1,721,066 research outputs found
Modelling the extensional deformation in the forelimb of fault-bend and fault-propagation anticlines
No full textDouble-edge fault-propagation folding: geometry and kinematics
No full textFault-bend folding is a common folding mechanism in thrust and fold belts worldwide. The widely used kink-band geometric model of
fault-bend folding necessitates complex ramp segmentations to reproduce the rounded shape of many natural thrust related anticlines.
Curvilinear hinge sectors provide a geometric and kinematic alternative solution to kink bands for modelling curved-hinge folds. We
developed an analytical solution for modelling fault-bend folding using circular hinge sectors. The velocity field of this kinematic solution is
different from that associated with the classical, kink-style model. Our solution predicts the development of curvilinear anticlines above
staircase fault geometries, the occurrence of limb rotation and, consequently, the development of rotational syngrowth wedges on both the
forelimb and the crest. Conversely to the kink-style kinematics, curvilinear hinge sectors imply a dependence of deformation intensity from
the fold shape and stratigraphic position of the folded layer. Application to natural thrust-related anticlines validates the effectiveness of
curvilinear fault-bend folding
Fault-bend folding as an end-member solution of (double-edge) fault-propagation folding.
No full textFault-bend folding is the most commonly used kinematic mechanism to interpret the architecture and evolution of thrust-related anticlines in thrust wedges. However, its basic requirement of an instantaneous propagation of the entire fault before hangingwall deformation, limits its kinematic effectiveness. To overcome this limitation, we used the interdependence between fold shape and fault slip versus propagation rate (S/P ratio) implemented in double-edge fault-propagation folding. We show that very small S/P values produce fault-propagation anticlines that, when transported forelandward along an upper décollement layer, closely resemble fault-bend anticlines. Accordingly, if small geometric discrepancies between the two solutions are accepted, transported double-edge fault-propagation provides an effective kinematic alternative to fault-bend folding. Even at very low S/P values, it in fact predicts a fast but finite propagation rate of the fault. We thus propose that double-edge fault-propagation folding provides a broadly applicable model of fault-related folding that includes fault-bend folding as an end-member kinematic solution
Rounding hinges to fault-bend folding: geometric and kinematic implications
No full textFault-bend folding is a common folding mechanism in thrust and fold belts worldwide. The widely used kink-band geometric model of
fault-bend folding necessitates complex ramp segmentations to reproduce the rounded shape of many natural thrust related anticlines.
Curvilinear hinge sectors provide a geometric and kinematic alternative solution to kink bands for modelling curved-hinge folds. We
developed an analytical solution for modelling fault-bend folding using circular hinge sectors. The velocity field of this kinematic solution is
different from that associated with the classical, kink-style model. Our solution predicts the development of curvilinear anticlines above
staircase fault geometries, the occurrence of limb rotation and, consequently, the development of rotational syngrowth wedges on both the
forelimb and the crest. Conversely to the kink-style kinematics, curvilinear hinge sectors imply a dependence of deformation intensity from
the fold shape and stratigraphic position of the folded layer. Application to natural thrust-related anticlines validates the effectiveness of
curvilinear fault-bend folding
Scaling relationship between pressure solution cleavage spacing and host-layer thickness.
No full textIndagine preliminare sulla micoflora del mantello della volpe (Vulpes vulpes, L) in Toscana
No full text
Detailed structural analysis of digital outcrops: a learning example from the kermanshah-qulqula radiolarite basin, zagros belt, iran
Full text linkA digital outcrop example and associated structural analysis of highly deformed sedimentary strata from the Zagros Belt of Iran is presented. By providing this site in open-access, downloadable format, we aim to make this excellent outcrop exposure accessible to a wide range of geoscientists. Digital data extraction techniques are used to constrain structural interpretations and cross section orientation, as well as kinematic restorations of interpreted structures. Structural analysis protocols provided here are well-suited to learning outcomes associated with digital cross section construction, interpretation and restoration. Complex deformation at the study locality and associated uncertainties in horizon and fault mapping yield interpretation and structural restoration results that are likely non-unique. Interpretation uncertainties are discussed in the context of geoscience education, with specific reference to the need for considering and assessing data quality and underlying geological assumptions. Our workflow and results can be used to bridge the gap between field-based training at undergraduate level and the proficiency in 3D digital environments required of professional geoscientists. By using digital outcrops to achieve learning outcomes, knowledge of underlying geological processes and practical skills in digital data handling and treatment can be effectively communicated to future geoscientists within the virtual environment
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Deformation pattern analysis and tectonic implications of a décollement level within the Central Apennines (Italy)
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