中国东部中生代安山岩的定量化研究

我国东部广泛发育着中生代火山岩,除台湾省为海相火山岩外,其余绝大部分为陆相火山岩,这是一套基、中、酸性陆相火山岩,次火山岩杂岩体,可概括称为安山岩建造,是环太平洋安山质火山岩带的一部分。 对我国东部火山岩和含矿火山岩盆地,前人已进行过很多研究,这些工作提供了大量基本地质资料和重要成果。本文在前人工作的基础上,从数学地质角度,应用数学方法和电子计算机研究了中国东部安山岩问题,并得到了初步结果。

OUANTITATIVE RESEARCH OF MESOZOIC ANDESITES OF EASTERN PART OF CHINA

The authors of this paper have studied Mesozoic andesites in Bast China quantitatively using mathematical methods and computers.Some preliminary results have been obtained.After dynamic cluster analysis,64 andesite specimens are picked out as typical rock specimens of representative regions.11 oxides of petrochemical analyses are selected as variables for geomathematical research.The typical rock specimens of andesites within representative regions have been studied by discriminant analysis,factor analysis,cluster analysis and nonlinear mapping.A discriminant function has been established,which may be used for classification of known rock specimens,on one hand,and identification of unknown rock specimens,on the other.Results obtained by the above mentioned methods verify the rationality of division of volcanic rocks of the eastern part of China into three groups by Wu Liren from their rock type characteristics.Each rock type group has its own character connected with degree of richness in alkaline and mineralization.Mean content of Na₂+ K₂O is 5.44%,7.59%,7.74% for the first,the second and the third rock type groups relatively.Results of geological and geomathematical researches show that the andesites of the first rock type group is closely conneted with iron mineralization,the rock type group is not related to iron minealization and the second group possesses a transition character.Besides,results obtained by multivariate methods present many other useful information which may be utilized for the further quantitative research of volcanic rocks of eastern part of China in a great detail.