Elizabeth Xu, MSc
E. Xu1, M.O. Anderson1, D. Summer1
1Department of Earth Science, University of Toronto, Toronto, ON, Canada
Metals are a crucial resource of the modern world used in all aspects of day-to-day life, from construction to technological innovation. Increasing demands on metal resources has led to increased mineral exploration on the seafloor in recent decades. Seafloor massive sulfides (SMS) are a potential source of base and precious metals including copper, zinc, lead, gold, and silver. These deposits have been found in extensional settings such as backarc basins or mid-ocean ridges (MOR) and were formed via the circulation of hydrothermal fluids in the oceanic crust. Volcanogenic massive sulfides (VMS) deposits are a significant host for base and precious metals, as well as trace amounts of other metals. SMS deposits are modern analogues of ancient VMS deposits which play a major role in Canada’s mining industry and economy. However, the timing of SMS deposition, whether it forms during nascent rifting or in mature stages of spreading, and relationship with volcanism remains unclear. This knowledge gap will be addressed by producing a remote-predictive structural and geologic map of the southern Vanuatu Coriolis Troughs —a nascent backarc rift that exceeds 100 km in length, 25 to 45 km in width, and exceeds 3 km in depth, mapped at a scale of 1:100,000.
As such, the objective of this study is to improve our understanding of structural and magmatic evolution of nascent backarc rifts in the Coriolis Troughs which will help to improve future exploration strategies. This process includes the compilation of ship-track bathymetry data and satellite altimetry data into an ArcGIS Pro workspace. For optimal visualization of structural features, hillshade and slope datasets— derived from bathymetry data, overlies the bathymetric data. Additionally, bathymetric data is reprocessed using “Terrain Texture Shading” (TTS) for three dimensional visualizations of subtle structural and surface features. Classification of geologic units are based on the completed structural map, seafloor morphology, and geophysical datasets, including vertical gravity gradient (VGG), Earth Magnetic Anomaly Grid (EMAG), and side-scan sonar data. In seismically active regions, shallow earthquake focal mechanism data, known as centroid moment tensors (CMTs), will be compared with the mapped lineament orientations to interpret fault kinematics, their stress regimes, and how geodynamic events control the formation and development of new structures. The mapping outcomes of this study will help us to better understand the timing of SMS deposition and how tectonic events and associated magmatism affect their formation.