Analogue Sandbox Models of Thrust Wedges with Variable Basal Frictions

Agarwal, K. K.; Agrawal, Girish

doi:10.1016/s1342-937x(05)70635-3

Cited by 25 publications

(17 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…6) confirmed the results of the physical models of critical sand wedges that were described in the literature (e.g., Schreurs et al 2006, Teixell and Koyi 2003, liu et al 1992, Agarwal and Agrawal 2002. Similarly to the sand, the slope angles in the microbeads models increased during progressive deformation and when a new thrust nucleated, the slope angle decreased and then resumed growing (Fig.…”

Section: Resultssupporting

confidence: 85%

Glass Microbeads in Analog Models of Thrust Wedges

D'Angelo

Gomes

2017

An. Acad. Bras. Ciênc.

View full text Add to dashboard Cite

Glass microbeads are frequently used in analog physical modeling to simulate weak detachment zones but have been neglected in models of thrust wedges. Microbeads differ from quartz sand in grain shape and in low angle of internal friction. In this study, we compared the structural characteristics of microbeads and sand wedges. To obtain a better picture of their mechanical behavior, we determined the physical and frictional properties of microbeads using polarizing and scanning electron microscopy and ring-shear tests, respectively. We built shortening experiments with different basal frictions and measured the thickness, slope and length of the wedges and also the fault spacings. All the microbeads experiments revealed wedge geometries that were consistent with previous studies that have been performed with sand. However, the deformation features in the microbeads shortened over low to intermediate basal frictions were slightly different. Microbeads produced different fault geometries than sand as well as a different grain flow. In addition, they produced slip on minor faults, which was associated with distributed deformation and gave the microbeads wedges the appearance of disharmonic folds. We concluded that the glass microbeads may be used to simulate relatively competent rocks, like carbonates, which may be characterized by small-scale deformation features.

show abstract

Section: Resultssupporting

confidence: 85%

Glass Microbeads in Analog Models of Thrust Wedges

D'Angelo

Gomes

2017

An. Acad. Bras. Ciênc.

View full text Add to dashboard Cite

show abstract

“…Another option is that the orientation of the basal detachment is uniform along strike and that the critical taper values are different due to along‐strike variation in the basal friction of the detachment, most likely due to pre‐tectonic basin heterogeneity [e.g., Agarwal and Agarwal , ]. This particular hypothesis is potentially supported by the observation that in many other fold‐thrust belts, surface slopes less than 1°, as observed in the Akharbakhar‐Qäbälä region are often diagnostic of extremely weak detachments, exploiting either evaporite horizons or overpressured shales [e.g., Davis and Engelder , ; Ford , ].…”

Section: Discussionmentioning

confidence: 99%

Structural geometries and magnitude of shortening in the eastern Kura fold‐thrust belt, Azerbaijan: Implications for the development of the Greater Caucasus Mountains

et al. 2013

View full text Add to dashboard Cite

[1] The Greater Caucasus are the northernmost extent of the Arabia-Eurasia collision and are thought to represent the main locus of shortening within the central portion of the collision zone between 40and 48 E. Recent work suggests that in detail, since the Plio-Pleistocene, much of the shortening in the eastern portion of the Caucasus system has been focused within the Kura fold-thrust belt along the southeastern margin of the Greater Caucasus. Here we present new field mapping and stratigraphic investigations of the eastern termination of the Kura fold-thrust belt in Azerbaijan to better constrain the structural geometries, magnitude of shortening, and initiation age for this portion of the fold-thrust belt. Our work suggests that this area of the fold-thrust belt exhibits significant along-strike variations in structural style and evolution and can effectively be divided into two distinct domains at~48 E. The western domain is characterized by a subcritical median surface slope and isolated folds and thrusts propagating out of sequence, whereas the eastern domain is dominated by a single duplex structure and a history of in-sequence development in a critically tapered wedge. We hypothesize that these variations result from changes in relative rates of syn-tectonic sedimentation, erosion, and convergence velocity along strike. We find that within the western domain, the fold-thrust belt has accommodated~12 km of total shortening. An unconformity within the western domain brackets the initiation age of this portion of the fold-thrust belt to between 1.8 and 0.88 Ma yielding permissible average shortening rates of between 6.7 and 13.6 mm/yr. Comparison of these average shortening rates to the geodetically measured shortening rate of 8 mm/yr indicates that since initiation, the fold-thrust belt has accommodated 83-100% of convergence between the Greater and Lesser Caucasus at this longitude.Citation: Forte, A. M., E. Cowgill, I. Murtuzayev, T. Kangarli, and M. Stoica (2013), Structural geometries and magnitude of shortening in the eastern Kura fold-thrust belt, Azerbaijan: Implications for the development of the Greater Caucasus Mountains, Tectonics, 32,

show abstract

“…The mechanical conditions under which these systems develop are also of critical importance, influencing the gross wedge geometries [ Davis et al ., ; Davis and Engelder , ; DeCelles and Mitra , ; Adam and Reuther , ], fault spacing [ Marshak and Wilkerson , ; Mandal et al ., ; Schott and Koyi , ; Agarwal and Agrawal , ; Bose et al ., ], and small‐scale features responsible for fluid transport and storage (e.g., fracture distributions, porosity, and permeability) [e.g., Sanz et al ., ]. However, mechanical constraints are difficult to obtain in the field and are less than reliable in ancient fold and thrust belts [ Gray et al ., ].…”

Section: Introductionmentioning

confidence: 99%

Effects of cohesion on the structural and mechanical evolution of fold and thrust belts and contractional wedges: Discrete element simulations

Morgan

2015

JGR Solid Earth

119

View full text Add to dashboard Cite

Particle-based numerical simulations of cohesive contractional wedges can yield important perspectives on the formation and evolution of fold and thrust belts, offering particular insights into the mechanical evolution of the systems. Results of several discrete element method simulations are presented here, demonstrating the stress and strain evolution of systems with different initial cohesive strengths. Particle assemblages consolidated under gravity, and bonded to impart cohesion, are pushed from the left at a constant velocity above a weak, unbonded décollement surface. Internal thrusting causes horizontal shortening and vertical thickening, forming wedge geometries. The mean wedge taper is similar for all simulations, consistent with their similar residual and basal sliding friction values. In all examples presented here, both forethrusts and back thrusts occur, but forethrusts accommodate most of the shortening. Fault spacing and offset increase with increasing cohesion. Significant tectonic volume strain also occurs, with the greatest incremental volume strain occurring just outboard of the deformation front. This diffuse shortening serves to strengthen the unfaulted domain in front of the deformed wedge, preconditioning these materials for brittle (dilative) failure. The reach of this volumetric strain and extent of décollement slip increase with cohesive strength, defining the extent of stress transmission. Stress paths for elements tracked through the simulations demonstrate systematic variations in shear stress in response to episodes of both décollement slip and thrust fault activity, providing a direct explanation for stress fluctuations during convergence.

show abstract

Analogue Sandbox Models of Thrust Wedges with Variable Basal Frictions

Cited by 25 publications

References 20 publications

Glass Microbeads in Analog Models of Thrust Wedges

Glass Microbeads in Analog Models of Thrust Wedges

Structural geometries and magnitude of shortening in the eastern Kura fold‐thrust belt, Azerbaijan: Implications for the development of the Greater Caucasus Mountains

Effects of cohesion on the structural and mechanical evolution of fold and thrust belts and contractional wedges: Discrete element simulations

Contact Info

Product

Resources

About