Siletz River Volcanics, Volcanic rock formation in Oregon Coast Range, United States.
The Siletz River Volcanics is a rock formation in the Oregon Coast Range created by underwater volcanic activity long ago. The basalt contains small cavities throughout its structure, which became filled with minerals over time.
This rock formation formed when the area was underwater, between roughly 58 to 51 million years ago. Scientists began studying these layers in the late 1800s to understand how marine volcanic activity created them.
The formation spans across nine Oregon counties, providing researchers with opportunities to study ancient marine volcanic processes.
Visitors can view this rock formation at several locations along the Oregon coast, though some places are more accessible than others. It helps to check which areas are open and what gear you might need before going.
The rocks contain shells and bones from ancient sea creatures, showing that this area was once an ocean floor. These remains give clues about what lived in these ancient waters.
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