CAJ | 학술논문

对国内外花岗岩体723对锆石U-Pb年龄（tZr）和全岩Rb-Sr等时线年龄（tRb）进行的相关分析,拟合出相关系数很高（R=0.997）,回归系数接近l的线性回归方程（tZr=1.0005×tRb+0.493041）。ΔtZr-Rb（tZr-tRb）频数统计分析表明：ΔtZr-Rb呈对称正态分布（偏度系数CSK=0.193；峰度系数CKU=6.722）,其均值为0.624 Ma,众数值为1.0 Ma。这表明花岗岩体锆石U-Pb定年的测定结果与全岩Rb-Sr等时线定年测定结果在允许的误差范围内是一致的。不存在花岗岩体锆石U-Pb年龄必定大于全岩Rb-Sr等时线年龄的规律表明，同位素热年代学方法只适用于研究花岗岩结晶固结后的低温热演化史。前人根据锆石U-Pb年龄和全岩Rb-Sr等时线年龄差值及相应同位素体系封闭温度研究的10个花岗岩体的冷却速率（CRZr-Rb）表明，它们与岩体体积尺度不相关，这有悖于“热物体的体积（质量）愈大，则在相同热物理条件下其冷却速率愈小”的热物理学基本定律。根据热传导理论及本文作者（2010）提出的侵位结晶时差概念我们得出“在相同热物理学条件下，体积尺度是决定花岗岩体冷却速率最主要因素”的结论。以上述10个花岗岩体为例，本文计算得出它们在结晶固结前高温阶段的冷却速率（CRECTD）并拟合出冷却速率与岩体体积尺度呈幂函数关系：CRECTD=7544.7×D-2.1686,计算结果符合热物理学基本定律。
대국내외화강암체723대고석U-Pb년령（tZr）화전암Rb-Sr등시선년령（tRb）진행적상관분석,의합출상관계수흔고（R=0.997）,회귀계수접근l적선성회귀방정（tZr=1.0005×tRb+0.493041）。ΔtZr-Rb（tZr-tRb）빈수통계분석표명：ΔtZr-Rb정대칭정태분포（편도계수CSK=0.193；봉도계수CKU=6.722）,기균치위0.624 Ma,음수치위1.0 Ma。저표명화강암체고석U-Pb정년적측정결과여전암Rb-Sr등시선정년측정결과재윤허적오차범위내시일치적。불존재화강암체고석U-Pb년령필정대우전암Rb-Sr등시선년령적규률표명，동위소열년대학방법지괄용우연구화강암결정고결후적저온열연화사。전인근거고석U-Pb년령화전암Rb-Sr등시선년령차치급상응동위소체계봉폐온도연구적10개화강암체적냉각속솔（CRZr-Rb）표명，타문여암체체적척도불상관，저유패우“열물체적체적（질량）유대，칙재상동열물리조건하기냉각속솔유소”적열물이학기본정률。근거열전도이론급본문작자（2010）제출적침위결정시차개념아문득출“재상동열물이학조건하，체적척도시결정화강암체냉각속솔최주요인소”적결론。이상술10개화강암체위례，본문계산득출타문재결정고결전고온계단적냉각속솔（CRECTD）병의합출냉각속솔여암체체적척도정멱함수관계：CRECTD=7544.7×D-2.1686,계산결과부합열물이학기본정률。
Using least squares regression procedure, a best regression equation (tZr=1.0005×tRb+0.493041) with high correlation coefficient (R=0.997) is fitted for 723 pairs of zircon U-Pb ages (tZr) and whole rock Rb-Sr ages (tRb) of granite plutons. The frequency analysis of 723 individual values of differences between tZr and tRb (ΔtZr-Rb) for granites shows symmetrical normal distribution (skewness CSK=0.193;kutrocess CKU=6.722) with the Mean of 0.624 Ma and the Mode of 1.0 Ma. These statistical characteristics indicate that for the granites as a whole, both the zircon U-Pb dating ages and the whole-rock Rb-Sr isochron ages are consistent within permissible errors. However, because of a time difference between emplacement age and crystallization-solidification age, this isotope thermochronological method can be applicable only for the stage after their crystallization-solidification. Based on the differences between zircon U-Pb ages and whole-rock Rb-Sr isochron ages and the closure temperatures of corresponding isotopic systems, previous researchers studied the cooling rates (CRZr-Rb) and thermal evolution history of 10 granite plutons, but these cooling rates are incorrelate to the volume change of granite plutons and contrary to the basic law of thermophysics, i.e., the cooling rate of a larger hot body should be slower compared with a smaller one. In this paper, based on the theory of thermal conductivity and using the concept of time difference between emplacement age and crystallization-consolidation age, developed by present authors (2010), we come to a conclusion that, at the same thermo-physical conditions, the volume scale is the most important parameter that controls cooling rate of the granite plutons. On the example of existing 10 granites, and for the high temperature thermal stage from magma emplacement to magma crystallization-consolidation, we derived a power function regression equation to describe the relationship of cooling rate with volume parameter D:CRECTD=7544.7×D-2.1686. The calculated results are obviously more reasonable and evidently conformable to the basic law of thermophysics..