Yi Huang

Doctoral / Post-doctoral researcher

THESIS SUBJECT

Studies of the Nd cycle and of past changes of the hydrology of intermediate- and deep-water masses in the South China Sea by using the Nd isotopic composition and trace elements concentrations analyzed on seawater, porewaters and foraminifera samples.

THESIS SUMMARY

The dissolved neodymium (Nd) isotope composition is a new proxy in paleoceanography to determine the origin of water masses in the ocean. However, the dissolved Nd cycle in the ocean is not yet well constrained and are still under debate. The South China Sea (SCS) is a key area to quantify the dissolved lithogenic Nd input to the Ocean and to reconstruct past changes of the hydrology of the western Pacific at high temporal resolution. It receives a huge quantity of suspended sediments (~700 million t/yr) from surrounding drainage basins responsible of high sediment accumulation rates in the northern SCS. Geochemical analyses (trace elements and εNd) will be investigated on sediment pore-water and seawater samples of the northern SCS (close to Gaoping and Penghu Canyons) to assess Nd lithogenic input and benthic flux from deep-sea sediments. These results will permit in turn to better understand the Nd budget of the SCS. Moreover, seawater and foraminifera samples collected along a N-S transect in the SCS will be analyzed to reconstruct present and past hydrological exchanges between the northern and the southern SCS as well between the SCS and the Philippines Sea since the last glacial period (last 25 kyr).

SUPERVISORS

Thesis supervisor : Christophe Colin (GEOPS, Université Paris-Saclay, France)

FUNDING

CSC (China Scholarship Council)