黑龙江西北部小古里河过钾质基性、超基性火山岩的发现

Discovery of Xiaogulihe perpotassic basic and ultrabasic volcanic rock in the north-west Heilongjiang province, China

本文报道了黑龙江省五大连池裂谷带北端出露的一套超基性、基性的过钾质火山岩,通过详细的野外调查,确认了火山岩的喷发顺序,肯定了火山岩从基性岩向超基性岩的演变以及它们的K_2O、TiO_2含量不断提高的事实。在此基础上作者对超基性-过钾质岩石的岩浆成因提出了初步认识,认为它们不是岩浆结晶分异作用的产物,而是在裂谷演化构造背景下的一次独立的深源岩浆事件。本文将小古里河的过钾质火山岩和乌干达及意大利等世界上著名的钾质火山岩进行了比较。

A suite of basic to urtrabasic per-potassic volcanic rocks in the north part of Wudalianchi rift belt, Heilongjiang province are reported in this paper. On the basin of detailed field investigation, eruption sequence of the volcanic rocks has been identified and was confirmed that they are evolved from basic to urtrabasic with the contant of K2O and TiO2 progressively. Such observation leads to a preliminary conclusion about the origin of the ultrabasic-per-potassic rocks, i.e. instead of the result of crystal fractionation of a parental magma, they are produced in an independent typhonic magmatic events against a tectonic background of rift evolution. The Xiaogulihe urtrabasic-perpotassic volcanic rocks were compared with famous potassic volcanic rocks in world as Uganda and Italy etc.