Waffle Rock - Reston, VA
Posted by: 
flyingmoose
N 38° 56.909 W 077° 22.152
18S E 294685 N 4313728
A mysterious Rock on display at the United States Geological Society.
Waymark Code: WM12MW2
Location: Virginia, United States
Date Posted: 06/17/2020
Views: 4
the sandstone layers that make up the rock were originally deposited about 300 to 250 million years ago. Then as the continent began to breakup by tectonic plate shifts, about 200 million years ago, the sandstone block was folded onto itself repeatedly creating cracks in the sandstone. In about another 100 million years, the cracks began to fill with iron oxide, leached from the surrounding rock by the percolating water. This iron oxide mixed with the sand grains in the cracks and formed a super hard material resistant to weathering compared to the surrounding sandstone pieces. As the sandstone rock eroded away, it left behind the hard iron-oxide waffle like pattern on the rock.
Type of Display: Geological
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