We went to Pinnacles NP, saw an interesting scene in our hike. There’s a hole and a foot print on the face of rock wall. Is it a fossil? Because it’s a vertical rock, and the foot print is going sideways. It certainly can’t be human, because of gravity. The size is too big for any local creatures. And the hole is even more fascinating.
I did some research: The hole is a weathered-out volcanic clast / erosional cavity in Pinnacles’ volcanic breccia. The “footprint” is the cavity to be. It may take tens of thousands of years to grow from footprint to a hole. At Pinnacles, this is most likely a weathering cavity in the volcanic rock, probably where a piece of the volcanic breccia was less resistant and eventually eroded away.
Pinnacles has lots of fascinating holes and cavities because erosion of its volcanic rocks is such a major part of how the park’s formations developed. The volcano at Pinnacles National Park erupted approximately 23 million years ago during the Miocene epoch.
Wow, I feel so much younger standing here. Time becomes touchable. A time capsule hidden in the mountain.