Titlebook: Gold; History and Genesis Robert W. Boyle Book 1987 Van Nostrand Reinhold 1987 economic geology.geology.mining.reef

deceive

,The Origin of Epigenetic Gold Deposits—The Granitization Theory,tween those supporting A. G. Werner (1750–1817) in his Neptunist theory of the sedimentary origin of granitic rocks and those who followed J. Hutton (1726–1797) in his Plutonist theory of the igneous (magmatic) origin of granites. During the early part of the nineteenth century the controversy was p

显示

LUT

,Origin of Epigenetic Gold Deposits—Secretion Theories,ins began with Agricola in the sixteenth century. Since then secretion theories have undergone considerable modification and embellishment. Two general concepts implicit in secretion theories are extant: lateral secretion (.), which postulates that the ore and gangue constituents were derived direct

未成熟

POINT

,Gold Deposits—Placers, Witwatersrand and other quartz-pebble conglomerates as fossil placers or modified placers, the placer type of auriferous deposit has provided more than two thirds of the world’s store of gold, about 80 × 10. grams (2.6 × 10. oz).

Outwit

Oxidation and Secondary Enrichment of Gold Deposits,e enrichment may be primarily the result of the chemical removal of a large part of the gangue minerals, in which case the gold migrates slowly downward by gravity or is left behind as a residual component. Such enrichments require no chemical movement of the gold; the lodes simply weather down and

Aerate

STIT

载货清单

撤退