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Identifying the origin of primordial volatiles in the Earth's mantle provides a critical test between models that advocate magma-ocean equilibration with an early massive solar-nebula atmosphere and those that require subduction of volatiles implanted in late accreting material. Here we show that neon isotopes in the convecting mantle, resolved in magmatic CO2 well gases, are consistent with a volatile source related to solar corpuscular irradiation of accreting material. This contrasts with recent results that indicated a solar-nebula origin for neon in mantle plume material, which is thought to be sampling the deep mantle. Neon isotope heterogeneity in different mantle sources suggests that models in which the plume source supplies the convecting mantle with its volatile inventory require revision. Although higher than accepted noble gas concentrations in the convecting mantle may reduce the need for a deep mantle volatile flux, any such flux must be dominated by the neon (and helium) isotopic signature of late accreting material. [ABSTRACT FROM AUTHOR]

Understanding the composition of the atmosphere over geological time is critical to understanding the history of the Earth system, as the atmosphere is closely linked to the lithosphere, hydrosphere and biosphere. Although much of the history of the lithosphere and hydrosphere is contained in rock and mineral records, corresponding information about the atmosphere is scarce and elusive owing to the lack of direct records. Geologists have used sedimentary minerals, fossils and geochemical models to place constraints on the concentrations of carbon dioxide, oxygen or methane in the past. Here we show that the triple oxygen isotope composition of sulphate from ancient evaporites and barites shows variable negative oxygen-17 isotope anomalies over the past 750 million years. We propose that these anomalies track those of atmospheric oxygen and in turn reflect the partial pressure of carbon dioxide () in the past through a photochemical reaction network linking stratospheric ozone to carbon dioxide and to oxygen. Our results suggest that was much higher in the early Cambrian than in younger eras, agreeing with previous modelling results. We also find that the 17O isotope anomalies of barites from Marinoan (∼635 million years ago) cap carbonates display a distinct negative spike (around -0.70‰), suggesting that by the time barite was precipitating in the immediate aftermath of a Neoproterozoic global glaciation, the was at its highest level in the past 750 million years. Our finding is consistent with the ‘snowball Earth’ hypothesis and/or a massive methane release after the Marinoan glaciation. [ABSTRACT FROM AUTHOR]

The article addresses the origin of the air-like xenon component using the ratios of two further isotopes. The results from the radiogenic isotopes indicate that the air-crust hybrid component, which is likely to be added to well gases through local contamination during their storage in the continental crust, can account for only about half of the 90 percent atmospheric xenon component revealed by the non-radiogenic xenon isotopes. They have concluded that some air-like xenon in the New Mexico well-gas samples is intrinsic to their mantle source seems robust.

This article informs that the existence or radioactive aluminium and other short-lived nuclides in the early solar system suggests a source of heat for melting planetesimals, and provides a way of deducing time differences between events. It also means that some stellar process must have created significant amounts of aluminium just before the solar system formed. It is further informed that of the objects found inside chondrites, two have particular significance in the early history of the solar system: calcium aluminium refractory inclusions (CAIs) and chondrules. CAIs are the earliest object yet identified that bear clear isotopic evidence of having formed inside the solar system.

The article provides information on the composition of isotopes. Isotopes are made through a decay of radioactive nuclei which provide an evidence of how the Earth was shaped. Based on the report made by Boyet and Carlson in the Earth and Planetary Science Letters, showed some clues by measuring the abundance of neodymium isotopes in volcanic rocks. Most of these short-lived elements were produced in the events which is followed by the formation of the Solar System.

Reports on Becky Alexander and colleagues' article in the "Journal of Geophysical Research" about the isotope chemistry, known as mass-independent fractionation. History of vegetation burning and its effects on oxidation reactions in the atmosphere; Fractionation of isotopes that occurs during most chemical and physical processes; Relative contributions of liquid-phase oxidation.