Geologic map of the west-central Buffalo National River region, northern Arkansas

The influence of sandstone caprock material on bedrock channel steepness within a tectonically passive setting: Buffalo National River Basin, Arkansas, USA

“…The low strength and fissile nature of the shale facilitates landsliding that transports large boulders wasted from the outcropping sandstone down the hillslope and over large distances (hundreds of meters) into the channel. Landslide deposits that originate at the Bloyd Formation are common throughout the basin, and many of the larger deposits have been mapped [ Hudson and Turner , , , ]. The larger Bloyd clasts are abundant as lag deposits within the tributary channels that drain from the caprock (Figure a), and in some cases clasts are sufficiently large to dwarf the channel.…”

“…LSDTopotoolbox generates channels that are divided into evenly spaced nodes, each node containing values for elevation, position, drainage area, and channel steepness. Each node was associated with a lithology by spatially joining nodes with geologic polygons available from United States Geological Survey geological maps [ Hudson and Turner , , , ].…”

“…The Ozarks Plateau region consists of a cratonic dome with a Precambrian core that is surrounded by an uplifted and subsequently dissected sequence of Paleozoic strata that gently dip away from the center of the dome [ McFarland , ; Guiccione , ]. The gently dipping stratigraphy (∼2 to 12°) consists of Ordovician to Pennsylvanian transgression and regression sequences, dominantly composed of limestone, sandstone, dolostone, and shale [ Hudson and Turner , ]. The Ozark Plateau region is typically divided into four physiographic regions, the St. Francois Mountains at the core of the dome; the Salem Plateau, which is mostly underlain by Ordovician dolomite; the Springfield Plateau, which is underlain by Mississipian‐age cherty limestone; and the Boston Mountain Plateau, which is underlain by Pennsylvanian sandstones and shales.…”

“…The Bloyd Formation caprock becomes sparse to absent in the lower reaches of the basin, and the Boone Formation dominates the plateau surfaces, so tributaries in the lower Buffalo River Basin do not incise through the Bloyd sandstone. Where the Bloyd sandstone caprock forms thick bluffs, large boulders of the unit are found on the hillslopes and in the channels below the cliffs [ Hudson and Turner , , ]. Because a large number of channels of various drainage areas incise through the same stratigraphic units, the basin provides an ideal location to study the changes in channel steepness as channels transition through lithologies with variable mechanical strengths.…”

Geologic map of the Murray Quadrangle, Newton County, Arkansas

“…Along cross section B-B', throw of the Boone Formation-Batesville Sandstone contact across Henson Creek fault is about 100 ft with lowering of an additional 150 ft by folding that mostly affects the downthrown southeastern block of the fault. The Henson Creek fault is interpreted to continue northward to merge with the southern end of the N.55°E.-trending Carlton fault (Hudson and Turner, 2014a), although poor bedrock exposure in the Panther Creek drainage within the Jasper 7.5-minute quadrangle obscures this connection. To the south, the Henson Creek fault terminates into the Keys Gap monocline that continues southwestward, aligning with parts of the Little Buffalo River valley in the center of the quadrangle and continuing along Thomas Creek in the south.…”