Calcrete in Quaternary Coastal Dunes in Southwestern Australia: A Capillary-rise Phenomenon Associated with Plants

摘要: ABSTRACT Non-pedogenic calcrete is forming as a thin sheet (10-50 cm thick) just above the water table in subsurface of barrier dune terrain South Western Australia. The response to regional evapo-transpirative regime. annual rainfall high but short duration, and it infiltrates rapidly into sandy substrates. Relatively air temperatures evaporation coupled with wind stress combine produce vapor deficit across terrain. vegetation responds by drawing upon phreatic pellicular vadose zone, thereby precipitating CaCO3. Where plants are not water, developing at top zone capillary rise. Various structure types developed study area, namely rhizoconcretionary, mottled, massive, laminar forms; these occur definite stratigraphic sequence related maturity profile, cover, thickness zone. Rhizoconcretionary forms zone; mottled massive calcrete, frequently capped develop These latter form that ubiquitous parallel table. Since feature table, may potentially transect boundaries unconformities. At local level various structural he used paleowater indicators.