A New Workflow to Assess Emplacement Duration and Melt Residence Time of Compositionally Diverse Magmas Emplaced in a Sub-volcanic Reservoir

Ratschbacher, Barbara C.; Keller, C. Brenhin; Schoene, Blair; Paterson, Scott R.; Anderson, J. Lawford; Okaya, D. A.; Putirka, Keith; Lippoldt, Rachel

doi:10.1093/petrology/egy079

Cited by 17 publications

(31 citation statements)

References 66 publications

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“…Magma VA and MARs have many important implications: They control the construction durations of magma reservoirs and melt residence timescales (e.g., Karakas et al, 2017;Ratschbacher et al, 2018), thus ultimately controlling crustal differentiation. Furthermore, in magma-rich arcs, the volume of magma added to the crust influences its rheology and mass balance causing crustal thickening and mountain building (e.g., .…”

Section: Introductionmentioning

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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Section: Introductionmentioning

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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“…8) suggests the zircons grew from different granitic melts from a compositional spectrum related by mixing. Given the apparent several-million-year difference in emplacement age between the northern and southern Merrimac plutons and that the crystallization history of individual plutonic intrusions is typically several hundreds of thousands of years (e.g., Matzel et al, 2006;Schoene et al, 2012;Ratschbacher et al, 2018), this spectrum of melts parental to the zircons likely reflects the mixing within a deeper-crustal source zone rather than shallow-level mixing between the magmas responsible for the plutons (e.g., Gray et al, 2008). Granitoids composing the Sierra Nevada batholith are considered to be generated in the lower crust (Ratajeski et al, 2005;Sisson et al, 2005), reflecting mixtures between mantle-derived and crustal components (e.g., Gray et al, 2008;Lackey et al, 2008).…”

Section: ■ Discussionmentioning

confidence: 99%

Influence of pre-existing structure on pluton emplacement and geomorphology: The Merrimac plutons, northern Sierra Nevada, California, USA

et al. 2021

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In much of the western Cordillera of North America, the geologic framework of crustal structure generated in the Mesozoic leaves an imprint on later plutonic emplacement, subsequent structural setting, and present landscape morphology. The Merrimac plutons in the northern Sierra Nevada (California, USA) are a good example of the influence of pre-existing structure at a larger scale. This paper updates and refines earlier studies of the Merrimac plutons, with the addition of analysis of gravity and magnetic data and new 206Pb/238U zircon dates. The gravity and magnetic data not only confirm the presence of two different neighboring plutons, but also (1) support the presence of a third pluton, (2) refine the nature of the contact between the Merrimac plutons as being structurally controlled, and (3) estimate the depth extent of the plutons to be ~4–5 km. The zircon 206Pb/238U dates indicate that the two main plutons have statistically different crystallization ages nearly 4 m.y. apart. Geomorphic analyses, including estimates of relief, roughness and drainage density and generation of chi plots, indicate that the two main plutons are characterized by different elevations with large longitudinal channel knickpoints that we speculatively attribute to possible reactivation of pre-existing structure in addition to lithologic variations influencing relative erosion susceptibility in response to prior accelerated surface uplift.

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“…(2018) and Ratschbacher et al. (2018) for all samples in our study to most objectively estimate the timing of emplacement (see supporting information and Section 2 for full model details).…”

Section: Methodsmentioning

confidence: 99%

“…This limits the ability of traditional approaches, such as the calculation of a weighted mean, to estimate emplacement age. As an alternative, we employed a Bayesian Markov Chain Monte Carlo (MCMC) model modified from Keller et al (2018) and Ratschbacher et al (2018) for all samples in our study to most objectively estimate the timing of emplacement (see supporting information and Section 2 for full model details). KINNEY ET AL.…”

Section: Zircon U-pb Geochronologymentioning

confidence: 99%

Zircon U‐Pb Geochronology Constrains Continental Expression of Great Meteor Hotspot Magmatism

Kinney

MacLennan

Keller

et al. 2021

Geophysical Research Letters

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A variety of dynamic processes shape the tectonic evolution of rifted continental margins, including hotspot magmatism (e.g., Morgan, 1971, 1983), lithospheric delamination (e.g., Nelson, 1992, and active mantle upwelling due to edge-driven convection (e.g., King & Anderson, 1998). The Eastern North American Margin experienced several significant post-orogenic and tectono-magmatic events since the initial rifting and fragmentation of the supercontinent Pangea approximately ca. 240 Myr ago (e.g., Mazza et al., 2017 and references therein). The northeastern United States in particular contains evidence for (a) multiple episodes of both rift-related and post-rift magmatism from the Late Triassic through the Cretaceous (e.g., Eby, 1987;McHone & Butler, 1984); (b) regional changes in exhumation rates in the late Cretaceous (e.g., Amidon et al., 2016;Crough, 1981; West & Roden-Tice, 2003); (c) seismic evidence for the presence of an active asthenospheric upwelling, the Northern Appalachian Anomaly (e.g., Menke et al., 2016). The youngest, post-rift igneous province in the region, the Cretaceous New England Québec (NEQ) Province (McHone & Butler, 1984), is a controversial aspect of our understanding of the tectonic evolution of the Eastern North American Margin. The NEQ plutons, with the Mesozoic kimberlite fields in Ontario (Heaman & Kjarsgaard, 2000) and the New England Seamount Chain (Duncan, 1984), are commonly considered to be a continental expression of magmatism associated with the purported Great Meteor Hotspot (GMH), interpreted to be a long-lived (>100 Myr) mantle plume (Sleep, 1990). However, a variety of other causal mechanisms have been invoked for the existence of this province (e.g.

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A New Workflow to Assess Emplacement Duration and Melt Residence Time of Compositionally Diverse Magmas Emplaced in a Sub-volcanic Reservoir

Cited by 17 publications

References 66 publications

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

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

Influence of pre-existing structure on pluton emplacement and geomorphology: The Merrimac plutons, northern Sierra Nevada, California, USA

Zircon U‐Pb Geochronology Constrains Continental Expression of Great Meteor Hotspot Magmatism

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A New Workflow to Assess Emplacement Duration and Melt Residence Time of Compositionally Diverse Magmas Emplaced in a Sub-volcanic Reservoir

Cited by 17 publications

References 66 publications

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

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

Influence of pre-existing structure on pluton emplacement and geomorphology: The Merrimac plutons, northern Sierra Nevada, California, USA

Zircon U‐Pb Geochronology Constrains Continental Expression of Great Meteor Hotspot Magmatism

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Product

Resources

About

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

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