Pete Tillman
Radiolarian Chert bluffs @ Estero Bluffs SP
Our favorite trail in the park goes right along the blufftops. Watch your step! You are looking north to Estero Head. The development below is the Abalone Farm and some very expensive houses.
It was a beautiful morning: sunny, bright, uncrowded, hardly any wind. Worth getting up early for!
en.wikipedia.org/wiki/Radiolarite will get you up to speed on the geology. This is a common rock-type around here: lower-plate rock scraped off the top of the descending Pacific slab. as it was forced under the North American plate. Thought to have originated in deep water far, far away....
The chert was used in the early days as road metal, and there are two old quarries on the hill above these bluffs. But the chert doesn't hold up well as gravel. Nowadays, crushed stone (various types of basalt) are used instead.
Radiolarian Chert bluffs @ Estero Bluffs SP
Our favorite trail in the park goes right along the blufftops. Watch your step! You are looking north to Estero Head. The development below is the Abalone Farm and some very expensive houses.
It was a beautiful morning: sunny, bright, uncrowded, hardly any wind. Worth getting up early for!
en.wikipedia.org/wiki/Radiolarite will get you up to speed on the geology. This is a common rock-type around here: lower-plate rock scraped off the top of the descending Pacific slab. as it was forced under the North American plate. Thought to have originated in deep water far, far away....
The chert was used in the early days as road metal, and there are two old quarries on the hill above these bluffs. But the chert doesn't hold up well as gravel. Nowadays, crushed stone (various types of basalt) are used instead.