Magnetic fabrics as strain markers in folded soft-sediment layers

Acknowledgements This study was supported by the Israel Science Foundation (ISF grants 868/17) and a grant from the Israeli Government under Geological Survey of Israel DS project 40706. We thank Catalina Luneburg and Stephen Laubach for efficient editorial handling, together with Ruth Soto and Manish A. Mamtani for helpful reviews and constructive comments. RW was inspired by John Ramsay while participating in a fieldtrip to the Alps led by John in 2002. GIA would like to take this opportunity to acknowledge John Ramsay's support while a post-doc at ETH Zurich in the late 1980's. TL had the privilege of showing John Ramsay outcrops of slump horizons and seismites in the lacustrine sediments of the Dead Sea region during John's visit to Israel in 2008.Peer reviewedPostprin

Characterising bed-parallel slip during gravity-driven deformation

Acknowledgements RW acknowledges the Israeli government GSI DS project 40706. SM acknowledges the Israel Science Foundation (ISF grant No. 1645/19) and the Ministry of National Infrastructures, Energy and Water Resources (grant #214-17-027). We thank Fabrizio Agosta for efficient editorial handling, together with Chris Morley and an anonymous reviewer who provided constructive comments that helped improve the paper.Peer reviewedPublisher PD

Criteria to discriminate between different models of thrust ramping in gravity-driven fold and thrust systems

RW was supported by the Israel Science Foundation (ISF grant No. 868/17). SM acknowledges the Israel Science Foundation (ISG Grant No. 1645/19) and the Ministry of National Infrastructures, Energy and Water Resources (grant #214-17-027). TL acknowledges the Israeli government GSI DS project 40706. We thank Stephen Laubach for efficient editorial handling of the manuscript together with Chris Morley, Hemin Koyi and an anonymous referee for detailed and constructive comments that much improved the paper.Peer reviewedPostprin

Upslope-verging back thrusts developed during downslope-directed slumping of mass transport deposits

Acknowledgements SM acknowledges the Israel Science Foundation (ISF grant No. 1436/14) and the Ministry of National Infrastructures, Energy and Water Resources (grant #214-17-027). RW was supported by the Israel Science Foundation (ISF grant No. 1245/11).Peer reviewedPostprin

Faulting, sediment loading, and flow of underlying ductile units : A case study from the Western Ionian Basin Offshore Eastern Sicily

Acknowledgements Bathymetric data are from a compilation provided by Gutscher et al. (2017) and from EMODnet open dataset (http://www.emodnet-bathymetry.eu/). Digital topography was achieved from the Japan Aerospace Exploration Agency (https://www.eorc.jaxa.jp/ALOS/en/aw3d30/index.htm). The authors also acknowledge the use of MOVE Software Suite granted by Petroleum Experts Limited (www.petex.com). Bernard Mercier de Lepinay (GeoAzur, Université de Nice/CNRS), is also acknowledged for the CIRCEE-HR seismic data processing. Juan I. Soto (The University of Texas at Austin) is warmly acknowledged for the critical and constructive discussions provided. The research was partly funded by the University of Catania in the framework of the project ‘SeismoFront’ (resp. G. Barreca), Grant n. 22722132176.Peer reviewedPostprin

Exploring the relative contribution of mineralogy and CPO to the seismic velocity anisotropy of evaporites

We present the influence of mineralogy and microstructure on the seismic velocity anisotropy ofevaporites. Bulk elastic properties and seismic velocities are calculated for a suite of 20 natural evaporate samples, which consist mainly of halite, anhydrite, and gypsum. They exhibit strong fabrics as a result of tectonic and diagenetic processes. Sample mineralogy and crystallographic preferred orientation (CPO) were obtained with the electron backscatter diffraction (EBSD) technique and the data used for seismic velocity calculations. Bulk seismic properties for polymineralic evaporites were evaluated with a rock recipe approach. Ultrasonic velocity measurements were also taken on cube shaped samples to assess the contribution of grain-scale shape preferred orientation (SPO) to the total seismic anisotropy. The sample results suggest that CPO is responsible for a significant fraction of the bulk seismic properties, in agreement with observations from previous studies. Results from the rock recipe indicate that increasing modal proportion of anhydrite grains can lead to a greater seismic anisotropy of a halite-dominated rock.Conversely, it can lead to a smaller seismic anisotropy degree of a gypsum-dominated rock until anestimated threshold proportion after which anisotropy increases again. The difference between thepredicted anisotropy due to CPO and the anisotropy measured with ultrasonic velocities is attributed to the SPO and grain boundary effects in these evaporites

The geometry and kinematics of sheath folds.

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Shear zone folds: records of flow perturbations or structural inheritance?

Deformation within shear zones can be both temporally and spatially variable, resulting in multiple generations of folds which display a range of scales and overprinting relationships in mylonitic rocks associated with high strain zones. Despite such complexities, two main fold associations are broadly recognized in many shear zone settings: early tight to isoclinal sheath folds, often with mylonitic limbs that are post-dated by one or more local generations of synshearing folds which are preserved within, or root downwards into mylonitic high strain zones. These latter structures locally fold the mylonitic foliation and lineation whilst displaying geometric characteristics that are kinematically compatible with the movement regime of the major shear zone. Using examples related to ductile thrusting in Moine metasediments of north Scotland, we show that both types of fold display predictable geometric patterns on fabric topology plots. Fold axes and axial surfaces display consistent changes in asymmetry and sense of obliquity relative to local, transport-parallel mineral lineations that can be used to map out a series of culminations and depression zones. The sheath folds preserve more acute, but almost identical geometric patterns compared to the later synshearing folds, with culmination and depression zones often coinciding in location and scale. Detailed analysis also demonstrates that the distribution of finite strain is systematically linked to the architecture of all folds and that clear and predictable relationships exist between the fabric topologies of both the sheath folds and synshearing folds. These consistent topological relationships could be explained in terms of a fold evolution model, where sheath folds represent a more highly deformed and evolved variety of synshearing folds originally generated during perturbations in ductile flow. However, an alternative fold inheritance model predicts that the gross structural architecture generated during sheath folding may subsequently control the geometry and govern the orientation of the synshearing folds. Both models may be widely applicable in a broad range of shear zorie environments.</p

Shear zones - an introduction and overview.

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