PeAt bog Records of Atmospheric Dust fluxes: Holocene palaeoenvironmental and palaeoclimatic implications for Southern South America – PARAD

Five main tasks:
1/ Peat coring and sub-sampling bogs in Tierra del Fuego
2/ Determining natural atmospheric dust sources and dynamics in during the Holocene using elemental and isotopic geochemistry in peat sequences and actual dust samples
3/ Determining botanical changes using peat macrofossils
4/ Establishing high restolution chronologies in peat sequences using radiocarbon dating
5/ characterizing dust particles using grain size analyser, SEM mineralogy and Itrax core scanner

To be expected for Fall 2012

Extend our understanding of South hemistpheric dust cycles and source as well as climate reconstructions and models by extending this research to other areas (Australia, South Atlantic Islands, etc.)

F. De Vleeschouwer and G. Le Roux will chair a session about peatlands and lakes as dynamic geochemical ecosystems (see session description here: www.vmgoldschmidt.org/2012/t12.htm)

F. DE VLEESCHOUWER, H. VANNESTE, S. BERTRAND, A. CORONATO, D. GAIERO, G. LE ROUX AND THE PARAD TEAM. Peat bog Records of Atmospheric Dust fluxes - Holocene palaeoenvironmental and paleoclimatic implications for South America. Goldschmidt Conference, June 2012. Abstract + poster.

Although peat bogs have been abundantly used to monitor past atmospheric pollution, less attention has been given to pre-anthropogenic signals, especially in the Southern Hemisphere. Yet they are important to 1/ better understand the different particle sources during the Holocene, and 2/ to tackle the linkage between atmospheric dust loads and climate change. The main objectives of PARAD are therefore: 1) to provide high-resolution continuous records of natural atmospheric dust using the elemental and isotopic signature of peat cores in South America, and 2) to assess the linkage between dust inputs and climate.
State-of-the-art analytical technologies will allow us to explore the use of a broad range of trace elements as dust proxies (soil particles, volcanism, cosmogenic dusts, marine aerosols). Radiogenic isotopes (Pb, Nd, Hf) will be used as tracers for fingerprinting predominant sources. Coupling these findings with biological proxies (plant macrofossils) and detailed age-depth modeling, we expect not only to identify and interpret new links between atmospheric dust chemistry and climate change but also to significantly improve our understanding of peat bogs as archives of climate change, and the role of dust in both palaeoenvironmental and palaeoclimatic changes. Our investigations will help in assessing: 1/ the global vs. local character of each peat record; 2/ the spatio-temporal variation of pre-anthropogenic atmospheric dust geochemical pattern and fluxes during the Holocene at a centennial resolution and 3/ the possible link between dust load and source patterns with climatic fluctuations. The excellent analytical platform of OMP (Observatoire Midi Pyrénées) and the growing scientific excellence of EcoLab-BIOGEOCHIM laboratory will ensure ideal conditions to develop this project. Moreover, the numerous collaborations of EcoLab and PI F. DE VLEESCHOUWER with various national and international laboratories will ensure a maximum multidisciplinarity and transverse collaborations.
Besides its main objectives, PARAD will bridge the gap between peat geochemists and paleoecologists and will feed three topics fitting well EcoLab and OMP topics: 1/ global change and adaptation of living organisms, 2/ land use and environmental changes (e.g. erosion) , and 3/ human impact on biodiversity.