Reverse stratigraphy

Reverse stratigraphy (sometimes known as inverted stratigraphy) is the result of a process whereby one sediment is unearthed by human or natural actions and moved elsewhere, whereby the latest material will be deposited on the bottom of the new sediment, and progressively earlier material will be deposited higher and higher in the stratigraphy.

In archeological excavations a common cause of inversions in the stratigraphy is the collapse of walls on river banks or other raised mounds where deposits which have been cut through behind the wall prior to collapse slip over the collapsed structure resulting in the structure being under the deposits that originated earlier in time.

In this case care must be taken to re-context the slipped deposits so the event of slippage appears in the correct place stratigraphically in the Harris matrix.

In these instances a clear understanding of the direction of "UP" and site formation processes is essential.

[1] Other human intervention, such as altering the ground level for architectural purposes by way of filling, can lead to an inversion of the stratigraphic layers.