C. Sandstones rarely have cross-bed inclinations < 10° and >30°; but they are common in eolian dunes The results shown in Fig. 7 are consistent with the trends originally noted when comparing the Nebraska Sand Hills with the Coconino Sandstone (Fig. 3). Note that relatively low dips (<10°) and high dips (>30°) are uncommon in the sandstone data, but relatively common in the eolian dune data. Note that a full quartile of dune measurements (25th to 50th, 9-15° in the center plot of Fig. 6) falls below the lower quartile of the sandstone measurements (25th to 50th, 15-20°, bottom plot of Fig. 6). Note that half of the “dunes” measurements (center plot Fig. 6) fall below 15°, 10% fall below 6°, and 10% occur above 33°; whereas in sandstones only 10% of the measurements fall below 12° and only 10% are greater than 27°. Analyzed in another way, 25.5% of the eolian measurements are less than 10° while 17.3% of the measurements are greater than 30°. In sandstones, only 1.4% of the measurements are less than 10° while 3.0% of the measurements are greater than 30°. D. Sandstone cross-bed dips are similar to each other, despite set thicknesses Set thicknesses for beds and cross-beds have typically been defined as laminae (0-1 cm), very thin beds (1-3 cm), thin beds (3-10 cm), medium beds (10-30 cm), thick beds (30-100 cm), and very thick beds (>100 cm) (McKee and Weir 1953; Allen 1963; Boggs 2012). However, this classification scheme does not recognize size differences for cross-bed sets thicker than 1 meter. McKee and Bigarella frequently use the term “large” to describe thick sets of what Fig. 6. A comparison of 5,785 points collected from the means of modern dunes, 855 dip measurements from modern dunes, and 5,242 dip measurements from sandstone cross-beds plotted as box plots. Most of the discussion in this paper centers around the “dunes” and “sandstones” data. Note that 25.5% of the dune data are less than 10°, and 17.3% of the data are greater than 30°. On the other hand, only 1.4% of the sandstone data are less than 10° and only 3.0% are greater than 30°. WHITMORE Cross-bed inclinations 2023 ICC 602
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