Volatile Reservoirs Research Articles

Effects of the Characterization Methods of Heptane Plus Components (C7+) on the Phase Behavior of Volatile Fluids

For reservoir fluids with strong volatile tendencies, such as gas condensate and volatile oil, the determination of the characteristic parameters of the equation of state has a great influence on the fluid phase behavior and subsequent reservoir engineering, production engineering, and surface facilities design calculations. However, the process of characterizing reservoir fluid lacks a unified and standardized procedure, and the methods are largely empirical and rather complicated. In this paper, three main stages are defined for the characterization of the equation of state parameters for these volatile reservoir fluids, including (1) determining the C7+ distribution, (2) calculating the equation of state parameters for the C7+ single-carbon component, and (3) lump components. The typical calculation methods in each step and their effects on the fluid phase behavior calculations are quantitatively analyzed and compared. Finally, the workflow and the suitable characterization methods for gas condensate and volatile oil phase behavior calculations are selected. The results show that C7+ distribution and C7+ single carbon component properties have a greater influence on the phase behavior prediction of condensate gas and volatile oil, while the lumping of C7+ single carbon component has relatively little influence.

Improvement of volatile switching in scaled silicon nanofin memristor for high performance and efficient reservoir computing.

Conductive-bridge random access memory can be used as a physical reservoir for temporal learning in reservoir computing owing to its volatile nature. Herein, a scaled Cu/HfOx/n+-Si memristor was fabricated and characterized for reservoir computing. The scaled, silicon nanofin bottom electrode formation is verified by scanning electron and transmission electron microscopy. The scaled device shows better cycle-to-cycle switching variability characteristics compared with those of large-sized cells. In addition, synaptic characteristics such as conductance changes due to pulses, paired-pulse facilitation, and excitatory postsynaptic currents are confirmed in the scaled memristor. High-pattern accuracy is demonstrated by deep neural networks applied in neuromorphic systems in conjunction with the use of the Modified National Institute of Standards and Technology database. Furthermore, a reservoir computing system is introduced with six different states attained by adjusting the amplitude of the input pulse. Finally, high-performance and efficient volatile reservoir computing in the scaled device is demonstrated by conductance control and system-level reservoir computing simulations.

An ALMA Molecular Inventory of Warm Herbig Ae Disks. II. Abundant Complex Organics and Volatile Sulphur in the IRS 48 Disk

The Atacama Large Millimeter/submillimeter Array (ALMA) can probe the molecular content of planet-forming disks with unprecedented sensitivity. These observations allow us to build up an inventory of the volatiles available for forming planets and comets. Herbig Ae transition disks are fruitful targets due to the thermal sublimation of complex organic molecules (COMs) and likely H2O-rich ices in these disks. The IRS 48 disk shows a particularly rich chemistry that can be directly linked to its asymmetric dust trap. Here, we present ALMA observations of the IRS 48 disk where we detect 16 different molecules and make the first robust detections of H213CO , 34SO, 33SO, and c-H2COCH2 (ethylene oxide) in a protoplanetary disk. All of the molecular emissions, aside from CO, are co-located with the dust trap, and this includes newly detected simple molecules such as HCO+, HCN , and CS. Interestingly, there are spatial offsets between different molecular families, including between the COMs and sulfur-bearing species, with the latter being more azimuthally extended and radially located further from the star. The abundances of the newly detected COMs relative to CH3OH are higher than the expected protostellar ratios, which implies some degree of chemical processing of the inherited ices during the disk lifetime. These data highlight IRS 48 as a unique astrochemical laboratory to unravel the full volatile reservoir at the epoch of planet and comet formation and the role of the disk in (re)setting chemical complexity.

Parylene-MoOx crossbar memristors as a volatile reservoir and non-volatile readout: a homogeneous reservoir computing system.

From the very beginning, the emulation of biological principles has been the primary avenue for the development of energy-efficient artificial intelligence systems. Reservoir computing, which has a solid biological basis, is particularly appealing due to its simplicity and efficiency. So-called memristors, resistive switching elements with complex dynamics, have proved beneficial for replicating both principal parts of a reservoir computing system. However, these parts require distinct behaviors found in differing memristive structures. The development of a homogeneous memristive reservoir computing system will significantly facilitate and reduce the fabrication process cost. The following work employs the co-existence of volatile and non-volatile regimes in parylene-MoOx crossbar memristors controlled by compliance current for this aim. The stable operation of the memristors under study is confirmed by low cycle-to-cycle and device-to-device variations of the switching voltages. For the transition between the volatile and non-volatile regimes, factors such as compliance current and reading voltage along with possible intrinsic origins are discussed. The results provide a foundation for the future hardware development of a homogeneous parylene-based reservoir computing system, considering high MNIST dataset classification accuracy (∼96%).

No thick carbon dioxide atmosphere on the rocky exoplanet TRAPPIST-1 c

Seven rocky planets orbit the nearby dwarf star TRAPPIST-1, providing a unique opportunity to search for atmospheres on small planets outside the Solar System1. Thanks to the recent launch of the James Webb Space Telescope (JWST), possible atmospheric constituents such as carbon dioxide (CO2) are now detectable2,3. Recent JWST observations of the innermost planet TRAPPIST-1 b showed that it is most probably a bare rock without any CO2 in its atmosphere4. Here we report the detection of thermal emission from the dayside of TRAPPIST-1 c with the Mid-Infrared Instrument (MIRI) on JWST at 15 µm. We measure a planet-to-star flux ratio of fp/f⁎ = 421 ± 94 parts per million (ppm), which corresponds to an inferred dayside brightness temperature of 380 ± 31 K. This high dayside temperature disfavours a thick, CO2-rich atmosphere on the planet. The data rule out cloud-free O2/CO2 mixtures with surface pressures ranging from 10 bar (with 10 ppm CO2) to 0.1 bar (pure CO2). A Venus-analogue atmosphere with sulfuric acid clouds is also disfavoured at 2.6σ confidence. Thinner atmospheres or bare-rock surfaces are consistent with our measured planet-to-star flux ratio. The absence of a thick, CO2-rich atmosphere on TRAPPIST-1 c suggests a relatively volatile-poor formation history, with less than {9.5}_{-2.3}^{+7.5} Earth oceans of water. If all planets in the system formed in the same way, this would indicate a limited reservoir of volatiles for the potentially habitable planets in the system.

The role of continental subduction in mantle metasomatism and carbon recycling revealed by melt inclusions in UHP eclogites.

Subduction is the main process that recycles surface material into the mantle. Fluids and melts derived by dehydration and partial melting reactions of subducted continental crust, a major reservoir of volatiles (i.e., H2O and CO2) and incompatible elements, can substantially metasomatize and refertilize the mantle. Here, we investigate glassy inclusions of silicate melt of continental origin found in Variscan ultrahigh-pressure eclogites to assess the continental crust contribution to mantle metasomatism and the journey of volatiles, carbon in particular, to the deep roots of mountain belts. We argue that the melt preserved in these inclusions is the agent responsible for mantle metasomatism and subsequent ultrapotassic magmatism in the Variscides. We propose that continental subduction can redistribute a substantial volume of carbon in the continental lithosphere, which is subsequently transferred to the continental crust during postcollisional magmatism and stored for a time length longer than that of the modern carbon cycle.

Evolution of the reservoirs of volatiles in the protosolar nebula

The supersolar abundances of volatiles observed in giant planets suggest that a compositional gradient was present at the time of their formation in the protosolar nebula. To explain this gradient, several studies have investigated the radial transport of trace species and the effect of icelines on the abundance profiles of solids and vapors formed in the disk. However, these models only consider the presence of solids in the forms of pure condensates or amorphous ice during the evolution of the protosolar nebula. They usually neglect the possible crystallization and destabilization of clathrates, along with the resulting interplay between the abundance of water and those of these crystalline forms. This study is aimed at pushing this kind of investigation further by considering all possible solid phases together in the protosolar nebula: pure condensates, amorphous ice, and clathrates. To this end, we used a one-dimensional (1D) protoplanetary disk model coupled with modules describing the evolution of trace species in the vapor phase, as well as the dynamics of dust and pebbles. Eleven key species are considered here, including H2O, CO, CO2, CH4, H2S, N2, NH3, Ar, Kr, Xe, and PH3. Two sets of initial conditions are explored for the protosolar nebula. In a first scenario, the disk is initially filled with icy grains in the forms of pure condensates. In this case, we show that clathrates can crystallize and form enrichment peaks up to about ten times the initial abundances at their crystallization lines. In a second scenario, the volatiles were delivered to the protosolar nebula in the forms of amorphous grains. In this case, the presence of clathrates is not possible because there is no available crystalline water ice in their formation region. Enrichment peaks of pure condensates also form beyond the snowline up to about seven times the initial abundances. Our model can then be used to compare the compositions of its different volatile reservoirs with those of comet C/2016 R2 PanSTARRS, Jupiter, Uranus, and Neptune. We find that the two investigated scenarios provide compositions of solids and vapors consistent with those observed in the bodies considered.

Origin of nitrogen on Mars: First in situ N isotope analyses of martian meteorites

Martian meteorites are key for assessing the isotopic characteristics of nitrogen in different martian reservoirs (i.e., mantle, crust, and atmosphere), and, ultimately, for constraining the source(s) of nitrogen trapped during the earliest stages of planetary accretion in the terrestrial planet-forming region. In this study, we analysed, for the first time, the nitrogen content and isotopic composition of glassy melt inclusions of Chassigny and of the mesostasis of five nakhlites (MIL 03346, Nakhla, NWA 6148, NWA 998, and Y 000593) by in situ secondary ion mass spectrometry. The nitrogen content of Chassigny melt inclusions, corrected for olivine overgrowth on the inclusion walls, varies from 4 ± 1 to 860 ± 45 ppm N, and the majority of δ15N values range from –35 ± 41 to +73 ± 36‰. The estimated nitrogen isotopic signature of the primitive melt, prior to degassing of N2 or NH3, is 0 ± 32‰. The mesostasis of nakhlites contains 2.7 ± 0.2 to 943 ± 156 ppm N, with δ15N values from –30 ± 37 to +348 ± 43‰. Whereas degassing of N2 or NH3 can explain the lowest nitrogen isotopic ratios measured in the nakhlite mesostasis, the 15N-enriched isotopic composition (δ15N > 150‰) of four nakhlites (MIL 03346, Nakhla, NWA 6148, and Y 000593) likely results from interaction of the mesostasis melt with the martian atmosphere during ejection. The δ15N values (+25 ± 42 and +77 ± 19‰) of two melt inclusions in Y 000593 are comparable to those of Chassigny, further confirming that these meteorites likely sample a common volatile reservoir in the martian interior. Overall, the new results indicate that the chassignite-nakhlite reservoir did not inherit nitrogen from the solar nebula but, instead, from chondritic-like materials. These findings further confirm that planetary bodies in the inner solar system accreted (isotopically) chondritic nitrogen during the first few million years of solar system history.

Volatiles of the active Mayotte volcanic chain: STA & EGA-MS analysis of volcanic products

In July 2018, a large (ca. 6.55 km3), deep (ca. 2.5 to 3.3 km b.s.l) submarine eruption started ca. 50 km east of Mayotte Island. Samples of fresh basanitic lava rims were collected by dredging, at various times and locations from the newly formed Fani Maoré Edifice (FME). The logistical response to this extraordinary event also enabled the dredging of shallow (ca. 1.2 to 1.6 km below sea level, b.s.l.), fresh phonolitic lava and bomb rims in the so-called Horse-Shoe Area (HSA), ca. 15 km east of Mayotte. Better-known subaerial counterparts of Holocene age, have also been sampled in the La Vigie Maar (LVM) phonolitic deposits (Petite-Terre, Mayotte Island), for comparison with submarine samples. These samples belong to a single volcanic chain that extends from LVM to FME passing through HSA. A novel combination of Simultaneous Thermal Analysis (STA), which involves Differential Scanning Calorimetry (DSC), Thermal Gravimetry Analysis (TGA), and Evolved Gas Analysis conducted by Mass Spectrometry (EGA-MS), enable a reconstruction of the volatile distributions and compositions (H2O, CO2, and SO2) of these samples. Calorimetric and degassing profiles of controlled heating runs reveal different volatile reservoirs distributed as a function of sample textures and compositions, which have been further investigated by Scanning Electron Microscopy (SEM), Electron Probe Micro-Analysis (EPMA), and Raman spectroscopy. A linear correlation observed between the TGA and H2O-EGA-MS signal intensities also enables the quantification of adsorbed-external vs. dissolved-magmatic H2O contents of the studied samples. The novel application of this approach to volcanic products is thus confirmed as a reliable method to determine volatile characteristics in a wide range of samples, yielding a quantitative description of volatile behavior within the associated magmatic systems and eruptions.

Water-rich C-type asteroids as early solar system carbonate factories

Micrometeorites represent a major potential source of volatiles for the early Earth, although often overlooked due to their small sizes and the effects of atmospheric entry. In this study we explore an unusual ∼2000 μm, fine-grained unmelted micrometeorite TAM19B-7 derived from a water-rich C-type asteroid. Previous analysis revealed a unique O-isotope composition and intensely aqueously altered geological history. We investigated its carbon isotopic composition using the NanoSIMS and characterized the carbon-bearing carriers using Raman and Near-Infrared spectroscopy. We found that TAM19B-7 has a 13C enriched bulk composition (δ13C = +3 ± 8 ‰), including a domain with 13C depletion (δ13C = −27.1 ‰). Furthermore, a few micro-scale domains show 13C enrichments (δ13C from +12.9 ‰ to +32.7 ‰) suggesting much of the particle’s carbon content was reprocessed into fine-grained carbonates, likely calcite. The heavy bulk C-isotope composition of TAM19B-7 indicates either open system gas loss during aqueous alteration or carbonate formation from isotopically heavy soluble organics. Carbonates have been detected on small body surfaces, including across dwarf planet Ceres, and on the C-type asteroids Bennu and Ryugu. The preservation of both carbonates with 13C enrichments and organic carbon with 13C depletion in TAM19B-7, despite having been flash heated to high temperatures (<1000 °C), demonstrates the importance of cosmic dust as a volatile reservoir.

Origin of Nitrogen Isotopic Variations in the Rocky Bodies of the Solar System

Noncarbonaceous (NC; inner solar system) meteorites have lower 15N/14N ratios than carbonaceous (CC; outer solar system) meteorites. Whether this is evidence of a primordial heterogeneity of N reservoirs in the protosolar disk remains unclear. In this study, I consider the N isotopic compositions of meteorite (chondrite, achondrite, and iron meteorite) parent bodies as a function of their growth zones. Despite the 15N/14N ratios of CC meteorites being generally higher than NC meteorites, there is a substantial overlap between them. Late-stage mixing of isotopically distinct reservoirs cannot explain this overlap. 15N/14N ratios of meteorites, independent of the growth zones, are correlated with the accretion ages of their parent bodies. A common correlation of the 15N/14N ratios of NC and CC chondrites with their peak metamorphic temperatures suggests that N isotopic compositions of meteorites were likely set by a universal time-dependent process—thermal evolution of their parent bodies by radiogenic heating. Therefore, heterogeneous N isotopic compositions of meteorites do not allude to isotopically heterogeneous primitive N reservoirs in the protosolar disk. Rather, it is likely that the N isotopic compositions of meteorites are a direct reflection of a differential response of labile 15N-rich and refractory 15N-poor components in common organic precursors to variable degrees of parent body processing. Consequently, the isotopic ratios of N, and other highly volatile elements like C and H, in meteorites do not reflect the isotopic compositions of primitive volatile reservoirs in the protosolar disk and thus cannot be used independently to cosmolocate volatile reservoirs in the disk.

Study on CO2–Water Co-Injection Miscible Characteristics in Low-Permeability Near-Critical Volatile Oil Reservoir

Low-permeability near-critical volatile reservoirs are characterized by light oil, complex fluid phase, and strong reservoir inhomogeneity, etc. Purely injecting CO2 will create a series of problems, such as serious gas channeling, low sweep efficiency, and low oil recovery. Therefore, in this paper, through a combination of experiments and simulations and in the process of studying the problem from simple to complex, we carried out phase equilibrium experiments for CO2-near-critical volatile oil and CO2-near-critical volatile oil-formation water, as well as experiments for minimum miscible pressure of slim-tube with pure CO2 and CO2–water co-injection to the comparative study of the miscible characteristics and displacement oil efficiency between pure CO2 injection and CO2–water co-injection. It provides an important reference for improving oil recovery by CO2–water co-injection in low-permeability near-critical volatile reservoir. The results of CO2-near-critical volatile oil/CO2-near-critical volatile oil-formation water phase equilibrium experiments show that the saturation pressure, density, and gas–oil ratio of the system increase, and the viscosity decreases with the increase in CO2 injection. In the three-phase system of CO2-near-critical volatile oil-formation water, the CO2 content in the flash gas of crude oil, gas–oil ratio, and gas–water ratio are negatively correlated with the water saturation. The results of slim-tube experiments and simulations on the miscible characteristics and displacement oil efficiency of pure CO2 injection and CO2–water co-injection show that the recovery degree of crude oil under CO2–water co-injection is higher than that of pure CO2 injection, and the CO2 dissolved transition section in oil and gas is shorter and the gas breakthrough time is later under CO2–water co-injection, which effectively increases the sweep efficiency and improves the degree recovery of crude oil. When CO2–water co-injection, the ratio of water is higher, the later the gas–oil ratio rises, the later the CO2 breakthrough, and the higher the degree of crude oil recovery. It indicates that when CO2–water co-injection, the ratio of water is higher, the more CO2 is dissolved in water, which effectively inhibits the occurrence of gas channeling and increases the sweep area, thus improving the degree recovery of crude oil. The research results of this paper provide an experimental basis and theoretical foundation for CO2–water co-injection for enhanced crude oil recovery in low-permeability near-critical volatile reservoirs.

Quantification of Volcano Deformation Caused by Volatile Accumulation and Release

AbstractCrustal‐stored magma reservoirs contain exsolved volatiles which accumulate in the reservoir roof, exerting a buoyancy force on the crust. This produces surface uplift and sudden loss of volatiles through eruption results in syn‐eruptive subsidence. Here, we present three‐dimensional, visco‐elasto‐plastic, numerical modeling results which quantify the ground deformation arising from the growth and release of a volatile reservoir. Deformation is mostly independent of crustal thermal distribution and volatile reservoir shape, but is a function of volatile volume, density and depth and crustal rigidity. We present a scaling law for the volatiles' contribution to syn‐eruptive subsidence and show this contributes ∼20% of the observed subsidence associated with the 2015 Calbuco eruption. Our results highlight the key role that volatile‐driven buoyancy can have in volcano deformation, show a new link between syn‐eruptive degassing and deflation, and highlight that shallow volatile accumulation and release may have a significant impact on ground deformation of volcanoes.

A Snowball in Hell: The Potential Steam Atmosphere of TOI-1266c

Abstract TOI-1266c is a recently discovered super-Venus in the radius valley orbiting an early M dwarf. However, its notional bulk density (∼2.2 g cm−3) is consistent with a large volatile fraction, suggesting that it might have volatile reservoirs that have survived billions of years at more than twice Earth’s insolation. On the other hand, the upper mass limit paints a picture of a cool super-Mercury dominated by &gt;50% iron core (∼9.2 g cm−3) that has tiptoed up to the collisional stripping limit and into the radius gap. Here we examine several hypothetical states for TOI-1266c using a combination of new and updated open-source atmospheric escape, radiative−convective, and photochemical models. We find that water-rich atmospheres with trace amounts of H2 and CO2 are potentially detectable (S/N &gt; ∼ 5) in less than 20 hr of James Webb Space Telescope (JWST) observing time. We also find that water vapor spectral features are not substantially impacted by the presence of high-altitude water or ice clouds owing to the presence of a significant amount of water above the cloud deck, although further work with self-consistent cloud models is needed. Regardless of its mass, however, TOI-1266c represents a unique proving ground for several hypotheses related to the evolution of sub-Neptunes and Venus-like worlds, particularly those near the radius valley.

Redox controls during magma ocean degassing

Nitrogen, carbon, hydrogen and sulfur are essential elements for life and comprise about 1% of terrestrial planet masses. These elements dominate planetary surfaces due to their volatile nature, but the Earth's interior also constitutes a major C-H-N-S reservoir. Resolving the origin of the surficial versus deep volatile reservoirs requires the past 4.5 Giga-years of mantle outgassing and ingassing processes to be reconstructed, involving many unknowns. As an alternative, we propose to define the primordial distribution of volatiles resulting from degassing of the Earth's magma ocean (MO). The equilibrium partitioning of C-H-O-N-S elements between the MO and its atmosphere is calculated by means of solubility laws, extrapolated to high temperatures and over a large range of redox conditions. Depending on the redox conditions, the amount of volatiles, and the size of the MO considered, we show that the last MO episode may have degassed 40-220 bar atmospheres, whereas hundreds to thousands of ppm of C-H-O-N-S can be retained in the magma. Two contrasting scenarios are investigated: reduced vs. oxidized MO. For reduced cases (<IW−2), an H-C ± N-rich atmosphere can be formed, whereas the atmosphere under oxidizing conditions (>IW + 2) would be dry and C-N-S-rich. An intermediate redox state produces a C-N atmosphere. In many cases, the present-day surficial abundances (atmosphere + ocean + crust) of C and N, the most volatile elements, are very close to the calculated primordial MO - atmosphere distribution. This probably means that lithospheric recycling and post-magma ocean degassing only moderately alter the surficial abundances of these elements. Sulfur, in contrast, must have been mostly outgassed by post-MO events. Changes in redox conditions during magma ocean degassing played a first order role in the composition of the primordial atmosphere of planets. We suggest that the more oxidized conditions on Venus due to H-loss may have played a role in the growth of a dry MO atmosphere on this planet compared to an H-bearing one on Earth. To verify these first order assertions, constraints on volatile behavior under extreme magma ocean conditions and upon magma ocean solidification are urgently needed.

The origin of high helium concentrations in the gas fields of southwestern Tanzania

Volatile elements are concentrated at Earth's surface, forming a rich atmosphere and oceans which enabled the eventual emergence of life. However, volatiles are also abundant in solid Earth reservoirs, such as the crust and mantle, and these reservoirs play a key role in moderating volatile movement throughout the planet. Continental cratons represent a potentially large, yet under-constrained volatile reservoir. When cratonic regions are catastrophically disrupted by large volcanic and/or rifting events, they release massive amounts of volatiles into Earth's atmosphere on geologically-abrupt timescales (e.g., Lowenstern et al., 2014; Muirhead et al., 2020). Here, we report gas data (He-Ne-N2-Ar-CO2) from seeps along the flanks of the Tanzanian craton, within the western branch of the East African Rift System (EARS) - a region where the stable continental craton is actively being broken apart by rifting and simultaneously heated by plume-induced volcanism. Bulk gas and noble gas isotopic data are reported in seeps from three regions: 1) the Rukwa Rift Basin (RRB), 2) the Lupa Hydrothermal System (LHS) and 3) the Rungwe Volcanic Province (RVP). Seep gases from the RRB are dominantly comprised of N2 and He, with >90% N2 concentrations, high 4He concentrations (2.4–6.9%) and radiogenic He isotopes (0.16–0.20 RA). Seeps in the LHS - located between RRB and RVP - are characterized by little-to-no N2, high CO2 contents (72–84%), relatively low He contents (0.008–0.15%), and higher 3He/4He (0.95–0.99 RA). RVP gases have high CO2 (78%) and low 4He (0.0003%) and more mantle-like He isotopes (3.27–4.00 RA) consistent with previous findings (Pik et al., 2006; Barry et al., 2013). All neon isotopes can be explained by mixing between air, high O/F crust and depleted Mid Oceanic Ridge Basalt (MORB) mantle-like signatures. RVP neon isotope seep data potentially suggest a solar-like deep mantle contribution, consistent with findings in rocks from the area (Halldórsson et al., 2014), however we note that this signal is difficult to discern from mass dependent fractionation (MDF). The largest 40Ar/36Ar anomalies occur in RRB, with resolvable excess 40Ar derived from radiogenic production in the crust. Using a noble gas solubility model, we calculate volumetric gas to water ratios (Vg/Vw) and show that Vg/Vw values are low for RRB (0.1), consistent with longer migration distances, whereas Vg/Vw are higher for LHS (Vg/Vw = 0.1–10) and RVP (Vg/Vw = 3–12), suggesting a more direct conduit for volatiles from source to surface. In summary, these data demonstrate interaction between two distinct helium sources, one of which is crustal in origin (most prominent in RRB) and the other being mantle-derived (enriched in RVP). The extent of mixing between the two is shown to be influenced by proximity to rift-related fault structures, groundwater interaction and magmatic heat.

Geological characteristics of China's Tianwen-1 landing site at Utopia Planitia, Mars

China's first Mars mission Tianwen-1 successfully touched down the surface of the southern Utopia Planitia on 15th May 2021. In this study we investigate the geological characteristics of the target landing site (Site 1) and a backup landing site (Site 2) on Utopia Planitia for Tianwen-1 Mission. Site 1 is located in a topographic low and generally flat area to the southern Utopia basin, while Site 2 is located in the Utopia-Elysium transition zone. Several geological features indicative of the presence of a large reservoir of volatiles are identified and mapped in detail for both landing sites, including pitted cones, giant polygons, rampart and pancake craters. The volcanism-related morphologies, e.g., lava flows, lahars, and dikes, are also mapped for Site 2. The compositional analysis reveals little exposures of hydrous materials due to dust cover and/or lacking of data coverage over the regions. Crater counting analysis showed that the Site 1 has an absolute model age of ~3.68 Ga and ~3.45 Ga when including and excluding ghost craters, respectively. The absolute model age of Site 2 is ~3.34 Ga. Finally, the evolutionary history of the Utopia Planitia is discussed, and the related scientific hypotheses to be tested for the in situ exploration are suggested. Our study provides a framework for the Tianwen-1 in situ exploration, which will impose important constraints on the nature and evolution history of the northern lowlands.

Origin and timing of volatile delivery (N, H) to the angrite parent body: Constraints from in situ analyses of melt inclusions

Angrites are derived from the earliest generation of differentiated planetesimals that accreted sunward of Jupiter’s orbit, and are, thus, key to constraining the timing and source(s) of volatile delivery to planetary bodies in the inner solar system. Here we investigate the nitrogen and hydrogen isotopic signatures of angrite melts by in situ secondary ion mass spectrometry (SIMS) analyses of mineral-hosted melt inclusions and interstitial glass in two of the oldest volcanic angrites: D’Orbigny and Sahara 99555. The most primitive melt trapped in Mg-rich olivines in D'Orbigny is characterized by δ15N values ranging from 0 ± 25 to +56 ± 29‰ and δD values between −348 ± 53 and −118 ± 31‰. This shows that the angrite mantle source sampled by D'Orbigny has a N-H isotopic composition that is similar to that of CM carbonaceous chondrites, whose parent bodies are thought to have accreted in the outer solar system. The low nitrogen and water contents measured in Sahara 99555 possibly indicate that its parental melt underwent a higher degree of degassing compared to D’Orbigny or, alternatively, that the two angrites do not sample the same volatile reservoir within the angrite parent body. Given the very old crystallisation age of D’Orbigny, our findings imply that nitrogen- and water-rich objects, presumably formed beyond the orbit of Jupiter, must have been present in the terrestrial planet-forming region within the first ~4 Ma after the formation of Ca-Al-rich inclusions (CAIs, the oldest materials in the solar system).

Subduction-Driven Volatile Recycling: A Global Mass Balance

Volatile elements (water, carbon, nitrogen, sulfur, halogens, and noble gases) played an essential role in the secular evolution of the solid Earth and emergence of life. Here we provide an overview of Earth's volatile inventories and describe the mechanisms by which volatiles are conveyed between Earth's surface and mantle reservoirs, via subduction and volcanism. Using literature data, we compute volatile concentration and flux estimates for Earth's major volatile reservoirs and provide an internally balanced assessment of modern global volatile recycling. Using a nitrogen isotope box model, we show that recycling of N (and possibly C and S) likely began before 2 Ga and that ingassing fluxes have remained roughly constant since this time. In contrast, our model indicates recycling of H2O(and most likely noble gases) was less efficient in the past. This suggests a decoupling of major volatile species during subduction through time, which we attribute to the evolving thermal regime of subduction zones and the different stabilities of the carrier phases hosting each volatile. ▪ This review provides an overview of Earth's volatile inventory and the mechanisms by which volatiles are transferred between Earth reservoirs via subduction. ▪ The review frames the current thinking regarding how Earth acquired its original volatile inventory and subsequently evolved through subduction processes and volcanism.

The Occurrence of Glycosylated Aroma Precursors in Vitis vinifera Fruit and Humulus lupulus Hop Cones and Their Roles in Wine and Beer Volatile Aroma Production.

Volatile aroma compounds found in grapes and hops may be present as both free volatiles and bound glycosides. Glycosides found in the raw materials are transferred to their respective fermented beverages during production where the odorless compounds may act as a reservoir of free volatiles that may be perceived by the consumer if hydrolyzed. A review of the literature on grape and wine glycosides and the emerging literature for glycosides in hops is presented in order to demonstrate the depth of history in grape glycoside research and may help direct new research on hop glycosides. Focus is brought to the presence of glycosides in the raw materials, the effect that winemaking and brewing have on glycoside levels, and current methods for the analysis of glycosidically linked aroma compounds.