porphyritic

How To Use porphyritic In A Sentence

• Sinai, grey granite dyked with decaying porphyritic trap, and everywhere veined with white and various-coloured quartzes. The Land of Midian
• It is dominated by variably foliated, medium-grained, even-textured to porphyritic biotite hornblende tonalite and quartz diorite.
• 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
• 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
• The breakthrough advancement of exploration in recent years on granitic type, remelting porphyritic type and syntectic porphyritic type ore deposits was discussed in detail.
• 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
• The original porphyritic texture with plagioclase phenocrysts is still recognizable.
• hornstone" type, with porphyritic developments of silicate minerals. The Economic Aspect of Geology
• 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.
• 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