A mineralogical, geochemical and geochronological study of postorogenic carbonatites in the Eden Lake Complex, Northern Manitoba | Posted on:2010-04-17 | Degree:M.Sc | Type:Thesis | University:University of Manitoba (Canada) | Candidate:Elliott, Barrett Robertson | Full Text:PDF | GTID:2440390002485752 | Subject:Geology | Abstract/Summary: | | The first documented carbonatites in Manitoba occur as dykes and pods up to 15 meters in length and several meters in width at Eden Lake hosted in a post-orogenic syenitic complex within the Trans-Hudson Orogen. The carbonatites consist dominantly of calcite with lesser clinopyroxene, feldspar, apatite and titanite. Primary and xenocrystic clinopyroxene have distinct compositions, whereas xenocrystic feldspar has well-developed plagioclase and alanite rims The whole-rock major- and trace-element composition of the carbonatite is consistent with global averages for calcio-carbonatites. Stable-isotope compositions of calcite indicate an igneous origin; the low delta 13C ratios may reflect the influence of subducted sedimentary carbonate. A zircon age of 1815+/-8 Ma corresponds with the time of emplacement, whereas younger titanite ages reflect local thermal history.;Although field relations suggest a genetic link to the host syenites, whole-rock geochemical data is incompatible with immiscibility or crystal fractionation models, suggesting a discrete mantle source for the carbonatite. | Keywords/Search Tags: | Carbonatites | | Related items |
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