Where your water goes

Rain that falls on Greater Sudbury ends up in the Atlantic Ocean

1. Your sub-basin

   Northern Lake Huron

2. then

   St. Lawrence River

3. It arrives here

   Atlantic Ocean

Everything that falls here works its way east and north to the Atlantic. It is the drainage that carried the fur trade inland and the log drives back out, and the one Atlantic salmon and American eel still use — the eel travelling the whole length of it to spawn in the Sargasso Sea.

Basin 02C (Canadian sub-drainage area)

Under your feet

Greater Sudbury sits on shale

About 2.5 billion years old — laid down before anything with a shell or a backbone existed.

All the kinds of rock, and how each one forms →

1. At the surface2.5 billion years oldNeither way

   Shale

   Huronian Supergroup (2.2 Ga to 2450 Ma); Elliot Lake Group; McKim Formation · Paleoproterozoic

   What it is

   Compressed clay and silt, laid down where the water was too quiet to move anything larger. The particles are flat and settle flat, which is why shale splits into sheets.

   How it wears

   Into chips, then into clay. It is weak, so it forms valleys and slumping banks rather than hills, and road cuts through it keep sliding.

   What it means above ground

   Heavy clay soil that holds water and drains badly. Shale is impermeable, so water runs off it rather than into it, and streams on shale rise and fall fast after rain.

2. Below, layer 22.5 billion years oldNeither way

   Shale

   Paleoproterozoic sedimentary rocks · Siderian

   What it is

   Compressed clay and silt, laid down where the water was too quiet to move anything larger. The particles are flat and settle flat, which is why shale splits into sheets.