Research Group Geodynamics Projects

MAG-track investigates the physical and chemical processes that control rupture propagation toward the trench during megathrust earthquakes, with a particular focus on the 2011 Mw 9.1 Tohoku-Oki earthquake. The project explores how coseismic frictional heating may alter fault strength, rock structure, and mineralogy, potentially promoting shallow slip along plate boundary faults.

The project develops an innovative approach that uses magnetic minerals as tracers of deformation, frictional heating, and fluid-rock interaction within fault zones. Central to the study are fault rock samples recovered during International Ocean Discovery Program Expedition 405 “JTRACK” from Site C0019 at the Japan Trench, where evidence of large coseismic slip was documented. Changes in magnetic properties will be analysed to distinguish the effects of frictional heating, fluid circulation, stress, and strain localisation during megathrust faulting.

To better constrain these processes, undeformed sediment samples from Site C0026 on the Pacific Plate will be experimentally deformed under controlled laboratory conditions and compared with naturally deformed fault rocks. The project combines structural geology, rock magnetism, mineral magnetic methods, and experimental deformation studies to better understand how magnetic signatures record earthquake-related processes.

This project forms part of the PhD research of Tingting Du and is supervised by Prof. Derya Gürer and Prof. André Niemeijer at Utrecht University. The project is carried out in collaboration with Dr. Hanaya Okuda at Japan Agency for Marine-Earth Science and Technology and Prof. Dr. Dr. Andrew P. Roberts at Australian National University.

MAG-track also builds on Gürer’s participation in IODP Expedition 405 as a structural geologist, providing direct access to unique fault rock samples during the expedition moratorium period. The project benefits from the interdisciplinary research environment of the Geodynamics Group and the developing heiMAG Laboratory for Earth Magnetism at Heidelberg University, integrating tectonics, paleomagnetism, and marine geoscience approaches.

By linking fault mechanics, mineral transformations, and magnetic signals, MAG-track aims to provide new insights into frictional heating, fluid flow, and shallow rupture propagation during megathrust earthquakes, contributing to a broader understanding of subduction zone hazards and earthquake processes.

This research programme investigates how fluids interact with oceanic lithosphere during its evolution from ridge formation to subduction at convergent plate boundaries. By integrating structural geology, isotope geochemistry, petrology, stratigraphy, and marine geophysics, the project explores how carbonation and hydrothermal alteration processes are recorded within oceanic crust and volcanic plateaus across multiple spatial and temporal scales.

The project combines samples and datasets from multiple International Ocean Discovery Program expeditions, including Expedition 405 “JTRACK” at the Japan Trench and Expedition 392 “Agulhas Plateau Cretaceous Climate” in the Southern Ocean. Together, these expeditions provide a unique opportunity to investigate fluid-rock interaction and carbonate formation in oceanic lithosphere at different stages of tectonic evolution — from early crustal maturation and hydrothermal circulation to subduction-related processes.

At the Japan Trench, exceptionally well-preserved basalt- and dolerite-hosted carbonate veins recovered from Hole C0019P preserve evidence of early seawater-driven alteration within Pacific oceanic crust currently entering subduction. U–Pb geochronology and isotope geochemistry indicate that carbonation occurred shortly after crust formation during the Early Cretaceous, likely linked to off-axis hydrothermal circulation following ridge-axis magmatism.

Complementary work associated with Expedition 392 investigates carbonate formation, alteration, and fluid circulation within the Agulhas Plateau and related Large Igneous Province systems of the Southern Ocean. These studies explore how volcanic plateau emplacement, hydrothermal activity, and ocean chemistry interacted during major Cretaceous environmental and tectonic events, including Oceanic Anoxic Event 2.

The project integrates U–Pb geochronology, Sr isotope analyses, trace-element geochemistry, cathodoluminescence imaging, EBSD, and structural observations with downhole logging data and regional seismic reflection profiles. By linking microtextures, isotope signatures, radiometric ages, and geophysical observations, the research reconstructs fluid pathways, timing of alteration, and carbonate precipitation within oceanic lithosphere.

Overall, this work aims to better understand the long-term evolution of oceanic crust, the role of fluids in modifying lithospheric properties, and the significance of carbonate formation for carbon sequestration and material cycling through Earth’s tectonic system.