Trace element constraints on the origin of the Baffin Bay lavas
The picritic volcanic suite of Baffin Island is comprised of two different types of magmas which are analogous to N and E-MORB. Although these two picritic lavas-types are spatially intermixed in the stratigraphic succession, they are distinct in terms of light rare earth elements (LREE), K/Ti and $...
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| Format: | Thesis |
| Language: | English |
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McGill University
1991
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| Online Access: | http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=60080 |
| Summary: | The picritic volcanic suite of Baffin Island is comprised of two different types of magmas which are analogous to N and E-MORB. Although these two picritic lavas-types are spatially intermixed in the stratigraphic succession, they are distinct in terms of light rare earth elements (LREE), K/Ti and $ sp{87}$Sr/$ sp{86}$Sr ratios. N-type lavas are depleted in LREE and have K/Ti ratio 0.5 and $ sp{87}$Sr/$ sp{86}$Sr ratios ranging between 0.7032 and 0.7039. Olivine fractionation and partial melting models involving a single homogeneous source can not reproduce the trace element differences between these two magma types. The generation of N and E-type magmas is most easily explained by small scale mantle heterogeneity. A possible model for the nature of the source is that of the head of a mantle plume which has an entrained depleted mantle. |
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