How To Use Porphyritic In A Sentence
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Sinai, grey granite dyked with decaying porphyritic trap, and everywhere veined with white and various-coloured quartzes.
The Land of Midian
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It is dominated by variably foliated, medium-grained, even-textured to porphyritic biotite hornblende tonalite and quartz diorite.
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In the Tintic district of central Utah, Paleozoic limestones have been intruded by monzonite (an acid granitic or porphyritic igneous rock), and covered by surface flows, the flows for the most part having been removed by subsequent erosion.
The Economic Aspect of Geology
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The ruddy syenite is dyked and veined by the familiar network of green-black porphyritic trap; the filons are disposed in parallels striking north-south, with a little easting; the dip is westerly (about 35 degrees mag.), and the thickness extends to hundreds of feet, often forming a foundation for the upper cliff.
The Land of Midian
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The breakthrough advancement of exploration in recent years on granitic type, remelting porphyritic type and syntectic porphyritic type ore deposits was discussed in detail.
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Further up, a broad porphyritic dyke crosses our path, then more trees, and we come to the gentle slope of a kind of granitic sand which composes the open space leading to the pass between Granite
The Lake of the Sky Lake Tahoe in the High Sierras of California and Nevada, its History, Indians, Discovery by Frémont, Legendary Lore, Various Namings, Physical Characteristics, Glacial Phenomena, Geology, Single Outlet, Automobile Routes, Historic Town
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The original porphyritic texture with plagioclase phenocrysts is still recognizable.
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hornstone" type, with porphyritic developments of silicate minerals.
The Economic Aspect of Geology
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The granite is porphyritic with biotite and hornblende as important minerals and lies to the south of the contact; the gneiss lies to the north of the contact.
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They are generally trap-rock, embracing the varieties of gray, porphyritic, hornblendic, sienitic, and amygdaloidal trap, and appear to have had no labor expended upon them except the chiseling of a groove around the middle for the purpose of attaching a withe to serve as a handle.
Ancient Mining on the Shores of Lake Superior
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The rock here is a porphyritic granite (porhyritic meaning that the stone has large-grained crystals, such as feldspar or quartz, dispersed in a fine-grained feldspathic matrix or groundmass).
Of Books and the Sea
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It is a light grey, porphyritic volcanic to subvolcanic rock, which shows almost no deformation.
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It is a light grey, porphyritic volcanic to subvolcanic rock, which shows almost no deformation.
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It grades inwards over tens to hundreds of metres into a coarser-grained porphyritic granodiorite.
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The plutons are composed of medium - to coarse-grained, porphyritic quartz monzonite, quartz syenite and granite, together with smaller amounts of equigranular gabbroic and monzonitic rocks.
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The biotite-granite continues these trends of increasing orthoclase over plagioclase and biotite over homblende, to produce a coarse-grained pink porphyritic rock in which orthoclase phenocrysts dominate.
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This regular disposition of lithoid basaltic lava and feldsparry vitreous lava is analogous to the phenomena of all trappean mountains; it reminds us of those phonolites lying in very ancient basalts, those close mixtures of augite and feldspar which cover the hills of wacke or porous amygdaloids: but why are the porphyritic or feldsparry lavas of the Peak found only on the summit of the volcano?
Travels to the Equinoctial Regions of America
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a native porphyritic green stone called beech-bowlder.
Customs and Fashions in Old New England
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Porphyritic acidic volcanic rocks are widespread and referred to a calc-alkaline suite from an active margin setting.
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A violet, coarse-grained, porphyritic quartz syenite, which makes up large parts of the pluton, was collected for dating.
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The rock here is a porphyritic granite (porhyritic meaning that the stone has large-grained crystals, such as feldspar or quartz, dispersed in a fine-grained feldspathic matrix or groundmass).
Of Books and the Sea
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This regular disposition of lithoid basaltic lava and feldsparry vitreous lava is analogous to the phenomena of all trappean mountains; it reminds us of those phonolites lying in very ancient basalts, those close mixtures of augite and feldspar which cover the hills of wacke or porous amygdaloids: but why are the porphyritic or feldsparry lavas of the Peak found only on the summit of the volcano?
Travels to the Equinoctial Regions of America
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Rhyolite dykes, which are commonly porphyritic with phenocrysts of either plagioclase or quartz, are intruded by dykes of hornblende tonalite, and the gabbro is likewise intruded by tonalite dykes.
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The majority of the rhyolites are porphyritic and contain phenocrysts of one or more of the following: plagioclase, clinopyroxene, magnetite, quartz and sanidine, plus accessory apatite and zircon.
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Coarser fractions additionally contain volcanic clasts of vesicular and porphyritic lava, tuff and pumice.
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The majority of the rhyolites are porphyritic and contain phenocrysts of one or more of the following: plagioclase, clinopyroxene, magnetite, quartz and sanidine, plus accessory apatite and zircon.
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We were stopped by a small circular wall of porphyritic lava, with a base of pitchstone, which concealed from us the view of the crater.
Travels to the Equinoctial Regions of America
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The rock here is a porphyritic granite (porhyritic meaning that the stone has large-grained crystals, such as feldspar or quartz, dispersed in a fine-grained feldspathic matrix or groundmass).
Of Books and the Sea
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The majority of the rhyolites are porphyritic and contain phenocrysts of one or more of the following: plagioclase, clinopyroxene, magnetite, quartz and sanidine, plus accessory apatite and zircon.
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They have a porphyritic texture with prismatic plagioclase phenocrystals, small, aciculate plagioclase crystals and a partially devitrified, near-opaque matrix.
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Coarser fractions additionally contain volcanic clasts of vesicular and porphyritic lava, tuff and pumice.
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These crystals eventually form the phenocrysts found in porphyritic rocks.
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They are enclosed within typical porphyritic granite, which has a gently dipping compositional layering that is parallel to the axial planes of the eye structures.
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The large shear zones may converge and are the hosts for the mineralization, but finer grained porphyritic dikes and sills that are located near mineralization are emplaced as laccolith type fillings parallel to the shear zone with north south structural boundaries.
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