Late Triassic - Late Jurassic subsidence analysis in Neuquén Basin central area

Abstract

This paper presents a detailed study of the tectonic subsidence evolution during the Late Triassic-Late Jurassic period in the central area of the Neuquén Basin. The methodology consisted of the integration of outcrop and subsurface data, in order to obtain tectonic subsidence curves for the analyzed period in the study area. The origin of the basin was linked to a lithospheric mechanical extension episode in the Late Triassic-Early Jurassic that, once completed, gave rise to a post-rift stage. The post-rift stage, comprised between Early Jurassic and Early Cretaceous, was classically assumed as dominated by thermal subsidence. Results obtained in this paper show that there is a change in the geometry of the tectonic subsidence curves, which depart considerably from the expected behavior for a basin dominated by thermal subsidence. Therefore, the post-rift stage of the Neuquén Basin for the study area would have had a more complex tectonic evolution than that determined exclusively by the thermal subsidence, and that superposition of mechanisms must be considered. From the available data, a shift from thermal to dynamic subsidence from the Middle Callovian onwards seems to be the most plausible explanation for the subsidence evolution observed in the study area.

Surface and mantle records reveal an ancient slab tear beneath Gondwana

“…2d and 3a). This process would have terminated between ~175 and 160 Myr as inferred from increased arc activity 27,28,44 , the appearance of the South Orkney Island slab in the Middle to Late Jurassic 30,37 , and the record of a sudden increase in back-arc subsidence interpreted as a dynamic effect triggered by subduction reactivation 45 (Fig. 1d).…”

“…The distributed character of intraplate extension in this region is interpreted as the result of a wide rifting mechanism controlled by pre-existing weak orogenic lithosphere 48–50 . Available surface geological information of this extensional stage mostly comes from the Neuquén basin 44,45,48–52 , while in the offshore Colorado basin this stage is only recognized from 2-D seismic reflection data 29 . The synextensional stage in the Neuquén basin is known as the Pre-Cuyano Cycle and is constrained between ~220 and ~181 Myr 44,51,52 .…”

Late Jurassic back‐arc extension in the Neuquén Basin (37°S): Insights from structural, sedimentological and provenance analyses

“…Legarreta & Gulisano, 1989). However, recent studies highlight subduction‐related processes exerting a significant role in the evolution of the basin (Scivetti & Franzese, 2019; Tapia et al, 2020; Vicente, 2006). In this context, the Neuquén Basin does not behave as a simple rift system but has two synrift episodes that could be controlled by upper mantle dynamics related to changes in the subduction zone configuration.…”

“…Although the Early Jurassic–Early Cretaceous interval is considered tectonically quiescent and dominated by thermal subsidence, there is evidence of brief tectonic activity, particularly in the southern basin margin (Guzmán et al, 2021; Mosquera & Ramos, 2006; Silvestro & Zubiri, 2008; Vergani et al, 1995; Zavala et al, 2020). In addition, based on subsidence analysis, Scivetti and Franzese (2019) propose that only the Cuyo Group (Sinemurian–Middle Callovian) would strictly constitute the post‐rift of the Neuquén Basin since Lotena Group sedimentation (Middle Callovian–Late Oxfordian) would have been mainly controlled by dynamic subsidence linked to the subducted slab beneath the western margin of Gondwana.…”

Architecture, Kinematics, and Tectonic Evolution of the Principal Cordillera of the Andes in Central Chile (∼33.5°S): Insights From Detrital Zircon U‐Pb Geochronology and Seismotectonics Implications

“…The upper Mendoza Group (Franzese & Spalletti, 2001; Franzese et al., 2003), represents the flooding of the Neuquén basin due to a thermal subsidence, event during the Late Jurassic‐Early Cretaceous, contemporaneous to a post‐rift phase (Howell et al., 2005; Pazos et al., 2020; Scivetti & Franzese, 2019). The Lo Valdes Formation overlies the Río Damas Formation, and is composed mainly by limestones and andesites (González, 1963; Hallam et al., 1986, Salazar & Stinnesbeckb, 2015).…”