Sluggish Hadean geodynamics: Evidence from coupled 146,147 Sm– 142,143 Nd systematics in Eoarchean supracrustal rocks of the Inukjuak domain (Québec)

Caro, Guillaume; Morino, Précillia; Mojzsis, Stephen J.; Cates, N. L.; Bleeker, Wouter

doi:10.1016/j.epsl.2016.09.051

Cited by 55 publications

(64 citation statements)

References 73 publications

(127 reference statements)

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“…The persistence of 142 Nd heterogeneity into the Archean, and as "late" as 2.7 Ga, particularly for felsic compositions (SI Appendix, Fig. S9), has been suggested to be due to the sluggish mixing behavior of the mantle in the Hadean and Archean, due to stagnant lid tectonics or sluggish mantle dynamics that would have slowed the mixing rate of the mantle (3,15). The data in Fig.…”

Section: Significancementioning

confidence: 92%

The¹⁴²Nd/¹⁴⁴Nd variations in mantle-derived rocks provide constraints on the stirring rate of the mantle from the Hadean to the present

Hyung

Jacobsen

2020

Proc. Natl. Acad. Sci. U.S.A.

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Early silicate differentiation events for the terrestrial planets can be traced with the short-lived146Sm-142Nd system (∼100-My half-life). Resulting early Earth-produced142Nd/144Nd variations are an excellent tracer of the rate of mantle mixing and thus a potential tracer of plate tectonics through time. Evidence for early silicate differentiation in the Hadean (4.6 to 4.0 Ga) has been provided by142Nd/144Nd measurements of rocks that show both higher and lower (±20 ppm) values than the present-day mantle, demonstrating major silicate Earth differentiation within the first 100 My of solar system formation. We have obtained an external 2σ uncertainty at 1.7 ppm for142Nd/144Nd measurements to constrain its homogeneity/heterogeneity in the mantle for the last 2 Ga. We report that most modern-day mid-ocean ridge basalt and ocean island basalt samples as well as continental crustal rocks going back to 2 Ga are within 1.7 ppm of the average Earth142Nd/144Nd value. Considering mafic and ultramafic compositions, we use a mantle-mixing model to show that this trend is consistent with a mantle stirring time of about 400 My since the early Hadean. Such a fast mantle stirring rate supports the notion that Earth’s thermal and chemical evolution is likely to have been largely regulated by plate tectonics for most of its history. Some young rocks have142Nd/144Nd signatures marginally resolved (∼3 ppm), suggesting that the entire mantle is not equally well homogenized and that some silicate mantle signatures from an early differentiated mantle (>4.1 Ga ago) are preserved in the modern mantle.

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Section: Significancementioning

confidence: 92%

The¹⁴²Nd/¹⁴⁴Nd variations in mantle-derived rocks provide constraints on the stirring rate of the mantle from the Hadean to the present

Hyung

Jacobsen

2020

Proc. Natl. Acad. Sci. U.S.A.

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“…The models represented by blue curves, of course, preclude any land‐based RNA formation prior to 3.8 Ga. Analyses of mica inclusions and oxygen isotope data in Hadean zircons suggest that the Hadean did have a small volume of crust with a composition similar to that of the modern crust . However, the continental area (and, by inference, the amount of sub‐aerial land) should not be confused with the volume of continental crust.…”

Section: Subaerial Land That Is Intermittently Dry Is Requiredmentioning

confidence: 99%

When Did Life Likely Emerge on Earth in an RNA‐First Process?

et al. 2019

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The widespread presence of ribonucleic acid (RNA) catalysts and cofactors in the Earth′s biosphere today suggests that RNA was the first biopolymer to support Darwinian evolution. However, most “path‐hypotheses” to generate building blocks for RNA require reduced nitrogen‐containing compounds not made in useful amounts in the CO2−N2−H2O atmospheres of the Hadean. We review models for Earth′s impact history that invoke a single ∼1023 kg impactor (Moneta) to account for measured amounts of platinum, gold, and other siderophilic (“iron‐loving”) elements on the Earth and Moon. If it were the last sterilizing impactor, by reducing the atmosphere but not the mantle Moneta, would have opened a “window of opportunity” for RNA synthesis, a period when RNA precursors rained from the atmosphere onto land holding oxidized minerals that stabilize advanced RNA precursors and RNA. Surprisingly, this combination of physics, geology, and chemistry suggests a time when RNA formation was most probable, ∼120±100 million years after Moneta′s impact, or ∼4.36±0.1 billion years ago. Uncertainties in this time are driven by uncertainties in rates of productive atmosphere loss and amounts of sub‐aerial land.

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“…First, we do not see a 142 Nd excess in mid‐ocean ridge basalt today—the signature has been effectively erased by mantle mixing over geological time, although at least one ocean‐island basalt (OIB) exception exists (Horan et al, ). However, despite expected vigorous mantle convection in the Hadean (O'Neill & Debaille, ), which should erase such mantle anomalies over ~90‐Myr timescales (Coltice & Schmalzl, ), we see these reservoirs survive over 800 Myr (e.g., see Caro et al, ). Second, the Itsaq and the Narryer terranes appear to have tapped separate mantle reservoirs that, despite both forming in the early Hadean, remain distinct in the upper mantle for that same period.…”

Section: Introductionmentioning

confidence: 57%

Lateral Mixing Processes in the Hadean

O’Neill

Zhang

2018

JGR Solid Earth

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Samples of ancient Eoarchean volcanism suggest the existence of isotopically distinct mantle domains. 142Nd evidence suggests that these domains formed within the first several hundred million years of Earth's history and were preserved until circa 3.7 Ga—a span of almost 800 Myr. Here we explore evolving mantle convection models under Hadean conditions to constrain mantle mixing dynamics and in particular focus on the generation, or preservation, of upper mantle hemispheric compositional anomalies. We find that initially radially homogenous models fail to produce hemispheric anomalies spontaneously due to mixing processes and that rheological and buoyancy effects, or asymmetric processes such as plate tectonics or meteorite impacts, do not generate long‐lived heterogeneities in upper mantle composition from homogenous initial conditions. In contrast, models initiated with compositional variations can preserve these hemispheric differences of periods >800 Myr despite vigorous internal convection, as a function of the proclivity of these models to exhibit stagnant‐lid behavior, resulting in isolated convection cells with restricted lateral transport.

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Sluggish Hadean geodynamics: Evidence from coupled 146,147 Sm– 142,143 Nd systematics in Eoarchean supracrustal rocks of the Inukjuak domain (Québec)

Cited by 55 publications

References 73 publications

The¹⁴²Nd/¹⁴⁴Nd variations in mantle-derived rocks provide constraints on the stirring rate of the mantle from the Hadean to the present

The¹⁴²Nd/¹⁴⁴Nd variations in mantle-derived rocks provide constraints on the stirring rate of the mantle from the Hadean to the present

When Did Life Likely Emerge on Earth in an RNA‐First Process?

Lateral Mixing Processes in the Hadean

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Sluggish Hadean geodynamics: Evidence from coupled 146,147 Sm– 142,143 Nd systematics in Eoarchean supracrustal rocks of the Inukjuak domain (Québec)

Cited by 55 publications

References 73 publications

The142Nd/144Nd variations in mantle-derived rocks provide constraints on the stirring rate of the mantle from the Hadean to the present

The142Nd/144Nd variations in mantle-derived rocks provide constraints on the stirring rate of the mantle from the Hadean to the present

When Did Life Likely Emerge on Earth in an RNA‐First Process?

Lateral Mixing Processes in the Hadean

Contact Info

Product

Resources

About

The¹⁴²Nd/¹⁴⁴Nd variations in mantle-derived rocks provide constraints on the stirring rate of the mantle from the Hadean to the present

The¹⁴²Nd/¹⁴⁴Nd variations in mantle-derived rocks provide constraints on the stirring rate of the mantle from the Hadean to the present