File:Paleosol (Cave Branch Member, Slade Formation, Upper Mississippian; Clack Mountain Road Outcrop, south of Morehead, Kentucky, USA) 25 (32416462308).jpg

Paleosol in the Mississippian of Kentucky, USA.

This outcrop is part of the Upper Mississippian Slade Formation in Kentucky. The unit was formerly known as the Newman Limestone ("They always change the names to protect the innocent!"). Slade Formation limestones are shallow ocean deposits. This section has numerous paleosol horizons (= ancient soils).

The clay-rich interval in the photo is a paleosol (= soil 9 of Ettensohn & Lierman, 1992). The paleosol continues to the base of the yellowish-brownish dolostone unit in the bottom third of the picture.

From Ettensohn & Lierman (1992): "Soil 9 includes parts of the Cave Branch Member and the uppermost 0.8 meters (2.5 feet) of the Mill Knob Member; it probably includes parts of all three horizons. The C horizon in this soil is represented by the upper 0.8 meters (2.5 feet) of Mill Knob dolomicrite and dolosiltite, which is melanized, brecciated, and exhibits nodular peds. In places it has been drastically thinned or is completely absent, having been completely altered to terra-rossa by dissolution. The overlying 3.1 meters (10 feet) of reddish-brown chunky claystones are included in the Cave Branch Member and represent a terra rossa or "weathered B" horizon. Solution-rounded clasts and "lenses" of dolosiltite throughout reflect the nature of the parent rock. Pseudo-anticlines, caliche thrusts, and downward-branching root casts are often defined by stress cutans or slickensides and are outlined by bluish-gray reduced clays reflecting gleization. Some of the pseudo-anticlines are 0.3 to 0.6 meters (1 to 2 feet) in amplitude and have periodicities of up to 9 meters (30 feet). The overlying 0.9 meters (3 feet) of dark-gray, chunky, claystone residuum contains finely disseminated organic matter and may represent the lower part of the A horizon. in fact, the dark-gray reduced nature of this part of the unit may be related to the presence of the organic matter. Although no rooting has been found here, in a similar Cave Branch deposit to the south, definite evidence of rooting was found."

Stratigraphy: Cave Branch Member over uppermost Mill Knob Member, Slade Formation, Upper Mississippian

Locality: roadcut next to the Clack Mountain Road-Route 519 intersection, south of Morehead, Kentucky, USA (vicinity of 38° 07’ 41.87” North latitude, 83° 24’ 47.04” West longitude)

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