Word Finder - basalt

definition

A hard mafic igneous rock of varied mineral content; volcanic in origin, which makes up much of the Earth's oceanic crust.

definition

A type of unglazed pottery.

The soil, of decomposed basalt, is wonderfully fertile.

Such rocks as basalt, diorite and trachyte are comparatively rare.

Large areas are overlain with trachyte, basalt, obsidian, tuff and pumice.

In most cases the eruptions appear to be of Pliocene or later date, but in the extreme north some of the basalt seems to belong to the Miocene period.

It is formed of basalt, trachyte and phonolite, and the soil is very fertile.

These rocks form a prominent feature underneath the basalt terraces of the east side of Skye, Raasay and Eigg.

Rocks belonging to the Cretaceous system at one time covered considerable areas on both sides of the Highlands, but they have been entirely stripped off the eastern side, while on the western they have been reduced to a few fragmentary patches, which have survived because of the overlying sheets of basalt that have protected them.

The objects found in these researches are in the museum, the most notable being a great basalt bull, probably once an object of cult in the Serapeum.

These are worked in brown basalt, syenite, porphyry, alabaster and limestone.

This iron is considered by several of the first authorities"on the subject to be of meteoric origin,' but no evidence hitherto given seems to prove decisively that it cannot be telluric. That the nodules found were lying on gneissic rock, with no basaltic rocks in the neighbourhood, does not prove that the iron may not originate from basalt, for the nodules may have been transported by the glaciers, like other erratic blocks, and will stand erosion much longer than the basalt, which may long ago have disappeared.

The hills west of the town consist of horizontal strata of sandstone covered with irregular pieces of basalt and the top of the hill on which the observatory stood was made level by taking away the basalt.

In later days, in the time of the Sargonid kings of Akkad or the monarchs of Ur, stones such is granite, basalt, diorite and dolerite were probably brought from the Sinaitic peninsula, if not from the western desert of Egypt, if the Red Sea coast is to be identified, as seems very probable, with Magan, " the place to which ships went," the land whence the Babylonians got some of their first stones for sculpture and architecture.

These beds, as well as the Cretaceous series, from which they are as yet only imperfectly distinguished, are associated with sheets of basalt, which penetrate them in great dikes, and in some places, owing to the wearing away of the softer sedimentary rocks, stand out in long walls running across the beds.

This iron seems, however, in several respects to be unlike the celebrated large nodules of iron found by Nordenskiold at Ovifak, but appears to resemble much more closely the softer kind of iron nodules found by Steenstrup in the basalt;' it stands exposure to the air equally well, and has similar Widmannstaten figures very sharp, as is to be expected in such a large mass.

The rocks on the verge of the Kisumu province of East Africa are mainly volcanic (basalt, tuff, lava, kenyte).

In the Eastern province the rocks are mainly quartz, gneiss and granite, with sandstone in Busoga, basalt round Mt Elgon, slate (Busoga) and iron- g stone (Busoga and Bukedi).

In the Rudolf province there and are the basalt, lava, tuff and kenyte of the volcanic mineralogy.

The ground is here covered with black basalt.

The tree has a remarkable appearance, due to shedding its primary branches for about five-sixths of its height and replacing them by a small bushy growth, the whole resembling a tall column crowned with foliage, suggesting to its discoverer, Captain Cook, a tall column of basalt.

They are formed of trachyte, dolerite and basalt.

Steenstrup in several places on the west coast enclosed as smaller or larger nodules in the basalt.

The lavas and ashes ejected by these volcanoes consist of liparite, dacite, andesite and basalt.

The summits of the flattopped hills about Betsy Cove, in the south-east of the island, are formed of caps of basalt.

Many of the oceanic islets are composed of coral limestone, which in this way becomes phosphatized; others are igneous, consisting of trachyte or basalt, and these rocks are also phosphatized on their surfaces but are not so valuable, inasmuch as the presence of iron or alumina in any quantity renders them unsuited for the preppration of artificial manures.

Dr Bunge found Bolshoy to consist of granite protruding from beneath non-fossiliferous deposits; while the promontory of Svyatoy Nos Qonsists of basalt hills, 1400 ft.

The volcanic fissures that allowed of the upwelling of basalt are represented by numerous dykes, many cutting the earlier lava-flows as well as all the beds below them.

The glens of Antrim are deep notches cut by seaward-running streams through the basalt scarp, their floors being formed of Triassic or older rocks.

In the Hauran 22.16 is shown by a basalt door (British Museum), and perhaps elsewhere in Syria (25).

On the north-west are several conical hills of basalt, which are surrounded by oases of fertile soil.

The sapphire occurs also in Europe, being found in the Iserweise of Bohemia and in the basalt of the Rhine valley and of Le-Puy-en-Velay in France, but the European stones have no interest as gems.

With the exception of the coral and a small amount of calcareous sandstone, the rocks are entirely volcanic and range from basalt to trachyte, but are mainly basalt.

They include colossal figures of Aesculapius and Bacchus, and the lower half of a seated Egyptian divinity in black basalt, bearing the cartouche of Tethmosis (Thothmes) I.

The town is still surrounded by the masonry walls of black basalt which give it the name of Kara or Black Amid; they are well built and imposing on the west facing the open country, but almost in ruins where they overlook the river.

Augite-andesite predominates, but basalt and rhyolite also occur.

In both occurrences, however, there is still the possibility that the eclogite or the basalt is not the original matrix, but may have caught up the already formed diamond from some other matrix.

In the middle of the ruins are the scattered remains of a synagogue of richly ornamental style built of black basalt.

An instructive example of the similar destruction of a much younger platform is to be found in the terraced plateaus of Skye, Eigg, Canna, Muck, Mull and Morven, which are portions of what was probably originally a continuous plain of basalt.

Above the highest Secondary rocks on the west coast come terraced plateaus of basalt, which spread out over wide areas in Skye, Eigg, 1VIull and Morven, and form most of the smaller islets of the chain of the Inner Hebrides.

These plateaus are composed of nearly horizontal sheets of basalt - columnar, amorphous or amygdaloidal - which, in Ben More, in Mull, attain a thickness of more than 3000 ft.

The presence of these fossils indicates that the eruptions were subaerial, and a comparison of them with those elsewhere found among Older Tertiary strata shows that they probably belong to the Oligocene stage of the Tertiary series of formations, and therefore that the basalt eruptions took place in early Tertiary time.

It appears to have resembled in its main features those remarkable outpourings of basalt which have deluged so many thousand square miles of the western area of the United States.

The eruptions were connected with innumerable fissures up which the basalt rose and from numerous points on which it flowed out at the surface.

These fissures with the basalt that solidified in them now form the vast assemblage of dykes which cross Scotland, the north of England and the north of Ireland.

Geologically, its northern half is composed of Torridonian sandstone, with basalt at points between the West coast and the centre, of gabbro in the south-east, with a belt of gneissose rocks on its east seaboard and of quartz-porphyry in the south-west.

The play of colour is exquisite, the basalt combining every tint of warm red, brown and rich maroon; sea-weeds and lichens paint the cave green and gold; while the lime that has filtered through has crusted the pillars here and there a pure snow-white.

South of the Yarmuk the formation is Cretaceous, Hauran basalt being found only in the eastern portion.

There are some small industries, embracing textile manufactures, oil mills and tanneries, and a trade in wine, while near the town are extensive quarries of basalt.

All the rocks are of basalt and greyishtinted lavas, excepting some beds of upraised coral.

Columnar basalt is seen in several places.

This iron needed no tempering, and the Celts had probably found it ready smelted by nature, just as the Eskimo had learned of themselves to use telluric iron embedded in basalt.