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Paris, November 14, 2007

The Himalayas : a powerful CO2 pump

Young mountains in the tropics, such as the Himalayas, undergo intense erosion, which tends to reduce the amount of carbon dioxide in the atmosphere. On the basis of a geochemical assessment covering the entire Himalayan basin, from its source, the Himalayan formations, to the final area of sediment deposition in the Bay of Bengal (Indian Ocean), researchers at CNRS-INSU(1) have been able to quantify the processes at work  and get a better picture of their power.   In this way they showed that the high erosion rates in the Himalayas led to the transport of huge quantities of organic debris, which is carried down by the great rivers and then rapidly buried in the Indian Ocean. As a result of this process, carbon becomes stored in the natural geological reservoir formed by this ocean basin. These findings, which were published in the 15 November issue of Nature, illustrate the role of erosion in the carbon cycle and in long-term climate regulation. Over time scales of several tens of millions of years the erosion of mountain chains thus plays a role in cooling the climate.

Notes :

1) INSU: Institut National des Sciences de l'Univers (National Institute of Earth and Astronomical Sciences)

The Center for petrographic and geochemical research(CNRS-INSU / Nancy-Université), the 'Geology and resource management' laboratory (CNRS-INSU / Nancy-Université) and the Geology laboratory (Ecole normale supérieure de Paris / CNRS-INSU)contributed to the analysis of rocks and/or sediments. The oceanographic exploration campaigns in the Bay of Bengal were carried out by "The Federal institute for geosciences and natural resources" (BGR, Germany).

This research was carried out with the backing of two CNRS-INSU programs, Eclipse and Relief de la Terre.

Références :

Efficient organic carbon burial in the Bengal fan sustained by the Himalayan erosional system. Valier Galy, Christian France-Lanord, Olivier Beyssac, Pierre Faure, Hermann Kudrass & Fabien Palhol. Nature. 15 November 2007.

Contacts :

Christian France-Lanord
T 03 83 59 42 20

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Priscilla Dacher
T 01 44 96 46 06

Communication CNRS-INSU
Christiane Grappin
T 01 44 96 43 37


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