Oligocene-Miocene deformational and depositional history of the Andean hinterland basin in the northern Altiplano plateau, southern Peru

Perez, Nicholas D.; Horton, Brian K.

doi:10.1002/2014tc003647

Cited by 49 publications

(50 citation statements)

References 87 publications

(149 reference statements)

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“…Spatially dissimilar records reveal a complex Paleogene history in which shortening in the northern transect overlapped with quiescence and upper crustal extension in the central and southern transects. Whereas the central Andes at 15–25°S shows a clear record of retroarc shortening in the 35–20 Ma window (Allmendinger et al, ; Carrapa & DeCelles, , ; Elger et al, ; Horton, , ; Horton et al, ; Müller et al, ; Oncken et al, ; Perez & Horton, ), regions south of ~28°S registered foreland quiescence with concurrent hinterland extension (Horton et al, ; Litvak et al, ; Winocur et al, ). Essential in this reconstruction is the profound along‐strike change from an extensional to a contractional record, with an apparent transition in the 20–30°S sector (Fosdick et al, ; Horton & Fuentes, ; Jordan et al, ).…”

Section: Variations In Andean Tectonic Regimesmentioning

confidence: 99%

Tectonic Regimes of the Central and Southern Andes: Responses to Variations in Plate Coupling During Subduction

2018

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Construction of the Andes has been governed largely by fluctuating contractional, neutral, and extensional tectonic regimes during differing degrees of mechanical coupling along the convergent plate boundary. These three contrasting regimes are likely regulated by geodynamic variations in absolute trenchward motion of South America and episodic regional shifts in the geometry of the subducting oceanic slab. Alternations among these three modes are revealed in syntheses of Mesozoic‐Cenozoic crustal deformation, basin evolution, and arc magmatism along orogen‐perpendicular transects across the central and southern Andes at 23°S, 35°S, and 43°S. Despite considerable along‐strike dissimilarities in the magnitude of deformation, a comparable tectonic regime typified the early Andean history, as defined by a transition from Late Jurassic‐Early Cretaceous postrift thermal subsidence to Late Cretaceous retroarc shortening. A key contradiction is expressed for the late middle Eocene to earliest Miocene, when neutral to extensional conditions affected retroarc to forearc regions, except in parts of the central Andes, which experienced retroarc shortening with only localized forearc extension. This mixed‐mode scenario during Paleogene time may reflect decoupling along the plate boundary (possibly during slab rollback within a retreating subduction system) in which widespread stasis or low‐magnitude extension dominated the southern Andes but was inhibited in the strongly shortened central Andes at 15–25°S where shallow subduction and/or high topography boosted plate coupling. Comparable temporal and spatial shifts in tectonic regime along the Andes and other convergent margins can be related to variable degrees of coupling during first‐order plate‐scale changes in convergence and second‐order regional cycles of slab shallowing and steepening.

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Section: Variations In Andean Tectonic Regimesmentioning

confidence: 99%

Tectonic Regimes of the Central and Southern Andes: Responses to Variations in Plate Coupling During Subduction

2018

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“…The boundary between the Amazonia and Arequipa domains is obscured by Paleozoic and younger cover rocks and various magmatic arcs. These rocks include Carboniferous to Early Jurassic "Gondwanide" granitoids and related Triassic rift basin deposits of the Mitu Group, both produced during the assembly and breakup of western Gondwana, (Sempere et al, 2002;Ramos, 2008;Mišković et al, 2009;Reitsma, 2012;Perez and Horton, 2014).…”

Section: Regional Geologymentioning

confidence: 99%

“…Two key similarities between Mesozoic strata of SE Peru, in particular the Mitu Group and Huancané Formation, and leucogneiss xenoliths lead us to suggest that the latter are the highly metamorphosed equivalents of the former. First, detrital zircon age spectra from Mesozoic strata (Reitsma, 2012;Perez and Horton, 2014; Fig. 10B) overlap the spectrum of leucogneiss sample 11MA20A, each containing distinct late Paleozoic to Late Triassic, early Paleozoic, and Mesoproterozoic age peaks.…”

Section: Metasedimentsmentioning

confidence: 99%

“…As mentioned previously, the volcano-sedimentary strata of the Mitu Group are thought to represent rift deposits produced during the initial stages of Gondwana disassembly (Kontak et al, 1990a;Sempere et al, 2002;Perez and Horton, 2014). Inversion of basins containing Mitu Group strata is thought to have commenced at a slow pace in Late Jurassic-Early Cretaceous time and culminated during the Andean orogeny (Sempere et al, 2002), although the precise timing of uplift is not well understood.…”

Section: Metasedimentsmentioning

confidence: 99%

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Constraints on plateau architecture and assembly from deep crustal xenoliths, northern Altiplano (SE Peru)

Chapman

Ducea

McQuarrie

et al. 2015

Geological Society of America Bulletin

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Newly discovered xenoliths within Pliocene and Quaternary intermediate volcanic rocks from southern Peru permit examination of lithospheric processes by which thick crust (60-70 km) and high average elevations (3-4 km) resulted within the Altiplano,the second most extensive orogenic plateau on Earth. The most common petrographic groups of xenoliths studied here are igneous or meta-igneous rocks with radiogenic isotopic ratios consistent with recent derivation from asthenospheric mantle ( 87 Sr/ 86 Sr = 0.704-0.709, 143 Nd/ 144 Nd = 0.5126-0.5129). A second group, consisting of felsic granulite xenoliths exhibiting more radiogenic compositions ( 87 Sr/ 86 Sr = 0.711-0.782, 143 Nd/ 144 Nd = 0.5121-0.5126), is interpreted as supracrustal rocks that underwent metamorphism at ~9 kbar (~30-35 km paleodepth, assuming a mean crustal density of 2.8 g/cm 3 ) and ~750 °C. These rocks are correlated with nonmetamorphosed rocks of the Mitu Group and assigned a Mesozoic (Upper Triassic or younger) age based on detrital zircon U-Pb ages. A felsic granulite Sm-Nd garnet wholerock isochron of 42 ± 2 Ma demonstrates that garnet growth took place in Eocene time. Monazite grains associated with quenched anatectic melt networks in the same rocks yield ion microprobe U-Pb ages ranging from 3.2 ± 0.2 to 4.4 ± 0.3 Ma (2σ). These disparate geochronologic data sets are reconciled by a model wherein Mesozoic cover rocks were transferred to >30 km depth beneath the plateau in the Eocene and progressively heated until at least Pliocene time. Isothermal de-compression and partial melting ensued as these rocks were entrained as xenoliths in volcanic host magmas and transported toward the surface. Mafic granulites and peridotites from the same xenolith suite comprise the basement of the metasedimentary sequence, exhibiting isotopic characteristics of Central Andean crust. Calculated equilibrium pressures for these basement rocks are >11 kbar, suggesting that the basement-cover interface lies beneath the northernmost Altiplano at ~30-40 km below the surface. Together, these results indicate that crustal thickening under the northernmost Altiplano started earlier than major latest Oligocene and Miocene uplift episodes affecting the region and was coeval with a flat slab-related regional episode of deformation. Total shortening must have been at least 20% more than previous estimates in order to satisfy the basement to cover depth constraints provided by the xenolith data. Sedimentary rocks at >30 km paleodepth require that Andean basement thrusts decapitated earlier Triassic normal faults, trapping Paleozoic and Mesozoic rocks below the main décollement. Magma loading from intense Cenozoic plutonism within the plateau probably played an additional role in transporting Mesozoic cover rocks to >30 km and thickening the crust beneath the northern Altiplano.

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“…These findings highlight that sources of different rock strengths such as quartzite and sandstone found in complex tectonic environments (e.g., pro‐ and retro‐foreland basins) can have their detrital age signatures significantly changed in modern river sands. Moreover, distorted grain age distributions within sediment reaching continental platforms can be preserved in siliciclastic rocks and in the product of their recycling (e.g., metamorphic rocks, Campbell et al, ; Perez & Horton, ; Sharman & Johnstone, ). Therefore, recognizing these distortions is important to more accurately (un) mix grain age distributions through modeling and inform provenance analysis from sedimentary archives.…”

Section: Discussionmentioning

confidence: 99%

Does Pebble Abrasion Influence Detrital Age Population Statistics? A Numerical Investigation of Natural Data Sets

et al. 2018

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Pebble abrasion is a key factor controlling the release of minerals into sand, but few attempts have been made to model how it could influence the liberation of minerals into the size fraction used in detrital geochronology. We perform a series of experiments with an abrasion model to test this influence using natural and synthetic data sets. Our results demonstrate that pebble abrasion can change the zircon mixing proportions of upstream source units as well as the age distribution of mixed fluvial sands. This change is particularly significant when there is strong contrast in rock resistance within the watershed. Pebble abrasion is one of many factors that can change the mixing proportion of sands, including hillslope gravel supply, erosion rates, and mineral fertility. In our study case (Marsyandi watershed, Himalaya), the abrasion model predicts age distributions that are statistically indistinguishable from those predicted by a no‐abrasion model. However, the relative erosion rates estimated by our model largely differ from the results of a no‐abrasion model and are closer to those from other studies that suggest a strong correlation between modern erosion rates, tectonics, and precipitation intensity in the Marsyandi watershed. These findings highlight that, even in cases where there is no statistical evidence of change between the modeled age distributions, abrasion can affect the erosion rates estimated from them. Therefore, quantifying the influence of abrasion on sand production is an essential step not only to predict mixing proportions but also to accurately retrieve erosion rates from the measured grain age distributions.

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Oligocene-Miocene deformational and depositional history of the Andean hinterland basin in the northern Altiplano plateau, southern Peru

Abstract: Cenozoic basin fill of the northern Altiplano plateau records the tectonic development of the

Cited by 49 publications

References 87 publications

Tectonic Regimes of the Central and Southern Andes: Responses to Variations in Plate Coupling During Subduction

Tectonic Regimes of the Central and Southern Andes: Responses to Variations in Plate Coupling During Subduction

Constraints on plateau architecture and assembly from deep crustal xenoliths, northern Altiplano (SE Peru)

Does Pebble Abrasion Influence Detrital Age Population Statistics? A Numerical Investigation of Natural Data Sets

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