Dover fault line – a scar from the collision of ancient continents

Dover town, also known as the town with a fault, bears a ‘scar’ – the fault line formed as a result of the collision between two ancient continents, Gondwana and Laurentia.

In an earlier post, I described the continental collisions that made Newfoundland. To summarise what happened – about 540 million years ago, a large ocean called Iapetus Ocean separated eastern and western regions of Newfoundland. The eastern region at that time, was part of the ancient continent of Gondwana, and the western regions were part of the ancient continent of Laurentia. Gondwana had the land which is now Africa and Europe and the current N American continent was part of Laurentia. Due to movements of the crust of the earth, the Iapetus Ocean started closing. And Gondwana and Laurentia collided into each other around 410 million years ago.

When the continents collided, the rocks in Gondwana were squeezed against the rocks that formed Iapetus Ocean floor. A new mountain range called the Appalachian Mountains were formed. Collision also caused significant stresses in the crust, leading to development of fractures and fault lines to relieve these stresses.  The Dover fault line is one such fault, that developed when Gondwana and Laurentia collided.

The two continents then welded and remained together for another 200 million years. Then, around 200 million years ago, the continents again separated. The split this time was at a line further away from the line of collision, thus leaving parts of Gondwana in Newfoundland.

Thus, the Dover fault line is the geological scar or remnant of a major continental collision that happened about 410 million years ago. It is about 200 to 500 m wide and runs across the island between Dover Bay on the northeast coast of the island and Hermitage Bay on the southern coast, as can be seen in the picture. It forms the boundary for the rocks that were once part of current N Africa and or Europe with the ocean floor rocks that formed the Appalachian Mountains. East of the Dover fault is the Avalon zone (Avalon, Burin and Bonavista Peninsulas of Newfoundland) containing the rocks from the ancient Africa/Europe. To the west is the Gander zone containing the Appalachian rocks.

We drove for about 4hrs from St. Johns to reach Dover Town. The look out point to see the fault, is a gentle climb for about 15 min from the car park in the Interpretation Centre and Museum. The fault line itself is not visible from the look out, but it was fascinating to see the landscape on either side of the Dover fault line – one side originating from ancient Gondwana (remaining parts currently in Africa and Europe) and the other side originating in ancient America.

Exhibits in the museum in the Interpretation Centre are useful in understanding this major event in the history of our planet. The display of different rocks and their origins was interesting

Dover town itself is charming rural coastal town. The view of the bays and the land from the lookout is magnificent.  On either side of the well-maintained path were blue berry and other bushes bearing large numbers of fruits.  And people picking the fruits.

The drive to Dover had beautiful landscapes, with magnificent rocks, trees and wildflowers. The road signs to Dover, and to the Interpretation Centre are not very helpful and so reaching there depends on GPS directions.

A bomber crashed near the trail to the look out point in 1942 during World War 2. The wreckage is still there.