The Oredezh and Staritsa beds, cropping out in the Borschovo section, considerably differ in the grain-size of siliciclastic deposits, sedimentary structures and cross-bedding
Along this study, the presence either of: 1) peculiar cross-bedding
and large channels (up to 4 m thick) locally filled up with a single set of coarsegrained, cross-bedded sandstones and conglomerates, 2) cross-bedding
defined by long and thick couplets of different grain sizes and 3) ironstones, wrinkle structures (probably microbially-induced sedimentary structures, MISS) and vertebrate tracks, and their mutual relationships were proven as interesting examples, not described previously (3, ironstones, wrinkle and vertebrate tracks) or that can lead to sedimentary environment misinterpretation (1, large-scale, cross bedded sands).
No matter what mechanism one might invent for transporting sediment during the global Flood, including Austin's recently proposed submarine liquefied sediment gravity currents, (79) it should be realized that the absurdly high sediment transport rates needed to deposit a regional-scale layer such as the Coconino Sandstone in a matter of days will always be at odds with the slow water velocities and gradual sediment transport rates needed to form even the most basic cross-bedding
Zion National Park in Utah is famed for the swirling ridges in the stone known as cross-bedding
Whipps Kendall Nelson Kennedy Thompson Criterion Ledges Ledges Ledges Ledges Ledges Number of Measurements 23 14 28 18 20 Vector Mean 201 199 148 173 172 Vector Magnitude 22.28 14.31 27.22 16.73 19.75 Circular Standard Deviation 14.29 17.35 13.50 21.51 8.98 Rayleigh's p 0.0000 0.0000 0.0000 0.0000 0.0000 Note: Paleocurrent data is from cross-bedding
. Paleocurrent rose diagrams using a non-linear scale (Nemec 1988) are shown in Fig.
Schlieren exhibit layering similar to cross-bedding
and preserve ripple marks along their base.
Sedimentary struc tures (graded beds, cross-bedding
) indicate traction and downslope transport of sandy sediments (McCloy 1984).
The predominant sedimentary structure in this subunit of the section is tabular-planar cross-bedding
(up to 1 m thick), as well as trough cross-bedding
The oncolitic packstone facies (F1) is arranged in decimeter to meter thick massive beds (up to 2.40 m) with occasional and poorly-preserved large-scale cross-bedding
(paleocurrents towards the E-NE, Fig.
Thickness of the sandstone beds range from 4 to 200 cm; they are lenticular, showing pinch and swell morphology, hummocky cross-stratification, parallel lamination (Plate 1a), trough cross-bedding
, flute casts, load casts (Plate.1b) and longitudinal ridges.
According to Fernandes and Coimbra (1996), the Adamantina formation consists of a combination of very fine-grained sandstone and fine pink to brown silty mudstones, with brown intercalation; this is usual in massive stratification or plane parallel bedding, alternating with medium and small cross-bedding
. The unit often displays other hydrodynamic structures such as ripple marks, cross-lamination thrusting, features cutting and filling gaps with intraformal conglomerates with argillaceous silt intraclast grading features at the top.
is a feature in sedimentary rock in which strata include internal sets of layers that are inclined at an angle to the original horizontal bedding of the rock unit as a whole (Fig.