At least such has been the case in the granitic magma of which Mr. Wilson now possesses the solidified results.
Mounting pressure within the reservoir may drive the magmafurther upward through structurally weak zones to erupt as lava at the surface.
Plugs that bear a particularly strong imprint of explosive eruption of highly gas-charged magma are called diatremes or tuff-breccia.
When the rock ultimately fails to permit continuedmagma ascent, earthquakes result.
Volcanic plugs are believed to overlie a body of magma which could be either still largely liquid or completely solid depending on the state of activity of the volcano.
Surface water percolates downward through the rocks below the Earth's surface to high-temperature regions surrounding a magma reservoir, either active or recently solidified but still hot.
Upon cooling, the liquidmagma may precipitate crystals of various minerals until solidification is complete to form an igneous or magmatic rock.
Precise determination of the location and magnitude of earthquakes by a well-designed seismic network--as the volcano inflates by the rise of magma, the enclosing rocks are deformed to the breaking point to accommodate magma movement.
The distinguishing feature of phreatic explosions is that they only blast out fragments of preexisting solid rock from the volcanic conduit; no new magma is erupted.
The essential feature of a composite volcano is a conduit system through which magma from a reservoir deep in the Earth's crust rises to the surface.
Much the same may be said of the dikes of cooled magma which have been injected along preëxisting fractures.
Under such circumstances the intruded magma expands less widely than is the case when an intruded sheet is formed, and a thick intrusion results, which lifts a small cover perhaps to a great height.
The heat of an intruded magma affects the rocks it traverses and produces what is termed contact metamorphism.
A magma forced upward in fissures in the earth's crust may meet moist rocks or even reservoirs of water, and in such instances steam or gases are produced and a new force is added, which may produce explosions.
A marked variation in the process just outlined occurs when, as the controlling condition, the intruded magma is highly viscous instead of highly fluid, and the friction of contact and of flow is greatly increased.
The simplest form of intrusion, the dike, results under whatever condition the summit portion of the magma comes to rest.
It should be added that when the bladder is filled with a soft magma a catheter may be introduced through the whole length of the urethra to be used in pumping water into the bladder.
There may, however, be a number of small calculi; indeed, they are sometimes so small and numerous as to form a small, pulpy magma by which the bladder is considerably distended.
Then there was a tremendous explosion, and the molten magma was thrown up with such a force that it was shattered into minute droplets, in the same way as water does when it is thrown forcibly into the air.
It is evident that not every droplet of the moltenmagma would form a single sphere, but that many also would swell up into a compound frothlike mass of pumice.
After gas evolution had ceased the mixture was saturated with zinc chloride and the magma distilled under reduced pressure.
A thick yellow magma resulted from which the crystals of chlorine hydrate were separated by pressing between filter paper at 0 deg.
Faiths melt; churches dissolve; morals fade; bonds fail; a universal magma of emancipated opinion seems to take the place of old-established dogma.
The advantage is more apparent than real, however, as the retention of the water until the magma has been shaken up and mixed with it hastens greatly its complete evacuation.
Sometimes this magma is condensed into a solid mass in the bladder by reason of the binding action of the mucus and other organic matter, and then forms a conglomerate stone of nearly uniform consistency and without stratification.
Later, in analyzing the shots and making a new sketch, Jeffrey Williams thought the magma front had grown slightly from the previous day, but since the first tracings were gone, there was no way of being sure.
The next step is to find out how fast the magma is rising.
The appearance of the magma under them, almost like a mushroom cloud in shape, was pretty ominous.
Now, twomagma areas were showing where only one had shown before.
Do you know any other way of releasing the magma safely?
Notice that themagma is not following the original channels.
Sometimes there is a central channel through which the magma can rise.
The scientists returned to the hotel, to continue their attempts to predict the magma movement based on data already in hand.
The memory of the earthquake was still fresh, and he was anxious to see if it had come from rising magma far below, or from some other source.
The magmawill reach the solid layer before we could possibly get to it with a tunnel.
Instantly the magma exploited the new weakness, pressure was released until .
At any rate, it is somewhat above this discontinuity that magma is formed.
Between these two extremes of position and age, we find that the crust has been, as it were, riddled with injections of the magma from below.
This important series brings before us the relations of the molten magma within the earth to the overlying crust and to the outer surface.
According to some investigators, it should be regarded as in large measure of meteoric origin, derived from the descent of rain into the earth, and its absorption by the molten magma in the interior.
In the first place, it will be evident from what has already been said, that that mineral which first crystallizes out from a molten magma is not necessarily the one with the highest melting point.
The composition of the magma will thereby change, and the mass will finally solidify to a mixture of orthoclase and silica, or orthoclase and potassium aluminate, according to the initial composition.
If the initial composition of the magma is represented by a point between the two eutectic points, orthoclase will separate first.
Powerful agitation is next given to the magma till it becomes quite uniform, when the mash-tun is covered over with canvas, and left in this state for two hours.
It has been suggested that the igneous magma may have secured the carbon by the melting of carbonaceous sediments through which it penetrated, but proof of this is difficult to obtain.
This graphite is considered to be of inorganic origin, formed by the breaking up of gaseous oxides of carbon in the original magma of the pegmatites.
The analcite clearly represents the magma left after the crystallization of the imbedded minerals, and it is evident that it can be formed only from a magma highly charged with water, and therefore under pressure.
They are so thoroughly injected with silica and also with typical granite magma as to make their reference to the country rock less secure on petrographical than on purely distributional grounds.
It might be supposed that the indicated change in the character of the complementary dikes could be ascribed to possible differentiation of the granite magma whereby a darker facies would be developed toward the Colpani contact.
He was feebly cognizant of emotions quite unknown; of unfamiliar sentiments, whose outlines were but just crystallizing out from the thick magma of his materialistic soul.
Just what will crystallize out of the magma is uncertain.
In some rocks there appear in the smoky glass brownish-yellow patches of the residual magma which under the microscope cannot be distinguished from palagonite.
They contain inclusions of the magma and give lamellar extinctions of andesine labradorite (20°-30°).
In the secondary changes, such as those associated with the early alteration of the propylites, these “magma lakelets” are the first affected.
The plagioclase phenocrysts are zoned and give extinctions of 15° to 25° (acid and basic andesine), whilst they often show magma inclusions.
Scattered about in the glass are little irregular patches, or “lakelets,” of residual magma composed of a yellowish feebly refractive material that I cannot distinguish from palagonite.
They contain usually abundant inclusions of themagma sometimes arranged zone-wise, and are frequently eroded.
They are in part corroded by the magma and give evidence of fracture in their present position, the re-union being sometimes effected by the growth of new substance.
It would seem from the peculiar erosion of the glass fragments that after the crushing a liquid magma occupied the interspaces, and afterwards solidified and underwent the palagonitic change.
It is semi-ophitic and contains in the smoky glass of the groundmass little irregular cavities filled with a yellowish residual magma like palagonite in character.
They are traversed by many fine cracks and contain an abundance of colourless dust-like inclusions, apparently altered magma products.
The bits of copper being placed in oxidation-chests, along with the magma of common salt and blue vitriol previously prepared in strata of half an inch thick, they are left for some time to their mutual reaction.
Next morning the drained magma is put into a strong bag, and squeezed in a press.
Whenever the first magma of clay has become dry, it is replaced by a second; and this occasionally in its turn by a third, whereby the sugar cone gets tolerably white and clean.
The silver is now to be precipitated by plunging plates of copper in the solution, and the magma which falls is to be well washed, and freed from the residuary particles of sulphate of copper by powerful compression.
It has been discovered, but without knowing why, that a little vinegar added to the water of the magma almost infallibly prevents that sudden stiffening of the deposit and stoppage of the stones.
Powerful agitation is given to the magma till it becomes quite uniform; a process which a vigorous workman piques himself upon executing in the course of a few minutes.
The magma (the mixture of crystalline sugar and sirup) is fed in gradually, by which means it is more likely to assume a position of equilibrium in the basket.
When this charger reached a certain rotary velocity, the magma would be hurled out over the edge by centrifugal force and evenly distributed on the wall of the main basket.
It had been noticed that when a charge of magma was put into a centrifugal in one mass, the sugar wall on the side of the basket was apt to form irregularly, too thick at base and of varied color.
An average sugar centrifugal will separate 600 pounds of magma perfectly in three minutes.
The communication between the vents of volcanoes would be complete and simple, without any lateral forcing of the lava through magma layers made expressly for the purpose; it would be an open and natural flow from one place to another.
Liquid matter on the interior surface of the shell, and gases in the hollow, better means for eruptions than magma layers.
Geologists are therefore thrown back upon their magma layers to look for the motive power for producing these grand eruptions, and they cannot get water down deep enough to do it.
He claims that geologists furnish him with a certain amount of positive evidence for the idea that water is an essential constituent of the liquid magma from which the igneous rocks have been derived.
