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Originally calcitic crinoid stem (in cross-section) diagenetically replaced by marcasite in a siderite concretion; Lower Carboniferous.. The term diagenesis, literally meaning "across generation", [3] is extensively used in geology.
A soil scientist examining horizons within a soil profile. Soil science is the study of soil as a natural resource on the surface of the Earth including soil formation, classification and mapping; physical, chemical, biological, and fertility properties of soils; and these properties in relation to the use and management of soils.
Subsidence frequently causes major problems in karst terrains, where dissolution of limestone by fluid flow in the subsurface creates voids (i.e., caves).If the roof of a void becomes too weak, it can collapse and the overlying rock and earth will fall into the space, causing subsidence at the surface.
Soil formation, also known as pedogenesis, is the process of soil genesis as regulated by the effects of place, environment, and history. Biogeochemical processes act to both create and destroy order within soils.
The seed bank is one of the key factors for the persistence and density fluctuations of plant populations, especially for annual plants. [4] Perennial plants have vegetative propagules to facilitate forming new plants, migration into new ground, or reestablishment after being top-killed, which are analogous to seed bank in their persistence ability under disturbance.
This is an accepted version of this page This is the latest accepted revision, reviewed on 19 February 2025. Water located beneath the ground surface An illustration showing groundwater in aquifers (in blue) (1, 5 and 6) below the water table (4), and three different wells (7, 8 and 9) dug to reach it. Groundwater is the water present beneath Earth's surface in rock and soil pore spaces and in ...
In mammals, invertebrates and most fish, [1] [2] the anus (pl.: anuses or ani; from Latin, 'ring' or 'circle') is the external body orifice at the exit end of the digestive tract (), i.e. the opposite end from the mouth.
Traditionally, land drains were formed in clay soils and peats by excavating a trench and forming a "tunnel" using flat stones. This was very labour-intensive but could often be done using free materials at hand.