Modern Atmosphere Research Articles

Using Io's Sulfur Isotope Cycle to Understand the History of Tidal Heating

AbstractStable isotope fractionation of sulfur offers a window into Io's tidal heating history, which is difficult to constrain because Io's dynamic atmosphere and high resurfacing rates leave it with a young surface. We constructed a numerical model to describe the fluxes in Io's sulfur cycle using literature constraints on rates and isotopic fractionations of relevant processes. Combining our numerical model with measurements of the 34S/32S ratio in Io's atmosphere, we constrain the rates for the processes that move sulfur between reservoirs and model the evolution of sulfur isotopes over time. Gravitational stratification of SO2 in the upper atmosphere, leading to a decrease in 34S/32S with increasing altitude, is the main cause of sulfur isotopic fractionation associated with loss to space. Efficient recycling of the atmospheric escape residue into the interior is required to explain the 34S/32S enrichment magnitude measured in the modern atmosphere. We hypothesize this recycling occurs by SO2 surface frost burial and SO2 reaction with crustal rocks, which founder into the mantle and/or mix with mantle‐derived magmas as they ascend. Therefore, we predict that magmatic SO2 plumes vented from the mantle to the atmosphere will have lower 34S/32S than the ambient atmosphere, yet are still significantly enriched compared to solar‐system average sulfur. Observations of atmospheric variations in 34S/32S with time and/or location could reveal the average mantle melting rate and hence whether the current tidal heating rate is anomalous compared to Io's long‐term average. Our modeling suggests that tides have heated Io for >1.6 Gyr if Io today is representative of past Io.

A study of the transient gas flow affected ion transmission in atmospheric pressure interfaces based on large eddy simulation for electrospray ionization mass spectrometry

Modern atmosphere pressure interface (API) enables high-efficiency coupling between mass analyzers in high vacuum and atmosphere ionization sources such as electrospray ionization (ESI) source. The transient gas flow entering API possesses strong compressibility and turbulent characteristics, which exerts a huge impact on ion transmission. However, the instantaneous nature and vortical morphology of the turbulence in API and its affection in ion transmission were hardly covered in the reported research. Here we conduct a transient turbulent flow-affected ion transmission evaluation for two typical APIs, the ion funnel and the S-lens, based on scale-resolving large eddy simulation and electro-hydrodynamical ion tracing simulation. In our simulation, the transient properties of the gas flow in the two APIs are illustrated and analyzed in-depth. After experimentally validated on a homemade ESI-TOF-MS platform, the results suggest that the ion funnel can achieve a higher droplet desolvation rate by introducing a unique droplet recirculation mechanism. Meanwhile, the less-dispersed gas flow in S-lens is beneficial in actuating ions axially. In conclusion, the application of the scale-resolving turbulence model helps us to understand the complicated fluid-ion interaction mechanism in APIs and is promising in the development of mass spectrometry instruments of higher performance.

Oxygen Isotope Fractionation Due to Non-Thermal Escape of Hot O from the Atmosphere of Mars

Secondary minerals in SNC meteorites from Mars exhibit O isotope ratios believed to be consistent with the non-thermal escape of O from the atmosphere. The primary source of the non-thermal O is the dissociative- recombination of O2+ in the ionosphere. I present here the results of a model that accounts for the probability of escape of non-thermal O isotopes due to collisions with overlying CO2, combined with a model for Rayleigh fractionation of the atmosphere remaining as a result of O escape. Previous analyses of MAVEN number density data have shown a strong variability with latitude and season of the heights of the homopause and exobase, with a mean homopause at 110 km and a mean difference of about 60 km. Rayleigh model results demonstrate a dependence on homopause height and on temperature profile and require a more accurate calculation of fractionation factors for the Rayleigh equation. Isothermal temperature profiles yield much smaller variation in 17O with homopause height. These results demonstrate the need for a careful assessment of O isotope enrichment due to non-thermal escape both for the modern atmosphere and for the evolution of the atmosphere over the age of the planet.

Pengaruh Suasana Tempat Dan Gaya Hidup Modern Terhadap Keputusan Pembelian Pada Konsumen Coffee Shop

The research article on the Influence of Place Atmosphere and Modern Lifestyle on Purchasing Decisions of Coffee Shop Consumers (Case Study on Coffee Ethics) is research that aims to build a research hypothesis on the influence between variables that will be used in further research. The method of this research article is to use quantitative methods, while the type of research used is descriptive research. The results of this research article are: 1) The influence of atmosphere has a significant influence on purchasing decisions; 2) The influence of modern lifestyle has a significant influence on purchasing decisions; 3) The influence of modern atmosphere and lifestyle has a significant influence on purchasing decisions.

“Cold capture” of micrometeorites in Archean and Quaternary atmospheres: Effects of dilute exospheres

Micrometeorites (MM) that undergo low heating could have provided a source of organic material to the Earth during the Archean (4-2.5 Ga ago) before life emerged, given that the density of interplanetary dust and larger grains were much higher than today. Amino acids are destroyed on atmospheric entry if the temperature rises above the pyrolysis temperature of few hundred degrees Celsius, depending on type of amino acid. A numerical study was carried out to obtain temperature statistics along relatively rare grazing angle trajectories in the Quaternary (modern) and Archean atmospheres to determine the probability of “cold capture” below pyrolysis temperatures. Effects of the thermospheric temperature and density was considered for the Quaternary atmosphere, and an extended hydrogen/helium envelope remnant from the protosolar nebula was considered for the Archean atmosphere.An important result for the Archean is an elevated “cold capture” probability (twice the capture probability of the modern atmosphere, up to 7%–8%) for low heating below 500 °C of small asteroidal grains around 20μm in diameter, and geocentric velocities in the range 3–5 km/s, provided that there was a remnant envelope. Cometary 20μm grains of higher geocentric velocities did not have such an elevated capture probability. If the Archean atmosphere did not have an envelope, it was found that these capture probabilities were lower than for the modern atmosphere for both cometary and asteroidal grains, due to smaller density scale height of the lower Archean atmosphere leading to faster heating rate. Radiative degradation of amino acids in these relatively small grains should be considered more closely since the X-ray and XUV-flux from the Sun was larger by a factor of about 5–10 in the Archean.Very low maximum temperatures were found for 20μm asteroidal and cometary grains in the Quternary atmosphere, with temperatures in the range 150–200 °C, but with a very small capture probability in this range of typically less than 0.3%. All 300μm asteroidal grains were heated to temperatures above 500 °C for all atmosphere models. The probability of heating to temperatures < 500 °C of 100μm asteroidal grains, was estimated to 0.3% or less for all models. Most 100μm cometary grains were heated to temperatures > 500 °C for all models.

Acetylenotrophic and Diazotrophic Bradyrhizobium sp. Strain I71 from Trichloroethylene-Contaminated Soils

Acetylene (C2H2) is a trace constituent of Earth’s modern atmosphere and is used by acetylenotrophic microorganisms as their sole carbon and energy source (Akob et al. 2018) Acetylenotrophs hydrate acetylene through a reaction catalyzed by acetylene hydratase, which is a heterogeneous class of enzymes. As of 2018, there were 15 known strains of acetylenotrophs including aerobic species affiliated with the Actinobacteria, and Firmicutes and anaerobic species affiliated with the Desulfobacterota. However, we hypothesized that there was an unknown diversity of acetylenotrophs in nature. We recently expanded the known distribution of acetylenotrophs via the isolation of the aerobic acetylenotroph, Bradyrhizobium sp. strain I71, from trichloroethylene (TCE)-contaminated soils (Akob et al. 2022). Strain I71 is a member of the class Alphaproteobacteria, and this is the first observation of an aerobic acetylenotroph in the Proteobacteria phylum. The isolate grows via heterotrophic and acetylenotrophic metabolism, and is diazotrophic, capable of nitrogen fixation. Acetylenotrophy and nitrogen fixation are the only two enzymatic reactions known to transform acetylene, and this is only the second isolate known to carry out both reactions (Akob et al. 2017, Baesman et al. 2019). Members of Bradyrhizobium are well studied for their abilities to improve plant health and increase crop yields by providing bioavailable nitrogen. The unique capability of Bradyrhizobium sp. strain I71 to utilize acetylene may increase the genus’ economic impact beyond agriculture as acetylenotrophy is closely linked to bioremediation of chlorinated contaminants (Mao et al. 2017, Gushgari-Doyle et al. 2021). Based on genome, cultivation, and protein prediction analysis, the ability to consume acetylene is likely not widespread within the genus Bradyrhizobium. These findings suggest that the suite of phenotypic capabilities of strain I71 may be unique and make it a good candidate for further study in several research avenues such as contaminant biodegradation and nutrient cycling.

Manifestation of National Traditions in the Works of Li Yuqiu

Li Yuqiu is one of China’s most infl uential composers. His accordion art is based on traditional musical culture. Using rich national and folklore music as a creative material, combined with Western compositional techniques, he carried out bold research in the fi eld of harmony, compositional structure and performance technique, thereby fi lling his works with a vibrant national style and modern atmosphere. Li Yuqiu’s accordion works span a wide range of genres, including sonatas, fugues, suites, solo compositions, concertos, and ensembles. They are valuable material for studying the way of nationalisation of accordion music in China. Within the framework of the article, the accordion works of Li Yuqiu are used as an object of study, the authors analyse national features in the composer’s works.

Toward the Origins of Quadruple Sulfur Isotope Anomalies in Modern Sulfate: A Multitracer Approach and Implications for Paleo- and Planetary Atmospheres

Sulfur isotope mass-independent fractionation signatures (S-MIF) have been widely found in modern sulfate aerosols. Their mechanistic origins and potential implications for atmospheric sulfate formation chemistry are however poorly understood. Of particular importance is that the mystery of modern sulfate S-MIF hinders precise interpretations of S-MIF in geological sediment and meteorite samples. Here, we examine several proposed origins of modern sulfate S-MIF using a multiple-tracer approach. Quadruple sulfur isotopes of sulfate aerosols collected from Guangzhou, a megacity in South China, were measured along with various chemical and isotopic tracers for high-altitude air masses, biomass burning, and mineral dusts in the same samples. Similar to previous studies, we found that negative Δ36S values in modern sulfate aerosols are linked to combustions, and to a larger extent, to high-temperature processes that may involve symmetry-dependent recombination reactions of sulfur. The origins of Δ33S anomalies widely observed in modern sulfate aerosols remain elusive and require further investigation before we can unambiguously use this proxy to quantify sulfur emission and transformation pathways in the modern atmosphere. From a comparative planetology perspective, we highlight that a complete understanding of S-MIF in modern aerosols is crucial for tracking paleo- and planetary atmospheres by multiple sulfur isotope measurements in Phanerozoic sediments and Martian meteorites because their S-MIF magnitudes are similar.

Biogeochemical Features of the Formation of the Holocene Sediments in Lake Dukhovoe at the Stage of Early Diagenesis in Eastern Baikalia

Abstract —A 6-meter core of the Holocene sediments in Lake Dukhovoe is studied. The material composition of the core is heterogeneous and has clear bedding. Lacustrine sediments are represented by the upper 293 cm. Each bed of the sediments is subjected to microbiological analysis. A high total number of heterotrophic bacteria is revealed in the upper (0–15 cm) and deeper (110–150 cm) sapropel intervals. Sulfate-reducing bacteria are identified only in Chrysophyceae cysts. The CaO/Fe2O3 ratio shows the degree of “carbonate content” of bottom sediments. It is low in the lake sapropel (0.2), which indicates the geochemical specificity (carbonate-free sapropel). Na, Mg, Al, Si, Al, Ca, Fe, Mn, Zr, and Cr concentrations in sapropel are within the average concentrations for the Earth’s crust, shale, and oceanic pelagic clays, while U and Mo concentrations exceed them. Phytoplankton is enriched in phosphorus (biogenic element) and chalcophile elements (Zn, Cd, Sn, Sb, Hg, Pb, and Cu), which characterize the pollution of the modern atmosphere of the Baikal region. Diagenetic processes result in the transformation of the pore waters, namely an increase in mineralization as compared to lake water, an increase in the concentrations of biogenic components (HCO3-, NH4+, NO3-, and PO43-) and a decrease in SO42-. Pyrite framboid accumulations are revealed in organomineral sediments below the horizon of 200 cm, and iron phosphates represented by vivianite are identified in sapropel.

Innovative applications of botanical motifs in interior design

As a form of artistic expression, the application of botanical motifs to interior design has a long history in China, and is an inheritance of our traditional culture and a reflection of traditional virtues. In modern society, the application of botanical patterns to interior design can achieve the effect of "returning to the basics". In the specific design, the application principles should be fully integrated in the space interface, interior furnishings, overall style and other aspects of comprehensive design, reflecting the modern atmosphere at the same time, to meet the needs of decoration.

Designing a building for music and dance performing arts in Bogor

This research aimed to design a building for music and dance performing arts in Bogor, West Java. In order to support the local government's work program, the building is designed so that art performers can create and express the results of these works and can be enjoyed by modern and contemporary art connoisseurs. Through such a building, West Java cultural arts can be preserved and inherited. The method used in the design refers to descriptive qualitative methods and uses literature studies and precedents, surveys and field observations. This is done in order to obtain complete data, then analyze every problem that exists. The resulting design concept is a building design with a cultural and modern atmosphere that is realized through a design theme, namely Semiotic and Taste Cultures with the intention of using a characteristic style that prioritizes simplicity of form, uses ornaments and follows the shape of the building's function.

The origin and distribution of the main oxygen sensing mechanism across metazoans.

Oxygen sensing mechanisms are essential for metazoans, their origin and evolution in the context of oxygen in Earth history are of interest. To trace the evolution of a main oxygen sensing mechanism among metazoans, the hypoxia induced factor, HIF, we investigated the phylogenetic distribution and phylogeny of 11 of its components across 566 eukaryote genomes. The HIF based oxygen sensing machinery in eukaryotes can be traced as far back as 800million years (Ma) ago, likely to the last metazoan common ancestor (LMCA), and arose at a time when the atmospheric oxygen content corresponded roughly to the Pasteur point, or roughly 1% of present atmospheric level (PAL). By the time of the Cambrian explosion (541-485Ma) as oxygen levels started to approach those of the modern atmosphere, the HIF system with its key components HIF1α, HIF1β, PHD1, PHD4, FIH and VHL was well established across metazoan lineages. HIF1α is more widely distributed and therefore may have evolved earlier than HIF2α and HIF3α, and HIF1β and is more widely distributed than HIF2β in invertebrates. PHD1, PHD4, FIH, and VHL appear in all 13 metazoan phyla. The O2 consuming enzymes of the pathway, PHDs and FIH, have a lower substrate affinity, Km, for O2 than terminal oxidases in the mitochondrial respiratory chain, in line with their function as an environmental signal to switch to anaerobic energy metabolic pathways. The ancient HIF system has been conserved and widespread during the period when metazoans evolved and diversified together with O2 during Earth history.

IOT sensor-based pollution management control technique

Environmental pollution generates heart muscle difficulties, breathing difficulties, and other medical problems affecting human civilization. The purpose of this paper was to offer a comprehensive resolution to the issue of pollution in modern civilization, which will enable us to track and address significant issues with general health, societal issues, and environmental problems. The proposed methodology seems to be an IoT unit in dealing with all these concerns, which includes effectively using various sensors to gather predictions of different kinds of contaminants on the earth. Present information on a website uses various sensors to gather estimates of various types of toxins in the earth and present information on a website that is accessible to everyone without charge. The devices and sensors that are installed at various points around us provide the research information. After gathering information from sensors, a comparison of the information is made using the Centralized Pollution Control Committee (CPCC). The proposed approach aids in reducing the pollution in the modern atmosphere, and as a result, pollution can indeed be decreased by making significant progress in that direction. Our proposed approach makes it possible for everyone in civilization to periodically measure and evaluate the quantity of pollution in their surroundings, a practice that leads inevitably to healthcare, ecological, as well as other social and economic problems.

Motivation, Satisfaction and Repurchase Intentions of Chinese Restaurant Customers: Evidence from the Accra Metropolis, Ghana

Purpose: Despite the fact that the customer base for Chinese restaurants in the Accra Metropolis is ever expanding, there is little evidence on the motivational and satisfaction elements that ramp up the customers’ repurchase desires; hence, denying these restaurants and others the opportunity to capitalise on these elements to maximise returns. This study, thus, using an explanatory research design, assessed the effect of motivation and satisfaction on repurchase intentions of customers of Chinese restaurants in the Accra Metropolis of Ghana.&#x0D; Methodology: Employing a multistage sampling technique, a sample of 218 customers were selected and included in the study. A structured closed-ended questionnaire was used to collect data for the analysis. Data were analysed using means, standard deviations, and regression techniques.&#x0D; Findings: The results showed that health, adventure, social interaction and family togetherness, culture and modern atmosphere drive Chinese restaurant customers to make repurchase decisions. It was also revealed that the Chinese restaurant customers find satisfaction in food quality, service quality, atmospherics and authenticity of services at the Chinese restaurants. Additionally, customer motivation and satisfaction were found to have significantly positive effects on repurchase intentions.&#x0D; Unique contribution to theory and practice: It was concluded that increased customer motivation and satisfaction is necessary for an expanded customer base for Chinese restaurants in the Accra Metropolis. Therefore, operators of Chinese restaurants should channel efforts into improving drivers for motivation and satisfaction.

딥러닝에 기반한 전통성의 비율별 한옥카페 디자인 가이드라인

This paper presents a direction that can be used as a reference for design by classifying images according to the ratio of traditionality of spaces that appear in hanok cafes. With the development of the times, the traditional hanok, which felt uncomfortable, was recklessly repaired and remodeled without standards to create a space suitable for the times. Therefore, in this paper, for the universalization of hanok in the modern era, the purpose of this paper is to examine the architectural elements by dividing the traditionality ratio of the hanok cafe by focusing on the hanok cafe, which is being used because of the transition of space rather than the hanok space, which is the meaning of residence. As a procedure for such research, learning data images of traditional hanok and modern interiors were collected and preprocessed. In addition, the test image was selected as the integrated result of the image data classified through prior research and the image data classified through deep learning, and Grad-CAM was used to check the distribution of traditionality. In deep learning, most of the ceiling wood is recognized as traditional, and the column is recognized in the structural part. And most of the furniture was perceived as a modern interior, and when low furniture made of wood was used, it appeared in the proportion of a traditional hanok. On the walls, traditional hanok was finished with plaster, clay, or Hanji(Korean paper), but in modern interiors, white walls were finished, so it was not recognized as a part that showed a lot of tradition. If the traditional ratio is low, even if the overall atmosphere leads to a modern atmosphere if a traditional ratio on the ceiling, create the atmosphere of a traditional hanok cafe.

High precision noble gas measurements of hydrothermal quartz reveal variable loss rate of Xe from the Archean atmosphere

Determining the composition of the Archean atmosphere and oceans is vital to understanding the environmental conditions that existed on the surface of the early Earth. The analysis of atmospheric remnants in fluid inclusions trapped in Archean-aged samples has shown that the Xe isotopic signature of the Archean atmosphere progressively evolved via mass-dependent fractionation, arriving at a modern atmospheric composition around the Archean-Proterozoic transition. The mechanisms driving this evolution are however not well constrained, and it is not yet clear whether the evolution proceeded continuously or via episodic bursts. Providing further constraints on the evolution of Xe in the Archean atmosphere is hampered by the limited amounts of atmospheric gas trapped within fluid inclusions during mineral formation, which impacts the precision at which the Archean atmosphere can be determined. Here, we develop a new crush-and-accumulate extraction technique that enables the heavy noble gases (Ar, Kr and Xe) released from crushing large quantities of hydrothermal quartz to be accumulated and analysed to a higher precision than was previously possible. Using this new technique, we re-evaluate the composition of atmospheric gases trapped within fluid inclusions of 3.3 Ga quartz samples from Barberton, South Africa. We find that the Xe isotopic signature is fractionated by +10.3 ± 1.0‰u−1 (2 SE) relative to modern atmosphere, which is within uncertainty of, but slightly lower than, the previous determination of 12.9 ± 2.4‰u−1 for this sample (Avice et al., 2017). We show for the first time that the Kr/Xe ratio measured within Archean quartz samples is enriched in Xe compared to the modern atmosphere, demonstrating that the atmosphere has lost Xe since the Archean. This further reinforces the proposal of atmospheric escape as the primary mechanism for Earth's Xe loss. We further show that the atmospheric Kr/Xe and Xe isotope fractionation recorded in the Barberton quartz at 3.3 Ga is incompatible with a model describing atmospheric loss at a continuous rate under a constant fractionation factor. This gives credence to numerical models of hydrodynamic escape, which suggest that Xe was lost from the Archean atmosphere in episodic bursts rather than at a constant rate. Refining the evolution curve of atmospheric Xe isotopes using the new technique presented here has the potential to shed light on discrete atmospheric events that punctuated the evolution of the Archean Earth and accompanied the evolution of life.

Aesthetic and Educational Aspects of Contact with Contemporary Religious Architecture

This article addresses the issue of the importance of contemporary architecture—especially Christian architecture—for the aesthetic and spiritual development of an individual. It also highlights the educational aspect that may arise in the framework of the contact of a human with the works of religious architecture. Among many things, the article points out the values of truth and beauty in the space of the sacrum. The major importance in the process of human development involves personal, individual and group experiences of meetings in various areas of religious architecture that operate with the language of signs and symbols, modern artistic forms, single-space harmony, and atmosphere—an invisible order of things. In recent years, a number of studies have been carried out that attempted to define what makes the place of sacrum sufficiently meaningful, mysterious, and still necessary in order to establish a spiritual relationship with the community of believers and with God, which is relevant in one’s transition to adulthood.

Organic synthesis associated with serpentinization and carbonation on early Mars.

Water-rock interactions are relevant to planetary habitability, influencing mineralogical diversity and the production of organic molecules. We examine carbonates and silicates in the martian meteorite Allan Hills 84001 (ALH 84001), using colocated nanoscale analyses, to characterize the nature of water-rock reactions on early Mars. We find complex refractory organic material associated with mineral assemblages that formed by mineral carbonation and serpentinization reactions. The organic molecules are colocated with nanophase magnetite; both formed in situ during water-rock interactions on Mars. Two potentially distinct mechanisms of abiotic organic synthesis operated on early Mars during the late Noachian period (3.9 to 4.1 billion years ago).

Was Venus Ever Habitable? Constraints from a Coupled Interior–Atmosphere–Redox Evolution Model

Abstract Venus’s past climate evolution is uncertain. General circulation model simulations permit a habitable climate as late as ∼0.7 Ga, and there is suggestive—albeit inconclusive—evidence for previous liquid water from surface geomorphology and mineralogy. However, it is unclear whether a habitable past can be reconciled with Venus’s inferred atmospheric evolution. In particular, the lack of leftover atmospheric oxygen argues against recent water loss. Here, we apply a fully coupled model of Venus’s atmospheric–interior–climate evolution from post-accretion magma ocean to present. The model self-consistently tracks C-, H-, and O-bearing volatiles and surface climate through the entirety of Venus’s history. Atmospheric escape, mantle convection, melt production, outgassing, deep water cycling, and carbon cycling are explicitly coupled to climate and redox evolution. Plate tectonic and stagnant lid histories are considered. Using this coupled model, we conclude that both a habitable Venusian past and one where Venus never possessed liquid surface water can be reconciled with known constraints. Specifically, either scenario can reproduce bulk atmospheric composition, inferred surface heat flow, and observed 40Ar and 4He. Moreover, the model suggests that Venus could have been habitable with a ∼100 m global ocean as late as 1 Ga, without violating any known constraints. In fact, if diffusion-limited water loss is throttled by a cool, CO2-dominated upper atmosphere, then a habitable past is tentatively favored by our model. This escape throttling makes it difficult to simultaneously recover negligible water vapor and ∼90 bar CO2 in the modern atmosphere without temporarily sequestering carbon in the interior via silicate weathering to enhance H escape.

Possible discontinuous evolution of atmospheric xenon suggested by Archean barites

The Earth's atmosphere has continually evolved since its formation through interactions with the mantle as well as through loss of volatile species to space. Atmospheric xenon isotopes show a unique and progressive evolution during the Archean that stopped around the Archean-Proterozoic transition. The Xe isotope composition of the early atmosphere has been previously documented through the analysis of fluid inclusions trapped within quartz and barite. Whether this evolution was continuous or not is unclear, requiring additional analyses of ancient samples, which may potentially retain remnants of the ancient atmosphere. Here we present new argon, krypton and xenon isotopic data from a suite of Archean and Proterozoic barites ranging in age from 3.5 to 1.8 Ga, with the goal of providing further insights in to the evolution of atmospheric Xe, whilst also outlining the potential complications that can arise when using barites as a record of past atmospheres. Xenon released by low temperature pyrolysis and crushing of two samples which presumably formed around 2.8 and 2.6 Ga show Xe isotope mass dependent fractionation (MDF) of 11‰.u−1 and 3.4‰.u−1, respectively, relative to modern atmosphere. If trapped Xe is contemporaneous with the respective formation age, the significant difference in the degree of fractionation between the two samples provides supporting evidence for a plateau in the MDF-Xe evolution between 3.3 Ga and 2.8 Ga, followed by a rapid evolution at 2.8–2.6 Ga. This sharp decrease in MDF-Xe degree suggests the potential for a discontinuous temporal evolution of atmospheric Xe isotopes, which could have far reaching implications regarding current physical models of the early evolution of the Earth's atmosphere.