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Deforestation, a significant threat to biodiversity, is accelerated by global demand for commodities. Although prior literature has linked deforestation to global supply chains, here we provide a fine-scale representation of spatial patterns of deforestation associated with international trade. Using remote sensing data and a multi-region input-output model, we quantify and map the spatiotemporal changes in global deforestation footprints over 15 years (2001-2015) at a 30-m resolution. We find that, while many developed countries, China and India have obtained net forest gains domestically, they have also increased the deforestation embodied in their imports, of which tropical forests are the most threatened biome. Consumption patterns of G7 countries drive an average loss of 3.9 trees per person per year. Some of the hotspots of deforestation embodied in international trade are also biodiversity hotspots, such as in Southeast Asia, Madagascar, Liberia, Central America and the Amazonian rainforest. Our results emphasize the need to reform zero-deforestation policies through strong transnational efforts and by improving supply chain transparency, public-private engagement and financial support for the tropics.

Global resources of heavy Rare Earth Elements (REE) are dominantly sourced from Chinese regolith-hosted ion-adsorption deposits in which the REE are inferred to be weakly adsorbed onto clay minerals. Similar deposits elsewhere might provide alternative supply for these high-tech metals, but the adsorption mechanisms remain unclear and the adsorbed state of REE to clays has never been demonstrated in situ. This study compares the mineralogy and speciation of REE in economic weathering profiles from China to prospective regoliths developed on peralkaline rocks from Madagascar. We use synchrotron X-ray absorption spectroscopy to study the distribution and local bonding environment of Y and Nd, as proxies for heavy and light REE, in the deposits. Our results show that REE are truly adsorbed as easily leachable 8- to 9-coordinated outer-sphere hydrated complexes, dominantly onto kaolinite. Hence, at the atomic level, the Malagasy clays are genuine mineralogical analogues to those currently exploited in China. Global resources of heavy Rare Earth Elements (REE) are dominantly sourced from Chinese regolith-hosted ion-adsorption deposits, yet the adsorption mechanisms remain unclear. Here, the authors find that heavy REE are adsorbed as easily leachable 8-coordinated outer-sphere hydrated complexes, dominantly onto kaolinite, in clays from both China and Madagascar. [ABSTRACT FROM AUTHOR]

Subduction of oceanic slabs can physically and chemically modify mantle wedges, but how mantle wedges are temporally evolved is difficult to be constrained. In this study, we use in situ zircon U–Pb ages and Hf–O isotopes of mafic intrusions to examine a coupled evolution of magmas and mantle sources above a subduction zone. Neoproterozoic mafic intrusions in the western margin of the Yangtze Block are mostly composed of gabbros that were formed in an arc system during 870–750 Ma followed by generation of voluminous slab-derived granitoids. The mantle wedge was progressively modified by slab fluids, sediment melts and altered oceanic crust (AOC) melts. Gabbros from the 870-Ma intrusion have normal δ18O (4.79‰ to 6.07‰), high εHf (+ 10.4 to + 15.0) and εNd (+ 4.0 and + 6.4) and were derived from a mantle source enriched by slab fluids. Gabbros from the 860–840-Ma intrusions have overall relatively high δ18O (5.61‰ to 7.42‰), but variable εHf values (− 3.5 to + 15.0) that are decoupled from εNd (+ 1.85 to + 3.87). These features are clearly suggestive of a mantle source modified by sediment melts. However, gabbros from the 820–780-Ma intrusions have relatively low δ18O (4.22‰ to 5.49‰), and constant εHf (+ 4.7 to + 9.6) that are decoupled from εNd (− 0.52 to + 1.92). Such features can be explained by a mantle source contaminated by 18O-depleted AOC melts. The widespread younger TTG-type granitoids were partial melts of the subducted oceanic slab and terminated the mafic magmatism in the region, indicating that slab break-off probably resulted in slab melting after a long period of subduction. Similar Neoproterozoic magmatism also occurred in Greater India and Madagascar, suggesting a giant Andean-type arc system along the western margin of Rodinia. In this arc system, mantle-derived magmas were dominated by an arc affinity in the earlier stage before 820 Ma and became rift-related after that, reflecting regional slab tearing and break-off. Our study also provides evidence for the linkage between the marginal subduction and the internal rifting in Rodinia, and suggest that slab break-off probably triggered its break-up. [ABSTRACT FROM AUTHOR]