摘要
本文重点以一个岩体的岩石学、矿物学等方面来讨论岩体岩石的某些特征及其与矿床的成因关系。在总结过程中,承蒙苏良赫、彭志忠、王述平等同志指导,在此谨致谢意。一、地质概况该岩体位于燕山沉降带中南缘隆起的西段(图1),受一近东西向深大断裂与北东向黑山寺断裂控制。
The emplacement of the intrusion which occurs in the western uplift bordering the southern part of the Yanshan depression is controlled by a deep fault and the Heishansi fracture.Pyroxenitic rocks,occurring in thin layers,are found in a rhythmic multilayered lopolith near the center of the intrusive body and the iron-phosphorus ore deposits have a tendency to occur in the middle—upper part of the intrusive.The evolution tendency of the intrusion is from alkali-ultrabasic to subalkaline and belong to the alkali-basalt magma series.It’s mineral content,oxidition coe-fficient,basicity and ratio of the related constituents,reveal a clear rhythmic variation.The ore-forming material of the deposits is originated from an iron-phosphorus magma.The deposition of the ore is largely controlled by the volatile components and basicity of the ore magma.During the cooling of the magma crystal field is formed,in which the crystallization sequence and the characteristics of the evolved lattice structure of silicate minerals are as follows:inosilicates(ferriaugite[SiO_(3)]^(-2))→laycr silicates(Biotite[Si_(2)O_(5)]^(2-))→framework of silicates(orthoclase[Si_(4)O_(8)]^(2-));the evolution of cations being:Fe^(2+),Fe^(3+),Mg^(2+),Ca^(2+)→Ca^(2+),P^(5+),Mg^(2+),Fe^(2+),Fe^(3+),Al^(3+),K^(1+)→K^(1+)Al^(3+).The volatile components were more favorable for Al^(3+),K^(1+),H_(2)SiO_(4)deposition at the upper fusion-field magma of crystallization,where alumina-silicates are formed while the iron-phosphorus ore-magma is deposited in the middle-upper part of the crystallization field.
作者
许晓峰
Xu Xiaofeng(North China Metallurgie-Geologic Corporation)
出处
《地质学报》
1980年第3期233-247,252,共16页
Acta Geologica Sinica
