Fluvial parent material
I thought alluvial (or fluvial) deposit has, or can have, stratification as size of deposited material depends on water velocity. The lab manual says "alluvial materials often have thick layers (strata) of different size material...", too. But I got a comment saying alluvium is not stratified to a question of the lab assignment 5 to which I answered "stratified - often has thick layers". Could you clarify which is correct -- alluvium is stratified or un-stratified? Thank you!
The comment I got on the lab assignment said: alluvium is "non-stratified with exception of when deposited on floodplain". Thanks.
Alluvial type of parent material is associated with several types of landforms such as as old streambeds, flood plains, deltas, fans, and levees. Depending in which of those landforms has alluvial material been deposited the thickens of the strata (or layers) will vary from couple of meters to several tenths of meters. Consequently, to see those thick layers one needs to undertake a very deep excavation. But when it comes to soil formation, only the top of those strata (layers) will actually have an impact on the soil that is formed on it.