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所收集的两个岩石样品,一个取自系岛花岗闪长岩,另一个取自杷木花岗闪长岩,主要是研究黑云母粒度与Rb和Sr含量及黑云母的Rb—Sr放射性年龄的相关变化。为此,从这些岩石样品中分离出黑云母晶体颗粒精制,分选成大小碎片,然后再分析。取自系岛和杷木花岗闪长岩的黑云母样品显示出粒度与Rb含量的相关变化具有相同性。且在粒度为500μm处有明显的间断(图1)。粒度由粗到细,Rb含量先是逐渐衰减、间断后急剧上升到高值,再降为平缓。这一间断解放释为存在有基性岩浆贯入到冷却的花岗闪长岩浆中,结果花岗闪长岩浆被加热。因为在结晶作用期间,岩浆不可能逐渐地消耗Rb,所以,粒度与Rb含量的相关变化取次于黑云母与共生岩浆之间的温度与Rb分配系数的相关变化。取自系岛花岗闪长岩中的黑云母样品的粒度组确定了一个单一的其年代为87.3±0.5Ma、原始~(87)Sr/~(86)Sr比值为0.70629±0.00013的等时线。取自杷木花岗闪长岩的黑云母样品的粒度组未确定出单一等时线,但表明了粒度与年代的相关变化(表2)。粒级大于24目时,得到这样的年代如93.4Ma和92.2Ma。这些年龄值可以解释在结晶作用期间所发生事件的集中原因。粒级小于32目时行到较为年轻的年龄值87.6±0.4Ma。这一年龄有可能圈出完整的结晶作用时间。24目～32目之间的粒级,给出人们难以理解的年轻年代值82.6Ma。
Two rock samples were collected, one from the Tongdao granodiorite and the other from the loamy granodiorite, mainly to study the biotite size and Rb and Sr contents and the Rb-Sr radioactive age of biotite Related changes. For this purpose, the biotite crystal particles were isolated from these rock samples and refined to size fractions, which were then analyzed. Biotite samples taken from the Shimane and Patam granodiorites showed similarities in particle size to the changes in Rb content. With a clear discontinuity at a particle size of 500 μm (Figure 1). Granularity from coarse to fine, Rb content first decay gradually rose to high after intermittent high, and then reduced to a gentle. This is interpreted as a release of basic magmas into the cooled granodiorite magma, resulting in the heating of the granodiorite magma. Because it is impossible for magma to gradually consume Rb during crystallization, the correlation between grain size and Rb content is derived from the correlation between temperature and Rb partition coefficient between biotite and the symbiotic magma. Granulometry of biotite samples taken from the Shimadao granodiorite identified a single isochronous age of 87.3 ± 0.5 Ma and a ratio of original 87 Sr / 86 Zr of 0.70629 ± 0.00013 line. A single isochrone line was not established for the size group of biotite samples taken from the Bamut granodiorite, but shows a correlation between grain size and age (Table 2). Grains larger than 24 mesh, get such age as 93.4Ma and 92.2Ma. These age values can explain the central cause of events that occur during the crystallization process. Grain size less than 32 mesh to a younger age of 87.6 ± 0.4Ma. This age is likely to circle the complete crystallization time. Grades of 24 to 32 mesh give a young age value of 82.6 Ma that is hard to understand.