Lapworth Lecture - Seafloor Spreading in 3D

Seafloor spreading is a fundamental Earth process, responsible for creating about two-thirds of our planet’s crust. The large-scale tectonic and magmatic processes at spreading ridges have been recognised for decades, largely through geophysical investigations. To fully understand seafloor spreading, however, we need to connect these large-scale observations with detailed, interdisciplinary studies of oceanic crustal rocks at the grain-scale.

Of particular interest are rocks from the lower oceanic crust, where the key magmatic activity occurs during spreading. These can be accessed in two main ways: by retrieving samples from areas where tectonics has raised the lower crust to depths reachable by scientific ocean drilling, or by studying ophiolites — slices of oceanic lithosphere exposed on land after being thrust onto the continents.

In this talk, Antony will present results of magnetic analyses of deep oceanic crustal rocks collected from both settings and show how these data provide insights into the tectonic and magmatic processes at the heart of seafloor spreading. This includes recent work on the Oman ophiolite, where magnetic fabrics in lower crustal gabbros and overlying sheeted dykes reveal, for the first time, a complete 3D picture of magma flow along an entire fast spreading ridge segment.

This talk is available in-person and on Zoom.

Open to everyone and free to attend.

About Antony

Antony Morris is Professor of Geophysics and Geodynamics at the University of Plymouth. As a geophysicist he is interested in applying physical methods to look at plate tectonic and geodynamic processes. In addition, Antony uses field studies to examine the evidence for oceanic crustal processes preserved in ophiolites (slices of oceanic crustal and mantle rocks that are exposed on land). Antony has worked mainly in the eastern Mediterranean orogenic belt, but also has extensive experience of engagement with the International Ocean Discovery Program (that collects rock and sediment samples from the present-day ocean basins via scientific ocean drilling).