Genesis of the Florida Canyon Nonsulfide Zn Ores (Northern Peru): New Insights Into the Supergene Mineralizing Events of the Bongará District

IF 5.5 1区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Economic Geology Pub Date : 2022-09-01 DOI:10.5382/econgeo.4941

Rita Chirico, N. Mondillo, M. Boni, M. Joachimski, M. Ambrosino, Y. Buret, A. Mormone, Luis Enrique Nazareno Beteta Leigh, Willy Huaman Flores, G. Balassone

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引用次数: 3

Abstract

The Florida Canyon Zn deposit in the Bongará Province of northern Peru consists of sulfide and nonsulfide mineralizations within dolomitized strata of the Triassic Chambará Formation, a member of the Triassic-Jurassic Pucará Group. The nonsulfide mineralization, which represents one third of the total resource, formed by supergene alteration of Mississippi Valley-type sulfide bodies. The nonsulfide assemblages occur in stratabound or fault-related, discordant zones that mimic the shapes of the former sulfide zones. Two nonsulfide facies can be distinguished: facies 1 – red zinc ores, which are characterized by smithsonite, or hemimorphite-dominant bodies that formed by direct replacement of primary sulfide assemblages, and facies 2 – white zinc ores, which are characterized by masses of colloform smithsonite formed by replacement of wall rock. The facies are distinct in bulk chemical composition and stable isotope geochemistry. Facies 1 shows high concentrations of Zn, Pb, Fe, Ge, Mn, and As, whereas facies 2 shows only high Zn and Cd concentrations. Enrichments in Ge, which have been reported in other Zn deposits of the Bongará Province, are associated with hemimorphite, Fe hydroxides, and remnant sphalerite in facies 1. The δ13C and δ18O signatures of smithsonite in both facies suggest that meteoric waters infiltrating the precursor sulfide bodies were affected by kinetic fractionation and originated from multiple sources at different altitude.

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佛罗里达峡谷非硫化锌矿(秘鲁北部)成因:对bongar地区表生成矿事件的新认识

位于秘鲁北部bongar省的佛罗里达峡谷锌矿床由三叠纪chambar组白云化地层中的硫化物和非硫化物矿化组成，该组属于三叠纪-侏罗纪pucar组。非硫化物矿化是由密西西比河谷型硫化物体表生蚀变形成的，占总资源量的三分之一。非硫化物组合出现在层控或与断层相关的不协调带中，这些不协调带模仿了以前硫化物带的形状。可区分出两种非硫化物相:相1为红色锌矿，其特征是由原生硫化物组合直接替代而形成的菱锌矿或半亚铁矿为主体;相2为白色锌矿，其特征是由围岩替代而形成的胶状菱锌矿团块。该相总体化学组成明显，同位素地球化学特征稳定。相1中Zn、Pb、Fe、Ge、Mn、As富集，相2中Zn、Cd富集。在bongar.com省的其他锌矿床中已报道的Ge富集与半亚铁、铁氢氧化物和1相残余闪锌矿有关。两相铁钼矿的δ13C和δ18O特征表明，渗入前驱硫化物体的大气水受动力学分馏作用的影响，来自不同海拔的多源。

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来源期刊

Economic Geology 地学-地球化学与地球物理

CiteScore

10.00

自引率

6.90%

发文量

120

审稿时长

6 months

期刊介绍： The journal, now published semi-quarterly, was first published in 1905 by the Economic Geology Publishing Company (PUBCO), a not-for-profit company established for the purpose of publishing a periodical devoted to economic geology. On the founding of SEG in 1920, a cooperative arrangement between PUBCO and SEG made the journal the official organ of the Society, and PUBCO agreed to carry the Society''s name on the front cover under the heading "Bulletin of the Society of Economic Geologists". PUBCO and SEG continued to operate as cooperating but separate entities until 2001, when the Board of Directors of PUBCO and the Council of SEG, by unanimous consent, approved a formal agreement of merger. The former activities of the PUBCO Board of Directors are now carried out by a Publications Board, a new self-governing unit within SEG.