Alexander Slade

Walther's Law - a conformable, vertical sequence of facies will be the product of a series of depositional environments which lay laterally adjacent to each other.

Understanding Walther's law is one of the most powerful foundational tools within sedimentology. It is useful from the individual bed level to sequence level. Most, if not all, argument should have Walthers Law ever present inbetween the lines. Most, if not all, lessons in sedimentology will have this law at their core.

Odd transitions in stratigraphy that do not entirely conform to this law indicates: something interesting has happened, something to explained, something to pay careful attention to. The presence of an uncomformity is a good first hypothesis. So careful, methodical attention should be made at the contact point of what should be separate formations. However, if it is found to be conformable then more sophisticated analyses are needed.

Sedimentary basins hold a long record of changes in hydrodynamic activity. Most changes are steady state and represent changes in the relationship of accommodation space for the sediment and sources of denudation (erosion). Much can be said about the paleogeography of a basin from these records, especially when an outlier - as mentioned above - is identified. Which may indicate something significant at the tectonic scale.

My lessons will mostly concentrate in one of two directions - 1.) What does the small scale potentially indicate towards the larger scale? And 2.), viewing the problem from the large scale, what should we then expect at the small scale?


“…plate tectonics emphasizes horizontal movements of lithosphere, which induce vertical
movements due to changes in crustal thickness, thermal character and isostatic adjustment.
These vertical movements cause the formation of sedimentary basins, uplift of sediment source
areas, and reorganisation of dispersal paths.” - William Dickinson