WebGraphic granite everywhere is found associated with pegmatites, and its presence serves as a well established criterion for the determination of a rock as pegmatite. As a matter of fact, Kemp (1924) points out that Haiiy originally used the word "pegmatite" for a rock that today would unquestionably be called graphic granite. WebThe occurrence of rare calcic myrmekite in mafic rocks remains unexplained. Graphic granite is an intergrowth, on a scale of 1 mm to 1 m, of subhedral skeletal quartz prisms in an alkali feldspar or sodic plagioclase host, which occurs in granitic pegmatites and rarely as megacrysts in granites.
[PDF] Micrographic Granite: More from Apollo 14 - ResearchGate
WebGranites generated in this way will vary in their geochemical properties, depending on the relative importance of crustal versus mantle magma systems. In general, they will have moderate to high initial temperatures, be meta-aluminous in composition, be variable but somewhat low in K/Na ratio, and have lower initial strontium and delta 18 O ratios than … WebAbstract For over a century, the origin of the quartz-feldspar intergrowth known as graphic granite has been debated in the literature. These textures have been produced experimentally during a study of the phase equilibria and nucleation and growth … round x 1
The Nature and Origin of Granite - W.S. Pitcher - Google Books
Webgraphic granite noun a pegmatite that has crystals of gray quartz imbedded in white or pink microcline in such a manner that they resemble cuneiform writing. Origin of graphic … Web31 de ago. de 1997 · The origin of granite has for long fascinated geologists though serious debate on the topic may be said to date from a famous meeting of the Geological Society of France in 1847. My own introduction to the subject began exactly one hundred years later when, in an interview with Profes sor H. H. Read, I entered his study as an amateur fossil … Webgraphic granite is due to simultaneous crystallization of the quartz and feldspar. In subsequent years, some investigators have concluded that graphic granite consists of … straw manufacturers