• Ancient Planar Cross Stratification

• Ancient Planar Cross Stratification

• Single set of cross strata in a planar bed

• Ancient Trough Cross Stratification (two faces of the same rock)

• Ancient Trough Cross Stratification

• Plan or Map View of Ancient Trough Cross Stratification

• Ancient Trough Cross Stratification

• Herringbone Cross Stratification

• Hummocky Cross Stratification

• Hummocky Cross Stratification

• Recent Alluval Deposits (Terrace at Redrock State Park, CA)

• Recent Alluval Deposits (Terrace at Redrock State Park, CA)

• Recent Fluvial Deposits (Alsek River, Alaska)

• Stratification due to bar migration.

• Same outcrop as above, but also showing channel fill deposits above the sandstones deposited by the bar.

• Quarry wall showing fluvial cross stratification, probably due to channel migration and bar accretion.

• Extension of the same quarry wall as above

• Climbing Dunes

• Ancient Dune Cross Stratification

• Cross Stratified Gravel

• Graded bedding with faint cross stratification deposited in a fluvial channel

• Cross stratification in a channel fill in a subaqueous turbidite fan

• Cross stratification in a channel fill in a subaqueous turbidite fan

The following photographs are of large-scale cross stratification that was deposited by the migration of giant dunes and/or large fluvial bars. Detailed analysis of the regional characteristics of these deposits would be required to distinguish between dune and bar deposition in many cases, and both might be present.

• Large Cross Stratification

• Large Cross Stratification

• Cross stratified sediment deposited by a migrating bar based on the abundance of more planar laminae that would be characteristic of a channel bottom.

• Different view of the bedform in the previous photo

The following photographs were taken by Jeff Mount during his Roy Shlemon Course in Applied Watershed Science class trip down the Copper River, Alaska and Yukon (see the Shlemon class web page). The river shown below was dammed by ice from the toe of a glacier, which created a very large lake. The ice dam broke catastrophically, producing a huge flood. The flood waters transported very large volumes of sediment in huge dunes. After normal river processes resumed, the river eroded into the flood deposits, exposing the cross stratification in these impressive dunes.

• Lake shoreline terraces from the lake

• Lake shoreline terraces from the lake and cross stratification in the river bank. This cross stratification may have been deposited by the flood waters.

• Remnants of giant dunes that migrated during the flood

• Large dune cross stratification and remnants of giant dunes

• Large dune cross stratification and remnants of giant dunes

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