Dear colleagues Apologies for Cross Posting The role of imperfections in mantle minerals to understand the origin of Earth's water EMU Medallist Lecture - Martha G. Pamato Dipartimento di Geoscienze, Università degli Studi di Padova, Padova, Italy Water is an essential ingredient for life and a ubiquitous component at the Earth's surface. Although it seems obvious to have water on Earth, its origin is still an unresolved mystery in Earth and planetary sciences. Yet, answering this question is fundamental to assessing the evolutionary history and modern structure of Earth and constrain the conditions for Earth-like planets to form. Comparing Earth's original deuterium-to-hydrogen ratio (D/H) with those of Solar System objects can constrain the provenance of water. However, this is a difficult task as Earth is an active planet and its D/H value might have significantly changed since its formation. To explain the origin of Earth's water, its primordial D/H ratio needs to be determined, and this can be achieved by finding a deep mantle reservoir that remained unaffected over geological time. Studying diamonds and their imperfections (related to the presence of H) may be the key as they are inert and robust time capsules resisting breakdown for over billions of years and can help elucidate whether H2O was already present in the deepest regions of our planet since its formation or whether it was transported to the Earth's interior at a later stage through subduction. This presentation will provide an overview of past and current findings on the role of imperfections in mantle minerals, with a focus on H in diamonds as a key to unravel the origin of Earth's water. The lecture will be held on April 11, 2025 at 2 p.m. GMT/3 p.m. CET on-line via Zoom. Please register in advance at registration Zoom link<https://zoom.us/meeting/register/2HklUD29TWmmTq6UixJXHw?fbclid=IwY2xjawJHwHRleHRuA2FlbQIxMAABHZc-BZ8IJcCWnmN-Qx3tbcLi08tPEgjhAkZBWbaBoOX9Vrq8Xkn-D9Gnng_aem_J0axeZJ4EI7mp7TrAWNkvQ#/registration> and you'll immediately receive a direct link to the meeting. Kevin Murphy Executive Director, Mineralogical Society of the UK and Ireland kevin@minersoc.org<mailto:kevin@minersoc.org>