Geology for Rock Stars
The Bay of Fundy – “… a failed ocean”
“Lumbering mastodons once roamed its rolling hills, caribou herds grazed its grassy valleys and noisy flocks of water fowl crowded its vast fringes of salt marshes. Today cod and halibut roam its sunken hills and valleys and migrating whales sweep 60 meters over head.”
J.A. Percy 1
This is the Bay of Fundy – then and now – and this is the story of how the Bay of Fundy come to be.
The Early Years
Between 600 and 200 million years ago (mya) continental masses drifted together – squeezing out the original Atlantic Ocean to form the super-continent of Pangea. During this time (400 mya) the Appalachian mountain range formed, with peaks higher than the present Rockies. The region that included the Bay of Fundy was close to the centre of Pangea. Over time shallow seas formed and evaporated leaving behind deposits of salt, potash and gypsum. Erosion of the Appalachians left thick deposits that eventually cemented into rocks. Trapped within these deposits (360 mya) were plants of the time – eventually forming fossils and beds of coal.
The Middle Years
190 million years ago Pangea was wrenched apart by forces deep within the Earth. Rift valleys formed during this process.The Bay of Fundy is one of the rifts valleys. A major rift (the Mid Atlantic Ridge) kept separating and the Atlantic Ocean was formed. This process continues today with North America and Europe separating by several centimetres a year. The Bay of Fundy rift failed to separate further. It is a “failed ocean”. Volcanic and eroded material flowed into the basins. Isle Haute is an example of the volcanic basalt that hardened at this time.
The Recent Years
A number of ice ages occurred over the past two million years, with beds of ice up to two kilometres thick scouring the landscape. The last receded only 13000 years ago exposing the present form of the Bay of Fundy. At this time the Bay was a quiet water way – cut off from the Atlantic Ocean by Georges and Browns Banks. Caribou and mammoths grazed on the present Georges Banks. As the sea levels continued to rise, partly due to the melting ice, the Banks became flooded and the Bay was connected to the sea. The giant tides were born.
1 J.A. Percy – Fundy in Flux -The Challenge of Understanding Change in the Sea
Next page, see geological time scale.
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