Thermodynamic

Modelling and

MT anomalies

National MT Workshop andAusLAMP South Australia

Klaus Regenauer-Lieb

And Team

UNSW, Sydney

Illuminating AusLAMP: Thermodynamics inversion for mineral systems project plan (LP170100233)

Unconventional Geomechanics is physics

based data assimilation in space and time Time – SpaceAusLAMP

Linkage Project

LP170100233

Linkage Project

LP170100233

When there are lots of Fluids in the ductile realm strange things happen

Weinberg, R. F., and K. Regenauer-Lieb

(2010), Ductile fractures and magma

migration from source, Geology, 38(4),

363-366, doi:10.1130/G30482.1.

Weinberg, R., M. Veveakis, and K. Regenauer-Lieb (2015),

Compaction bands and melt segregation from migmatites,

Geology, 43(6), 471-474, doi:10.1130/G36562.1.

Can deep fluids sources be imaged by MT?

Conductors at depth sign of Deep Fluids ?

How do fluids flow through solid granites?

Granite sample

Permeability: Local Porosity theory

• 1.3 micron resolution CT scan

Fusseis et al. 2009 (Nature)

Just at percolation

threshold enables flow

Deep fluid transfer in shear zones

drive mineral forming processes

Dissolution Precipation of K-feldspar in mid-crustal granite mylonites

Luca Menegon, Giorgio Pennacchioni, Richard Spiess (2008)

Northern Flinders Ranges

Low resistivity proxy for fluid dissolution-precipitation reactions triggering dynamic permeable networks?

Why do the anomalies pond at the brittle ductile transition

Open Questions

But how can we model fluid transfer?

Sommer, K. Regenauer-Lieb, B. Gasharova, H. Jung, The

formation of volcanic centers at the Colorado Plateau in the

western United States. Journal of Geodynamics 61, 154-171 (2012).

The effect of material damage can be incorporated in a far from equilibrium Thermodynamics approach

No Equilibrium

Thermodynamics 1. The macroscopic kinetic energy of the

whole system is constant ✔

2. No exchange of matter takes place with

the outside world No

3. No work is done on the total system No

4. No heat flows out of the surroundings

into the system

1-D far from equilibrium shear zone Model

Chemical Shear Zones | Thomas Poulet11 |

• Normalised and reduced system of equations

• Dimensionless Groups:

Lewis number 𝐿𝑒

Gruntfestnumber 𝐺𝑟

heat diffusion

mass diffusionLe

𝜕Δ𝑃

𝜕𝑡=

𝜕

𝜕𝑧

1

𝐿𝑒

𝜕Δ𝑃

𝜕𝑧+

Λ

𝑚𝜎′𝑛

𝜕𝑇

𝜕𝑡+ 𝜇𝑟 1 − 𝜙 1 − 𝑠 𝑒

−𝐴𝑟𝑐 𝛿𝑇1+𝛿𝑇

𝜕T

𝜕𝑡=

𝜕𝑇

𝜕𝑧2+ 𝐺𝑟 𝑒

−𝛼Δ𝑃+𝐴𝑟𝑚𝛿𝑇1+𝛿𝑇 − 𝐷𝑎 1 − 𝜙 1 − 𝑠 𝑒

−𝐴𝑟𝑐 𝛿𝑇1+𝛿𝑇

Damköhlernumber 𝐷𝑎

Arrhenius number 𝐴𝑟𝑐

Mathematical system

𝐷𝑎 =𝑑𝑖𝑓𝑓𝑢𝑠𝑖𝑜𝑛 𝑜𝑓 𝑚𝑎𝑠𝑠

𝑐ℎ𝑒𝑚𝑖𝑐𝑎𝑙 𝑟𝑒𝑎𝑐𝑡𝑖𝑜𝑛 𝑟𝑎𝑡𝑒

𝐺𝑟 =ℎ𝑒𝑎𝑡 𝑑𝑖𝑓𝑓𝑢𝑠𝑖𝑜𝑛

ℎ𝑒𝑎𝑡 𝑝𝑟𝑜𝑑𝑢𝑐𝑡𝑖𝑜𝑛

Da, Le and Gr define critical time scales for instabilities

Alevizos, S., T. Poulet, S. Walsh, T. M. Durdez, M.

Veveakis, and K. Regenauer-Lieb (2017), The dynamics

of multiscale, multiphysics faults: part II-episodic stick-

slip can turn the jelly sandwich into a crème brûlée,

Tectonophysics.

Episodic Tremor and Slip

THE OSCILLATOR

A.Creeping shear post-failure

B.Shear Heating in creeping chemical process zone

C.Chemical reaction/ decomposition of the skeleton (excess pore pressure)

D.Reverse chemical reaction

Poulet, T., E. Veveakis, K. Regenauer-Lieb, and D. A. Yuen (2014), Thermo-Poro-Mechanics of chemically active creeping faults. 3: The role of Serpentinite in Episodic Tremor and Slip sequences, and transition to chaos, Journal of Geophysical Research: Solid Earth, 119(6), 4606–4625 doi:10.1002/2014JB011004.

Cascadia Episodic Tremor and Slip ETS

THCM effects in rocks | E. Veveakis

Rogers, 2003

Brudzinski, 2007

Nonvolcanic tremor is observed in close association with geodetically observedslow-slip events in subduction zones.

Predicted Serpentinite oscillator

THCM effects in rocks | E. Veveakis

Predicted: Serpentinite oscillator solid line (2003/2004 perturbation of GPS station)

Observed: Blue dots GPS data

Does cyclical deep fluid release provide a key to understanding Earth surface instabilities?

A fundamental thermo-chemo-mechanical oscillator characterized by shear heating, fluid release, fast slip and slow backward reaction in carbonates, serpentinites, sediments and granites.

The oscillator can explain episodic ductile localization in large thrust systems (Glarus) Episodic Tremor and Slip in Subduction Zones (Cascadia, Hikurangi Trench), buckling of the interior of the Australian continent (Musgrave, Arunta) and creep fractures in the Geodynamics Deep Geothermal Well in Australia Cooper Basin .

We propose it as a universal mechanism connecting geodynamic and seismological time-scales

Shelly and Hardebeck 2010

Far from equilibrium model 2 or 3-DUsing simplification from high-T material sciences: damage mechanics

Creep Fractures are well known in Ceramics

The test checks the creep fracture strength of samples ranging from sizes smaller than a matchstick down to samples of diameter 100mm.

Early stage

creep fracture

Creep fractures in Ceramics

A. C. F. Cocks and M. F.

Ashby, progress in

materials science, 1982,

Vol. 27, pp. 189 to 244

Incre

asin

g s

train

Micro-

pores/cracks

on grain

boundaries

fibre pullout

SiC-SiCf Ceramic

Matrix Composite

1300º C

Integrating the Oscillator over time allows 2D/3D modeling, here granitic composition

400-500∘C Redbank shear zone creep

fractures, dissolution-precipitation traces

Regenauer-Lieb et al. 2009

Numerical model of the shear zone

with chemical reactions

Veveakis et al. 2013

Temperature

pre

ssure

etime

Sandiford et al. 2004, Quigley et al. 2010

Compression atextremely low strain rates

<10-16 s-1

CollisionHot Granite

under

strong

compression

Geodynamic Driver for creep fractures

Deep

Well

The Clean Base LoadEnergy Dream

Example Geothermal

Reservoir

“GEODYNAMICS”

PROJECT

In Australia

Hydrogen Embrittlement

Ruptured through 7 m concrete

How can we understand deep permeability?

Televiewer image of a

permeable zone @

~250°C4.5 km depth

Is permeability triggered

by dissolution

precipitation reactions?

Fluid

pathway

Courtesy of

Geodynamics

Creep damage

Cooper Basin pilot

2012

unpublished

5

10

15

km

Modelled

cross

section

230° C cut off

Model versus Observations

images courtesy of Geodynamics Ltd

First fracture at 4134m No fracture at

top ~of granite

Key Observations

• Fractures only exist and can be stimulated for

temperatures > 230° C

• Fractures do not propagate into the sediments

• In excess of 35 MPa fluid overpressure

• Fluid equilibrated within pegmatitic granite

Conclusion: Fractures appear to be generated by a mineral dissolution reaction driven by geodynamic work

<4,100 m depth

Far from Equilibrium Buckling problem

Are Conductors at depth sign of Deep Fluids ?

Granite sample

2D

model

Buckling

Austral

ia

By creep

fractur

e

500 Myrs compression of Australia

1Regenauer-Lieb, K., M. Veveakis, T. Poulet, and Ali Karrech (2015), Multiscale, Multiphysics

Geomechanics for Geodynamics applied to Buckling Instabilities in the Middle of the Australian Craton, Philosophical Magazine, 95(28-30), 3055-3077.

Conductors delineate the mechanism of buckling

UNSW Team: Dynamic Modelling of MT-Anomalies in the Crust • Flinders Case• Gawler Case• Northern Territory (Cloncurry case study)

Macquarie Team: 3D Probabilistic Inversion for the Entire Model,• End of Q2 2019 1D Inversion Australia wide• End Q1 2020 3D Inversion on a case study (TISA)

Where to go from here? January 2019 – July 2020

CONTACT: Prof. Klaus Regenauer-Lieb

UNSW Minerals and Energy Resources Engineering

Research Chair and Discipline Leader Petroleum Engineering

UNSW SYDNEY NSW 2052 AUSTRALIA

E: klaus@unsw.edu.au