DEPOSITIONAL-ENVIRONMENTS OF THE EARLY PROTEROZOIC ESPANOLA FORMATION, ONTARIO, CANADA

The carbonate-rich Espanola Formation forms part of the Huronian Supergroup, deposited in Early Proterozoic time between about 2.5 and 2.1Ga ago. The Espanola Formation overlies glacigenic diamictites of the Bruce Formation and is gradationally overlain by fluvial sandstones of the Serpent Formation. Most carbonate is detrital in origin. Paleocurrents suggest a northerly source. The restricted nature of the basin, postglacial warming, and shallower marine conditions could have been factors in carbonate precipitation. -from Authors