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The Xikuangshan antimony (Sb) deposit is the largest Sb deposit in the world; however, the metal source and cycling and a holistic understanding of the deposit genesis remain equivocal. Sulfur isotope signatures offer a means of fingerprinting different sources in a hydrothermal deposit, although one must be careful to rule out subsequent isotope fractionation during fluid ascent, mixing, and ore precipitation. Here, we investigated the sulfur isotope composition of stibnite occurring at depth in the Xikuangshan deposit to distinguish the isotopic signals from the source and the superimposed imprint from near-surface–derived sulfur mixing or isotopic fractionation. All stibnites from the deep orebodies displayed limited δ34S variation from +6.8‰ to +8.4‰, despite their widely varying depths. These results provide direct evidence that δ34S values measured in deep orebodies are representative of the isotopic composition of initial fluids. The most likely factor controlling the variation of the sulfur isotopes in shallow stibnites (+3.5‰ to +16.3‰) is a series of hydrothermal processes, including Rayleigh fractionation during ore precipitation, fluid boiling induced by pressure release, and/or local input of pyrite from wall rocks via fluid-rock interaction. Accordingly, we conclude that the Neoproterozoic basement served as the metal source. We propose a holistic genetic model wherein we envisage that Sb and S were leached from the basement rocks, and the ore-bearing fluids ascended along a deep fault and eventually precipitated beneath the Devonian shale cap. Thus, sulfur isotopic systematics represent a powerful repository for interrogating the metal source and cycling in the hydrothermal ore system.

Understanding the mechanisms governing biological invasions has implications for population dynamics, biodiversity, and community assembly. The enemy escape hypothesis posits that escape from enemies such as herbivores and predators that were limiting in the native range helps explain rapid spread in the introduced range. While the enemy escape hypothesis has been widely tested aboveground, data limitations have prevented comparisons of below- ground mechanisms for invasive and noninvasive introduced species, which limits our understanding of why only some introduced species become invasive. We assessed the role of soil biota in driving plant invasions in a phylogenetic meta−analysis, incorpo- rating phylogeny in the error structure of the models, and comparing live and sterilized conditioned soils. We found 29 studies and 396 effect size estimates across 103 species that compared live and sterilized soils. We found general positive effects of soil biota for plants (0.099, 95% CI=0.0266, 0.1714), consist- ent with a role of soil mutualists. The effect size of soil biota among invaders was 3.2× higher than for natives, the strength of effects was weaker for older conditioning species with a longer introduced history, and enemy escape was stronger for distant relatives. In addition, invasive species had a weaker allocation tradeoff than natives. By demonstrating that the net effect of soil biota is more positive for invasive than native and noninvasive introduced species, weakens over time since introduction, and strengthens as phy- logenetic distance increasing, we provide mechanistic insights into the considerable role of soil biota in bio- logical invasions, consistent with the predictions of the enemy escape hypothesis.

Table S1: Sulfur isotopic compositions of stibnite in the Xikuangshan deposit.

The alkaline complex in the southwest region of Luxi Terrane of the North China Craton is spatially correlated with the newly discovered Longbaoshan REE deposit. Its petrogenesis, however, remains ambiguous. In this study, we present an integrated petrology, whole-rock geochemistry, sphene U-Pb and rare earth element data from the Longbaoshan alkaline complex to investigate the petrogenesis, magma source and tectonic evolution. The Longbaoshan alkaline complex consists of mafic to intermediate rocks of hornblende diorite and alkaline hornblende syenite porphyry, biotite monzonite porphyry and aegirine diorite porphyrite. The hornblende diorites show a composition of low SiO2, high MgO, Fe2O3 and moderate Na2O, CaO and are metaluminous and medium-to-high-K calc-alkaline. The hornblende syenite porphyries, biotite monzonites and argirine diorite porphyrites display a relatively higher content of SiO2, Na2O, K2O and Al2O3 and lower contents of MgO, Fe2O3 and CaO and are metaluminous, peralkaline, high-K calcic-alkaline and shoshonite. The sphene U-Pb data shows that the parent magma of the hornblende diorite was emplaced at ca. 120 Ma. All these samples show a common depletion in Th, Nb-Ta and Zr-Hf and enrichment in large ion lithophile elements (e.g., Pb, Ba, Sr) and Light Rare Earth Elements. The magma may have experienced fractionation of pyroxene, amphibole, sphene, apatite and zircon during its evolution. The variable La content, La/Sm, Rb/Sr and (Ta/Th) N ratios indicate that the parent magma may produce by partial melting of a mantle source that was interacted with sediment-derived melts in a subduction setting. Therefore, we propose that the parent magma of the Longbaoshan alkaline complex was derived from a lithospheric mantle which was metasomatized by sediment-derived melt in a prior subduction process. The enriched magma was emplaced through an extension process and experienced subsequent fractionation and assimilation with the continental crust during the rollback of the Paleo Pacific Ocean plate.

Gemstones are minerals of gem qualities used for adornment and decoration with the attributes of beauty, durability and rarity. Traditionally, although China has been regarded as the most important source for nephrite, over the past decades, a large variety of gemstone resources have been newly discovered in China owing to continuous exploration works. The vast land with various geological and geochemical backgrounds is rich in gemstone resources with potential for new deposits discoveries. In pegmatites, gemstones are related to granitic magma events and mainly occur in pegmatitic cavities, such as tourmaline, aquamarine, spodumene, spessartine, moonstone, quartz, apatite, and topaz. The eruption of Tertiary basaltic magma provides gem-quality sapphire, spinel, olivine, garnet, and zircon. The supergene oxidation zones of some copper and iron deposits in Hubei and Anhui province host gem-quality turquoise and malachite. Moreover, the formation of the nephrite deposit in China is mostly related to the carbonatite and serpentinite rocks involved in the metamorphic-metasomatic processes. This paper comprehensively introduces the distribution of gemstones deposits, as well as the gemological and mineralogical characteristics of gemstones in China. Our present investigation provides insights into the gemstone potential of China for further exploitation.