Petrology of the Turnagain ultramafic complex, northwestern British Columbia
Petrology of the Turnagain ultramafic complex, northwestern British Columbia
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DOI：
10.1139/e80-071
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发表时间：
1980-06
影响因子：
1.4
通讯作者：
T. Clark
中科院分区：
文献类型：
--
作者：
T. Clark
特纳顿超镁铁质杂岩是阿拉斯加型杂岩，可能是晚三叠世时代。其中心带为纯橄榄岩，外层为辉石岩、橄榄单斜辉石岩、单斜辉石岩、纯橄榄岩、角闪石(稀有岩)、基性角闪石和含斜长石(稀有岩)。该建筑群在很大程度上是受断层限制的。中心纯橄榄岩侵入一个地区的含辉石岩石中；在其他地区，两个带是分级的。小规模的分层作用发生在局部，最常见的是外带。在区域变形过程中，由于褶皱作用，分层倾角很大。超镁铁质岩石一般只有部分蛇纹岩，主要由橄榄石、单斜辉石、辉石、金云母和铬尖晶石组成。外带含有零星的铁-镍-铜硫化物。橄榄石在中心纯橄榄岩中的镁含量最高(Fo94.9)，在橄榄石单斜辉石中最富铁(Fo80.2)。单斜辉石是透辉石，遵循铁的富集化趋势。矿物中的微量元素含量较高。
The Turnagain ultramafic complex is an Alaskan-type complex of possible Late Triassic age. It has a central zone of dunite and an outer zone of wehrlite, olivine clinopyroxenite, clinopyroxenite, dunite, hornblendite (rare), and basic hornblende and plagioclase-bearing rock (rare). The complex is largely fault-bounded. The central dunite intrudes the pyroxene-bearing rocks in one area; elsewhere the two zones are gradational. Small-scale layering occurs locally, and is most common in the outer zone. Layering dips steeply due to folding during regional deformation. The ultramafic rocks are generally only partly serpentinized, and consist largely of olivine, clinopyroxene, pargasite, phlogopite, and chrome spinel. The outer zone contains sporadic concentrations of iron–nickel–copper sulfides. Olivine is most magnesian (Fo94.9) in the central dunite, and most iron-rich (Fo80.2) in olivine clinopyroxenite. Clinopyroxene is diopside and follows an iron-enrichment trend. Minor-element contents of minerals indic...