Paleopedology
Paleopedology (palaeopedology in the United Kingdom) is the discipline that studies soils of past geological eras, from quite recent (Quaternary) to the earliest periods of the Earth's history.
Paleopedology can be seen either as a branch of soil science (pedology) or of paleontology, since the methods it uses are in many ways a well-defined combination of the two disciplines.
Paleopedology's earliest developments arose from observations in Scotland circa 1795 whereby it was found that some soils in cliffs appeared to be remains of a former exposed land surface.
In 1892 Eugene W. Hilgard had related soil and climate in the United States in the same manner, and by the 1950s analysis of Quaternary stratigraphy to monitor recent environmental changes in the northern hemisphere had become firmly established.
This has allowed many developments in paleoecology and paleogeography to take place because soil chemistry can provide a good deal of evidence as to how life moved onto land during the Paleozoic era.
Patterns of root traces including their shape and size, is good evidence for the vegetation type the former soil supported.
Chemical analysis of soil fossils generally focuses on their lime content, which determines both their pH and how reactive they will be to dilute acids.
With the aid of X-ray diffraction, paleosols can now be classified into one of the 12 orders of soil taxonomy (Oxisols, Ultisols, Alfisols, Mollisols, Spodosols, Aridisols, Entisols, Inceptisols, Gelisols, Histosols, Vertisols and Andisols).
Paleopedology is an important scientific discipline for the understanding of the ecology and evolution of ancient ecosystems, both on Earth and the emerging field of exoplanet research, or astropedology.
[2] Soils can be thought of as open systems in that they represent a boundary between the Earth and the atmosphere where materials are transported and are changed.
Soils can also be considered to be energy transformers in that they are physical structures of material that are modified by naturally occurring processes.
The Sun constitutes the primary energy source for soils and significantly outweighs any heat generated by radioactive decay flowing up from deep within the Earth's crust.
The deposition of sediment, or the addition of groundwater or rain, can also be considered an energy gain because new minerals and water can alter preexisting materials within the soil.
The large amount of influences that effect the formation of soils can be simplified to five main factors: climate, organisms, topographic relief, parent material, and time.
More importantly however, CLORPT allows for a theoretical framework when creating natural experiments for the study of soil formation.
One of the most large-scale influences regarding the classification of climate was created in 1918, then modified over two decades by the German meteorologist Vladimir Köppen.
However, qualifying these general effects of organism activity can be difficult because the level of their expression is as related to their nature as it is to the amount of time available for soil formation.
Whereas a bone, leaf, or stem might provide enough information to positively identify a particular species, trace fossils rarely allow for such a precise identification.
This advantage makes trace fossils in paleosols especially important because they allow for interpretation of the animal's behavior in its natural environment.
A great example of this is the simple shallow fossilized burrows of solitary bees that make their homes in soil.
For example, steep alpine slopes have sparse vegetation with soils that are eroded by snow melt, agitated by frost heave, and impacted by rock fall.
These processes create thin, shallowly rooted, lightly weathered and rocky soils that are indicative of a mountain slope environment.
The size and degree of these processes do not allow for strict analysis as topographic functions because of the extensive variation in climate, vegetation, parent materials, and land surface age at different elevations on a mountainside.
Other instances of sedimentary surface cementation, or fine interbedded sequences of clay and sand, could be considered to be not conducive to the formation of a soil.
