MONOPOL
(Indian MONsOon PaleO-variabiLity) (2012-2016) and DIPOMOUSS (2023-2024)
Funding: ANR (2012–2016) / IFREMER (2023–2024)
Project leader: F. Bassinot (LSCE)
Co-leader of the MONOPOL project: L. Beaufort (CEREGE)
Partner laboratories:
CEREGE (CNRS–Aix-Marseille University)
EPOC (CNRS–University of Bordeaux I)
GEOPS (University of Paris-Saclay, Paris-Sud Orsay campus)
IPGP (University of Paris-Diderot)
MNHN (Paris)
Tongji University (Shanghai)
China University of Geosciences (Beijing)
Peking University (Beijing)
The Indo-Asian monsoon is a major climatic phenomenon due to its economic and societal impact on one of the most densely populated regions on the planet, and due to the scale of the heat and moisture transfers involved, which make it a key component of the planet’s global climate. However, the natural variability of the Indo-Asian monsoon remains poorly understood, and its future evolution is difficult to model due to the complexity of the processes and interactions at play (i.e. ocean dynamics, vegetation response, teleconnections with mid- and high-latitudes, monsoon/ENSO/IOD/ITF coupling) .
The MONOPOL and DIPOMOUSS projects aim to study water and sediments in the tropical Indian Ocean (eastern and central) in order to reconstruct the past variability of the Indo-Asian monsoon and its sensitivity to different types of forcing during the Quaternary. It is based on the analysis of water and sediment cores collected in 2012 during the MONOPOL oceanographic expedition (aboard the N/O Marion Dufresne II), and those to be collected in 2020 during the DIPOMOUSS oceanographic expedition using rosettes, CASQ and CALYPSO corers and an interface corer (multi-tube). It brings together six laboratories: CEREGE, EPOC, GEOPS, IPGP, LSCE and MNHN, and forms part of an international collaboration within the IGBP/PAGES – IMAGES (International Marine Global Changes Study).
In practical terms, the paleoceanographic and paleoclimatic reconstructions are based on a multi-tracer approach, comprising biological tracers (e.g. studies of calcareous nannofossil and pollen assemblages), sedimentary and geochemical tracers (e.g. Ti/Al, δ18O, Mg/Ca). Past changes in Himalayan weathering in relation to monsoon variations are established on the basis of the analysis of sedimentary tracers (clays, laser grain size analysis) and geochemical tracers (major and trace elements combined with Nd, Sr and Pb isotopes).
Our team focuses in particular on the Indian monsoon and its impact on the dynamics of i) Himalayan erosion and sediment transport to the ocean, as well as the distribution of Nd isotopes in the Bay of Bengal and their past evolution (impact of erosion); ii) surface waters and the depth of the thermocline/nutricline, which have a significant impact on primary producers (notably coccolithophores); and iii) subsurface and intermediate water hydrology on the scale of glacial-interglacial cycles.