Oblique transported phosphate nodule in bioclastic shale subunit of Lake Neosho Shale
The arrow points to an oblate phosphate nodule in the
that lies edgewise to the bedding. At the I-170 outcrop oblate nodules
also occur in the phosphatic shale subunit in the Lake Neosho Shale,
where they are oriented with the long axis parallel to bedding. These
nodules in the bioclastic shale were clearly eroded from the phosphatic
shale and deposited in new orientations in the bioclastic shale subunit.
This is a highly weathered portion of the I-170 outcrop,
water has dissolved minerals from certain lithologies and introduced
them into other lithologies, producing this kaleidoscope of colors. The
pronounced color change near the middle of the photograph marks the
contact between the bioclastic shale and underlying phosphatic shale.
Due to permeability differences, minerals became concentrated along
that contact, producing a distinct line analogous the iron oxide stained
layer at the base of the Mulberry Member.
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