Mangrove forests are geosystems and ecosystems generated by rapid deposition of sediments on the coast in tropical and subtropical areas. Our scientists are studying the rapid clay mineral transformations taking place in these dynamic environments.
Mangrove sediments form near the mouths of rivers, where abundant land sediments and organic matter are deposited in areas protected from tides and high-energy waves. These sediments are rapidly colonised first by plants and then mangrove trees.
The sediments in tropical areas are usually rich in kaolinite and iron oxides, both of which accumulate in newly formed mangrove forests.
Mangrove environments are powerful mineral reactors, with some of the fastest sedimentary mineral transformations on the planet.
Mineral reactions are triggered by a combination of factors:
As a result:
Mangrove forests are very active sedimentary environments where the original minerals are quickly transformed. This is in contrast to most other sedimentary environments, which are typically passive.
The study of these dynamic environments provides a view of the reactions at different stages, allowing us to investigate the mechanisms that produce them.
We are studying mineral transformations in eight mangrove forests along the Brazilian coast, where the composition of sediments and water regimes vary.
Cretaceous rocks from central Spain contain clay minerals intriguingly similar to those found in present-day Brazilian mangrove forests. These include kaolinite, iron oxides and iron-rich clay, which appear to have been deposited in a coastal environment.
Learning to read the mangrove signature in ancient rocks can help us to define past climates and environments, because:
This project is funded by the Sao Paulo State Research Foundation and the Brazilian Research Agency.
Dr Javier Cuadros
Economic and Environmental Earth Sciences Division
Natural History Museum
+44 (0)20 7942 5543
A clay mineral containing Si and Al, typical of tropical soils.
A clay mineral containing Si, Al, Mg, Fe, Na and Ca. Common in temperate soils.