Bubnoff unit

Bubnoff unit

The Bubnoff unit (abbreviated B) is a unit of speed equal to 1 m / 106 a. In other words, 1 B is equal to 1 meter in 1,000,000 years, 1 millimeter in 1,000 years, or one micrometer per year. The Bubnoff unit is employed in geology to measure rates of lowering of earth surfaces due to erosion. Erosion speed of 1 B also means that 1 m³ of earth is being removed from an area of 1 km² in 1 year (Kearey 2001).

Compared to everyday phenomena, erosion is under most circumstances (excluding rapid events like landslides) an extremely slow process, calling for such a specialized unit. For instance, the current average rate of erosion over Earth's landmasses has been estimated at 30 B (30 m in a million years). There are, however, great regional differences in erosion speed. As an extreme example the watershed area of the Semani River in Albania is eroding at a rate of almost 3000 B (3 millimeters per year), the river having been estimated to transport about 4600 tons of earth per year from the average square kilometer in its watershed (Hall 1993).

References

Hall, A. (1993) The Work of Rivers. In Duff, D. (ed.) "Holmes' Principles of Physical Geology", Chapman & Hall, London, 312-345.

Kearey, P. (2001) "The New Penguin Dictionary of Geology". Penguin, London, 336 pp.


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  • Bubnoff unit — (B)    a unit used in geology to measure erosion rates. One Bubnoff unit is equalto the removal of one micrometer per year (µm/a), or one millimeterper thousand years, or one meter per million years (m/Ma). First proposedin 1968, the unit is… …   Dictionary of units of measurement

  • Geologic time scale — This clock representation shows some of the major units of geological time and definitive events of Earth history. The Hadean eon represents the time before fossil record of life on Earth; its upper boundary is now regarded as 4.0 Ga.[1] Other… …   Wikipedia

  • B —    1. informal abbreviation for billion, generally meaning the American billion 109. This abbreviation is non metric: the metric abbreviation for 109 is G, standing for the prefix giga . The B form has been used in such units as Bcf (billion… …   Dictionary of units of measurement

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