Diagenesis (the Petrologic principle)

Diagenesis is the process that describes physical and chemical changes in sediments first caused by water-rock interactions, microbial activity, and compaction after their deposition. Increased pressure and temperature only start to play a role as sediments become…

Autochthon and allochthon

An autochthon in structural geology is a large block or mass of rock which is in the place of its original formation relative to its basement or foundation rock. It can be described as rooted to…

1911 EncyclopĂŠdia Britannica/Limonite

LIMONITE, or Brown Iron Ore, a natural ferric hydrate named from the Gr. λΔÎčΌώΜ (meadow), in allusion to its occurrence as “bog-ore” in meadows and marshes. It is never crystallized, but may have a…

Supergene (geology) and something called gossan cap

In ore deposit geology, supergene processes or enrichment are those that occur relatively near the surface as opposed to deep hypogene processes. Supergene processes include the predominance of meteoric water circulation (i.e. water derived from precipitation) with concomitant oxidation and chemical weathering. The…