The role of backstop shape during inversion tectonics physical models

Abstract

The style of deformation of rocks from basin-infilling sequences in positively inverted natural basins was discussed upon the results of laboratory experiments carried out in sandboxes with sand packs laid down in the space between two wooden blocks. The space simulated stages of crustal extension leading to (1) a half graben due to extension above a listric extensional detachment, with the blocks simulating the footwall and hanging wall, or (2) a graben, with the blocks simulating the external margins that drifted apart above a horizontal detachment. Combinations of two different angles were used to simulate the dip of curved normal faults along the internal face of the wooden blocks. Backstops in the half graben had a convex up internal face. Backstops in the graben had a concave up internal face. Shortening was partitioned in forward and backward movements within the sand packs, and the kinematics of contraction was largely influenced by the convex or concave internal faces. A buttress effect characterized by rotation of the sand pack close to the footwall was stronger for footwall with steeper-dipping internal faces. The results were compared to other physical experiments and applied to an inverted basin found in nature.

The Rio Pardo salient, northern Araçuaí orogen: an example of a complex basin-controlled fold-thrust belt curve

“…The existence of a D 1 /D 2 bivergent fold-thrust wedge in the interior of the hinge zone is another peculiar feature of the Rio Pardo salient. As indicated by field observations and analogue modeling, double wedges develop in places where stresses of almost equal magnitudes and distributions act on opposite sides of a rock package (Marshak & Wilkerson 2004, Gomes et al 2010, Forte et al 2014). Our data, as shown on the cross-section of Figure 7, demonstrate that the double wedge of the Rio Pardo salient is quite asymmetric, with a relatively small retro-wedge and a large pro-wedge.…”

Dynamic mechanism of tectonic inversion and implications for oil–gas accumulation in the Xihu Sag, East China Sea Shelf Basin: Insights from numerical modelling

“…Marques and Nogueira () used a sandbox experiment to analyse the effect of direction and the amount of the shortening during inversion. Gomes et al (), using an analogue experiment to explore the role of listric faults in the basin tectonic inversion, determined that the shape of the fault had a strong impact on the reactivation of a pre‐existing normal fault. Wang et al () used a sandbox experiment to reproduce the formation, evolution, and tectonic inversion processes of the Xihu Sag.…”

“…In order to explore basin tectonic inversion characteristics and the main influencing factors, many previous analogue experiments and numerical models on basin inversion have been discussed (Buiter & Pfiffner, 2003;Buiter, Pfiffner, & Beaumont, 2009;Dai et al, 2015;Dai, Li, Lou, Suo, & Yu, 2014;Gomes, DanderferFilho, Posada, & Silva, 2010;Marques & Nogueira, 2008;Panien, Schreurs, & Pfiffner, 2005;Sandiford, 1999;Sibson, 1985;Ventisette, Montanari, Sani, & Bonini, 2006;Wang, Li, Guo, Suo, & Dai, 2017). Buiter and Pfiffner (2003) used a numerical model to discuss the effect of listric faults in basin tectonic inversion.…”

Análise Da Reativação De Falhas Normais Através Da Modelagem Física Com O Uso Do Particle Image Velocimetry.

“…Os estudos de modelagem analógica que abordam a inversão positiva utilizam bloco rígido para induzir a geometria da falha (lístrica, planar ou rampa), e o pacote sedimentar representado por areia, argila ou a mistura desses materiais (Buchanan & Mcclay, 1991;Gomes et al, 2006;Gomes et al, 2010;Keller & McClay, 1995;Konstatinovskaya, et al, 2007;Koopman et al, 1987;McClay, 1989segundo McClay, 1995, 1995Yamada & McClay, 2003 entre outros). Mesmo com desvantagem, dada pela não deformação do bloco rígido, este tipo de modelo analógico tem desempenhado papel importante para decifrar e validar informações sobre a arquitetura estrutural final e a geometria interna de uma bacia invertida.…”