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The successful return of lunar soil samples from the northern Oceanus Procellarum by the Chang'E 5 (CE-5) mission has provided unprecedented ground-truth information for the previously unexplored region of the Moon. In particular, the particle size and mineral constituents of the CE-5 soil samples are of critical importance to interpret remote sensing data. With a Raman-based particle analysis system, we show that the particle size properties and mineral constituents of the CE-5 soil can be simultaneously determined with a small sample size (ca. 30 μg). The CE-5 sample scooped from the lunar surface has an overall small size between 0.4 μm and 73.9 μm (mean=3.5 μm), and mainly consists of pyroxene (39.4%), plagioclase (37.5%), olivine (9.8%), Fe-Ti oxides (1.9%), glass (8.3%) and other minor or trace phases. The results are consistent with previous analyses with larger sample sizes. In addition to minimum sample consumption, this method requires very little sample preparation, and can rapidly build a large database with each particle precisely traceable. Therefore, this novel technique is particularly suitable for the analysis of future returned soil samples from extraterrestrial bodies. [ABSTRACT FROM AUTHOR]

The Ediacaran–Cambrian Phosphogenic Episode is the Earth's first true phosphogenic event and resulted in worldwide phosphate deposits, which occurred during the processes of the Neoproterozoic Oxygenation Event. The Ediacaran Doushantuo Formation (ca. 635–551 Ma) of Weng'an area in central Guizhou, South China, contains two economic phosphorite beds (the Lower and Upper Phosphorite Beds). This paper presents a detailed stratigraphic, sedimentological and mineralogical study of multiple outcrop and drill core sections of the Doushantuo Formation across the Weng'an area, and identified 11 lithofacies and 4 types of phosphatic grains. Significant differences in lithofacies and grain types between the upper and lower phosphate deposits are observed, indicating that the two sets of phosphate deposits are the products of two distinct phosphogenic processes. The Lower Phosphorite Bed mainly consists of banded and laminated phosphorites, contains micro-oncoids formed by microbially-mediated precipitation and peloids formed by in-situ chemically oscillating reactions, indicating a biochemical and chemical enrichment of phosphorus to sediments during the Early Ediacaran Period. The Upper Phosphorite Bed is mainly composed of carbonaceous, massive, and stromatolitic phosphorites, contains bioclasts (phosphatized spheroidal fossils), and intraclasts formed by hydrodynamic agitation, suggesting that the major accesses of phosphorus to sediments were the remineralization of organic P. Deposition of the two economic phosphorite beds was controlled by two sea-level cycles. Such differences have also been documented in contemporaneous phosphate-bearing successions in Brazil and Mangolia, indicating a significant shift in global phosphogenic mechanism during the early and middle Ediacaran, which may be due to the changes in redox conditions in seawater, associated with the Neoproterozoic Oxygenation Event. These regional active P-cycle processes could produce more free oxygen, which may have contributed to the upcoming Phanerozoic global oxidation. [ABSTRACT FROM AUTHOR]

Previously undescribed Ediacaran macrofossils are documented in and close to a quarry southwest of Zigui in Shunyang Valley, near Sixi Village, Yangtze Three Gorges region, Hubei Province, China. Discoidal impressions, vendotaenids, and a new branching form occur in bedded carbonates through the entire 235 m thickness of the Dengying Formation. The quarry and nearby outcrops in the stream valley have significant potential for further discoveries of Ediacaran macrofossils. [ABSTRACT FROM AUTHOR]

Lunar soil is a fine mixture of local rocks and exotic components. The bulk-rock chemical composition of the newly returned Chang'E-5 (CE-5) lunar soil was studied to understand its chemical homogeneity, exotic additions, and origin of landing site basalts. Concentrations of 48 major and trace elements, including many low-concentration volatile and siderophile elements, of two batches of the scooped CE-5 soil samples were simultaneously obtained by inductively coupled plasma mass spectrometry (ICP-MS) with minimal sample consumption. Their major and trace elemental compositions (except for Ni) are uniform at milligram levels (2–4 mg), matching measured compositions of basaltic glasses and estimates based on mineral modal abundances of basaltic fragments. This result indicates that the exotic highland and KREEP (K, rare earth elements, and P-rich) materials are very low (<5%) and the bulk chemical composition (except for Ni) of the CE-5 soil can be used to represent the underlying mare basalt. The elevated Ni concentrations reflect the addition of about 1 wt% meteoritic materials, which would not influence the other bulk composition except for some highly siderophile trace elements such as Ir. The CE-5 soil, which is overall the same as the underlying basalt in composition, displays low Mg# (34), high FeO (22.7 wt%), intermediate TiO 2 (5.12 wt%), and high Th (5.14 µg/g) concentrations. The composition is distinct from basalts and soils returned by the Apollo and Luna missions, however, the depletion of volatile or siderophile elements such as K, Rb, Mo, and W in their mantle sources is comparable. The incompatible lithophile trace element concentrations (e.g., Ba, Rb, Th, U, Nb, Ta, Zr, Hf, and REE) of the CE-5 basalts are moderately high and their pattern mimics high-K KREEP. The pattern of these trace elements with K, Th, U, Nb, and Ta anomalies of the CE-5 basalts cannot be explained by the partial melting and crystallization of olivine, pyroxene, and plagioclase. Thus, the mantle source of the CE-5 landing site mare basalt could have contained KREEP components, likely as trapped interstitial melts. To reconcile these observations with the initial unradiogenic Sr and radiogenic Nd isotopic compositions of the CE-5 basalts, clinopyroxene characterized by low Rb/Sr and high Sm/Nd ratios could be one of the main minerals in the KREEP-bearing mantle source. Consequently, we propose that the CE-5 landing site mare basalts very likely originated from partial melting of a shallow and clinopyroxene-rich (relative to olivine and orthopyroxene) upper mantle cumulate with a small fraction (about 1–1.5 %) of KREEP-like materials. [ABSTRACT FROM AUTHOR]

The lunar regolith layer preserves abundant information on the internal properties of the Moon as well as the space-surface interactions. By gardening and overturning through time, the regolith layer is heterogenous and soils from different depths could record the complex evolution history of the Moon. Chang'e-5 (CE-5) successfully returned scooped samples and drilled samples from the northeastern Oceanus Procellarum of the Moon. In this study, one scooped sample (0–3 cm depth, S0) and two drilled samples (~10 cm depth, S10; and ~ 65 cm depth, S65) were employed to analyze their granulometry and mineralogy by micro Raman spectroscopy. The grain size increases with depth, and the median grain size of S0, S10, and S65 are Φ5.45 (30.2 μm), Φ4.47 (45.0 μm), and Φ3.37 (96.4 μm), respectively. Their mineral types and contents are pyroxene (33.4–40.5 vol%), plagioclase (30.4–33.8 vol%), olivine (9.0–13.1 vol%), glass (6.9–10.7 vol%), Fe Ti oxide (6.7–7.5 vol%), cristobalite (0.2–3.8 vol%), quartz (0.4–0.9 vol%), and phosphate (0.2–0.6 vol%). The size-dependent mineral modes reveal the relationship between grain size and mineralogy. The mineral modal abundances of 3 soil samples at different depths are roughly similar to that of CE-5 basalts. Raman peak position of quartz may record a peak shock pressure of 31.4 GPa. 5–9 vol% plagioclase amorphization reflects that at least 2–9% exogenous materials in CE-5 soil samples are ejected from craters with diameters larger than 3 km located beyond 50 km from the landing site. • Granulometry and mineralogy of CE-5 soil samples from three different depths were analyzed by micro-laser Raman spectroscopy. • The grain size distribution of CE-5 lunar soil exhibits an increasing trend with depth. • The mineral constituents of the soil samples are consistent throughout various depths. • Highly shocked materials were observed, including shocked quartz, quartz glass, and plagioclase glass. • Exogenous materials account for >2–9% of the CE-5 samples. [ABSTRACT FROM AUTHOR]

[Display omitted] • Arsenic in green fertilizers retards the decomposition of struvite. • Arsenic is readily attenuated by newberyite during the transformation. • Arsenic species incorporated is AsO 4 3- in struvite but HAsO 4 2- in newberyite. Struvite recovered from wastewaters is an increasingly popular green fertilizer but can sequester hazardous heavy metal(loid)s, including arsenic. The recycled struvite applied as fertilizers in soils often undergoes dissolution and subsequent transformation to newberyite over time, potentially resulting in arsenic contamination. Therefore, understanding the fate of arsenic during struvite transformation to newberyite is critical to its safe application. Herein, we have investigated the effects of arsenic on the transformation of struvite to newberyite and examined the associated consequences of this transformation for arsenic mobilization. Our results demonstrate that low arsenic contents have minor but detectable retardation on the struvite-newberyite transformation, and high arsenic loading can severely inhibit this transformation. However, the mechanisms of the struvite-newberyite transformation are independent of the arsenic concentrations. Most arsenic is retained in the solids during the struvite-newberyite transformation. Also, the arsenic contents in both struvite and newberyite increase with increasing the initial pH values. Moreover, spectroscopic analyses and first-principles calculations show that the dominant arsenic species incorporated is AsO 4 3- in struvite but HAsO 4 2- in newberyite. These results have important implications for understanding the roles of arsenic in struvite-based green fertilizers and developing optimal applications of these materials for the remediation of arsenic contamination in aqueous environments. [ABSTRACT FROM AUTHOR]

The terminal Ediacaran Dengying Formation in the eastern Yangtze Gorges area, South China is well known for hosting diverse Ediacaran-type macrofossils and trace fossils. However, the depositional processes of this carbonate succession are still poorly known. Here we present detailed sedimentological data on the Dengying carbonates in four sections across the eastern Yangtze Gorges area, with an emphasis on tempestites in limestones of the Shibantan Member of Dengying Formation that have largely been overlooked. The Shibantan limestones in the studied sections contain extensive autochthonous microbial mats and storm-related deposits, including calcirudite, individual swaley cross-stratified calcarenites, hummocky cross-stratified fine- to very fine-grained calcarenites, normally graded calcarenites, calcarenite-calcisiltite beds in discrete units, and soft-sediment deformed beds. The spatial variation of facies suggests that the Shibantan Member was deposited on a carbonate ramp with an intra-ramp lagoon. With the upward shallowing of water depth and progradation of storm-generated sediments, the ramp gradually become steeper, as characterized by the occurrence of soft-sediment deformation structures and graded bedding in the middle of the member. The abundance of tempestites in the Shibantan limestones suggests that the Shibantan Basin was located in low-latitude regions frequently affected by tropical storms, consistent with previous paleogeographic reconstructions. Storm events probably brought nutrients into the environment and contributed to the rapid burial and preservation of macrofossils. The Shibantan limestones thus provide another example of a massflow-related taphonomic window for the Ediacaran organisms that is comparable to the fossil preservation style in the Ediacaran siliciclastic rocks. • Eight facies have been recognized from the Dengying Formation. • Tempestites are abundant in the Shibantan limestones. • The Shibantan Member was deposited on a carbonate ramp with an intra-ramp lagoon. • The Shibantan Basin was located in low-latitude regions affected by tropical storms. • Storm events contributed to the preservation of Ediacaran-type fossils. [ABSTRACT FROM AUTHOR]