Influence of surface processes and initial topography on lateral fold growth and fold linkage mode

Abstract

Elongation of randomly distributed fold segments and their potential linkage are important for hydrocarbon exploration because it can greatly influence the morphology of the reservoir and both migration and accumulation of hydrocarbons in antiformal traps. Here we study the effects of surface processes and the presence of a topographic slope on the different linkage modes that can occur, and how these parameters affect the required horizontal offset for perturbations to link. The proposed numerical model represents a sedimentary cover detached over a much weaker basal décollement layer. The upper surface is modified by mass redistribution, which is achieved by a combination of fluvial and hillslope processes. Several series of simulations were performed: (1) without surface processes or regional slope, (2) with regional slope only, (3) with fluvial incision and hillslope processes, and (4) with hillslope processes only. Model results show that the presence of a regional slope reduces the critical distance required for the transition between linkage and no linkage modes, whereas erosion and redeposition of sediments, on the contrary, increase this distance. The location of the saddle point, where fold segments link, and its vertical distance to the crests of the anticlines are different compared to the case without erosion or initial topographic slope, which potentially can affect the morphology of hydrocarbon traps. Moreover, both erosion and redeposition of sediments enhance the fold elongation (growth along the fold axis), once the erosion velocity exceeds the folding velocity. Model results have been compared to the Zagros Fold Belt.

Topographic controlled forcing of salt flow: Three‐dimensional models of an active salt system, Canyonlands, Utah

“…External forces that initiate salt-related deformation include tectonics [Daudré and Cloetingh, 1994;Vendeville and Jackson, 1994;Letouzy et al, 1995], sedimentation [Ge et al, 1997;Gemmer et al, 2004;Hudec et al, 2009;Trudgill, 2011;Goteti et al, 2012], hydrology and dissolution [Aftabi et al, 2010;Gutierrez et al, 2012;Guerrero et al, 2014], and differential unloading due to erosion [Mège et al, 2013;Messager et al, 2014;Collignon et al, 2015]. The structural expression is dependent not only on these external forces but also on internal conditions such as salt and overburden rheology, topography and relief, and salt geometry [Poliakov and Podladchikov, 1992;Letouzy et al, 1995;Ter Heege et al, 2005;Allken et al, 2013;Collignon et al, 2015;Kettermann et al, 2015]. We aim to explore how a spatially complex landscape interacts with these processes, the feedback that are generated in a system with multiple driving forces, and determine the scaling of resulting salt structures.…”

Folding and necking across the scales: a review of theoretical and experimental results and their applications

“…The numerical studies mentioned above investigated fundamental mechanical folding and necking processes, but numerical solutions are also useful to study the coupling of folding and necking with other processes such as (i) the generation of heat during folding due to dissipative rock deformation (shear heating) and the related thermal softening caused by thermo-mechanical feed-back with temperaturedependent rock viscosity (Hobbs et al, 2007(Hobbs et al, , 2008Burg and Schmalholz, 2008), (ii) the conversion of macroscale mechanical work into microscale mechanical work during the reduction and growth of mineral grain size and related softening due to grain size reduction (Peters et al, 2015), (iii) the impact of metamorphic reactions on rock deformation (Hobbs et al, 2010), (iv) coupling of crustal folding or necking with erosion in 2-D (Burg and Podladchikov, 2000;Burov and Poliakov, 2001) and 3-D (Collignon et al, 2015) or (v) the coupling of folding with salt diapirism (Fernandez and Kaus, 2014). A detailed outline of a coupled thermodynamic approach to study rock deformation and the resulting structures is given in the recent textbook by Hobbs and Ord (2014).…”

Modeling of wind gap formation and development of sedimentary basins during fold growth: application to the Zagros Fold Belt, Iran

“…The SPM employed here was initially developed for coupling surface processes with lithospheric and crustal dynamics (Lithospheric and Mantle Evolution Model [LaMEM]; Kaus et al ., ; Popov and Kaus, ; Kaus et al ., ) with a focus on the effects of surface processes (i.e. erosion and sedimentation) on fold dynamics at the scale of the fold‐and‐thrust belt (Collignon et al ., , ). The model broadly follows the approach of Simpson and Schlunegger () and is described in details in Collignon et al .…”