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Salts in the Earth's early ocean
We all know that today ocean waters are very salty. Two things help scientists figure out what salt may have been part of the Earth's early oceans. Since there are very little sedimentary rocks
of ages older than 2.5 billion years (see geologic time
) that means either
- 1.) there must have been mostly igneous rocks at the beginning of time
- 2.) maybe the Earth was covered with water everywhere such that change of igneous to sedimentary rock took a long time (turbulent action in rivers and streams is required to break igneous rock apart).
Anyway, since igneous rocks are made of mostly of iron and aluminum, those were the only rocks around, and these rocks are easily destroyed by acids
in an environment with no oxygen such as that of the early Earth, the waste products of erosion by acid
, namely chlorine and iron from the rocks and the acid, had no where to go but into the ocean. Thus the early ocean was full of chrorine and iron.
What induced a change into this environment was the introduction of free oxygen due to the activity of early life. Free oxygen is an agent of change, ready to attack other molecules and react with them. In the early ocean environment, oxygen from life attacked iron from erosion.
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