Hells Canyon
How much time exists in the cliffs around us? How much is there and how much is missing? The cliffs of Hells Canyon contain rocks that can be aged at over 300 million years old and just a few thousand years young. We traveled through the Snake River canyon as it has cut its way down the many levels of geologic history to expose the roots of very old islands chains that once migrated across the proto Pacific Ocean on a crash course with the continent.
We enjoyed the comfort of a very powerful jetboat as we marveled at the sheer walls of granite, limestone, and basalt. The oldest rocks were the most jagged and the canyon the narrowest at the southern end of our trip. As we moved north after our turnaround the rocks became younger and younger. The largest gap in time was when we left the limestone ridges of the Hells Canyon National Recreation Area and reentered the flat lying basalt cliffs of the Columbia Plateau Basalts. This contact that we rode by in a few seconds represents a missing stage in geologic time of over 100 million years. Where did all the geologic history go? Was there 100 million years of rock there to be removed? The younger basalts that were erupted over the older material have been aged at about 12 million years (What is a few 100,000 years among friends). The pancake layering of the basalt flows could be seen along the river, their interfaces etched with temporary greenness. The youngest of the rocks seen were the water flood deposits from the glacial times just a few thousand years ago when the rivers of the area all ran with much greater volume and velocity than today.
The rocks were home to the occasional sighting of biological interest. Osprey, mule deer, rocky mountain big horn sheep, but the stars of the day were defiantly the grand geology of Hells Canyon.
How much time exists in the cliffs around us? How much is there and how much is missing? The cliffs of Hells Canyon contain rocks that can be aged at over 300 million years old and just a few thousand years young. We traveled through the Snake River canyon as it has cut its way down the many levels of geologic history to expose the roots of very old islands chains that once migrated across the proto Pacific Ocean on a crash course with the continent.
We enjoyed the comfort of a very powerful jetboat as we marveled at the sheer walls of granite, limestone, and basalt. The oldest rocks were the most jagged and the canyon the narrowest at the southern end of our trip. As we moved north after our turnaround the rocks became younger and younger. The largest gap in time was when we left the limestone ridges of the Hells Canyon National Recreation Area and reentered the flat lying basalt cliffs of the Columbia Plateau Basalts. This contact that we rode by in a few seconds represents a missing stage in geologic time of over 100 million years. Where did all the geologic history go? Was there 100 million years of rock there to be removed? The younger basalts that were erupted over the older material have been aged at about 12 million years (What is a few 100,000 years among friends). The pancake layering of the basalt flows could be seen along the river, their interfaces etched with temporary greenness. The youngest of the rocks seen were the water flood deposits from the glacial times just a few thousand years ago when the rivers of the area all ran with much greater volume and velocity than today.
The rocks were home to the occasional sighting of biological interest. Osprey, mule deer, rocky mountain big horn sheep, but the stars of the day were defiantly the grand geology of Hells Canyon.
