Geometry and kinematics of compressional growth structures and diapirs in the La Popa basin of northeast Mexico: Insights from sequential restoration of a regional cross section and three‐dimensional analysis

Abstract

[1] Diapirism in the La Popa basin NE Mexico was triggered and sustained by compressional décollement tectonics. Coeval development of contractional structures and diapirs was recorded by growth strata of Late Cretaceous-Tertiary age. A palinspastic reconstruction of a regional cross section, based on the restoration of growth strata related to both diapirs and detachment folds, was carried out. On the basis of this reconstruction and field data, a three-dimensional geometrical study was done to quantify the movement of evaporites within the detachment horizon and two diapirs. The latter allowed determining the tectonodiapiric potential of a structure or set of structures (i.e., the amount of ductile rocks forced to flow in association with the growth of a tectonic structure, which is not accommodated by thickening of the ductile horizon nor by the tectonic structure itself, and is capable of producing diapiric phenomena). This study demonstrates that there is a direct coupling between tectonodiapiric potential and diapiric activity. Geometrical results show that the main factors that controlled the amount of ductile material moved as a consequence of compressional tectonics were shortening, the depth to detachment, the folding style, and the style of deformation process (i.e., pure shear/simple shear). In response to folding, the overburden experienced a downward movement that was the major cause of diapiric phenomena. In addition to field and geometrical data, mechanical data indicate that forceful intrusion was the prevailing emplacement mechanism. Temperatures (>150°-197°C) and strain rates (in the order of 10 À16 -10 À17 s À1 ) calculated for top of the evaporite layer were adequate for the flow of these rocks from the initiation of compression onward. However, an inferred overpressure in the ductile layer should be considered the key factor for the emplacement mechanism.

Geometry and kinematics of the Nuncios detachment fold complex: Implications for lithotectonics in northeastern Mexico

“…Although some workers have interpreted a large basement step or fault beneath the leading edge of the Monterrey Salient [e.g., Gray et al , 2001], our depth‐to‐detachment calculations suggest a roughly 2 km thickness of evaporites persists northward into the southern La Popa Basin. This is compatible with large thicknesses of evaporites interpreted there by Millán‐Garrido [2004], and with the presence of evaporite diapirs and withdrawal basins [e.g., Weidie and Martinez , 1970; Laudon , 1984; Giles and Lawton , 1999]. We therefore prefer the interpretation that thick accumulations of Difunta Group strata most likely halted the northward transport of the Sierra Madre orogenic wedge.…”

“…Thrust fault locations reproduced from interpretations by Padilla y Sanchez [1982]. See Rowan et al [2003] and Millán‐Garrido [2004] for the detailed geology of the La Popa Basin. See McBride et al [1974] for the detailed geology of the Parras Basin.…”

“…Although it is generally agreed that the regional detachment beneath the Monterrey Salient is somewhere in the evaporites of the Minas Viejas Formation, there are few published reports of specific depth‐to‐detachment measurements or calculations in the area [e.g., Gray and Johnson , 1995]. There are similarly no published records of the thickness of evaporites beneath the Monterrey Salient, although Goldhammer et al [1991] estimated 1000 m of pretectonic thickness, and some published cross sections (Figure 10) show deformed thicknesses of 1–2 km beneath synclines in the interior of the fold belt [e.g., Marrett and Bentham , 1997; Marrett and Aranda‐Garcia , 1999], or locally up to 6 km of evaporites beneath portions of the adjacent Parras and La Popa basins [e.g., Gray et al , 2001; Millán‐Garrido , 2004].…”

“…See Figure 2 for a fifth example. Section (a) from Millán‐Garrido [2004], (b) from Gray et al [2001], (c) from Marrett and Aranda‐Garcia [1999], and (d) from De Cserna [1956]. Note the highly variable interpretations of basement geometry, detachment layer thickness and depth to detachment.…”

Sedimentology and Sequence Stratigraphy of Shallow Marine Sediments in a Syn-Rift Setting: Hugin Formation, South Viking Graben

“…The basin forms a segment of a foreland basin that roughly parallels the deformational front of the Sierra Madre Oriental fold and thrust belt (Aschoff and Giles, 2005). Diapirism within the basin was triggered and sustained by compressional décollement tectonics (Millan-Garrido, 2004). This compression started no later than Campanian-Maestrichtian times and continued until at least the Tertiary (Millan-Garrido, 2004).…”