Isotopic analysis of Fe has proved to be a productive tool for the study of the formation and evolution of planetary bodies. The Fe isotopic studies on the Moon revealed that low-Ti and high-Ti ...basalts are positively correlated with TiO2 contents, indicating the occurrence of Fe isotopic fractionation during lunar magma ocean differentiation (Weyer et al., 2005; Liu et al., 2010; Wang et al., 2015; Sossi and Moynier, 2017). If true, very low-Ti basalts may be more representative of the lunar mantle than high-Ti and low-Ti basalts. Thus, an Fe isotopic study of very low-Ti basalts is required to investigate the Fe isotopic evolution scenario during lunar magma ocean differentiation.
In this study, we measured Fe isotopic ratios of soil samples from the Soviet Luna missions, Luna 16, 20, and 24, using MC-ICP-MS. Bulk soil samples without isolation of components and separated monomineralic grains (olivine, pyroxene, and agglutinate) were dedicated for the Fe isotopic study. Among our samples, Luna 24 soil is recognized as very low-Ti basalt. Evidence of non-mass-dependent Fe isotopic fractionation was not found in bulk soils and separated monomineralic olivine, pyroxene, and agglutinate grains. Lunar regolith samples are weathered by meteorite impacts on the Moon’s surface. A mature regolith sample, L1613, showed clearly distinguished Fe isotopic compositions between the fine-grained fraction (δ57Fe = 0.54 ± 0.06‰) and the coarse-grained fraction (δ57Fe = 0.20 ± 0.06‰). Such Fe isotopic differences among different size fractions were smaller in the submature sample (L2001) and the immature sample (L24130.3). The Fe isotopic ratios of separated grains show that agglutinates have higher δ57Fe values than bulk and monomineralic grains, indicating abundant nanophase Fe in agglutinates and partial evaporation of Fe during its melting.
The δ57Fe value for the coarsest-grained fraction of L24130.3 was found to be 0.08 ± 0.04‰, which is the first Fe isotopic composition reported for lunar samples with very low-Ti mare basalt composition. This value is clearly lower than previously reported δ57Fe values for high-Ti and low-Ti basalts and is nearly identical to those of Mg-suite rocks. This observation is consistent with the Fe isotopic evolution model during lunar magma ocean differentiation (Sossi and Moynier, 2017). Our results related to very low-Ti basalt showed that the bulk silicate Moon has lower Fe isotopic composition than the value estimated from averaged low-Ti or high-Ti basalts.
Given the data known to date, including our results, we conclude that it is most likely that Earth and the Moon have the same Fe isotopic composition. We believe that isotopically heavy Fe of silicate Earth is balanced by isotopically light Fe of Earth’s core, as suggested by Galimov’s (2011) model for the formation of the Earth-Moon system.
This paper makes an analysis of black feminism in the album Bom mesmo e estar debaixo d'agua, of the singer Luedji Luna, from the concepts of "Crossroads" (Encruzilhada) (Martins, 2021), and Safe ...Spaces (Collins, 2019). The analisis take the images of "Chororo", "Ain't I a Woman?" and "Lencois" to discuss the process of self-definition (Collins, 2019) in the artist's body, that activate female-crossroads when walks by the time and the space.
Bulk composition data for 24 chemical elements are presented for regolith samples (<1 mm fines) from each of the 62 half‐centimeter dissection intervals along the 31 cm length of the 76001 vertical ...drive tube collected by astronauts at the base of the North Massif at station 6 of the Apollo 17 landing site. The core regolith is nearly uniform in composition with depth although the concentrations of Sc and Sm, for example, decrease from 28.5 μg g−1 Sc and 5.93 μg g−1 Sm at the top 2.5 cm to 26.9 μg g−1 Sc and 5.55 μg g−1 Sm at the bottom 2.5 cm. This change reflects an increase with depth in the relative abundance of Sm‐poor, feldspathic material, from 48.4% at the top to 50.1% at the bottom. On the basis of compositional mass balance, the feldspathic (nonmare) material of the station 6 regolith requires a substantial proportion of an Mg‐rich lithology, ~27% when modeled as troctolite sample 76535. The remaining 73% is nominally Sm‐poor anorthositic norite in composition. No such Mg‐rich component is required to account for the composition of the regolith of the South Massif (stations 2 and 3). The total feldspathic component of the North Massif regolith, normatively an anorthositic troctolite (74 vol% plagioclase, olivine:pyroxene = 55:45, Mg′ = 78%), is very similar to that of the nonmare component of the Luna 20 regolith collected 910 km to the southeast on the Crisium ejecta deposit. We also present new composition data for 21, 25, and 16 small lithic fragments (0.1–3.9 mg each) from the regoliths of the Luna 16, 20, and 24 missions.
This paper investigates the causes and the consequences of the FTX digital currency exchange’s failure in November 2022. Analysing on-chain data, we report that FTX heavily relied on leveraging and ...misusing its native token, FTT, and we show how this behaviour exacerbated the company’s fragile financial situation. To gain further insights into the downfall, we employ state-of-the-art network science instruments to model the evolutionary dependency structures of 199 cryptocurrencies on an hourly basis, and we investigate tick-by-tick public trades at the time of the events. We identify the collapse of the Terra-Luna ecosystem as the pivotal event that triggered a significant decrease in the exchange’s liquidity. Results suggest that the crash was actively accelerated by Binance tweets causing a systemic reaction in the cryptocurrency market. Finally, identifying the actors who mostly benefited from the FTX’s collapse and highlighting a generalised trend toward centralisation in the crypto space, we emphasise the importance of genuinely decentralised finance for a transparent, future digital economy.
•We investigate the causes and the consequences of the FTX exchange’s failure.•We use hourly closing price, on-chain data and public transaction data.•We use state-of-the-art instruments from network science (i.e., TMFG).•We identify the collapse of the Terra-Luna as the trigger for the FTX’s crash.•We highlight a generalised trend toward centralisation in the crypto space.
We quantitatively describe the main events that led to the Terra project’s failure in May 2022. We first review, in a systematic way, news from heterogeneous social media sources; we discuss the ...fragility of the Terra project and its vicious dependence on the Anchor protocol. We hence identify the crash’s trigger events, analysing hourly and transaction data for Bitcoin, Luna, and TerraUSD. Finally, using state-of-the-art techniques from network science, we study the evolution of dependency structures for 61 highly capitalised cryptocurrencies during the down-market and we also highlight the absence of herding behaviour analysing cross-sectional absolute deviation of returns.
•We describe the Terra project’s features and the mechanisms that led to its failure.•We use network science and herding approaches to capture dependency structures.•The vicious dependence of the Terra project on the Anchor protocol is reported.•We uncover BTC’s reference role during the first phase of the collapse.•Herding behaviour is not detected during the down market.
The results of our regional and local studies of the Fecunditatis basin and Mare Fecunditatis, and areas adjacent to the Luna 16 landing site suggest the following. If the Fecunditatis basin is an ...impact structure, which is consistent with the crustal thickness models and gravity data, it predates the Nectaris basins (∼4.17 Ga). The unusually flat topographic profile of the Fecunditatis basin can be explained by viscous relaxation of the original topography of the basin and the subsequent filling of the basin by ejecta from the Nectaris and Crisium basins. The results of our crater size-frequency measurements within the mare domain of the Fecunditatis basin yield an absolute model age (AMA) of ∼3.81 Ga. Thus, the population of all recognizable craters within Mare Fecunditatis denotes the existence of an extensive episode/episodes of resurfacing that has erased the ancient crater population accumulated after the Fecunditatis impact event but before the mare emplacement. Our determinations of AMAs of the surface of Mare Fecunditatis (∼3.45 Ga) are consistent with most radiometric age determinations from the Luna 16 samples that are clustered at ages of ∼3.5–3.4 Ga. The current Mare Fecunditatis surface is likely to represent the latter episodes of volcanism, the main phase of which was active during this time interval. Although older radiometric ages have not yet been reported, the presence of older basalts in the Luna 16 sample should not be ruled out, taking into account the likely multiple sources of its materials and the complex nature of the emplacement of lavas in Mare Fecunditatis. The thickness of mare basalts in Mare Fecunditatis are highly variable. At the regional scale, thicknesses are most likely at least ∼1.5 km, in order to be able to hide a significant number of ancient larger craters. In the areas of partly or completely flooded craters, the mare thickness increases up to ∼2–2.7 km. In the vicinity of the Luna 16 landing site, however, the thickness of the most than a few hundred meters.
•The unusual topographic profile of the Fecunditatis basin can be explained by viscous relaxation of the original topography.•Recognizable craters within Mare Fecunditatis suggest the existence of an extensive episode of resurfacing before the mare emplacement.•Our determinations of AMAs of the surface of Mare Fecunditatis (∼3.45 Ga) are consistent with most radiometric age determinations from the Luna 16 samples (∼3.5–3.4 Ga).•Older radiometric age of Mare Fecunditatis materials should not be ruled out.
This paper is based on a study of sociocultural intervention of art in the current global and local problems, as it takes shape in the work of the Peruvian artist Rustha Luna Pozzi.-Escot (Lima, ...1973), specifically through his "Armed Women" project, presented in the last 10-years at various exhibitions and performances in Peru, France and Germany. These are representations of the woman fighter, who transforms her traditional everyday referents into signs of combat, to assume an active and transforming role in society, re-meaning her story.
