The First Andean Compressive Tectonic Phase: Sedimentologic and Structural Analysis of Mid‐Cretaceous Deposits in the Coastal Cordillera, Central Chile (32°50′S)

Boyce, Daniel; Charrier, Reynaldo; Farías, Marcelo

doi:10.1029/2019tc005825

Cited by 28 publications

(10 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Subduction has been active along the Chile margin since at least the Jurassic, continuing to the present (Maloney et al 2013 and references therein), while deformation and uplift of the SCA have been recorded since the Late Cretaceous (Fennell et al 2015;Boyce et al 2020). A major contractional phase occurred from the Miocene through the Quaternary (e.g., Jordan et al 1997;Giambiagi and Ramos 2002;Giambiagi et al 2003;Sagripanti et al 2017;Horton 2018).…”

Section: Geologic Settingmentioning

confidence: 87%

Lithospheric density structure of the southern Central Andes constrained by 3D data-integrative gravity modelling

Piceda

Scheck‐Wenderoth

Dacal

et al. 2020

Int J Earth Sci (Geol Rundsch)

View full text Add to dashboard Cite

The southern Central Andes (SCA) (between 27° S and 40° S) is bordered to the west by the convergent margin between the continental South American Plate and the oceanic Nazca Plate. The subduction angle along this margin is variable, as is the deformation of the upper plate. Between 33° S and 35° S, the subduction angle of the Nazca plate increases from sub-horizontal (< 5°) in the north to relatively steep (~ 30°) in the south. The SCA contain inherited lithological and structural heterogeneities within the crust that have been reactivated and overprinted since the onset of subduction and associated Cenozoic deformation within the Andean orogen. The distribution of the deformation within the SCA has often been attributed to the variations in the subduction angle and the reactivation of these inherited heterogeneities. However, the possible influence that the thickness and composition of the continental crust have had on both short-term and long-term deformation of the SCA is yet to be thoroughly investigated. For our investigations, we have derived density distributions and thicknesses for various layers that make up the lithosphere and evaluated their relationships with tectonic events that occurred over the history of the Andean orogeny and, in particular, investigated the short- and long-term nature of the present-day deformation processes. We established a 3D model of lithosphere beneath the orogen and its foreland (29° S–39° S) that is consistent with currently available geological and geophysical data, including the gravity data. The modelled crustal configuration and density distribution reveal spatial relationships with different tectonic domains: the crystalline crust in the orogen (the magmatic arc and the main orogenic wedge) is thicker (~ 55 km) and less dense (~ 2900 kg/m3) than in the forearc (~ 35 km, ~ 2975 kg/m3) and foreland (~ 30 km, ~ 3000 kg/m3). Crustal thickening in the orogen probably occurred as a result of stacking of low-density domains, while density and thickness variations beneath the forearc and foreland most likely reflect differences in the tectonic evolution of each area following crustal accretion. No clear spatial relationship exists between the density distribution within the lithosphere and previously proposed boundaries of crustal terranes accreted during the early Paleozoic. Areas with ongoing deformation show a spatial correlation with those areas that have the highest topographic gradients and where there are abrupt changes in the average crustal-density contrast. This suggests that the short-term deformation within the interior of the Andean orogen and its foreland is fundamentally influenced by the crustal composition and the relative thickness of different crustal layers. A thicker, denser, and potentially stronger lithosphere beneath the northern part of the SCA foreland is interpreted to have favoured a strong coupling between the Nazca and South American plates, facilitating the development of a sub-horizontal slab.

show abstract

Section: Geologic Settingmentioning

confidence: 87%

Lithospheric density structure of the southern Central Andes constrained by 3D data-integrative gravity modelling

Piceda

Scheck‐Wenderoth

Dacal

et al. 2020

Int J Earth Sci (Geol Rundsch)

View full text Add to dashboard Cite

show abstract

“…These differences are rooted in complex tectonic and magmatic episodes of shortening and extension that span from the Neoproterozoic to the Quaternary [26,[28][29][30][31][32][33][34][35]. Major pulses of Andean deformation are thought to have occurred during the Late Cretaceous and Miocene [36,37], when the style of deformation was significantly influenced not only by the characteristics of the subducting plate [38][39][40], but also by the reactivation of inherited tectonic heterogeneities, which influenced Cenozoic phases of erosion, sedimentation, and geomorphic evolution [41]. The SCA are subdivided into four first-order morphotectonic provinces: the forearc, the magmatic arc, the back-arc, and the foreland (Figure 1; [3,26,42]).…”

Section: Introductionmentioning

confidence: 99%

Controls of the Lithospheric Thermal Field of an Ocean-Continent Subduction Zone: The Southern Central Andes

et al. 2022

View full text Add to dashboard Cite

In an ocean-continent subduction zone, the assessment of the lithospheric thermal state is essential to determine the controls of the deformation within the upper plate and the dip angle of the subducting lithosphere. In this study, we evaluate the degree of influence of both the configuration of the upper plate (i.e., thickness and composition of the rock units) and variations of the subduction angle on the lithospheric thermal field of the southern Central Andes (29°–39°S). Here, the subduction angle increases from subhorizontal (5°) north of 33°S to steep (~30°) in the south. We derived the 3D temperature and heat flow distribution of the lithosphere in the southern Central Andes considering conversion of S wave tomography to temperatures together with steady-state conductive thermal modeling. We found that the orogen is overall warmer than the forearc and the foreland and that the lithosphere of the northern part of the foreland appears colder than its southern counterpart. Sedimentary blanketing and the thickness of the radiogenic crust exert the main control on the shallow thermal field (<50 km depth). Specific conditions are present where the oceanic slab is relatively shallow (<85 km depth) and the radiogenic crust is thin. This configuration results in relatively colder temperatures compared to regions where the radiogenic crust is thick and the slab is steep. At depths >50 km, the temperatures of the overriding plate are mainly controlled by the mantle heat input and the subduction angle. The thermal field of the upper plate likely preserves the flat subduction angle and influences the spatial distribution of shortening.

show abstract

“…The present‐day configuration of the SCA is the result of a complex tectonic evolution that spans from the Neoproterozoic to the Quaternary, including episodes of terrane accretion, shortening, and extension (Astini et al., 1995; Azcuy & Caminos, 1987; Giambiagi et al., 2003; Jordan et al., 1983; Kay et al., 2006; Llambias & Sato, 1990; Mpodozis & Kay, 1990; Ramos, 1988). The ongoing subduction beneath the South American plate has been active since at least the Late Jurassic (Maloney et al., 2013 and references therein), although major pulses of Andean deformation are thought to have occurred during the Late Cretaceous and the Miocene (Boyce et al., 2020; Fennell et al., 2015). The onset of flat subduction north of 33°S is thought to have occurred at ∼19 Ma (Jones et al., 2014, 2015, 2016), finally attaining its present‐day subhorizontal angle at ∼7–6 Ma (see Kay & Mpodozis, 2002; Kay et al., 2006; Ramos et al., 2002).…”

Section: Introductionmentioning

confidence: 99%

Long‐Term Lithospheric Strength and Upper‐Plate Seismicity in the Southern Central Andes, 29°–39°S

Piceda

Scheck‐Wenderoth

Cacace

et al. 2022

Geochem Geophys Geosyst

View full text Add to dashboard Cite

We examined the relationship between the mechanical strength of the lithosphere and the distribution of seismicity within the overriding continental plate of the southern Central Andes (SCA, 29°–39°S), where the oceanic Nazca Plate changes its subduction angle between 33°S and 35°S, from subhorizontal in the north (<5°) to steep in the south (∼30°). We computed the long‐term lithospheric strength based on an existing 3D model describing variations in thickness, density, and temperature of the main geological units forming the lithosphere of the SCA and adjacent forearc and foreland regions. The comparison between our results and seismicity within the overriding plate (upper‐plate seismicity) shows that most of the events occur within the modeled brittle domain of the lithosphere. The depth where the deformation mode switches from brittle frictional to thermally activated ductile creep provides a conservative lower bound to the seismogenic zone in the overriding plate of the study area. We also found that the majority of upper‐plate earthquakes occurs within the realm of first‐order contrasts in integrated strength (12.7–13.3 log Pam in the Andean orogen vs. 13.5–13.9 log Pam in the forearc and the foreland). Specific conditions characterize the mechanically strong northern foreland of the Andes, where seismicity is likely explained by the effects of slab steepening.

show abstract

The First Andean Compressive Tectonic Phase: Sedimentologic and Structural Analysis of Mid‐Cretaceous Deposits in the Coastal Cordillera, Central Chile (32°50′S)

Cited by 28 publications

References 41 publications

Lithospheric density structure of the southern Central Andes constrained by 3D data-integrative gravity modelling

Lithospheric density structure of the southern Central Andes constrained by 3D data-integrative gravity modelling

Controls of the Lithospheric Thermal Field of an Ocean-Continent Subduction Zone: The Southern Central Andes

Long‐Term Lithospheric Strength and Upper‐Plate Seismicity in the Southern Central Andes, 29°–39°S

Contact Info

Product

Resources

About