Manitoba carbonate dispersal analyses in till

In northern Manitoba, Paleozoic calcareous clasts were glacially dispersed westwards for distances up to 260 km beyond the limit of carbonate bedrock, within subglacial environments of reduced ice-bed coupling and fast ice flow. The dispersal pattern in the surface till reflects the interaction of Keewatin and Hudson-Labrador ice in the region during multiple glaciations. The Ca-rich till is not homogeneous, but exhibits spatially-variable dilution by entrainment of local to regionally sourced granitoid and greenstone belt clasts and recycled (inherited) low concentrations of other farther-travelled clasts (exotic Precambrian shield clasts and Dubawnt Supergroup erratics).

The data suggest that carbonate dispersal occurred prior to deglaciation, and that the maximum westward extent of Ca-rich tills has been subject to spatio-temporal overprinting (re-working) by Keewatin ice of northern and/or northeastern provenance.


Ongoing hand-contoured data analysis

Till-matrix total carbonate metadata, Manitoba (Microsoft® Excel® file)
Till-matrix clast metadata, Manitoba (Microsoft® Excel® file)


Calcareous pebbles in till matrix (<63 µm, mixed ct. % and wt. %)
Click image to enlarge

Calcareous pebbles in till matrix (<63 µm, mixed ct. % and wt. %); click image to enlarge


Total carbonate in till matrix (<63 µm)
Click image to enlarge

Total carbonate in till matrix (<63 µm); click image to enlarge


Relevant Manitoba literature

A note on data reliability:
This compilation is based on different types of geochemical analyses, incorporating data presented at various scales. The data points are hand-contoured, to provide a general picture of the dispersal pattern, and the contour patterns are likely incorrect where only a few data points exist.

back to top