玄武岩的大地构造岩石化学特征与判别的初步研究

本文用地洼学说的大地构造观点,对与地壳演化的深部作用有密切关系的玄武岩类岩石的一些岩石化学数据进行研究,指出反映深部作用差异的地槽、地台、地洼三阶段玄武岩时空分布的三个高峰,揭示出三阶段玄武岩类岩石,总的存在由拉斑玄武岩系列→钙碱性玄武岩系列→碱性玄武岩系列的演化规律,以及三阶段玄武岩浆源的深度有逐渐加深的趋势。最后提出了一个较简明的判别不同大地构造属性玄武岩的岩石化学标志图。

GEOTECTONIC PETROCHEMICAL FEATURES OF BASALTS AND THEIR DISCRIMINATIONS

The authors of this paper use Diwa theory to conduct a research on the petrochemical data of basalts which closely related to plutonic action process in the depth. It is pointed out that there are three peaks of three-stage (geosymcline, platform, and Diwa stage )basaltic temporal-spatial distribution, and they indicate the difference of plutonic action. The authors also discloses the evolutionary laws of basaltic rocks of three stages. It is considered that the evolutionary trends are as follows: the basaltic rocks is from tholeiite series to calc-a kaline basitic rock series,and then to alkaline basaltic rock series,the depth of basaltic magmatic hearth become deeper gradually,and the upper mantle is from depletion to non-depletion. Finally,the authors put forward a petrochemical diagram for discriminatiog the geotectonic attribution of basalts.