Chapter 3 Genesis of Volcanic Ash Soils

摘要: Publisher Summary Volcanic ash or tephra is commonly unconsolidated, comminuted materials containing a large quantity of volcanic glass which shows the least resistance to chemical weathering. Therefore, tephras weather rapidly resulting in formation amounts noncrystalline materials. This process occurring preferentially was first called “andosolizatiod" by Duchaufour. Development A horizons andosolization characterized accumulation organic matter, matter stabilization active Al and Fe, carbonic acid weathering (allophanic) versus (nonallophanic), andformation laminar opaline silica. Formation B proceeds primarily with no significant translocation Al, dissolved carbon. preferential such as allophane, imogolite, silica, ferrihydrite, Al/Fe humus complexes characteristic feature andosolization. Such not specific Andisols. It also widely observed for tephra-derived Spodosols making it difficult separate Andisols according solid-phase criteria. can form relatively short time under most climates throughout world.