to N.E.; this is succeeded by a belt of gabbro, and finally the eastern border is again occupied by micaceous and chloritic schists.
With the J urassic beds is associated an extensive series of eruptive rocks (gabbro, peridotite, serpentine, diorite, granite, &c.); they are chiefly of Jurassic age, but the eruptions may have continued into the Lower Cretaceous.
Gabbro occurs in the peninsula of Fethland; diorite in Northmavine between Rinas Voe and Mavis Grind; and epidote-syenite in Dunrossness.
A soil of very close texture, the gabbro, is found, most largely in the north-east.
It appears to consist chiefly of gabbro, peridotite, serpentine and other very basic eruptive rocks, which are believed to be of Cretaceous age.
They are accompanied by intrusions of diabase and gabbro, and they are sometimes folded, sometimes but little disturbed.
Immense -sheets of dolerite, gabbro, or allied basic rocks indicate eruptive materials intruded as sills or poured out as lavas contemporaneously with the sedimentary formations among which they lie.
A remarkable feature in the volcanic phenomena was the disruption of the basaltic plateaus by large bosses of gabbro and of various granitoid rocks.
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.
These mountains, consisting of various sorts of gneiss, intrusive granite and gabbro, have been formed partly by faulting but mainly by erosion, the lines of which have been determined by the presence of faults or the presence of relatively soft rocks.
The oldest rocks exposed are gneiss, talc-schist and serpentine, with intrusive masses of gabbro and diabase.
The large deposits at Falun in Sweden occur with serpentine in gneiss, and those at Montecatini, near Volterra in the province of Pisa, serpentine and gabbro.
Intrusions of hyperite, gabbro (anorthite-gabbro at Radmanso in the province of Stockholm) and diorite are also abundant.
Lithologically they are crystalline schists, together with granite, diorite, gabbro and other igneous rocks.
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.
In the south-east of the island, in the parish of Lon, there exist a few mountains of gabbro, a rock which does not occur in any other part of Iceland.
During this time of comparative rest, rhyolites were extruded locally in county Antrim; and there is very strong evidence that the granite of the Mourne Mountains, and that which cuts the Carlingford gabbro, were added at the same time to the crust.
- The ancient or plutonic igneous rocks (including granite, syenite, diorite, gabbro, porphyry, porphyrite, norite retinite) appear at various points of the two previously described regions.
Von Hochstetter of the Austrian expedition classified the most important formations thus: eruptive, serpentine and gabbro; marine deposits, probably late Tertiary, consisting of sandstones, slates, clay, marls, and plastic clay; recent corals.
Peridotite and gabbro form much of the eastern peninsula (Banggai).
See also cut-off grade Gabbro A coarse grained igneous rock consisting of calcic feldspar, pyroxene and commonly hornblende and/or olivine: appx.
Stage 7 Cross Yorkshire Street to the Royal Bank of Scotland which has a plinth of polished black gabbro called Bon Accord.
gabbro rock thin section, Open University slide.
gabbro slabs on the floor of the hanging valley, Coir ' a ' Mhadaidh.
The black gabbro contains pyroxene and pigmented plagioclase feldspars.
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