Size-dependent comminution, tectonic mixing, and sealing behavior of a “structurally oversimplified” fault zone in poorly lithified sands: Evidence for a coseismic rupture?

We studied a structurally oversimplified, extensional fault zone developed in poorly lithified, quartz-rich, high-porosity sandy sediments of the seismically active Crotone Basin (southern Italy). The fault zone consists of a cm-thick, discrete fault core embedded in virtually undeformed wall sediments. By combining grain size, shape, and microstructural analyses with mineralogical analyses and permeability measurements, we investigated the influence of initial sedimentological characteristics of sands on the final faulted granular products and related hydrologic properties. Faulting produces a general grain-size and porosity reduction by changing both the grain-size and shape distributions. We document a combination of intragranular fracturing, spalling, and flaking of grain edges in the fault core, which do not depend on grain mineralogy. The dominance of cataclasis, also confirmed by fractal dimensions >2.6, is generally not expected at a deformation depth

[1]  W. Haneberg,et al.  Controls on Fault‐Zone Architecture in Poorly Lithified Sediments, Rio Grande Rift, New Mexico: Implications for Fault‐Zone Permeability and Fluid Flow , 2013 .

[2]  John L. Wilson,et al.  Permeability alteration in small-displacement faults in poorly lithified sediments: Rio Grande Rift, Central New Mexico , 2013 .

[3]  F. Storti,et al.  Grain size and permeability evolution of soft-sediment extensional sub-seismic and seismic fault zones in high-porosity sediments from the Crotone basin, southern Apennines, Italy , 2010 .

[4]  J. Caine,et al.  Structural and geochemical characteristics of faulted sediments and inferences on the role of water in deformation, Rio Grande Rift, New Mexico , 2009 .

[5]  A. Braathen,et al.  Slipped deformation bands: A new type of cataclastic deformation bands in Western Sinai, Suez rift, Egypt , 2008 .

[6]  C. Wibberley,et al.  Recent advances in the understanding of fault zone internal structure: a review , 2008 .

[7]  K. Cashman,et al.  Microstructures developed by coseismic and aseismic faulting in near-surface sediments, San Andreas fault, California , 2007 .

[8]  James P. Evans,et al.  Fractured dirt: Deformation textures and processes in sediment and other unconsolidated deposits , 2007 .

[9]  K. Mair,et al.  Deformation bands in sandstone: a review , 2007, Journal of the Geological Society.

[10]  A. Braathen,et al.  Shear zones in porous sand: Insights from ring-shear experiments and naturally deformed sandstones , 2007 .

[11]  Geoffrey C. P. King,et al.  Mechanical origin of power law scaling in fault zone rock , 2007 .

[12]  Jean-Pierre Petit,et al.  The mechanics of fault distribution and localization in high-porosity sands, Provence, France , 2007 .

[13]  P. Galli,et al.  Archaeoseismic evidence for a Late Roman earthquake in the Crotone area (Ionian Calabria, Southern Italy): Seismotectonic implications , 2006 .

[14]  G. Rawling,et al.  Structural record of the mechanical evolution of mixed zones in faulted poorly lithified sediments, Rio Grande rift, New Mexico, USA , 2006 .

[15]  P. Galli,et al.  Two unknown M > 6 historical earthquakes revealed by palaeoseismological and archival researches in eastern Calabria (southern Italy). Seismotectonic implications , 2006 .

[16]  S. Minor,et al.  Regional survey of structural properties and cementation patterns of fault zones in the northern part of the Albuquerque basin, New Mexico : implications for ground-water flow , 2006 .

[17]  J. Anthony,et al.  Influence of particle characteristics on granular friction , 2005 .

[18]  C. Perale,et al.  Stratigraphy and sedimentology of fault-controlled backstepping shorefaces, middle Pliocene of Crotone Basin, Southern Italy , 2005 .

[19]  F. Chester,et al.  Laboratory deformation of granular quartz sand: Implications for the burial of clastic rocks , 2005 .

[20]  K. Mair,et al.  Grain fracture in 3D numerical simulations of granular shear , 2005 .

[21]  Marc S. Hendrix,et al.  High-Resolution Particle Size Analysis of Naturally Occurring Very Fine-Grained Sediment Through Laser Diffractometry , 2004 .

[22]  Frank J. Pazzaglia,et al.  Geomorphic expression of active tectonics in a rapidly-deforming forearc, Sila massif, Calabria, southern Italy , 2004 .

[23]  G. Prosser,et al.  Anatomy and evolution of a Mediterranean‐type fault bounded basin: the Lower Pliocene of the northern Crotone Basin (Southern Italy) , 2004 .

[24]  Kenneth Pye,et al.  Particle size analysis by laser diffraction , 2004, Geological Society, London, Special Publications.

[25]  G. Prosser,et al.  Architectural styles of prograding wedges in a tectonically active setting, Crotone Basin, Southern Italy , 2003, Journal of the Geological Society.

[26]  A. Aydin,et al.  Petrophysical Constraints on Deformation Styles in Aztec Sandstone, Southern Nevada, USA , 2003 .

[27]  John M. Sigda,et al.  Are faults preferential flow paths through semiarid and arid vadose zones? , 2003 .

[28]  G. Rawling,et al.  Cataclasis and particulate flow in faulted, poorly lithified sediments , 2003 .

[29]  Francesco Salvini,et al.  Particle size distributions in natural carbonate fault rocks: insights for non-self-similar cataclasis , 2003 .

[30]  Karen Mair,et al.  Influence of grain characteristics on the friction of granular shear zones , 2002 .

[31]  Mark I. Richardson,et al.  A first look at dust lifting and dust storms near the south pole of Mars with a mesoscale model , 2002 .

[32]  I. Main,et al.  Influence of confining pressure on the mechanical and structural evolution of laboratory deformation bands , 2002 .

[33]  James P. Evans,et al.  Structural heterogeneity and permeability in faulted eolian sandstone: Implications for subsurface modeling of faults , 2002 .

[34]  K. Høeg,et al.  Porosity loss in sand by grain crushing—experimental evidence and relevance to reservoir quality , 2002 .

[35]  G. Rawling,et al.  Internal architecture, permeability structure, and hydrologic significance of contrasting fault-zone types , 2001 .

[36]  T. Blenkinsop.  Deformation Microstructures and Mechanisms in Minerals and Rocks , 2000 .

[37]  K. Cashman,et al.  Cataclasis and deformation-band formation in unconsolidated marine terrace sand, Humboldt County, California , 2000 .

[38]  S. Roux,et al.  Size effects in single grain fragmentation , 1999 .

[39]  S. Laubach.  A Method to Detect Natural Fracture Strike in Sandstones , 1997 .

[40]  Teng-fong Wong,et al.  The transition from brittle faulting to cataclastic flow: Permeability evolution , 1997 .

[41]  Teng-fong Wong,et al.  The transition from brittle faulting to cataclastic flow in porous sandstones: Mechanical deformation , 1997 .

[42]  James P. Evans,et al.  Fault zone architecture and permeability structure , 1996 .

[43]  Beatriz Menéndez,et al.  Micromechanics of brittle faulting and cataclastic flow in Berea sandstone , 1996 .

[44]  J. V. Dijk,et al.  Neotectonic rotations in the Calabrian Arc; implications for a Pliocene-Recent geodynamic scenario for the Central Mediterranean , 1995 .

[45]  C. Sammis,et al.  The micromechanics of friction in a granular layer , 1994 .

[46]  D. Pollard,et al.  Microstructure of deformation bands in porous sandstones at Arches National Park, Utah , 1994 .

[47]  M. Antonellini,et al.  Effect of Faulting on Fluid Flow in Porous Sandstones: Petrophysical Properties , 1994 .

[48]  A. Moretti.  Note sull'evoluzione tettono-stratigrafica del bacino Crotonese dopo la fine del Miocene , 1994 .

[49]  A. Maltman.  The Geological deformation of sediments , 1994 .

[50]  D. J. Hagerty,et al.  One‐Dimensional High‐Pressure Compression of Granular Media , 1994 .

[51]  James P. Evans,et al.  Internal structure and weakening mechanisms of the San Andreas Fault , 1993 .

[52]  T. Blenkinsop.  Cataclasis and processes of particle size reduction , 1991 .

[53]  James H. Dieterich,et al.  The frictional properties of a simulated gouge having a fractal particle distribution , 1989 .

[54]  Chris Marone,et al.  Particle-size distribution and microstructures within simulated fault gouge , 1989 .

[55]  Ronald L. Biegel,et al.  The kinematics of gouge deformation , 1987 .

[56]  C. Scholz.  Wear and gouge formation in brittle faulting , 1987 .

[57]  Robert H. Osborne,et al.  Self-similar cataclasis in the formation of fault gouge , 1986 .

[58]  Frederick M. Chester,et al.  Implications for mechanical properties of brittle faults from observations of the Punchbowl fault zone, California , 1986 .

[59]  E. Pittman.  Effect of Fault-Related Granulation on Porosity and Permeability of Quartz Sandstones, Simpson Group (Ordovician), Oklahoma , 1981 .

[60]  G. Borradaile.  Particulate flow of rock and the formation of cleavage , 1981 .

[61]  A. Aydin.  Small faults formed as deformation bands in sandstone , 1978 .

[62]  G. Mandl,et al.  Shear zones in granular material , 1977 .

[63]  Richard H. Sibson,et al.  Fault rocks and fault mechanisms , 1977, Journal of the Geological Society.

[64]  J. T. Engelder,et al.  Cataclasis and the Generation of Fault Gouge , 1974 .

[65]  J. J. Gallagher,et al.  Experimental studies relating to microfracture in sandstone , 1974 .

[66]  P. K. Weyl,et al.  Influence of Texture on Porosity and Permeability of Unconsolidated Sand , 1973 .

[67]  W. C. Krumbein,et al.  Manual of sedimentary petrography , 1966 .

[68]  J. Handin,et al.  Chapter 6: Experimental Deformation of St. Peter Sand: A Study of Cataclastic Flow , 1960 .