Public lecture: Hydrothermal fields from the Mid-Atlantic Ridge – The role of brecciate rocks in ore formation

By Isabel Costa (INCITE and IDL-FCUL)

Lucky Strike and Menez Gwen hydrothermal fields are located in the Mid-Atlantic Ridge (MAR), southwest of the Azores islands. In the areas surrounding the active sites, the alteration processes affecting basaltic rocks are prominent and form hydrothermal breccias by the circulation of low temperature hydrothermal fluids in diffuse vents. These breccias play an important role in the protection of subseafloor hydrothermal sulphide deposits by forming an impermeable cap due to the high content in siliceous material. Since the discovery and description of recent mineralized submarine hydrothermal deposits, comparison with ancient volcanic massive sulphide deposits is appropriate. Thus, the model for the formation of the Atlantic brecciated rocks can explain some of the processes taking place in the early phase of development of old deposits, where equivalent siliceous material is found in the hanging wall of the ore bodies.

Public lecture: Seafloor Mineral Resources

Public lecture: SEAFLOOR MINERAL RESOURCES by Prof. Vesselin Dekov

on 4th Dec., 2018, 6:00pm

@ ISE, USJ – Institute of Science and Environment of the University of Saint Joseph. Speakers´ Hall. Rua de Londres 106, Macau, China. 中國澳門倫敦街一零六號（環宇豪庭三樓）

Abstract

The lecture will discuss the main characteristics, types, mode of formation, occurrence and economic value of the major seafloor mineral resources. It will comment on the mineral potential of the continental margins and formation of marine placers, on the formation and possible mining of the polymetallic Mn-nodules at the abyssal plains, on the deposition of Co-rich Fe-Mn-crusts at the seamounts, and on the spectacular polymetallic hydrothermal sulphides precipitated at mid-ocean ridges, back-arc basins and volcanic arcs. The lecture is designed for students, researchers but also for non-professionals.