Diagenetic alteration of a Mesozoic fluvial gold placer deposit, southern New Zealand

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• 作者：Gemma Kerr ; Kirstine Malloch ; Kat Lilly ; Dave Craw ; ^{dave.craw@otago.ac.nz}
• 关键词：Alluvial ; Gold ; Clay ; Smectite ; Authigenic ; Groundwater
• 刊名：Ore Geology Reviews
• 出版年：2017
• 出版时间：April 2017
• 年：2017
• 卷：83
• 期：Complete
• 页码：14-29
• 全文大小：9698 K
• 卷排序：83

文摘

Diagenesis of terrestrial sediments causes geochemical and mineralogical transformations of detrital gold and host rocks. Mesozoic paleoplacers in New Zealand have undergone extensive diagenesis under low redox conditions and high pH. Detrital gold rims have recrystallised to micron scale grains with lowered Ag contents (1–3 wt%). Alteration of sedimentary clasts contributes to cementation by calcite, pyrite, clays, gold, and vivianite. Diagenetic effects increase with age, and Mesozoic-Archean paleoplacers are well-lithified, affecting mine processing.