Genesis
Silica-undersaturated igneous rocks typically are formed by low degrees of partial melting in the Earth's mantle. Carbon dioxide may dominate over water in source regions. Magmas of such rocks are formed in a variety of environments, including continental rifts, ocean islands, and supra-subduction positions in subduction zones. Nepheline syenite and phonolite may be derived by crystal fractionation from more mafic silica-undersaturated mantle-derived melts, or as partial melts of such rocks. Igneous rocks with nepheline in their normative mineralogy commonly are associated with other unusual igneous rocks such as carbonatite.
Read more about this topic: Nepheline Syenite
Famous quotes containing the word genesis:
“Behold I have given you every herb bearing seed which is upon the face of all the earth, and every tree, in which is the fruit of a tree yielding seed; to you it shall be for meat.”
—Bible: Hebrew Genesis 1:29.
But in a later context, God told the disgraced Adam, “and thou shalt eat the herb of the field” (Genesis 3:18)
“Nature centres into balls,
And her proud ephemerals,
Fast to surface and outside,
Scan the profile of the sphere;
Knew they what that signified,
A new genesis were here.”
—Ralph Waldo Emerson (1803–1882)
“Power is, in nature, the essential measure of right. Nature suffers nothing to remain in her kingdoms which cannot help itself. The genesis and maturation of a planet, its poise and orbit, the bended tree recovering itself from the strong wind, the vital resources of every animal and vegetable, are demonstrations of the self-sufficing and therefore self-relying soul.”
—Ralph Waldo Emerson (1803–1882)