Metamorphic Sentence Examples
The central plateau consists almost entirely of metamorphic rocks with extensive tracts of granite in Unyamwezi.
In many deposits of iron ores found in connexion with igneous or metamorphic rocks small quantities of phosphate occur.
Consisting of red sandstones, mudstones and conglomerates, they are inclined at high angles usually away from the granite massif and the encircling metamorphic rocks.
In the Umzimkulu river and in the Tugela river below its junction with the Buffalo, metamorphic limestones are associated with schists, gneisses and granites.
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.Advertisement
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.
The lodes occur in Silurian metamorphic micaceous schists, intruded by granite, porphyry and diorite, and traversed by numerous quartz reefs, some of which are gold-bearing.
Some of the metamorphic rocks may belong to the older Palaeozoic period, but the greater part of the series is probably Archaean.
This great series of metamorphic rocks, the geological age of which is still unsettled, has had a powerful effect on the scenery, especially along the Highland line.
While the general elevation is 7000 to 9000 ft., the individual peaks, consisting largely of granites and metamorphic slates, reach altitudes of 10,000 ft.Advertisement
The oldest rocks, consisting of slate, mica-schists and grits, which have been correlated with the metamorphic series of the eastern Highlands, form an incomplete ring round the granite in the north of the island and occupy the whole of the west coast from Loch Ranza south to Dougrie.
Slate is a metamorphic rock made of sandstone and shale.
The first group is the more important and includes some of the commonest metamorphic rocks.
The foundation of the island is formed of metamorphic and igneous rocks, which appear in the Sierra Maestra and are exposed in other parts of the island wherever the comparatively thin covering of later beds has been worn away.
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
Metamorphosed sedimentary rocks are widely distributed in the schistose series, but they are distinctly subordinate to the meta-ignecius rocks, and they are so highly metamorphic that stratigraphic methods are not usually applicable to them.
There is a central region, roughly triangular in shape, with its base resting upon the Quaternary K Triassic Tertiary Carboniferous q & Metamorphic 7 Jurassic Aegean Sea and its apex in Servia.
It is, however, not impossible that the metamorphic series includes also some of the Lias.
Schists, as a rule, are found in regions composed mainly of metamorphic rocks, such as the Central Alps, Himalayas, and other mountain ranges, Saxony, Scandinavia, the Highlands of Scotland and north-west of Ireland.
They are soft and lustrous, with a peculiarly smooth feel, and though often confounded with mica-schists may be distinguished by their richness in magnesia; many of them contain tremolite or actinolite; others have residual grains of olivine or augite; and here also every gradation can be found between the unmodified igneous types and the perfectly metamorphic schists.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.
The rocks in the Arakan range and its spurs are metamorphic, and comprise clay, slates, ironstone and indurated sandstone; towards the S., ironstone, trap and rocks of basaltic character are common; veins of steatite and white fibrous quartz are also found.
While igneous and metamorphic crystalline rocks form the bulk of the Adirondack area, it is surrounded by a ring of ancient Palaeozoic sediments in which these peripheral lowlands have been developed.
Wherever it comes to the surface it comes up from beneath younger rocks which are, as a rule, less metamorphic. By means of deep borings it is known at many points where it does not appear at the surface, antI is believed to be universal beneath younger systems.
Their geological formation is metamorphic gneiss, veined with felspar and quartz, and interspersed with reddish porphyrite.Advertisement
The island is composed largely of crystalline and metamorphic rocks, but contains some cretaceous areas which hold extensive beds of coal, especially on the east coast.
These porphyritic rocks form a characteristic feature of the southern Andes, and were at one time supposed to be metamorphic; but they are certainly volcanic, and as they contain marine fossils they must have been laid down beneath the sea.
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.
There too the hydrographical network, as well as the south-west to north-east strike of the clay-slates and metamorphic schists on Ditmar's map, seem to indicate the existence of two chains running south-west to north-east, parallel to the volcanic chain of S.-E.
The form of his ideals was modified by the metamorphic glow of Transcendentalism which passed through the region of Boston in the second quarter of the 19th century.
The difference in character of the Jurassic beds on the two sides of the chain appears to indicate that a ridge existed Metamorphic Plutonic & Volcanic in that period.
The Alai is a well-defined ridge with steep slopes, and both it and the Terek-tau, which prolongs it towards the Kokshal-tau, are flanked next the Ferghana valley by what appear to be the old uplifted strata both of the old Palaeozoic series of metamorphic limestones and of the newer Tertiary series of softer conglomerates and sandstones.
I Silurian (and Cambrian?) "Dalradian" Metamorphic Series .Diorite and allied Basic Rocks '?-t =i=' Granite and allied Acid Rocks montory the conglomerates of this period rest with striking unconformity on the Dingle Beds and Upper Silurian series.
The Senonian limestone itself, which rests in the extreme north on Trias or even on the schists, is often conglomeratic and glauconitic at the base, the pebbles being worn from the old metamorphic series.
The Highland boundary fault separates the metamorphic bedrock of the highlands and the old red sandstone underlying the lowlands.
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.
Where there is complete freedom from stagnant water in the ground, and abundant room for the spread of its branches to light and air, the larch will flourish in a great variety of soils, stiff clays, wet or mossy peat, and moist alluvium being the chief exceptions; in its native localities it seems partial to the debris of primitive and metamorphic rocks, but is occasionally found growing luxuriantly on calcareous subsoils; in Switzerland it attains the largest size, and forms the best timber, on the northern declivities of the mountains; but in Scotland a southern aspect appears most favourable.
Practically all the remaining area in these islands is occupied by metamorphic schists and gneisses which occur in great variety and with which are associated numerous dikes and masses of intrusive igneous rock.
Most of them are the metamorphic products of igneous rocks, among which extrusive rocks, many of them pyroelastic, predominate.
Students studying structural geology in one term and metamorphic petrology in the next are able to synthesize information they obtain from both courses.
Solid Geology The bulk of the basement rock on either side of Loch Ness is classified as metamorphic, mostly schists.
This county includes in the north an area of the gneiss that is discussed under county Donegal, and, west of Omagh, a metamorphic region that stretches in from the central axis of Tyrone.
In some cases it appears to have segregated from a basic eruptive magma, and in other cases to have resulted from metamorphic action.
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 famous ruby mines of Upper Burma are in metamorphic rock, while the jadeite of the Bhamo neighbourhood is associated with the Tertiary intrusions of serpentine-like rock already noticed.'
E Arabian Sea Ba Of G A L e Geological information incomplete Desert Deposits Quaternary Tertiary Mesozoic Palaeozoic Archaean and Metamorphic Younger Volcanic Rocks English Miles b iuHi iiiiuiiiiii after llargl,aua Geology The geology of Asia is so complex and over wide areas so little known that it is difficult to give a connected account of either the structure or the development of the continent, and only the broader features can be dealt with here.
The other metamorphic areas of the north present even greater difficulties, owing to the absence of any overlying strata older than the Old Red Sandstone.
They comprise Seil, Easdale, Torsay, Luing and Shuna, and owe their name to the fact that they are composed mainly of metamorphic rocks, Easdale, Torsay and Luing being entirely slate, Seil mostly slate with some porphyrite in the north, and Shuna gneissose.
Like the highlands of eastern Asia, those of Turkestan are mostly built up on Pre-Cambrian gneisses and metamorphic slates, resting upon granites, syenites, old orthoclase porphyries, and the like.
The great difference in character, however, between the Silurian strata at Pomeroy in county Tyrone and the adjacent metamorphic series makes it highly probable that the latter masses are truly Archean.
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.
Even if the volcanic and intrusive basic rocks prove to be Ordovician (Lower Silurian), which is very doubtful, the metamorphic series of the core is clearly distinct, and appears to be " fundamental " so far as Ireland is concerned.