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Pacific Coastal & Marine Science Center

Bedform Sedimentology Site: “Bedforms and Cross-Bedding in Animation”

Cross-Bedding, Bedforms, and Paleocurrents

Dip plots, static images, and captions

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Dip plot; see caption below.
Static image of cross-section; see caption below.

FIG. 36.  Structure formed by bedforms with pseudorandom plan-form geometry.

RECOGNITION: These bedforms have crestlines that are in phase at some locations and out of phase at others.  The resulting structures have a more random appearance and have characteristics of both in-phase and out-of-phase bedforms (Figs. 32 and 34). The polar plot is indistinguishable from those of bed- forms with crestlines that are exactly out of phase (FIG. 34).

ORIGIN: This kind of geometry may be more common than the more regular three-dimensional geometries emphasized in this publication (Figs. 32 and 34, in particular).  Figure 37 shows a real example. Irmen and Vondra (2000) described eolian sandstones that they inferred were deposited by dunes with similar geometry.


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