Quantifying crustal thickness over time in magmatic arcs

Profeta, Lucia; Ducea, Mihai N.; Chapman, James B.; Paterson, Scott R.; Gonzales, S.; Kirsch, Moritz; Petrescu, Lucian; DeCelles, Peter G.

doi:10.1038/srep17786

Cited by 383 publications

(284 citation statements)

References 36 publications

(55 reference statements)

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“…Crustal thickness with uncertainty is calculated following the method of Profeta et al . [] (see the supporting information). Note that the 122–82 Ma samples that are inferred to have originated from the subducting Neo‐Tethyan oceanic crust and some 35–9 Ma samples with high (La/Yb)n (>24) that are not constrained to a geophysically determined Moho depth [ Profeta et al ., ] are not used in the crustal thickness discussions.…”

Section: Methods and Resultsmentioning

confidence: 63%

“…Comparison between the compositions of recently emplaced intermediate continental calc‐alkaline magmatic rocks and geophysically determined crustal thickness, as well as studies from global correlations and specific orogens, show that geochemical indices can be used to track quantitatively temporal variations of crustal thickness in continental arcs [ Chiaradia , ; Chapman et al ., ; Profeta et al ., ]. An extended application of this approach in this paper to the Gangdese arc in southern Tibet (Figure a), and assuming Airy isostatic compensation, enables us to quantify the crustal thickness of the arc and reconstruct the spatial and temporal uplift history of the Gangdese Mountains.…”

Section: Introductionmentioning

confidence: 99%

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Raising the Gangdese Mountains in southern Tibet

et al. 2017

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The surface uplift of mountain belts is in large part controlled by the effects of crustal thickening and mantle dynamic processes (e.g., lithospheric delamination or slab breakoff). Understanding the history and driving mechanism of uplift of the southern Tibetan Plateau requires accurate knowledge on crustal thickening over time. Here we determine spatial and temporal variations in crustal thickness using whole‐rock La/Yb ratios of intermediate intrusive rocks from the Gangdese arc. Our results show that the crust was likely of normal thickness prior to approximately 70 Ma (~37 km) but began to thicken locally at approximately 70–60 Ma. The crust reached (58–50) ± 10 km at 55–45 Ma extending over 400 km along the strike of the arc. This thickening was likely due to magmatic underplating as a consequence of rollback and then breakoff of the subducting Neo‐Tethyan slab. The crust attained a thickness of 68 ± 12 km at approximately 20–10 Ma, as a consequence of underthrusting of India and associated thrust faulting. The Gangdese Mountains in southern Tibet broadly attained an elevation of >4000 m at approximately 55–45 Ma as a result of isostatic surface uplift driven by crustal thickening and slab breakoff and reached their present‐day elevation by 20–10 Ma. Our paleoelevation estimates are consistent not only with the C–O isotope‐based paleoaltimetry but also with the carbonate‐clumped isotope paleothermometer, exemplifying the promise of reconstructing paleoelevation in time and space for ancient orogens through a combination of magmatic composition and Airy isostatic compensation.

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Section: Methods and Resultsmentioning

confidence: 63%

Section: Introductionmentioning

confidence: 99%

Raising the Gangdese Mountains in southern Tibet

et al. 2017

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“…Crustal thickness calculations based on the Sr/Y ratios (Chiaradia, 2015;Profeta et al, 2015) in the studied Jurassic plutons have yielded values between 3 and 38. This suggests a normal to relatively thin crust characterized by values between 25 km and 45 km, as has also been suggested by the subsiding nature of the Jurassic to Early Cretaceous basins (Sarmiento-Rojas et al, 2006).…”

Section: Cs Rb Ba Th U Nb K La Ce Pb Pr Sr P Nd Zr Sm Eu Ti Dy Y Yb Lumentioning

confidence: 99%

Late Jurassic to Early Cretaceous plutonism in the Colombian Andes: A record of long-term arc maturity

Bustamante

Archanjo

Cardona

et al. 2016

Geological Society of America Bulletin

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Integrated geochemical, isotopic, and geochronological constraints from Jurassic plutonic rocks of the Central Cordillera in Colombia were used to determine the tectonic setting and long-term tectonomagmatic evolution of the Northern Andes. We examined three plutonic units with compositions that vary from diorite to granite and with U-Pb zircon crystallization ages from 165 Ma to 129 Ma. These units are interpreted as subduction-related magmas, as indicated by their K 2 O, Na 2 O contents, light to heavy rare earth element (LREE/HREE) ratios, and Pb isotope signatures. The Nd and Hf isotope compositions of these magmatic events become more juvenile (radiogenic) with time. This compositional record suggests an arc maturity trend in which partial melting of basaltic and peridotitic sources becomes more significant than radio genic subducted sediments or the ancient continental crust. Global-scale tectonic reconstructions suggest that Late Jurassic to Early Cretaceous subduction of the Farallon oceanic plate under the Andean continental margin became highly oblique. The consequence was a reduction of the fusible sedimentary budget commonly incorporated during subduction into the mantle, leaving a more refractory mantle with a more primitive compositional signature, and a major decrease in magmatic activity in the Early Cretaceous. In addition, the magmatic evolution recorded in the North Andean Jurassic arc shows that long-term source evolution and regionalscale plate-tectonic processes also play an important role in the compositional evolution and volumes of magmatic products in convergent settings.

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“…The vertical thickness of this box (and thus the overall crustal thickness) can be estimated by (a) examining geophysical data for recent comparable arc systems, (b) using geochemical proxies indicative of crustal thickness (e.g., Sr/Y ratios; Profeta et al, 2015), (c) simple geochemically constrained mass balance calculations (e.g., Jicha & Jagoutz, 2015), and/or (d) using isostatic mass balance modeling predicting crustal thicknesses (e.g., . These box thicknesses agree well with exposed crustal depths in each of the sections as constrained by geobarometry (see detailed description of areas and constraints on crustal depth in the supporting information).…”

Section: 1029/2018gc008031mentioning

confidence: 99%

Spatial and Depth‐Dependent Variations in Magma Volume Addition and Addition Rates to Continental Arcs: Application to Global CO₂ Fluxes since 750 Ma

Ratschbacher

Paterson

Fischer

2019

Geochem Geophys Geosyst

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Magma transfer from the mantle to the crust in arcs is an important step in the global cycling of elements and volatiles from Earth's interior to the atmosphere. Arc intrusive rocks dominate the total magma mass budget over extrusive rocks. However, their total volume and rate of addition is still poorly constrained, especially in continental arcs. We present lateral (forearc to backarc) and depth‐dependent (volcanics to deep crust) magma volume additions and arc‐wide magma addition rates (MARs) calculated from three continental arc crustal sections preserving magma flare‐up periods. We observe an increase in volume addition with depth and less magma added in the forearc (~15%) and backarc (~10% to 30%) compared to the main arc. Crustal‐wide MARs for each section are remarkably similar and around 0.7–0.9 km3/km2/Ma. MARs can be used to estimate CO2 fluxes from continental arcs. With initial magma CO2 contents of 1.5 wt.%, global continental arc lengths, and MARs, we calculate changes in C (Mt/year) released from continental arcs since 750 Ma. Calculated present‐day global C fluxes are similar to values constrained by other methods. Throughout the Phanerozoic, assuming equal durations of flare‐up and lull magmatism, calculated continental CO2 flux rates vary between 4 and 18 Mt C/year with highest values in the Mesozoic. These fluxes are considered minima since the intake of mantle and/or crustal carbon is not considered. Magmatic episodicity in continental arcs and changes in arc thickness and width are critical to consider when calculating MARs through time.

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Quantifying crustal thickness over time in magmatic arcs

Cited by 383 publications

References 36 publications

Raising the Gangdese Mountains in southern Tibet

Raising the Gangdese Mountains in southern Tibet

Late Jurassic to Early Cretaceous plutonism in the Colombian Andes: A record of long-term arc maturity

Spatial and Depth‐Dependent Variations in Magma Volume Addition and Addition Rates to Continental Arcs: Application to Global CO₂ Fluxes since 750 Ma

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Quantifying crustal thickness over time in magmatic arcs

Cited by 383 publications

References 36 publications

Raising the Gangdese Mountains in southern Tibet

Raising the Gangdese Mountains in southern Tibet

Late Jurassic to Early Cretaceous plutonism in the Colombian Andes: A record of long-term arc maturity

Spatial and Depth‐Dependent Variations in Magma Volume Addition and Addition Rates to Continental Arcs: Application to Global CO2 Fluxes since 750 Ma

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Spatial and Depth‐Dependent Variations in Magma Volume Addition and Addition Rates to Continental Arcs: Application to Global CO₂ Fluxes since 750 Ma