The History of Oxygen in Earth’s Atmosphere
In Earth’s atmosphere history, oxygen levels have changed significantly. This includes hydrogen, helium, carbon dioxide and nitrogen composition in the air.
Geology
Is Vaalbara Earth’s First Supercontinent?
The evidence that Vaalbara (2.7-3.6 billion years ago) was the first supercontinent is mainly based on their sedimentary sequences and magnetic orientation.
Banded Iron Formation (BIF): How These Rocks Got Their Stripes
Long ago, oxygen filled the oceans. It mixed with iron which reacted by rusting. The seafloor collected rusted iron called banded iron formation (BIF).
Great Oxygenation Event: How Oxygen Filled the Atmosphere
Over 4 billion years ago, Earth’s atmosphere was mostly methane & nitrogen. The Great Oxygenation Event marks a time when free oxygen filled the atmosphere.
Pangea Fossils: Evidence of the Pangaea Supercontinent
At one point in time, all continents were merged together as one supercontinent “Pangea”. We’ve used fossil evidence to know continental drift exists.
Pacific Ring of Fire: Volcanoes, Earthquakes and Plate Tectonics
The Pacific Ring of Fire has the most active chains of volcanoes in the world. This is because tectonic plates collide and sink at these zones of subduction.
Divergent Plate Tectonics: Boundaries that Pull Apart
Beneath the oceans, lava erupts every day from mid-oceanic ridges. These divergent plate boundaries pull apart from each other creating new igneous rock.
North American Plate: Tectonic Boundary Map and Movements
The North American plate extends all the way over the North pole to Siberia. It also includes Greenland, Cuba, the Bahamas and part of the Atlantic Ocean.
How Was the Grand Canyon Formed?
Like a stack of pancakes, younger rock layers pile on top of older layers. We use the law of superposition to reveal Earth’s age and Grand Canyon geology.
The Cenozoic Era: From Dinosaur Extinction to Human Evolution
The Cenozoic Era started with the extinction of dinosaurs and moved into the age of mammals.This led to the diversification and increase in size of mammals.
Was the Late Heavy Bombardment a Violent Stage in Earth’s History?
At the end of the Hadean Eon, the Earth was in the late bombardment stage. Earth and the entire solar system was pelted by asteroids, comets and objects.
How Does the Supercontinent Cycle Work?
If you went 200 million years back in time, Earth was 1 supercontinent. Now, it’s made up of 7 separate continents. This is the supercontinent cycle at work.
What Is Pangaea? Piecing Together the Supercontinent Jigsaw Puzzle
About 200 million years ago, all the continents were together as one giant supercontinent known as Pangaea. Over time, these continents have broken apart.
Mass Wasting: Weathering, Erosion and Transport
From the remarkable process of plates colliding and building mountains. They are only to be dismantled by mass wasting (weathering, erosion and transport).
What is Radioactive Decay Inside Earth?
Four radioactive isotopes inside Earth account for 50% of its internal heat. Like a slow cooker, they slowly release heat within the planet keeping it warm.