Investigating the basal shear zone of the submarine Tuaheni Landslide Complex, New Zealand: a core‐log‐seismic integration study

2021 ◽  
Author(s):  
G.J. Crutchley ◽  
J. Elger ◽  
J. Kuhlmann ◽  
J.J. Mountjoy ◽  
A. Orpin ◽  
...  
Keyword(s):  
New Zealand ◽  
Shear Zone ◽  
Basal Shear

Free gas distribution and basal shear zone development in a subaqueous landslide – Insight from 3D seismic imaging of the Tuaheni Landslide Complex, New Zealand

2018 ◽  
Vol 502 ◽  
pp. 231-243 ◽  
Author(s):  
Felix Gross ◽  
Joshu J. Mountjoy ◽  
Gareth J. Crutchley ◽  
Christoph Böttner ◽  
Stephanie Koch ◽  
...  
Keyword(s):  
New Zealand ◽  
Shear Zone ◽  
Seismic Imaging ◽  
3D Seismic ◽  
Gas Distribution ◽  
Free Gas ◽  
Zone Development ◽  
Basal Shear

Characterization of the Rapanui mass‐transport deposit and the basal shear zone: Mount Messenger Formation, Taranaki Basin, New Zealand

Sedimentology ◽  
2020 ◽  
Vol 67 (4) ◽  
pp. 2111-2148 ◽  
Author(s):  
Sebastian Cardona ◽  
Lesli J. Wood ◽  
Brandon Dugan ◽  
Zane Jobe ◽  
Lorna J. Strachan
Keyword(s):  
New Zealand ◽  
Mass Transport ◽  
Shear Zone ◽  
Basal Shear

The Luco dei Marsi deep-seated gravitational deformation: first evidence of a basal shear zone in the central Apennine mountain belt (Italy) 

2021 ◽  
Author(s):  
Emiliano Di Luzio ◽  
Marco Emanuele Discenza ◽  
Maria Luisa Putignano ◽  
Mariacarmela Minnillo ◽  
Diego Di Martire ◽  
...  
Keyword(s):  
Rock Mass ◽  
Shear Zone ◽  
Engineering Geology ◽  
Slope Deformation ◽  
European Alps ◽  
Structural Constraints ◽  
Normal Faulting ◽  
Central Apennines ◽  
Gravity Driven ◽  
Basal Shear

<p>The nature of the boundary between deforming rock masses and stable bedrock is a significant issue in the scientific debate on Deep-Seated Gravitational Slope Deformations (DSGSDs). In many DSGSDs the deforming masses move on a continuous sliding surface or thick basal shear zone (BSZ) [1-3]. This last feature is due to viscous and plastic deformations and was observed (or inferred) in many worldwide sites [4]. However, no clear evidence has been documented in the geological context of the Apennine belt, despite the several cases of DSGSDs documented in this region [5-6].</p><p>This work describes a peculiar case of a BSZ found in the central part of the Apennine belt and observed at the bottom of a DSGSD which affects the Meso-Cenozoic carbonate ridge overhanging the Luco dei Marsi village (Abruzzi region). The NNW-SSE oriented mountain range is a thrust-related Miocene anticline, edged on the east by an intramountain tectonic depression originated by Plio-Quaternary normal faulting. The BSZ appears on the field as a several meters-thick cataclastic breccia with fine matrix developed into Upper Cretaceous, biodetritic limestone and featuring diffuse rock damage.</p><p>The gravity-driven process was investigated through field survey, aerial photo interpretation and remote sensing (SAR interferometry) and framed into a geological model which was reconstructed also basing on geophysical evidence from the CROP 11 deep seismic profile. The effects on slope deformation determined by progressive displacements along normal faults and consequent unconfinement at the toe of the slope was analysed by a multiple-step numerical modelling constrained to physical and mechanical properties of rock mass.</p><p>The model results outline the tectonic control on DSGSD development at the anticline axial zone and confirm the gravitational origin of the rock mass damage within the BSZ. Gravity-driven deformations were coexistent with Quaternary tectonic processes and the westward (backward) migration of normal faulting from the basin margin to the inner zone of the deforming slope.</p><p><strong>References</strong></p><p>[1] Agliardi F., Crosta G.B., Zanchi A., (2001). Structural constraints on deep-seated slope deformation kinematics. Engineering Geology 59(1-2), 83-102. https://doi.org/10.1016/S0013-7952(00)00066-1.</p><p>[2] Madritsch H., Millen B.M.J., (2007). Hydrogeologic evidence for a continuous basal shear zone within a deep-seated gravitational slope deformation (Eastern Alps, Tyrol, Austria). Landslides 4(2), 149-162. https://doi.org/10.1007/s10346-006-0072-x.</p><p>[3] Zangerl C., Eberhardt E., Perzlmaier S., (2010). Kinematic behavior and velocity characteristics of a complex deep-seated crystalline rockslide system in relation to its interaction with a dam reservoir. Engineering Geology 112(1-4), 53-67. https://doi.org/10.1016/j.enggeo.2010.01.001.</p><p>[4] Crosta G.B., Frattini P., Agliardi F., (2013). Deep seated gravitational slope deformations in the European Alps. Tectonophysics 605, 13-33. https://doi.org/10.1016/j.tecto.2013.04.028.</p><p>[5] Discenza M.E., Esposito C., Martino S., Petitta M., Prestininzi A., Scarascia-Mugnozza G., (2011). The gravitational slope deformation of Mt. Rocchetta ridge (central Apennines, Italy): Geological-evolutionary model and numerical analysis. Bulletin of Engineering Geology and the Environment,70(4), 559-575. https://doi.org/10.1007/s10064-010-0342-7.</p><p>[6] Esposito C., Di Luzio E., Scarascia-Mugnozza G., Bianchi Fasani G., (2014). Mutual interactions between slope-scale gravitational processes and morpho-structural evolution of central Apennines (Italy): review of some selected case histories. Rendiconti Lincei. Scienze Fisiche e Naturali 25, 161-155. https://doi.org/10.1007/s12210-014-0348-3.</p>

scholarly journals The internal structure and composition of a plate boundary-scale serpentinite shear zone: The Livingstone Fault, New Zealand

2019 ◽  
Author(s):  
Matthew S. Tarling ◽  
Steven A. F. Smith ◽  
James M. Scott ◽  
Jeremy S. Rooney ◽  
Cecilia Viti ◽  
...  
Keyword(s):  
New Zealand ◽  
Internal Structure ◽  
Shear Zone ◽  
Plate Boundary ◽  
Shear Zones ◽  
East Side ◽  
Local Dispersion ◽  
Fine Grained ◽  
Shear Sense ◽  
Tectonic Settings

Abstract. Deciphering the internal structural and composition of large serpentinite-dominated shear zones will lead to an improved understanding of the rheology of the lithosphere in a range of tectonic settings. The Livingstone Fault in New Zealand is a > 1000 km long terrane-bounding structure that separates the basal portions (peridotite; serpentinised peridotite; metagabbros) of the Dun Mountain Ophiolite Belt from quartzofeldspathic schists of the Caples or Aspiring Terranes. Field and microstructural observations from eleven localities along a strike length of c. 140 km show that the Livingstone Fault is a steeply-dipping, serpentinite-dominated shear zone tens to several hundreds of metres wide. The bulk shear zone has a pervasive scaly fabric that wraps around fractured and faulted pods of massive serpentinite, rodingite and partially metasomatised quartzofeldspathic schist up to a few tens of metres long. S-C fabrics and lineations in the shear zone consistently indicate a steep Caples-side-up (i.e. east-side-up) shear sense, with significant local dispersion in kinematics where the shear zone fabrics wrap around pods. The scaly fabric is dominated (> 98 vol %) by fine-grained (≪ 10 μm) fibrous chrysotile and lizardite/polygonal serpentine, but infrequent (

Post-emplacement fluid-driven intrusion fracturing and quartz-sand injections at the basal shear zone of the Esla Nappe (Cantabrian Zone, NW Iberia)

2020 ◽  
Author(s):  
Manuel Ignacio de Paz Álvarez ◽  
Sergio Llana Fúnez ◽  
Juan Luis Alonso
Keyword(s):  
Shear Zone ◽  
Quartz Sand ◽  
Fracture Aperture ◽  
Fault Rock ◽  
Cantabrian Zone ◽  
Injection Process ◽  
Bedding Planes ◽  
Dehydration Reactions ◽  
Nw Iberia ◽  
Basal Shear

<p>The Esla Nappe is located in the external foreland and thrust belt of the Variscan Orogen in the NW Iberian Massif (Cantabrian Zone, NW Iberia). It is formed by a near-complete Palaeozoic sedimentary succession. With a displacement of around 19 km, the nappe was emplaced along a thin (<2–3 m) basal shear zone (ENBSZ) located at an estimated minimum depth of 4 km. Emplacement took place during the Moscovian (ca. 312 Ma). Fault-rock assemblages record a variety of alternating deformation mechanisms and processes, including cataclastic flow,  pressure solution and hydrofracturing and vein precipitation. All these processes are considered evidence of an aseismic stable behaviour of the ENBSZ, where deformation was influenced by secular variations in the fluid pore pressure.</p><p>Following emplacement, the ENBSZ was breached by clastic dykes and sills which were intruded following re-opened previous anisotropies, including bedding planes, thrust surfaces, joints and stylolites. Together, they constitute an interconnected network of quartz sand-rich lithosomes reaching structural heights occasionally exceeding 20 m above the ENBSZ. The orientation of the dykes suggests that the injection process took place under low differential stress conditions in the hangingwall, and near-lithostatic fluid pore overpressure conditions in the footwall. The injected slurry consisted of overpressured pore fluid, quartz-sand grains derived from the footwall and entrained host-derived fragments. Depending on fracture aperture and slurry composition, a variety of fluid velocities can be inferred in the order of 15–30 cm/s. Thin pure injections of quartz grains (ca. <1 cm) were characterised by a laminar flow (Re<2100), whereas the thickest quartz and host-derived mixed injections (~1 m) displayed a fully turbulent flow (Re~2 x 10<sup>4</sup>).</p><p>The causes for the fluids to reach near-lithostatic fluid overpressures within the uppermost footwall remain unknown. It is not possible to rule out a seismic trigger, but the absence of extreme shear localization structures typical of seismic slip suggests that the injection process was driven by fluid progressive accumulation, possibly related with clay dehydration reactions, tectonic loading, pore compaction or fluid migration from underlying formations. Actual breaching and injection may have been allowed by a decrease in bedding-parallel compressive stresses in the Esla Nappe associated with the subsequent evolution of the thrust-wedge.</p>

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