Unravelling hydrothermal alteration in basaltic ocean crust

Seafloor hydrothermal vents, also known as black chimneys (featured image; Copyright: Woods Hole Oceanographic Institution), produce valuable mineral resources through fluid-rock reactions beneath the seafloor – a process called hydrothermal alteration. On basaltic ocean crust, hydrothermally-altered regions are generally found to be less magnetic, which provides a way to detect seafloor hydrothermal vents. By collaborating with Prof. Chunhui Tao group from the Second Institute of Oceanography, we analyzed a large set of rock samples recovered from the Southwest Indian Ridge. Results were recently published in Geophysical Research Letters (Wang et al., 2020; https://doi.org/10.1029/2020GL087578) that discloses the detailed alteration pathway in hydrothermal vent hosting mid-ocean ridge.

Dr. Chang was awarded a Royal Society-Newton Advanced Fellowship

Dr. Chang was recently awarded a personal fellowship – a Newton Advanced Fellowship from the UK Royal Society. This fellowship provides funding support for Dr. Chang and his group for collaborating with Prof Richard Harrison group at the Department of Earth Sciences, Cambridge University, on a project entitled ‘A machine-learning approach to multiscale environmental magnetism’. This project will employ sets of cutting-edge nanoscale 2D/3D imaging techniques, machine-learning based data analyses, and computational modelling to develop new multiscale environmental magnetic analytical tools. The new tools will enable extracting key environmental signals from natural samples at an unprecedent level. Additional funding support for this project is provided by the National Natural Science Foundation of China (NSFC).

AGU 100 years

An exciting week at the 2019 American Geophysical Union (AGU) Fall meeting at San Francisco during the 100-years anniversary of AGU. Our team had a total of 7 presentations with two invited talks, covering research topics from new multi-domain theory to micromagnetic modelling of biogenic magnetite and to an improved understanding of sediment remanence acquisition, from new FORC protocols to Machine-Learning assisted image processing of magnetic mineral assemblages, from tracing abrupt environmental shifts during ancient global warming to hydrothermal circulation in the mid-ocean ridges.

Magnetosomes modelled

We modelled magnetosomes of various sizes and geometries in the full micro-magnetic model MERRILL. Our first preliminary results show very interesting phenomena such as super-vortex states for larger magnetosomes. We are also investigating the different switching modes of magnetosomes, such as coherent rotation, alternating rotation and vortex rotation.

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