Hells Canyon, the Snake River, Idaho
As the river winds its way to the sea it carves through rock, carves through time. What better way to see evidence of the geological history of an area? The Columbia River and its tributaries have not always been located where they are today. Stream erosion and the cutting of the channels has been challenged and the rivers diverted into new channels by flows of lava that have repeatedly altered the landscape over the last fifteen million years. In this photo, spectacularly curved columns of the Pomona basalt, one of the more recent flows, mark an ancestral canyon of the Clearwater River that was filled with lava twelve million years ago. This intracanyon flow originated in Idaho and can be traced all the way to the coast of Washington, a distance of about 500 miles. Today the Sea Lion passed several exposures of this distinctive black lava flow and we marveled at the geometry of the basalt columns.
As the river winds its way to the sea it carves through rock, carves through time. What better way to see evidence of the geological history of an area? The Columbia River and its tributaries have not always been located where they are today. Stream erosion and the cutting of the channels has been challenged and the rivers diverted into new channels by flows of lava that have repeatedly altered the landscape over the last fifteen million years. In this photo, spectacularly curved columns of the Pomona basalt, one of the more recent flows, mark an ancestral canyon of the Clearwater River that was filled with lava twelve million years ago. This intracanyon flow originated in Idaho and can be traced all the way to the coast of Washington, a distance of about 500 miles. Today the Sea Lion passed several exposures of this distinctive black lava flow and we marveled at the geometry of the basalt columns.
