Pangaea supercontinent rifting apart
At one point in time, all continents were merged together as one supercontinent.
This supercontinent “Pangaea” (sometimes spelled Pangea) eventually tore apart from continental rift. But it took millions of years to do this.
So how do we know that Pangaea existed?
There were several clues that led to the discovery of the Pangea supercontinent.
For example, we can connect the pieces today and see how remarkably well they fit. Also, we can examine the fossils we find today on each continent and check for resemblances.
The first clue was how the continents fit like a jigsaw puzzle
Like a jigsaw puzzle, the Earth’s crust has 15 or 20 separate pieces of minor and major plate tectonics. These pieces are the plate tectonics that ride on soft melted rock underneath.
All continents were together as a supercontinent (Pangaea). Over time, these continents have broken apart and moved apart through continental drift.
But it wasn’t until We started exploring beneath the oceans until we realized the vast chains of mount on the ocean sea floor. These ridges and trenches are scars from opening up of plates at ridges.
It was the first piece of evidence that continents are embedded in something bigger. In fact, they are being pulled and dragged like they are on giant conveyor belts.
Now, we know they were once together because it’s not only that continents fit together, but the same types of rocks are on the west coast of Africa and the east coast of South America.
Using fossil evidence to prove continental drift
After the mass extinction of dinosaurs, geologists have dug up fossils from around the world. They’ve kept a thorough record documenting the species and location.
Geologists found two very interesting facts:
- The first thing geologists found was that some dinosaurs were better suited for water, air and land. During the era of dinosaurs, pterodactyls preyed upon fish from the sky. But the lystrosaurus was a herbivore and ate small plants on land.
- The second thing geologists uncovered was the distribution of fossils on land. For instance, they found lystrosaurus fossils in India, Africa and Antarctica.
So how can land herbivores exist on separate continents?
What did the fossil evidence show?
We know that land herbivores couldn’t fly. Nor we’re they capable of swimming.
The reason is because Earth existed as one giant supercontinent Pangaea. But over time, the land masses separated apart into the 7 continents and 5 oceans that we see today.
Now we know that plate tectonics was the mechanism that tore continents apart.
Because of the fossil evidence, we know the Mesozoic Era experienced significant continental rift.
Fossils only come from sedimentary rocks
Sedimentary rocks are the only type of rocks that may contain fossils. If you see a rock with a fossil, you can automatically assume that it is a sedimentary rock.
These are the rocks that can incorporate bones, shells and exoskeletons from living organisms such as shells which are compacted sea creatures.