How to use Intrusions in a sentence
Ansariya, which presently springs up into a high chain of Jurassic limestone with basaltic intrusions, whose peaks rise to 10,000 ft.
They are accompanied by intrusions of diabase and gabbro, and they are sometimes folded, sometimes but little disturbed.
Elsewhere the forms are Palaearctic with intrusions from the east; but the length of the Syrian strip and the variety of its surface relief admit of considerable difference in the species inhabiting different districts.
In northern Africa a continuous sequence of volcanic events has taken place from Eocene times to latest Tertiary; but in South Africa it is doubtful if there have been any intrusions later then Cretaceous.
The earlier supporters of the organic theory held that it was a product of the natural distillation of coal or carbonaceous matter; but though in a few instances volcanic intrusions appear to have converted coal or allied substances into oil, it seems that terrestrial vegetation does not generally give rise to petroleum.Advertisement
Upon all which intrusions many unspeakable evils did follow.
The most striking feature in the geology of Russia is its remarkable freedom from disturbances, either in the form of mountain folding or of igneous intrusions.
The ticket furnished an easy means for guarding the meetings of the society against intrusions."
South and west of the Fossa Magna the beds are thrown into folds which run approximately parallel to the general direction of the coast, and two zones may be recognizedan outer, consisting of Palaeozoic and Mesozoic beds, and an inner, consisting of Archaean and Palaeozoic rocks, with granitic intrusions.
The volcanoes of Bolivia lie almost entirely in the Western Cordillera - the great summits of the eastern range, such as Illimani and Sorata, being formed of Palaeozoic rocks with granitic and other intrusions.Advertisement
The shaman journeys or passes his/her hands over the client's body to detect intrusions.
It has even used people's very natural fear of terrorism to justify intrusions that having nothing to do with tackling that threat.
There are also a number of igneous intrusions into the Coal Measures.
Minerals Mineralization may occur around the small number of granitic intrusions of the area.
Such systems could be targeted through unauthorized intrusions, DDoS attacks, worms, Trojan horse programs, or malicious insiders.Advertisement
We are also seeing the increased use of cyber intrusions by criminal groups who attack systems for purposes of monetary gain.
Similar hacker intrusions are regularly experienced by all other US military services and government agencies.
The area is characterized by mainly Dalradian schist and gneiss with intrusions of granite.
On the highest surface all intrusions are governed by the location of the polar vortex.
Intrusions of granitic massifs in the Devonian period formed the primitive mountain axis of Victoria, which extends east and west across the state and forms the nucleus of the Victorian highlands.Advertisement
The mountain group of North Wales is the largest and loftiest; its scenery resembles that of the Scottish Highlands because of the juxtaposition of ancient Palaeozoic rocks - Cambrian and Ordovician, often altered into slate - and contemporaneous volcanic outbursts and igneous intrusions.
Of course, you counteract these stressful intrusions by having a plan.
Putting yourself on this list won't guarantee the absence of telemarketers, but it should help to minimize these intrusions.
Similar granitic intrusions occurred in New South Wales and Queensland, and built up a mountain chain, which ran north and south across the continent; its worn-down stumps now form the east Australian highlands.
These are penetrated by intrusions of granitic and felsitic character; one of these masses in Papa Stour is a handsome pink felsite.Advertisement
Intrusions of a serpentine-like rock break through the Miocene strata north of Bhamo, and similar intrusions occur in the western ranges.
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.'
Most of the island is occupied by the band of the old rocks, which include mica, glaucophane and sericite-schists and slates; there are small intrusions of granite, and numerous dikes and masses of basic eruptive rocks.
It appears to consist in the main of a continuation of an axis of old schists and slates, with granite intrusions, and flanked by coastal plains with Cretaceous or Jurassic, and Miocene beds, with Pleistocene sands and reefs and volcanic rocks.
The wild and barren west of this county, including the great hills on Achill Island, is formed of "Dalradian" rocks, schists and quartzites, highly folded and metamorphosed, with intrusions of granite near Belmullet.
Here and there they are penetrated by granitic intrusions which are also Pre-Carboniferous.
The oldest rocks, consisting of crystalline schists with numerous intrusions of granite, porphyry and diorite, occupy the eastern portion of the country between the Nilesouth of Assuan and the Red Sea.
But the most important igneous masses are the great intrusions of syenitic granite and of basic rock which penetrate the Cretaceous beds.
Intrusions of hyperite, gabbro (anorthite-gabbro at Radmanso in the province of Stockholm) and diorite are also abundant.
The eastern ranges of the Bolivian Andes are formed of Palaeozoic rocks with granitic and other intrusions; the Western Cordillera consists chiefly of Jurassic and Cretaceous beds, together with the lavas and ashes of the great volcanoes; while the intervening plateau is covered by freshwater and terrestrial deposits through which rise ridges of Palaeozoic rock and of a series of red sandstones and gypsiferous marls of somewhat uncertain age (probably, in part at least, Cretaceous).
There is no axial zone of gneiss, but intrusions of granite and other plutonic rocks occur, and the famous ore deposits are found chiefly near the contact of these intrusions with the schists.
The central and most picturesque part of the district is formed of great masses of volcanic ashes and tuffs, with intrusions of basalts and granite, all of Ordovician (Lower Silurian) age.
Mid Wales is built up, for the most part, of Silurian or Ordovician rocks, practically free from igneous intrusions except in the south-west.
A few small outcrops occur where still more ancient strata have been raised to the surface, as, for instance, in Charnwood Forest, where the Archaean rocks, with intrusions of granite, create a patch of highland scenery in the very heart of the English plain; and in the Lickey Hills, near Birmingham, where the prominent features are due to volcanic rocks of very ancient date.
The Devonian period, as in Victoria, was marked by a series of granitic intrusions, which altered the older beds on the contact, while the quartz-porphyry dikes, which are intrusive in the Silurian rocks at the Mount Bischoff tin mine, doubtless belong to this period.
The Spiti shales are succeeded conformably by Cretaceous beds (Gieumal sandstone below and Chikkim limestone above), and these are followed without a break by Nummulitic beds of Eocene age, much disturbed and altered by intrusions of gabbro and syenite.
Igneous intrusions consist only of unimportant dikes of trap. The most striking and uniformly characteristic geologic feature of the mountains is their internal structure, consisting of innumerable parallel, long and narrow folds, always closely appressed in the eastern part of any crosssection (Piedmont Plateau to Great Valley), less so along a central zone (Great Valley and Valley Ridges), and increasingly open on the west (Allegheny and Cumberland Plateaus).