Soil water and groundwater Chemical weathering

Water falling to the surface of continents in any form of precipitation, upon striking the surface, undergoes major modifications both in mode of transport and chemical composition. Infiltration is the flow of water from the ground surface into the ground. Once infiltrated, the water becomes soil moisture or groundwater. 

In the cryosphere, precipitated snow undergoes transformation into ice layers. Drilling of so-called ice-cores gives us insights into the chemical composition of the palaeoatmosphere. Ice cores have been taken from many locations around the world, especially in Greenland and Antarctica. In January 1998, the collaborative ice-drilling project between Russia, the United States and France at the Russian Vostok station in East Antarctica yielded the deepest ice core ever recovered, reaching a depth of 3623 m. Preliminary data indicates the Vostok ice-core record ex- 

In the biosphere, rain that is not lost back to the atmosphere by evaporation from the ground or from trees may pass deep underground, only to emerge at a much later date (Table 2.27) in a river or lake. Water coming into contact with rocks (and derived soils) reacts with primary minerals contained in them. The minerals dissolve to varying extents, and some of the dissolved constituents react with one another to form new, secondary minerals. Dissolution is mainly controlled by the water acidity provided from plant mineralization (humic acids), atmospheric carbonic acid and acid rain . The overall process is called chemical weathering (see Chapter 2.2.2.5, Eqs. 2.62 and 2.62 Berner and Berner 1996). 

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