Interpreting sedimentological facies.
The first year university geology classes are always taught: “The present is the key to the past”. A principle of the Uniformitarianism introduced by Charles Lyell. This tells us that we can observe what is happening now, assume that the rules of nature have not significantly changed through time, and apply the results of the observation to the geological record (the past) to deduce how these rocks have formed.
But, what if the sedimentological record is as complicated as this one here?
Here we have sediments being deposited by the river (fluvial - river channel), shed of the mountains (alluvial fans) and blown in by the wind (aeolian dunes). If this record was to be preserved, a geologist would have a difficult job trying to unravel what environment these sediments were formed in.
This is one of those things that make Geology different from the other sciences. One cannot just measure something and get a number which will define the geological environment. Geology requires trained and experienced eye to take good observation upon which one can build an interpretation.
… and is probably a reason why geologist always argue.
Herbert Harold Read once said:
“The best geologist is he who has seen the most rocks.” (Read, 1940)
