hole-rock Rb-Sr isochron age of 114 Ma in Yanbei granite porphyry and single grained zirconU-Pb age of 138 Ma in Tashan granite porphyry indicate that these two tin-bearing porphm beth arethe products of Late Yenshan magmatic activity.

• 笔者选择了岩背和塌山两个含锡花岗斑岩进行了系统的同位素地球化学研究。 岩背花岗斑岩的全岩Rb－Sr等时线年龄（114Ma）和塌山花岗斑岩单颗粒锗石U－Pb年龄（138Ma）表明，这两个含锡花岗斑岩都是燕山晚期岩浆活动的产物。