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Gold deposit styles and placer gold characterisation in northern and east-central Madagascar

August 20, 2009

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
Title Gold deposit styles and placer gold characterisation in northern and east-central Madagascar
DOI
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
Series Title
Series Number
Index ID 70156818
Record Source USGS Publications Warehouse
USGS Organization Central Mineral and Environmental Resources Science Center