摘要
新疆黄山含铜镍矿镁铁-超镁铁杂岩体热侵位于下石炭统干洞组变余砂岩、砂质灰岩、细碧玢岩中。杂岩体分为三个侵入期,其中第二期岩石构成了黄山岩体主体。分异较好,由下向上、由西向东可分出辉石橄榄岩相、橄榄二辉岩相、二辉岩相、苏长辉长岩相、辉长岩相。杂岩体是原始岩浆经过深部液态分异和金属硫化物熔离后的派生岩浆结晶形成。这种派生岩浆具富镁、贫碱、低钙特征,归属于橄榄拉斑玄武岩系列。杂岩体结晶温度为1500—860℃,压力为0.26—0.250GPa,fo_2为10^(-11)—10^(-13)。
Huangshan Cu Ni ore-bearing mafic-ultramafic complex is located at southern limb, eastern sector of Jueluotage an-
ticlinorium, Tianshan fold belt. The complex is 3.8km in length, 0.7km wide in average and stretches more than 1.5km
in depth. It thermally emplaced into the blastosandstone, sandy limestone, spilite of Gandong formation, Lower Carbonif-
erous. The emplacement age of the complex is about 300Ma.
The complex could be divided into three periods, and of which, the second period that has composed the major part of
the complex was best differentiated. From bottom to top and west to east, pyroxene-peridotite, olivine-websterite, web-
sterite, hypersthene-gabbro and gabbro facies can be divided in proper order. The An% of plagioclase, the En% of or-
thopyroxene gradually decrease from pyroxene-peridotite faces to gabbro facies.
The complex is neither a product of tectonic emplacement of residul mantle nor one of primary basaltic magma by
crystallzation directly. It was formed by the crystallization of secondary magma derived from primary magma which had
undergone deep liquid differentiation and immiscible separation of metal sulfide. The derived magma is rich-Mg, poor-al-
kali and low-Ca, and should belong to olivine tholeiite basaltic series.
The diagenesis temperature of the complex is about 1500-860℃, the pressure about 260-250MPa, and the oxy-
gen fugacity about 10^(-11)-10^(-13).
关键词
铜镍矿
镁铁岩
超镁铁岩
岩石学
Huangshan
mafic-ultramafic complex
primary basaltic magma
differention
immiscible separation
chemical evolution
