Our study

Formation of
laterites in
intertropical soil


Our main studied area is the Guyana craton (Brazil, French Guiana, Suriname), but we have other targets in Brazil and Malawi (Africa)
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The RECA project gathers an international consortium made of skilled researchers in the identification of lateritic soils, dating methods, environmental mineralogy; isotope geochemistry, and modeling approaches of the formation of weathering profiles.
- Cécile Gautheron
The mission

Studying the soil in intertropical area


Laterites are deep weathering covers of the critical zone that occupy 80% of the total soil-mantle volume of the Earth’s landscape and significantly participate to the global geochemical budget of weathering and erosion, and greenhouse gas consumption. Some studies have already investigated the timing of their formation and evolution in response to climatic and geodynamic forcing, but important questions are still obscure.

The RECA++ project is addressing the topics of functioning and evolution of climate, oceans and major cycles and the continental surfaces evolution with the critical zone and biosphere evolution, by reconstructing the influence of climate change laterites formation. The RECA++ project is regrouping different French, Brazilian and European research academic groups and non-academic groups interested by those questions. The originality of the RECA++ project is to combine chronometric, weathering and climatic proxies developed in the recent years in order to build a comprehensive and predictive scenario of laterite formation and evolution.

We will concentrate our effort on geodynamically stable Guyana Shield (Brazil, Suriname, French Guiana) and Central Amazonia regions, where laterites formed through the whole Cenozoic and can be associated with major geomorphological units. However, other targets have been identified though time in Brazil and Malawi.

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the details

What do we do ?


Step 1

The primary objective is the understanding and predictive modelling of the evolution of the continental surface, especially laterites that are part of the critical zone. We study the laterite formation and evolution, in response to climatic and geodynamic forcings through a combination of mineralogical, chronometric and geochemical tools will be used to build a new integrated scenario of their laterite formation. By revealing the record of ancient formation conditions, we will trace and quantify weathering processes as a function of time.

Step 2

This ambitious multidisciplinary project also proposes, to understand the formation though time of various laterites of the Brazilian craton and in Malawi. The studied lateritic profiles will be dated using absolute dating methods to reveal the weathering episodes since at least 60 Ma. The geochemical analysis of the different profiles using conventional and non-conventional Li, Si and Fe isotopic methods will help to decipher the specific weathering conditions linked to the various stages of laterite formation.

Step 3

To achieve those goals, the RECA project gathers 5 French groups will have an expert role in the project, 2 non-academic partners with the French Geological Survey, and one energy company, 1 German group, and 2 Brazilian groups. The project now regroups additional laboratories that have joined the project since its starting allowing to name the project RECA++.
The team

Meet with the team !


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Research

More than 10 international laboratories are working in the RECA++ project

Management

The project is divides into 1 communication task and 5 scientific tasks

Teamwork

The RECA++ team meets every six months to exchange about the project results
critical zone

Geological targets


Our group working hypothesis of the project is that laterite profiles record the long-term evolution of both climate (temperature, rainfall) and rates of weathering/erosion processes. We are concentrating our effort on the Guyana Shield, Central Amazonia and Minas Gerais, where different lateritic sites have been identified according to their geomorphologic situation and their potential ancient age, i.e. up to a few tens or hundreds of million years. Another site in Namibia has also been investigated.
the info

Reca Laterite in one glance.


Researchers
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Locations
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Tropical area
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