Tin-bearing magnetite with nanoscale Mg-Si defects: Evidence for the early stages of mineralization in a skarn system

Frontiers in Earth Science

Earth Science

Benjamin P. Wade¹  Ashley D. Slattery¹  Kathy Ehrig²  Liam Courtney-Davies³  Cristiana L. Ciobanu⁴  Nigel J. Cook⁵  Jing Xu⁶  Liyuan Wang⁶ 

[1] Adelaide Microscopy, The University of Adelaide, Adelaide, SA, Australia;BHP Olympic Dam, Adelaide, SA, Australia;John de Laeter Centre, Curtin University, Perth, WA, Australia;School of Chemical Engineering and Advanced Materials, The University of Adelaide, Adelaide, SA, Australia;School of Civil, Environmental and Mining Engineering, The University of Adelaide, Adelaide, SA, Australia;Zijin School of Geology and Mining, Fuzhou University, Fuzhou, China;

关键词: magnetite;    HAADF STEM;    crystal structure;    skarn;    Dulong;    cassiterite;    humite group;   

DOI  :  10.3389/feart.2022.994153

 received in 2022-07-14, accepted in 2022-08-29,  发布年份 2023

来源: Frontiers

【 摘 要 】

Tin-bearing magnetite is reported from several types of magmatic-hydrothermal ore deposits. The question of whether tin is incorporated within solid solution, as Sn4+, or as nanoinclusions remains open, however. We report a micron- to nanoscale investigation of Sn (Mg, Si)-bearing magnetite from serpentinite in the Dulong Zn-Sn-In skarn, South China, with the dual aims of understanding the mechanisms involved in accommodating Sn and associated elements into the Fe-oxide, and the inferences that this carries for constraining the early stages of skarn formation. Magnetite preserves a range of textures that record the evolution of metasomatism during prograde growth of grain cores and retrograde rim replacement. Observations reveal the presence of chondrodite and sellaite (MgF2) as nanoscale inclusions preserved in magnetite. This implies initiation of the Dulong mineralizing system during a humite-bearing, magnesium skarn stage. Magnesium-Si defects, forming along (110) planes prior to Sn-enrichment, are recognized for the first time. Release of high volatile, F-rich fluids is interpreted to lead to precipitation of cassiterite inclusions along <111*> directions in magnetite.

【 授权许可】

Unknown   
Copyright © 2023 Xu, Ciobanu, Cook, Slattery, Ehrig, Wade, Courtney-Davies and Wang.