Washington State has a very interesting geologic history as does the rest of the Pacific Northwest. What does not seem as a hot bed for volcanoes is, and has been for millions upon millions of years. This area has also seen it's fair share of earthquakes rattle and bring the area to a halt. In contrast, the land is also in a rebuilding state, as new mountains are springing up. Many different agents have gone into the sculpting of this state, and many more are continuing to act on it to bring another new shape to the land.
Geologic history of Washington stretches back more than a billion years and has survived through violent volcanic eruptions, large-scale earthquakes and even an Ice Age which gave the land much of it's current look. Around 1.2 billion years ago, the lands on Earth began to push together and plate tectonics created a giant continent known as Rodinia, which is Russian for "homeland." This was the dominant landmass of Earth for nearly 350 million years. Western North America used to lie next to what is now Australia and Antarctica. This world was a dark and hostile one, where the only life to exist was probably single-celled organisms. Oxygen in the atmosphere was only 5% of what it is today, and was lacking the protective ozone layer to shield it from harmful radiation. These are the conditions in which Washington formed under more than a billion years ago. A group of ancient sedimentary rocks had accumulated in a basin in the area of northwest North America. Theses rocks have been named "Belt Supergroup" after a town in Montana. The makeup of these rocks is siltstone and limestone. Some areas of Washington exhibit these belts very well, such as the eastern Okanogan highlands and most of the mountains in Glacier National Park. .
750 million years ago Rodinia began to break up, and it started to break apart in what is now east-central Washington. This split ran north to south, and it moved slowly at one inch a year, and it resembled the modern rift between Saudi Arabia and Northeast Africa.
