Deep mantle roots and continental emergence: implications for whole-Earth elemental cycling, long-term climate, and the Cambrian explosion

Lee, Cin-Ty A.; Caves, Jeremy K.; Jiang, Huaidong; Cao, Wenrong; Lenardic, Adrian; McKenzie, N. Ryan; Shorttle, Oliver; Yin, Qing‐Zhu; Dyer, Blake

doi:10.1080/00206814.2017.1340853

Cited by 68 publications

(34 citation statements)

References 80 publications

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“…Our model of Coorg Block evolution implies an increase in both crustal thickness and continental emergence in the 3.5‐ to 3.1‐Ga period. This contrasts with global models based on numerical modeling of continental emergence that are younger (Neoarchean, Flament et al, ; Neoproterozoic, Lee et al, ) but is broadly correlative to models of increasing crustal thickness around 3.0 Ga (Dhuime et al, ). We do not constrain the area of emerged crust, but we expect it to be large enough to affect the composition of the regional sedimentary budget.…”

Section: Discussionmentioning

confidence: 79%

“…Similarly, the emergence of large areas of continental crust above sea level is also predicted to occur around the late Archean, based on both numerical models (Flament et al, 2008;Vlaar, 2000), and geochemical evidence (Pons et al, 2013;Szilas et al, 2016). However, numerical models for continental emergence are built on several wide-ranging assumptions such as Earth's thermal evolution and continental crustal growth rate and have wide-ranging estimates from the Hadean to the Neoproterozoic (Lee et al, 2018;Maruyama & Ebisuzaki, 2017).…”

Section: Introductionmentioning

confidence: 99%

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Capturing the Mesoarchean Emergence of Continental Crust in the Coorg Block, Southern India

Santosh

2018

Geophysical Research Letters

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The emergence of Earth's continental crust above sea level is debated. To assess whether emergence can be observed at a regional scale, we present zircon U‐Pb‐Hf‐O isotope data from magmatic rocks of the Coorg Block, southern India. A 3.5‐Ga granodiorite records the earliest felsic crust in the region. Younger phases of magmatism at 3.37–3.27 and 3.19–3.14 Ga, comprising both reworked crust and juvenile material, record successive crustal maturation. We interpret an elevation in δ18O through time as an increase in both the amount of sediment recycling and hence, crustal thickening, as well as an increase in the emerged area of continental crust available for weathering. Geochemical signatures do not point to any apparent change in geodynamic regime. We interpret the isotopic evolution of these rocks as solely reflecting regional emergence and thickening of the continental crust, assisted by the increasing strength of the lithosphere.

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Section: Discussionmentioning

confidence: 79%

Section: Introductionmentioning

confidence: 99%

Capturing the Mesoarchean Emergence of Continental Crust in the Coorg Block, Southern India

Santosh

2018

Geophysical Research Letters

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“…4b. While the original interpretation of this record has been obviated by plate tectonics (77), the paradigm of monotonic continental emergence as a result of global cooling has persisted (78,79). We suggest that this paradigm must be reevaluated.…”

Section: Inferences and Conclusionmentioning

confidence: 85%

Neoproterozoic glacial origin of the Great Unconformity

Keller¹,

Husson²,

Mitchell³

et al. 2019

Preprint

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The Great Unconformity, a profound gap in Earth's stratigraphic record often evident below the base of the Cambrian system, has remained among the most enigmatic field observations in Earth science for over a century. While long associated directly or indirectly with the occurrence of the earliest complex animal fossils, a conclusive explanation for the formation and global extent of the Great Unconformity has remained elusive. Here we show that the Great Unconformity is associated with a set of large global oxygen and hafnium isotope excursions in magmatic zircon that suggest a late Neoproterozoic crustal erosion and sediment subduction event of unprecedented scale. These excursions, the Great Unconformity, preservational irregularities in the terrestrial bolide impact record, and the first-order pattern of Phanerozoic sedimentation can together be explained by spatially heterogeneous Neoproterozoic glacial erosion totaling a global average of three to five vertical kilometers, along with the subsequent thermal and isostatic consequences of this erosion for global continental freeboard.

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“…The similarity in the range of the fluxes underscores the likelihood of the geologic carbon cycle maintaining an equilibrium state over million-year timescales (Berner and Caldeira, 1997). Endogenic CO 2 fluxes should change, however, as paleogeography, hypsometry, sea level, and the thermal states of Earth's crust and mantle change (e.g., Kelemen and Manning, 2015;Lee et al, 2018). How endogenic CO 2 fluxes temporally change, concomitant with other changes in the Earth system, remains an open question.…”

Section: Metamorphic Decarbonation In the Geologic Carbon Cyclementioning

confidence: 99%

Remnants and Rates of Metamorphic Decarbonation in Continental Arcs

Ramos¹,

Lackey²,

Barnes³

et al. 2020

GSAT

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Metamorphic decarbonation in magmatic arcs remains a challenge to impose in models of the geologic carbon cycle. Crustal reservoirs and metamorphic fluxes of carbon vary with depth in the crust, rock types and their stratigraphic succession, and through geologic time. When byproducts of metamorphic decarbonation (e.g., skarns) are exposed at Earth's surface, they reveal a record of reactive transport of carbon dioxide (CO 2 ). In this paper, we discuss the different modes of metamorphic decarbonation at multiple spatial and temporal scales and exemplify them through roof pendants of the Sierra Nevada batholith. We emphasize the utility of analogue models for metamorphic decarbonation to generate a range of decarbonation fluxes throughout the Cretaceous. Our model predicts that metamorphic CO 2 fluxes from continental arcs during the Cretaceous were at least 2 times greater than the present cumulative CO 2 flux from volcanoes, agreeing with previous estimates and further suggesting that metamorphic decarbonation was a principal driver of the Cretaceous hothouse climate. We lastly argue that our modeling framework can be used to quantify decarbonation fluxes throughout the Phanerozoic and thereby refine Earth systems models for paleoclimate reconstruction.

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Deep mantle roots and continental emergence: implications for whole-Earth elemental cycling, long-term climate, and the Cambrian explosion

Cited by 68 publications

References 80 publications

Capturing the Mesoarchean Emergence of Continental Crust in the Coorg Block, Southern India

Capturing the Mesoarchean Emergence of Continental Crust in the Coorg Block, Southern India

Neoproterozoic glacial origin of the Great Unconformity

Remnants and Rates of Metamorphic Decarbonation in Continental Arcs

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