Gold deposit styles and placer gold characterisation in northern and east-central Madagascar
Microchemical characterisation of bedrock and placer gold grains from six gold districts within the Archaean domains and intervening Neoproterozoic Anaboriana-Manampotsy belt of northern and east-central Madagascar show few opaque inclusions (e.g pyrrhotite, Bi tellurides) but wide range of Ag contents (40wt%). Some districts exhibit multiple source populations of grains. The ‘greenstone belt’ terranes have an orogenic gold signature locally with an intrusion-related to epithermal overprint. Proterozoic metasediments with felsic to ultramafic bodies yield dominantly intrusion-related gold. A high proportion of secondary gold (<0.5wt% Ag) is related to recycling of paleoplacers and erosion of post-Gondwana planation surfaces and indicates that some mesothermal gold systems were already partially to wholly removed by erosion by the PermoTriassic.
Citation Information
Publication Year | 2009 |
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Title | Gold deposit styles and placer gold characterisation in northern and east-central Madagascar |
Authors | Peter E. J Pitfield, Michael T. Styles, Cliff D. Taylor, Roger M. Key, Bauer, A Ralison |
Publication Type | Conference Paper |
Publication Subtype | Conference Paper |
Index ID | 70156818 |
Record Source | USGS Publications Warehouse |
USGS Organization | Central Mineral and Environmental Resources Science Center |