The distribution of gold in quartz in magmatic, contact-metasomatic and hydrothermal-vein material from many regions of the country is discussed on the basis of NAA and spectrochemical data. The maximum average Au values were obtained from quartz in gabbro-diorites, diorites, syenite-diorites and monzonites (4-4.8 X 10-7%) from granitic intrusions in folded regions; minimum values were found for quartzes in granites, aplites, pegmatites and charnockites (1.6-2.6 X 10-7%). A regular reduction is established in the average Au content in quartz from granitic rocks of varying composition and age, from basic to silicic rocks, and from early to young phases. Quartz from granitic rocks altered autometasomatically often shows a 1.3-2-fold reduction in Au content compared with quartz from unaltered rocks, suggesting that Au is removed from continental granitic rocks during alkaline autometasomatism. Quartz from a stage of acidic leaching of magnesian and limestone skarns is characterized by increased Au content (KH 17-164). Gold enters quartz of varying origin in four basic forms: atomic and molecular dissipation, finely dispersed in a sulphide phase, sorption and as large native gold crystals.- T.R.
|Название основной публикации||Izvestiya Akademii Nauk SSSR, Seriya Geologicheskaya|
|Состояние||Опубликовано - 1982|
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)
- Environmental Science(all)