INTRODUCTION

The Southern Province is a part of the Canadian Shield dating back to the Paleoproterozoic (about 2.4-1.7 billion years ago). It contains all of the sediments collected off of the coast of the Archean Superior Craton. The rocks of the Southern Province, and in particular, the Huronian Supergroup are of global significance because they are the best preserved Paleoproterozoic sedimentary succession anywhere in the world. They tell us about the conditions on the surface of the planet at a time when, otherwise, very little is known. From this succession, we can see evidence for dramatic fluctuations in climate from 'icehouse' conditions with severe glaciations, to hot and humid near 'tropical' conditions when vast rivers wore down the landscape. It also contains evidence for some of the earliest life known, and for the oxygenation of the Earth's atmosphere.

In some ways, the sedimentology and stratigraphy of the Southern province is most closely analogous to the West Antarctic Rift Basin: a low-lying area between two segments of Antarctica that are being pulled apart. Eventually, this rift basin might evolve into what's called a passive margin if separation continues and a new plate boundary is formed . Though glaciation in Antarctica in general started about 40 million years ago, the West Antarctic Rift Basin has not been ice covered the entire time. There have been periods of meltbacks when large river systems ran through the area, and times where the area has been submerged by the ocean.

The Southern Province is also a good place to learn about cross cutting relationships, which geologists use to figure out if one thing is older than another. A dike for example that cuts through a host rock has to have been formed after the host rock, not before. If that dike is folded, it means that folding happened after the intrusion of the dike. Early geologists working in this region devoted much energy to the determination of the order of events and used such cross cutting relationships to determine the history of this part of shield. It was in part through these observations that the patchwork nature of the Canadian Shield was recognized.

The Southern Province is also one of the most resource-rich parts of Georgian Bay. Precambrian quartzites (essentially a metamorphosed sandstone, similar in composition and hardness to chert), were quarried as early as 10,000 years ago by PaleoIndians making stone tools at Sheguiandah on northern Manitoulin Island. Slate was also used for tool-making. The sedimentary rocks of the Southern Province also host minerals like copper (at Bruce Mines), uranium (for example near Elliott Lake), and iron. The Sudbury Region, north of Georgian Bay hosts globally-important nickel, copper and iron deposits which were discovered in 1883 during construction of the Canadian Pacific Railway. These metals are concentrated here thanks to intense heat, fracturing, and hydrothermal activity that resulted during the collision of a giant meteorite, 10 km in diameter, about 1.85 billion years ago.

By the end of this lesson, you will be able to