Supplemental Material: Subduction polarity reversal facilitated by plate coupling during arc-continent collision: Evidence from the Western Kunlun orogenic belt, northwest Tibetan Plateau

Materials and methods, Figures S1–S6, and Tables S1–S7.  </p

Maturation from oceanic arcs to continental crust: Insights from Paleozoic magmatism in West Junggar, NW China

Understanding the processes involved in the transformation of juvenile basaltic oceanic arc crust into mature continental crust remains a key challenge in Earth sciences. In this contribution, we present a comprehensive synthesis of in situ zircon Usingle bondPb age and Hfsingle bondO isotope data for Paleozoic intrusions within the West Junggar oceanic arc, NW China. Our study reveals four distinct pulses of magmatic activity: Early Cambrian to Early Ordovician (515 to 486 Ma); Late Ordovician to Middle Devonian (445 to 392 Ma); Early Carboniferous (343 to 310 Ma) and Late Carboniferous to Middle Permian (309 to 259 Ma). These pulses have varied spatial and temporal distributions. All magmatic rocks display consistently high zircon Hf and whole-rock Nd isotope values, but substantial variations in zircon O isotopes. There are two groups of intrusions: those with high zircon δ18O (>6.5‰) and those with mantle-like zircon δ18O (ca. 5.5‰). The high zircon δ18O intrusions are predominantly concentrated in the southern West Junggar and their Hf and Nd isotopes indicate the involvement of supracrustal material and juvenile basaltic crust in their petrogenesis. Binary mixing calculations indicate a contribution from the supracrustal rocks ranging from 10% to 50%. The intrusions with mantle-like zircon δ18O are found primarily in northern West Junggar with a small amount occurring in southern West Junggar. The intrusions record a variety of magma sources and processes as demonstrated by Hfsingle bondO isotope and geochemical data. These data indicate partial melting of metasomatized depleted mantle, mixing of depleted mantle and juvenile crust, and partial melting of trapped juvenile oceanic crust or mafic lower crust. Hf model ages reveal significant crustal growth in the West Junggar, characterized by three distinct episodes of crust formation occurring at approximately 656–684 Ma, 524–536 Ma, and 441–471 Ma, involving periodic remelting of igneous material derived from a depleted mantle source. This newly-formed crust maintains a mantle-like oxygen isotope composition despite being repeatedly sampled by magmas for up to 0.26 Ga. Since the timing of crustal growth occurred independently of the major magmatic pulses, the latter reflect primarily reworking and remelting processes. Two significant episodes of magmatic activity, the late Silurian to early Devonian and the late Carboniferous to early Permian, preserve a signature of ocean ridge subduction. High-temperature magmatism during these periods promoted extensive melting of the mafic lower crust, oceanic crust, and supracrustal rocks, leading to the compositional transformation from basaltic to felsic continental crust. This comprehensive compilation provides valuable insights into granite petrogenesis, crustal evolution, and the diverse processes involved in the maturation of oceanic arc crust and its contribution to continental crust formation and evolution

The role and significance of juvenile sediments in the formation of A-type granites, West Junggar oceanic arc (NW China): Zircon Hf-O isotopic perspectives

Oceanic arc subduction systems are the loci of substantial recycling of oceanic crust and production of juvenile arc crust that differentiates to more evolved felsic crust. Inevitably, some juvenile sediments are subducted with the oceanic crust. However, distinguishing the incorporation of juvenile sediments in oceanic arcs is not always straightforward, because they may not measurably shift many geochemical signatures, such as Sr and Nd isotopes, of oceanic arcs. Nevertheless, combined zircon U-Pb, Hf, and O isotope data can provide a powerful tool to decipher sedimentary flux into oceanic arc magmas, and here we report a case study for the late Paleozoic A-type granites from the West Junggar oceanic arc in the southern Central Asian Orogenic Belt. These plutons contain hastingsite and iron biotite diagnostic minerals and have high alkali, FeOT/MgO, Zr, and Ga/Al, but possess low CaO contents, and strongly negative Eu, Sr, and Ba anomalies, demonstrating their close affinity with A-type granites. Zircon U-Pb analyses indicate that these A-type granites emplaced in the Late Carboniferous to Early Permian (ca. 307-298 Ma). Their high zircon £Hf(t) values (+12.4 to +15.5), suggest that the mag- mas were derived from a mantle or juvenile crustal source. However, their 818Ozrn (+7.2%c to +11.9%c) values are significantly higher than that of the mantle, and modeling using Hf-O isotope and rare earth element data indicate the assimilation of sedimentary materials at a proportion of -50%. Our data suggest that juvenile sediments (e.g., greywacke) played an important role in the formation of the studied A-type granites. The re-melting of sedimentary material induced by the late Carboniferous ridge subduction can promote the transition from an intra-oceanic arc to continental crust. Our results show that the subduction and re-melting of juvenile sediments in oceanic arc systems could be an important mechanism for the maturation of oceanic arc crust

Health and environmental consequences of crop residue burning correlated with increasing crop yields midst India's Green Revolution

The Green Revolution (GR) enhances crop yields significantly that contributes greatly to the social and economic development of many less developed countries. However, the increasing crop yields might rise crop residue biomass burning, leading to adverse environmental and health consequences. We assess the impact of crop residue burning associated with the GR-induced growing crop yields on benzo[a]pyrene (BaP) pollution, a congener of polycyclic aromatic hydrocarbons with strong carcinogenicity. We find a significant increasing trend of BaP emission and contamination from crop residue biomass burning from the mid-19605 to 2010s in India, coinciding with the growing crop yields occurring during the GR. Our results reveal that agricultural BaP emission driven lifetime lung cancer risk (ILCR) in India increased 2.6 times from the onset of GR in the mid-1960s to 2014 and the 57% population in India was exposed to the BaP level higher than the India national standard (1 ng m(-3)). We show that the reduction of open crop residue burning during the rice and wheat residue burning period would be a very effective measure to reduce BaP environmental contamination and health risk

Number of death due to industrial accidents in China.

<p>Data from: National Economy and Society Developed Statistical Bulletin 2010–2015 from National Bureau of Statistics of the People’s Republic of China.</p

The final assessment result of risk score for each district.

<p>The final assessment result of risk score for each district.</p