I graduated from the University of Liverpool in 2016 with a first class MeSci geology degree. My main interests lie in structural, geomechanics and sedimentological disciplines, for which I tailored my undergraduate modules toward.

During my 3rd year project I spent 7 weeks mapping in the Spanish Pyrenees looking at carbonate and clastic syn-tectonic sediments within a wedge top basin.

For my 4th year project I conducted a field based investigation of the facies controls on deformation band development within a mixed Aeolian-fluvial formation of the Sherwood sandstone group. Particularly the effect of grain size distribution on deformation band density and geometry within a fluvial end member unit. This put me in perfect stead to continue this research on a grander scale by undertaking a PhD at Keele.

Research and scholarship


Sedimentary controls on secondary processes: Deformation bands in reservoirs

Supervisors: Dr Ian Stimpson (Keele)

Dr Oliver Wakefield (BGS)


The type and distribution of lithofacies, borne of primary sedimentological processes, has a direct control on the physical properties of sediment bodies, and it is therefore unsurprising that facies distributions exert some control on the development and distribution of small-scale structures, such as deformation bands, which are the main deformation element of fault zones in porous sandstones [1].

The relationships between deformation bands and larger scale faults have been well documented [2] as have relationships to bulk lithology [3], but little attention has been given to controls on deformation band formation by depositional processes and facies directly. Preliminary field observations, by the present authors indicate that structural deformation bands occur preferentially within clean, aeolian sandstones, and less so in more immature (but good reservoir) fluvial facies subject to the same regional and local stresses. However, the structures and exact geometries that these deformation bands inhabit, and their relationships to lithofacies, are poorly understood.

This project undertakes a detailed field campaign using the well-exposed, mixed aeolian-fluvial Sherwood Sandstone Group (SSG) of the Cheshire Basin as a principal case study, with additional fieldwork in Utah, USA, using the Kayenta formation which provides a well-studied site for comparison. The SSG contains a full range of aeolian and fluvial facies types and, crucially, is well exposed in a range of outcrops that allow a three-dimensional insight. Its importance in the Cheshire basin is highlighted by continued research as an oil reservoir, with the Bowland shale as its source, as well as shale gas, an anologue to the East Irish sea and North Sea basins, and more recently has been highlighted for its potential as a low enthalpy geothermal resource [4].

Data collection will be used to create a detailed sedimentological framework that will establish the geometries and distribution of both aeolian and fluvial facies types. This framework will be used to construct models that detail i) the occurrences, geometries and connectedness of deformation bands, and, ii) porosity and permeability data of both deformation bands and lithofacies (using a field permeameter and lab analysis).

I will develop generic models of possible lithofacies control(s) on deformation bands, and deformation styles. Additionally, poro-perm data combined with detailed petrographic work will be used to identify potential impacts to reservoir quality in three-dimensions resulting from a range of deformation geometries and any anisotropy associated with such assemblages. The results from this completed project could therefore be used to better highlight lithofacies types that are more or less susceptible to deformation band formation and as such, address aspects of reservoir management.

[1] Fossen, H., et al. 2007. Deformation bands in sandstone: a review. Journal of the Geological Society 164(4): 755-769.

[2] Kolyukhin, D., Schueller, S., Espedal, M.S. & Fossen, H. 2010. Deformation band populations in fault damage zone—impact on fluid flow. Computational Geosciences, 14, 231-248.

[3] Pittman, E.D. 1981. Effect of fault-related granulation on porosity and permeability of quartz sandstones, Simpson Group (Ordovician), Oklahoma. AAPG bulletin, 65, 2381-2387.

[4] Hirst, C. M., et al. 2015. UK Low Enthalpy Geothermal Resources: the Cheshire Basin.         


  • Karl Clark, Ian G. Stimpson, Oliver Wakefield (Poster) 2019, Permeability reduction by cataclastic deformation bands in mixed aeolian-fluvial facies reservoirs, TSG - Bergen, Norway.
  • Karl Clark, Ian G. Stimpson, Oliver Wakefield. (Poster + Oral pres), 2019, A petrographic and microstructural analysis of deformation bands in sandstone reservoirs, EGYPS - Cairo, Egypt.
  • Karl Clark, Dan R. Faulkner, John D. Bedford, Ian G. Stimpson (Poster), 2019, Deformation mechanism of unconsolidated quartz sands as a function of grain size distribution: Insights into deformation band formation in mixed aeolian-fluvial reservoirs, AAPG ACE - San Antonio, Texas. USA.
  • Karl Clark, Ian G. Stimpson, Dan R. Faulkner, John D. Bedford. (Oral Presentation), 2019, Sedimentary controls on secondary processes: Deformation bands in reservoirs, CDT Annual Conference, Edinburgh, UK.
  • Karl Clark (Poster), 2019, Experimental Deformation of Unconsolidated Quartz Sands, Examining the Effects of Grain Sorting on Deformation Band Formation Within Mixed Aeolian-Fluvial Reservoirs, San Francisco, USA, AGU Fall Meeting.
  • O. Wakefield, E. Hough, K. D. Clark. 2016. Primary and Secondary Controls on Reservoir Quality; Relationships Between Lithofacies and the Development of Deformation Bands. Poster. AAPG Calgary, Canada.

School of Geography, Geology and the Environment
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Keele University