矿床地质2025，Vol.44Issue(2)：365-388,24.DOI:10.16111/j.0258-7106.2025.02.007
南美州圭亚那地盾北部奥罗拉金矿床地质特征及找矿预测
Geological characteristics and prospecting prediction of Aurora gold deposit in northern Guiana Shield,South America
摘要
Abstract
The Aurora Gold Mine,located in the northern part of the Guiana Shield in the northern Amazon Craton of South America,is a typical orogenic gold deposit with a resource estimate of 184 tons of gold at a grade of 2.54 g/t.This study,based on field geological surveys,detailed core logging,petrography,and mineralogy,provides a pre-liminary summary of the geological characteristics of the typical deposits in the Aurora gold mine,including the Rory's Knoll(RK),Mad Kiss(MK),and Aleck Hill(AH).The Aurora gold mine is situated at the bend of a large NW-trending shear zone on the eastern side of a felsic intrusive rock base.Gold mineralization is structurally con-trolled,distributed in late-stage structures,and closely related to multiple NW-NNW-trending shear zones and tight folds.Based on the ore texture,ore body morphology,vein characteristics and wall rock properties,the type of Aurora gold mine is divided into two categories:within intermediate to acidic intrusive rocks(RK and MK)and within volcanic rocks(AH).The mineralization is closely associated with quartz-carbonate veins,with gold main-ly found in quartz-carbonate-sulfide veins and disseminated pyrite on both sides of the veins.The primary ore types are vein,stockwork,and disseminated,followed by breccia.Gold mineralization predominantly occurs as native gold,electrum,and minor telluride-gold minerals,with intergranular,adsorbed,inclusional,and fracture-hosted gold as the primary textures.The deposits in the Aurora gold mine exhibit distinct alteration zoning,classi-fied into two types based on the mineralization:Type Ⅰ alteration,associated with felsic intrusions(RK and MK),with a broader alteration zone spanning 15～20 m.The proximal zone is characterized by quartz-albite-ankerite-sericite,the intermediate zone by sericite-chlorite-ankerite,and the distal zone by magnetite-calcite-epidote-chlo-rite.Type Ⅱ alteration,associated with metavolcanic rocks(AH),has a narrower alteration range of 5～10 m,with a proximal zone of quartz-albite-ankerite-sericite-chlorite and a distal zone of magnetite-calcite-epidote-chlorite.Type Ⅰ alteration is characterized by a wider bleaching extent relative to Type Ⅱ alteration,accompanied by de-creased chlorite concentrations in the proximal zone and diminished magnetite content in the distal zone.Based on the geological characteristics and orebody distribution of the Aurora gold mine,it is inferred that there is sig-nificant exploration potential at depth and along the edges of the deposit.For prospecting and exploration of the Guyana Shield covered by dense tropical rainforest and thick weathering,the method is based on large-scale aero-magnetic+MMI(Mobile Metal Ion)or other deep-penetrating geochemistry+Reverse Circulation/Diamond drill-ing verification.The granite intrusive rock+regional shear zone+high-gold anomaly area in the greenstone belt are favorable prospecting targets.关键词
地质特征/找矿预测/绿岩带金矿/造山型金矿/圭亚那地盾Key words
geological characteristics/prospecting prediction/greenstone gold deposits/orogenic gold de-posits/Guiana Shield分类
天文与地球科学引用本文复制引用
张俊杨,单思齐,傅其斌,刘洋树,吴炳生,王勤,刘晗,李永辉,祝新友..南美州圭亚那地盾北部奥罗拉金矿床地质特征及找矿预测[J].矿床地质,2025,44(2):365-388,24.基金项目
本文得到紫金矿业集团股份有限公司科技项目(编号:4201KY2023110002)资助 （编号:4201KY2023110002）
