Banded, or layered, gabbroic complexes in which monomineral or bimineral varieties are well developed have been described from Montana, the Bushveld in South Africa, and the island of Skye. There are also gabbro complexes that are locally streaky and inhomogeneous and are not regularly layered,…

Dec 1, 2013 · Simple modally layered and irregularly banded rocks, collectively called the layered gabbro series, were recovered from all three drill holes, comprising >50% of the core.

Sep 13, 1978 · gabbro, but ranges in composition from quattz diorite to anorthosite. It formsa portion of the Josephine Ul-tramafic Complex in the Klamath Mountains of southw

Banding.-The banding noted in many igneous rocks is an alternation of mineralogically unlike layers or flat lenses (Figs. i, 2, 3, and 4). The dip and strike of the bands can be estimated in many cases, but may show minor undulations and bunches. In some cases the layers are all thin, but in others they range more widely, up to a hundred feet.

Jan 25, 2021 · The mafic dykes are essentially banded gabbros composed of plagioclases, pyroxenes, amphiboles, biotites and opaques. Their textures range from porphyroblastic to porphyritic. The intermediate dykes are monzonites and monzodiorites and are characterized, respectively, by cataclastic and mylonitic textures.

As a fact, the seg- regated ores are far from the base; the best concentrations are bands centrally placed in banded gabbro. Ores near the base are contact ores or xenoliths, and the gabbro at the base shows very

Nov 1, 2018 · Cumulate gabbro shows a clearly banded structure with layers of plagioclase and clinopyroxene (Fig. 2 b). The contacts between the different lithological units within the ophiolite are fault-bound, as are the contacts between the ophiolite and sandstone, shale, and fine-grained conglomerates of the Late Jurassic–Early Cretaceous flysch.

Vertical banding, consisting of a rhythmic repetition of gabbroic and anorthositic layers, occurs within a narrow zone in the north-western part of the island group. The complex pseudo- sedimentary structures exhibited by this banding are described and illustrated in detail, and their origin is briefly discussed.

The deformation of country-rock and gabbro is compared and three stages in the conversion of layered gabbro to concordant lineated and foliated metagabbro are recognized.

Oct 1, 1996 · The banded marginal gabbro defines the boundary of the arcuate pluton. The layered interior gabbro occurs within the center of the pluton at higher stratigraphie levels.