Heat and helium in the Earth

O’Nions, R.K.; Oxburgh, E. R.

doi:10.1038/306429a0

Cited by 318 publications

(123 citation statements)

References 20 publications

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“…This points to a terrestrial mantle reservoir supplying the mid-ocean ridges that is relatively homogeneous with respect to its 3 He/(UCTh) composition and provides a critical insight into the volatile-solid evolution of the mantle system (e.g. Kurz et al 1982;Allègre et al 1983;O'Nions & Oxburgh 1983). Isotopic evidence for the existence of a mantle reservoir separate and distinct from the convecting mantle is provided by high 3 He / 4 He ocean island volcanism (Kurz et al 1982; figure 1).…”

Section: Helium: the Case For An Accretionary Volatile Reservoir In Tmentioning

confidence: 99%

“…To effect the extreme convection required for such efficient outgassing will require a substantial advance in our understanding of the mantle rheology of the early Earth. Until then, we argue that the strongest explanation for the observed mantle 3 He/ 4 He, low [ 3 He] and [UCTh] remains a flux of high 3 He/ 4 He material from a gas-rich reservoir deeper in the mantle system (Kurz et al 1982;Allègre et al 1983;O'Nions & Oxburgh 1983;Kellogg & Wasserburg 1990;Porcelli & Wasserburg 1995).…”

Section: Helium: the Case For An Accretionary Volatile Reservoir In Tmentioning

confidence: 99%

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What CO ₂ well gases tell us about the origin of noble gases in the mantle and their relationship to the atmosphere

Ballentine

Holland²

2008

Phil. Trans. R. Soc. A.

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Study of commercially produced volcanic CO 2 gas associated with the Colorado Plateau, USA, has revealed substantial new information about the noble gas isotopic composition and elemental abundance pattern of the mantle. Combined with published data from midocean ridge basalts, it is now clear that the convecting mantle has a maximum 20 Ne/ 22 Ne isotopic composition, indistinguishable from that attributed to solar wind-implanted (SWI) neon in meteorites. This is distinct from the higher 20 Ne/ 22 Ne isotopic value expected for solar nebula gases. The non-radiogenic xenon isotopic composition of the well gases shows that 20 per cent of the mantle Xe is 'solar-like' in origin, but cannot resolve the small isotopic difference between the trapped meteorite 'Q'-component and solar Xe. The mantle primordial 20 Ne/ 132 Xe is approximately 1400 and is comparable with the upper end of that observed in meteorites. Previous work using the terrestrial 129 I-129 Xe mass balance demands that almost 99 per cent of the Xe (and therefore other noble gases) has been lost from the accreting solids and that Pu-I closure age models have shown this to have occurred in the first ca 100 Ma of the Earth's history. The highest concentrations of Q-Xe and solar wind-implanted (SWI)-Ne measured in meteorites allow for this loss and these high-abundance samples have a Ne/Xe ratio range compatible with the 'recycled-aircorrected' terrestrial mantle. These observations do not support models in which the terrestrial mantle acquired its volatiles from the primary capture of solar nebula gases and, in turn, strongly suggest that the primary terrestrial atmosphere, before isotopic fractionation, is most probably derived from degassed trapped volatiles in accreting material.By contrast, the non-radiogenic argon, krypton and 80 per cent of the xenon in the convecting mantle have the same isotopic composition and elemental abundance pattern as that found in seawater with a small sedimentary Kr and Xe admix. These mantle heavy noble gases are dominated by recycling of air dissolved in seawater back into the mantle. Numerical simulations suggest that plumes sampling the core-mantle boundary would be enriched in seawater-derived noble gases compared with the convecting mantle, and therefore have substantially lower 40 Ar/ 36 Ar. This is compatible with observation. The subduction process is not a complete barrier to volatile return to the mantle.

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Section: Helium: the Case For An Accretionary Volatile Reservoir In Tmentioning

confidence: 99%

Section: Helium: the Case For An Accretionary Volatile Reservoir In Tmentioning

confidence: 99%

What CO ₂ well gases tell us about the origin of noble gases in the mantle and their relationship to the atmosphere

Ballentine

Holland²

2008

Phil. Trans. R. Soc. A.

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“…A layered mantle has been inferred as a means of maintaining distinct geochemical reservoirs, particularly noble gas compositions measured between midocean ridge basalts and plume-related ocean island basalts (e.g. Allegre et al 1983;O'Nions & Oxburgh 1983) and large-ion lithophile elements budgets of the crust and mantle (e.g. Jacobsen & Wasserburg 1979;O'Nions et al 1979).…”

Section: Mantle Evolutionmentioning

confidence: 99%

Palaeoproterozoic supercontinents and global evolution: correlations from core to atmosphere

Reddy

Evans

2009

115

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The Palaeoproterozoic era was a time of profound change in Earth evolution and represented perhaps the first supercontinent cycle, from the amalgamation and dispersal of a possible Neoarchaean supercontinent to the formation of the 1.9-1.8 Ga supercontinent Nuna. This supercontinent cycle, although currently lacking in palaeogeographic detail, can in principle provide a contextual framework to investigate the relationships between deep-Earth and surface processes. In this article, we graphically summarize secular evolution from the Earth's core to its atmosphere, from the Neoarchaean to the Mesoproterozoic eras (specifically 3.0-1.2 Ga), to reveal intriguing temporal relationships across the various 'spheres' of the Earth system. At the broadest level our compilation confirms an important deep-Earth event at c. 2.7 Ga that is manifested in an abrupt increase in geodynamo palaeointensity, a peak in the global record of large igneous provinces, and a broad maximum in several mantle-depletion proxies. Temporal coincidence with juvenile continental crust production and orogenic gold, massive-sulphide and porphyry copper deposits, indicate enhanced mantle convection linked to a series of mantle plumes and/or slab avalanches. The subsequent stabilization of cratonic lithosphere, the possible development of Earth's first supercontinent and the emergence of the continents led to a changing surface environment in which voluminous banded iron-formations could accumulate on the continental margins and photosynthetic life could flourish. This in turn led to irreversible atmospheric oxidation at 2.4-2.3 Ga, extreme events in global carbon cycling, and the possible dissipation of a former methane greenhouse atmosphere that resulted in extensive Palaeoproterozoic ice ages. Following the great oxidation event, shallow marine sulphate levels rose, sediment-hosted and iron-oxide-rich metal deposits became abundant, and the transition to sulphide-stratified oceans provided the environment for early eukaryotic evolution. Recent advances in the geochronology of the global stratigraphic record have made these inferences possible. Frontiers for future research include more refined modelling of Earth's thermal and geodynamic evolution, palaeomagnetic studies of geodynamo intensity and continental motions, further geochronology and tectonic syntheses at regional levels, development of new isotopic systems to constrain geochemical cycles, and continued innovation in the search for records of early life in relation to changing palaeoenvironments.

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“…We will refer to this association as the standard earth energy paradigm (SEEP). Although this picture is now widely accepted, it has been shown to have some long-standing discrepancies with geophysical observations; see in particular O'Nions and Oxburgh (1983), Oxburgh and O'Nions (1987), and van Kekan et al (2001). That there is heat being released from the earth is not in question.…”

Section: Introductionmentioning

confidence: 99%

Thermal energy generation in the earth

Fj¹,

Reitz²

2014

Nonlin. Processes Geophys.

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Abstract. We show that a recently introduced class of electromagnetic composite particles can explain some discrepancies in observations involving heat and helium released from the earth. Energy release during the formation of the composites and subsequent nuclear reactions involving the composites are described that can quantitatively account for the discrepancies and are expected to have implications in other areas of geophysics -for example, a new picture of heat production and volcanism in the earth is presented.

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Heat and helium in the Earth

Cited by 318 publications

References 20 publications

What CO ₂ well gases tell us about the origin of noble gases in the mantle and their relationship to the atmosphere

What CO ₂ well gases tell us about the origin of noble gases in the mantle and their relationship to the atmosphere

Palaeoproterozoic supercontinents and global evolution: correlations from core to atmosphere

Thermal energy generation in the earth

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Heat and helium in the Earth

Cited by 318 publications

References 20 publications

What CO 2 well gases tell us about the origin of noble gases in the mantle and their relationship to the atmosphere

What CO 2 well gases tell us about the origin of noble gases in the mantle and their relationship to the atmosphere

Palaeoproterozoic supercontinents and global evolution: correlations from core to atmosphere

Thermal energy generation in the earth

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What CO ₂ well gases tell us about the origin of noble gases in the mantle and their relationship to the atmosphere

What CO ₂ well gases tell us about the origin of noble gases in the mantle and their relationship to the atmosphere