Hawaii

The continuing process of lava eruption on the Hawaiian Big Island in 2002The Hawaiian Islands provide an ideal natural laboratory for the study of weathering processes. Lava of a rather similar initial composition have been continuously erupting for more than 5 million years. By studying weathering products on lavas of different ages, we can see the full progression of the weathering process and of soil formation

This picture shows the continuing process of lava eruption on the Big Island in 2002.



Cloud breaks over the leeward side of Kohala peninsulaThe climate on Hawaii also varies in a predictable way. The islands have significant relief and sit in the easterly trade winds. This means that the eastern side of each island experiences high rainfall as air is forced upwards, while the western side of each island sits in the rain shadow and is dry. The significant relief also means that temperatures vary � from warm tourist beaches on the coast, to permanent snow on the peaks. This predictable climate means that we can study, not only rocks of a wide range of ages, but also rocks which have been weathered in a wide range of climate environments.

This picture shows the large shield volcano which makes the island of Maui in the far distance. In the middle ground is an example of the rain shadow effect. The clear break in the clouds sits over the leeward side of Kohala peninsula. The two sides of this peninsula experience dramatically different rainfall as a consequence of this effect.



Water sampling of the Wailuku River on the Big IslandAt Oxford we are using Hawaii as a natural laboratory to study the role of weathering in the cycling of elements and isotopes. By measuring the primary rocks, the soils which form on them, and the rivers which drain from them, we are able to see how elements are released during weathering and what isotope fractionation occurs during this process. This work will provide better information about how important elements, such as those which act as nutrients, are released during weathering. It will also produce geochemical tools which can be used to assess the rate and style of weathering in the geological past.

This picture shows water sampling of the Wailuku River on the Big Island.