The Himalaya is one region of the world where tectonic and climate interact dramatically. Since the India-Asia collision, the exhumation of the Himalayas has interacted with the Asian monsoon to generate one of the most intense erosion fluxes on Earth. If tectonic clearly forces the monsoon, it acts in turn on the mountain chain structure by controlling the intensity and distribution of erosion. Himalayan erosion finally contributes to the global reduction in atmospheric CO2 pressure responsible for the Oligocene glaciation. However, the direct sedimentary records of these processes during the Neogene are essentially unexplored or limited and inadequate for quantitative approaches. This project builds on IODP Expedition 354 which cored at transect at 8°N in the Bengal Fan. Through a multidisciplinary approach combining synthesis of seismic stratigraphy and architecture of the Bengal Fan, geochronology and geochemistry, this project is designed to quantify Himalayan erosion fluxes during Neogene and Quaternary.

Continental atmospheric relative humidity is a key-climate parameter poorly captured by global climate models. A model-data comparison approach, applicable beyond the instrumental period, is essential to progress on this issue. However, there is a lack of past humidity proxies. The first objective of the HUMI-17 project is to combine expertise from LSCE and CEREGE in triple oxygen isotopic measurements to develop a new proxy of past relative humidity in continental areas, namely the triple oxygen isotopic composition of plant silica (phytoliths). Calibration of the proxy requires determination of the triple oxygen isotopic fractionations in play in the water cycle at the soil/plant/atmosphere interface. For that purpose, we will benefit from the unparalleled capacity of environmental conditioning and online measurements in growth chambers offered by the CNRS Ecotron facility. Relative humidity, temperature, pCO2 and day/night alternation will vary independently. Then, special attention will be paid to scale up the proxy and the water cycle monitoring from the growth chamber to the natural environment using the equipped outdoor sites of the O3HP and of the AMMA-CATCH national observation service. Additionally, impact of vegetation sources and of taphonomy on the 17O-excess of phytoliths will be investigated using plants, soils and surface sediment samples collected along current gradients of climate and vegetation. The second objective of HUMI-17 is to foster our knowledge of the interactions between climate (including humidity) and vegetation during pre-anthropic periods. For that purpose, we will produce three local records of past changes in atmospheric humidity and vegetation that will be compared to multi-proxy reconstructions already available and to downscaled outputs of coupled climate-vegetation models. Additionally, we will use the triple isotopic composition of atmospheric oxygen (O2) to reconstruct past changes in biosphere productivity at the global scale. The O2 cycle is directly linked to the water cycle and evolution of global productivity is a key parameter when studying past changes in the global water cycle. We will take advantage of the Ecotron growth chamber experiment to quantify, at the soil/plant/atmosphere interface, the successive fractionations leading to the ?17O of atmospheric O2. Then a coupled model-data approach will be used to produce an update estimation of the biosphere productivity during the last climatic cycle. Records of ?17O of O2 measured in ice cores are available for that purpose. The HUMI-17 project is based on an already existing collaboration between CEREGE/IMBE, LSCE and Ecotron to which will be added HSM (for AMMA-CATCH), the Department of Earth Sciences (Western University, Canada) and The Rosenstiel School of Marine and Atmospheric Science (University of Miami, USA). Our research will be structured around the following tasks: 1) growth chamber calibrations, 2) field calibrations, and 3) past climate and vegetation changes reconstructions. The amount of aid claimed to the ANR is 531k€ (for 4 years).

The ANR MEDSALT project aims to consolidate and expand a scientific network recently formed with the purpose to use scientific drilling to address the causes, timing, emplacement mechanisms and consequences of the largest and most recent 'salt giant' on Earth: the late Miocene (Messinian) salt deposit in the Mediterranean basin. After obtaining the endorsement of the International Ocean Discovery Program (IODP) on a Multiplatform Drilling Proposal (umbrella proposal) in early 2015, the network is planning to submit a site-specific drilling proposal to drill a transect of holes with the R/V Joides Resolution in the evaporite-bearing southern margin of the Balearic promontory in the Western Mediterranean - the aim is to submit the full proposal before the IODP dealine of April 1st 2017, following the submission of a pre-proposal on October 1st 2015. Four key issues will be addressed: 1) What are the causes, timing and emplacement mechanisms of the Mediterranean salt giant ? 2) What are the factors responsible for early salt deformation and fluid flow across and out of the halite layer ? 3) Do salt giants promote the development of a phylogenetically diverse and exceptionally active deep biosphere ? 4) What are the mechanisms underlying the spectacular vertical motions inside basins and their margins ? Our nascent scientific network will consit of a core group of 22 scientists from 10 countries (7 European + USA + Japan + Israel) of which three french scientists (G. Aloisi, J. Lofi and M. Rabineau) play a leading role as PIs of Mediterranean drilling proposals developed within our initiative. Support to this core group will be provided by a supplementary group of 21 scientists that will provide critical knowledge in key areas of our project. The ANR MEDSALT network will finance key actions that include: organising a 43 participants workshops to strengthen and consolidate the Mediterranean drilling community, supporting the participation of network scientists to seismic well site-survey cruises, organising meetings in smaller groups to work on site survey data and finance trips to the US to defend our drilling proposal in front of the IODP Environmental Protection and Safety Panel (EPSP). The MEDSALT drilling initiative will impact the understanding of issues as diverse as submarine geohazards, sub-salt hydrocarbon reservoirs and life in the deep subsurface. This is a unique opportunity for the French scientific community to play a leading role, next to our international partners, in tackling one of the most intellectually challenging open problems in the history of our planet.