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| 美国内华达Goldstrike矿区卡林型贝茨金矿同变形的富矿分带(续) | |
| 作者姓名： | Stephen G. Peters Gregory C. Ferdock Maria B. Woitsekhowskay Robert Leonardson Jerry Rahn |
| 作者单位： | 1. 美国地质调查所 里诺分部, 内华达大学 马凯矿业学院,美国 内华达 里诺 89557-0047 2. 美国内华达大学 马凯矿业学院 地质科学系,美国 内华达 里诺 89557-0047 3. 巴利克Goldstrike矿业有限公司 矿山地质部,美国 内华达 埃尔科 89803 |
| 摘 要： | (接第 1期第 1 6页 )3 富矿分带与控制因素贝茨金矿中不同矿石矿物组合和蚀变类型的分布与构造背景、围岩岩石及在矿体中的位置有关。根据形态、矿物组成和地质背景可分出几种空间形式截然不同的矿石类型 ,彼此之间由废石或低含金量的岩石所分隔。富矿体的地球化学、矿物学、地质及冶金方面的分带在三维空间上是连续的。富矿体的形状和定位与 Peters向斜构造的特征 ,沉积岩的岩石组成以及闪长岩接触带的几何形态和厚度有关 (图 6 A,B)。根据对不同的矿石类型和围岩类型的研究结果 ,对不同的富矿体进行了分类和判别。 Pe-ters( 1 996 ,1 9… |
| 关 键 词： | 卡林型金矿 同变形 富矿分带 美国 金矿床 |
| 收稿时间： | 1999/9/30 0:00:00 |
ORESHOOT ZONING IN THE CARLIN-TYPE BETZE OREBODY, GOLDSTRIKE MINE, EUREKA COUNTY, NEVADA |
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| Stephen G. Peters,Gregory C. Ferdock,Maria B. Woitsekhowskay,Robert Leonardson,Jerry Rahn.ORESHOOT ZONING IN THE CARLIN-TYPE BETZE OREBODY, GOLDSTRIKE MINE, EUREKA COUNTY, NEVADA[J].Contributions to Geology and Mineral Resources Research,2000,15(2):115-132. | |
| Authors: | Stephen G Peters Gregory C Ferdock Maria B Woitsekhowskay Robert Leonardson and Jerry Rahn |
| Institution: | U. S. Geological Survey, Reno Nevada 89557 0047, U. S.;Mackay School of Mines, University of Nevada, Reno Nevada 89557-0047, U. S.;U. S. Geological Survey, Reno Nevada 89557 0047, U. S.;Barrick Goldstrike Mines, Inc., Elko Nevada 89803, U. S.;Barrick Goldstrike Mines, Inc., Elko Nevada 89803, U. S. |
| Abstract: | The giant Betze gold ore body, the largest Carlin typ deposit known in the northcentral Carlin trend, Nevada is composed of individual high grade oreshoots that contain different geologic, mineralogic and textural characteristics. The orebody is typical of many structurally controlled Carlin type deposits, and is hosted in thin-bedded, impure carbonate or limy siltstone, breccia bodies, and intrussive or calc-silicate rock. Most ores in the Betze orebody are highly sheared and brecciated and show evidence of syndeformational hydrothermal deposition. Hydrothermal alteration is scale dependent, either in broad, pervassive alteration patterns or in areas related to various oreshoots. Alteration includes decarbonitization(~decalcification) of carbonate units, argillization(illite clay), and silicification. Patterns of alteration zoning in and surrounding the Betze orebody define a large porous dilated volume of rock where high fluid flow predominated. Local restriction of alteration to narrow illite-and clay-rich selvages around unaltered marble of calc-silicate rock phacoids implies that fluid flow favored permeable structures and deformed zones. Gold mainly present as disseminated sub-micron-sized particles, commonly associated with As-rich pyrite although one type of oreshoot contais micron-size free gold. Oreshoots form a three dimensional zoning pattern in the orebody within a WNW-striking structural zone of shearing and shear foloding, termed the Dillon deformation zone(DDN). Main types of oreshoots are;(1)rutile bearing siliceous oreshoots; (2)illite-clay-pyrite oreshoots; (3)realgar-and orpiment-bearing oreshoots; (4)stibnite-bearing siliceous oreshoots; (5)polymetallic oreshoots. Ore textures, gouge. phylloitic rock, alteration style and previously documented isotopic and fluid inclusion data, all indicate a weakly to moderately saline fluid that ascended and cooled during structural displacement. Carlin-type deposits are characterized by relatively uniform, low gold grades. However, recent open pit exposures in deep hypogene parts of the Betze orebody and other gold deposits in the Carlin trend suggest that some orebodies are composed of distinct high-grade oreshoots that are zoned complexly in three dimensions. |
| Keywords: | Carlin type gold depopsit syndeformation oreshoot zoning Nevada U S |
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