Metamorphic-rocks Sentence Examples
The first group is the more important and includes some of the commonest metamorphic rocks.
The central plateau consists almost entirely of metamorphic rocks with extensive tracts of granite in Unyamwezi.
Some of the metamorphic rocks may belong to the older Palaeozoic period, but the greater part of the series is probably Archaean.
In the region of Adigrat the metamorphic rocks are invariably overlain by white and brown sandstones, unfossiliferous, and attaining a maximum thickness of moo feet.
The mountain ranges of the east of Brazil, from Cape St Roque to the mouth of the river Plate, are composed chiefly of crystalline and metamorphic rocks.Advertisement
It consists of a series of plateaus formed of sedimentary rocks which mainly belong to three formations of widely separated ages, and which rest on a platform of granitic and metamorphic rocks.
They occur (a) in crystalline igneous and metamorphic rocks as an original constituent, (b) in veins associated with igneous rocks, and (c) in sedimentary rocks either as organic fragments or in secondary concretionary forms.
In many deposits of iron ores found in connexion with igneous or metamorphic rocks small quantities of phosphate occur.
As in the neighbouring mainland of Caithness, these rocks rest upon the metamorphic rocks of the eastern schists, as may be seen on Pomona, where a narrow strip is exposed between Stromness and Inganess, and again in the small island of Graemsay; they are represented by grey gneiss and granite.
Consisting of red sandstones, mudstones and conglomerates, they are inclined at high angles usually away from the granite massif and the encircling metamorphic rocks.Advertisement
The second is the zone of the snowy peaks and of the lower Himalaya, and is composed chiefly of crystalline and metamorphic rocks together with unfossiliferous sedimentary beds supposed to be of Palaeozoic age.
The metamorphic rocks compose the main mass of the tableland, and are exposed in every deep valley in Tigre and along the valley of the Blue Nile.
The metamorphic rocks of the rest of Mainland are principally coarse gneisses, micaceous and chloritic schists, quartzites, &c.; in these rocks at Tingwall and Wiesdale considerable beds of limestone occur, which may be followed across the island in a northerly direction to Yell Sound, and to Dales Voe in Delting.