Thursday, December 28, 2017

Point Reyes Conglomerate

Outcrop of Point Reyes Conglomerate
Point Reyes Conglomerate is exposed on the Point Reyes peninsula. It can be found at the end of the Chimney Rock Trail around the overlook of Chimney Rock and the cliff arch. Next to the Lighthouse Visitor Center—at the other tip of the ocean-surrounded headlands—the conglomerate formation is exposed next to the lighthouse trail (shown above and below). There, on a display panel, and also on a web page it has been described with the following words [1,2]: 

The intriguing rock exposure in front of you is part of a formation that caps the highest hills in this area. The Point Reyes Conglomerate is a formation consisting of a sandy matrix embedded with pebbles, cobblestones, and boulders. Geologists estimate that the formation may be over 50 million years old.

Using less formal terminology, the conglomerate has been described as geologic cookie batter [3].

Features of exposed sandstone and Point Reyes Conglomerate

Watch out for similar conglomerate outcrops and sandstone features while taking a rest on your way down to or up from the lighthouse plateau.

 Lighthouse plateau downstairs

References  and related posts
[1] Point Reyes Lighthouse:
[2] Point Reyes Conglomerate:
[3]  Lighthouse, Point Reyes National Seashore, National Park Service, Marin Count:

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