Basement-cover interaction in the mountain front of the Northern Neuquén fold and thrust belt (37°10' – 37°40' S), Argentina. (June 2020)

• Record Type: Journal Article
• Authors: Turienzo, Martín; Sánchez, Natalia; Lebinson, Fernando; Peralta, Florencia; Araujo, Vanesa; Irastorza, Ainara; Dimieri, Luis
• Is Part Of: Journal of South American earth sciences. Volume 100(2020)
• Publication Date: 2020-06
• Subjects: Neuquén basin -- Thick-skinned structures -- Seismic interpretation -- Thrust systems; Geology -- Latin America -- Periodicals; Earth sciences -- Latin America -- Periodicals; Geology -- Antarctica -- Periodicals; Earth sciences -- Antarctica -- Periodicals; Geology -- Caribbean Area -- Periodicals; Earth sciences -- Caribbean Area -- Periodicals; Géologie -- Amérique latine -- Périodiques; Sciences de la terre -- Amérique latine -- Périodiques; Géologie -- Antarctique -- Périodiques; Sciences de la terre -- Antarctique -- Périodiques; Géologie -- Caraïbes (Région) -- Périodiques; Sciences de la terre -- Caraïbes (Région) -- Périodiques; Earth sciences; Geology; Antarctica; Caribbean Area; Latin America; Periodicals; 550.5
• DOI: 10.1016/j.jsames.2020.102560
• Languages: English
• ISSNs: 0895-9811

Abstract

Abstract: The deformation front of the Neuquén fold and thrust belt (~37°30′S) comprises kilometer-scale basement-involved anticlines, related to development of the Las Yeseras and Pampa Tril thrust systems, connected with a wide frontal syncline. The interpretation of more than 70 seismic lines led to the construction of a time-structure map at top of the Cuyo Group (Middle Jurassic), which shows a structural high east of the Tromen volcano produced by the superposition of thick-skinned structures. Moreover, data from 35 oil wells constrain the along-strike variations in structural reliefs. The structural relief of the Las Yeseras anticline increase from north to south, between ~1000 m and 2000 m, while the structural relief of the Pampa Tril anticline reaches its maximum height of 3700 m in the north and decreases southwards to only 1600 m height and then disappears. Three structural cross-sections based on surface and subsurface information show the overall structural style dominated by north-trending basement-involved anticlines, with subhorizontal backlimbs and maximum structural reliefs around 3–4 km, associated with thick-skinned thrust systems and without significant participation of inverted normal faults. Calculated thick-skinned shortenings are ~8.3 km (14.8%) in the north and ~4 km (7.8%) in the south, which principally reflects the decreasing displacement of the Pampa Tril thrust system. Along-strike structural changes were locally controlled by WNW transfer zones that can be interpreted as SSW-dipping preexisting normal faults with minor positive inversion. Thin-skinned structures that form oil fields at depth are genetically associated with the thick-skinned thrust systems, thus the understanding of basement-cover interaction in the mountain fronts will aid to future hydrocarbon explorations and to comprehend the mechanisms of Andean mountain building. Highlights: Basement-involved anticlines form the deformation front of the Northern Neuquén FTB. The Las Yeseras and Pampa Tril thrust systems, ~ N-S, control thick-skinned deformation. Thick-skinned structures show variable style, structural relief and shortening along-strike. WNW transfer zones are interpreted as slightly inverted SSW-dipping normal faults.