This is a 20 x 20 cm boulder surface directly in front of panel 4. This is a good example of Schnebly Hill Sandstone with a major flat surface fracture zone in which the fracture area was filled with multiple layers of clay sized to medium grained clastic fracture fill material. The total fracture fill zone is several millimeters thick with most layers being less than 1 mm. Directly between the native sandstone (light brown) and the fracture fill (beige/tan) is a very thin zone of iron enriched sandstone (dark brown) that is hypothesized to have been created deep within the earch prior to exposure of the rocks at the surface. Any aquifer fluids moving thru the sandstone would have been trapped at the surface of the fracture fill which is less permeable slowing fluid movement and allowing precipitation of the iron. The sandstone itself is not significantly patinated implying that it was exposed fairly recently by erosion by exfoliation of the fracture filling material.
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