【摘要】 <正> 海南岛北部(琼北地区)广泛分布着第四纪玄武岩,根据地质和地貌特征,风化壳发育程度,玄武岩和沉积地层之间接触关系以及玄武岩古地磁测量结果,可以分成四期(图1)。更多还原

【Abstract】 In this paper, the oxygen isotope composition of tektites (Leigongmo) and quaternary basalts from Hainan Island have been analysed. The oxygen isotopic analysis indicates that (1) the reproducibility of oxygen isotopic analysis of tektites, whether heating the nickle vessel in reaction process or not, is always good, the analysis is within the accuracy higher than ±0.1‰; (2) there are two δ18O values of tektites higher, but their fission track ages are slightly lower. Both of them are related to thermal events; (3) the δ18O values of basalts from the late stage of Early Pleistocene are generally lower. This implies that the oxygen isotope composition of basaltic magma in this stage was different from that of basaltic magma in other stages; (4) the δ18O value of tuff is higher, because of its higher content of water; (5) there exist obvious differences in oxygen isotope compositions between tektites and Quaternary basalts, so no genetic relationship can be found between them.更多还原