Abstract

To assist in the interpretation of gravity anomalies in northern Manitoba and northeastern Saskatchewan, a part of the western Canadian Shield, the average densities of 2004 Precambrian rock samples, grouped according to rock type, are tabulated. Relatively positive anomalies may be expected over greenstone belts (2.85 g/cm3), sedimentary gneisses (2.79 g/cm3), granulites (2.73 g/cm3), and mafic to ultramafic intrusions—diorite (2.77 g/cm3), gabbro (3.00 g/cm3), and peridotite (3.19 g/cm3), whereas negative anomalies may be expected over granitic rocks (2.64 g/cm3). These results are consistent with results from other areas.The average composition of a slab of surface rock in this part of the western Canadian Shield is shown to be granodioritic with an average density of 2.67 g/cm3.

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