Sub-critical Cracking Induced by Magmatism (SCIM)

Project overview

This project will quantify the impact of sub-critical cracking on rocks around magma intrusions. Our central hypothesis is that chemical reactions intrinsic to contact aureole metamorphic processes, driven by hydrothermal activity and elevated temperatures, will induce sub-critical cracking.

SCIM will deliver three translatable advances:

• development of an innovative experimental set-up that, unlike previous methods, allows high-temperature, fluid-saturated cracking of samples;
• the first systematic, quantitative appraisal of sub-critical (and critical) cracking microstructural and microchemical characteristics
• fracture models that better incorporate chemical and thermal controls on cracking.

SCIM will provide the knowledge and tools needed to build sub-critical cracking into volcano deformation models, geothermal prospecting, critical mineral/metal exploration, and beyond.

Approach

SCIM will innovatively blend microstructural and geochemical laboratory analyses of low- to high-temperature rock deformation experiments with numerical modelling and field-scale case studies.

Our four objectives will allow us to characterise indicators and effects of sub-critical cracking in realistic rock, fluid, and temperature conditions around intrusions.

Objectives:

1. Measure in the laboratory how different rocks crack in aureole conditions
2. Expand the parameter space and scale of objective 1 by developing novel numerical models that sub-critically crack rocks and rock masses in aureole conditions
3. Search for tell-tale markers of sub-critical cracking around exposed intrusions, guided by objectives 1 and 2
4. Quantify changes in rock strength and permeability due to sub-critical cracking in models and exposed aureoles.

The timeliness of SCIM follows emerging consensus that sub-critical cracking impacts rock strength and fluid flow (permeability) in many geological settings. We have assembled a unique team of expert investigators to advance this field of study into magmatic systems. Recent advances in drone photogrammetry, computing power, microanalytical techniques, and high-temperature experimental monitoring now make SCIM possible.

Work package integration and feedbacks in SCIM highlighting how we will achieve our four objectives.

Funding: Natural Environment Research Council (NERC) Pushing the Frontiers

For more details read the project proposal.