Facts of this kind seem to favor the position of certain geologists that magmas may assimilate the rocks they invade.
The original source of water, as well as of air, is in molten magmas coming from below.
The copper was probably deposited by hot solutions related to the igneous rocks, either issuing from the magmas or deriving heat and dissolved material from them.
This is the so-called "inorganic" theory, that oil comes from magmas and volcanic exhalations.
They are probably solid, but in a potentially plastic condition, and become fused and may be forced upward through fissures in the condition of igneous magmas when pressure is relieved.
In a continental environment, magmas are generated in the Earth's crust as well as at varying depths in the upper mantle.
The variety of molten rocks in the crust, plus the possibility of mixing with molten materials from the underlying mantle, leads to the production of magmas with widely different chemical compositions.
These magmas commonly will be modified or changed in composition during passage through the granitic layer and erupt on the surface to form volcanoes built largely of non-basaltic rocks.
Because the granitic crustal layer is absent, the magmas are not appreciably modified or changed in composition and they erupt on the surface to form basaltic volcanoes.
All magmas contain dissolved gases, and as they rise to the surface to erupt, the confining pressures are reduced and the dissolved gases are liberated either quietly or explosively.
During passage through the granitic layer, magmas are commonly modified or changed in composition and erupt on the surface to form volcanoes constructed of nonbasaltic rocks.
If magmas cool rapidly, as might be expected near or on the Earth's surface, they solidify to form igneous rocks that are finely crystalline or glassy with few crystals.
Magmas which thus reach the surface of the earth are described as lavas, and the rocks produced by their consolidation are extrusive or volcanic rocks.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "magmas" in a variety of sentences. We hope that you will now be able to make sentences using this word.
