岩石熔化过程中。
文摘Continental crust rocks can be grouped into three petrochemical, systems, i.e.,oxygen-poor, transitional, and oxygen-rich system, which are intimately related to the intensity of crustal movement. Stable areas in the crust are characterized by rocks of oxygen-poor system, while rocks of oxygen-rich system are typical of active regions.Rocks of the transitional system form all gradations between the two systems Parallel to the orogenic cycle in crustal movement an evolutionary cycle from low to high oxygen content can always be recognized with respect to rocks in each system. On the other hand, with regard to rocks of the same type in the same petrochemical system, apart from the influence of crustal movement intensity, a tendency of increasing oxygen content with decreasing orogenic age is noticeable. As a region changes from active into gradational geologically, oxygen content is found decreasing for rocks of the same type,or vice versa. In this context, new implications may be attached to studies on petrochemical system : (1) A“family tree” can be established for rocks, thus sheding light on their evolutionary hlstoryand geneses (2)To provide information on the intensity of crustal movement, i.e., the tectonic nature for the studied area at the time of magma generation, and (3) To aid in determining petrogenetie age of magmatic rocks and in making geological divisions.
文摘恒星氦燃烧阶段3α反应和^(12)C(α,γ)^(16)O反应相互竞争,两者的反应率共同决定了氦燃烧结束后^(12)C与^(16)O的丰度比,该比值是大质量恒星后继演化以及伴随的元素核合成过程的初始条件。目前,氦燃烧^(12)C(α,γ)^(16)O反应起始T_9=0.2处,天体物理模型要求的反应率的精确度要低于10%,然而尚未有实验或理论给出满足要求的结果。最为直接和可靠地获取^(12)C(α,γ)^(16)O反应率的方法,就是尽可能往低能区测量其天体物理S因子,然后通过理论外推到感兴趣的能区。为此基于经典的R-矩阵理论,建立了适用于低能核反应的多道、多能级的约化R-矩阵理论来拟合几乎所有可用的^(16)O系统的实验数据。配合使用协方差统计和误差传播理论,拟合外推得到了客观的、内部自恰的和唯一性好的^(12)C(α,γ)^(16)O反应天体物理S因子。总的外推S因子STOT(0.3 Me V)=162.7±7.3 keV·b,理论上首次给出达到恒星演化与元素核合成模型的最低要求的S因子。基于计算给出的全能区的S因子,数值积分给出了温度位于0.04≤T_9≤10的^(12)C(α,γ)^(16)O天体物理反应率。在T_9=0.2处,推荐的反应率为(7.83±0.35)×10^(-15)cm^3mol^(-1)s^(-1)。
