The water availability deficit is a governance crisis and an environmental, social, and economic risk. This study presents a spatial multicriteria approach for mapping Water Scarcity Vulnerability (WSV) and a comparative analysis of criteria weighting techniques to support the management of water resources in semiarid regions. Initially, nine vulnerability indicators were identified from a literature review and spatialized through a Geographic Information System (GIS) for a water donor region and another recipient from the São Francisco River, in the semiarid region of Brazil. Subsequently, one subjective and two objectives weighting techniques were implemented and compared to measure the weights of the indicators. Finally, the Viekriterijumsko Kompromisno Rangiranje (VIKOR) method was combined with GIS to construct WSV maps. The results indicate the conditions of WSV in the transposition water donor region can be more critical than the region receiver, and the choice of the weighting method influences the results of the multicriteria-GIS approaches. The WSV mapping approach can be helpful for water management decision-making to identify priority areas and spatial inequalities. The comparative analysis in this study can provide a valuable reference for choosing weighting methods in spatial multicriteria applications.
The Beiya porphyry-skarn Au deposit is one of the largest gold deposits in China, temporally and spatially associated with Eocene intrusions in a post-collisional setting in western Yunnan, China. In this study, we report new whole-rock geochemistry, Sr-Nd isotope, zircon U-Pb geochronology and in situ zircon Hf-O isotopes of quartz-monzonite and biotite-monzonite porphyries from the Beiya deposit. The porphyry-skarn mineralization at the Beiya deposit is mainly associated with the quartz monzonite porphyry (35.8 ± 0.6 Ma), while the biotite-monzonite porphyry (34.3 ± 0.5 Ma) represents a post-mineralization intrusion crosscutting the main orebodies and the quartz-monzonite porphyry. Both intrusions have high-K and adakitic composition and are characterized by high Sr/Y ratios, high SiO2 and Al2O3 concentrations (SiO2 = 69.80–73.86 wt%; Al2O3 = 14.11–15.19 wt%), and low MgO, Cr, and Ni concentrations (MgO = 0.2–1.0 wt%; Cr = 1.76–11.13 ppm; Ni = 2.52–11.72 ppm). Their Sr-Nd isotope compositions (87Sr/86Sr = 0.7066–0.7077; εNd(t) = ?5.3 to ?1.5) are consistent with the lower crustal-derived amphibolite xenoliths (87Sr/86Sr = 0.7060–0.7100; εNd(t) = ?10.0 to 0.0), indicating that they might be derived from a thickened juvenile lower crust beneath the Yangtze Craton. The biotite-monzonite porphyry has lower zircon δ18O values of +5.3‰ to +6.8‰ and higher εHf(t) values of ?2.3 to +5.5 than those of the quartz-monzonite porphyry with δ18O values of +7.1‰ to +8.2‰ and εHf(t) values of ?3.8 to +1.5, implying that they were derived from different parts of the lower crust. High Ba/La and Pb/Ce ratios suggest that the quartz-monzonite porphyry is derived from a volatiles-rich reservoir. Relatively higher La/Yb, Sm/Yb and Dy/Yb ratios of the biotite-monzonite porphyry indicate residual garnet in the source, indicating a deeper source than that of the quartz-monzonite porphyry. The hydrous components should be represented by the amphibole-rich lithologies, which has relatively shallower depth than that of the garnet-bearing mafic thickened lower crust. Our data suggest that the mineralized quartz-monzonite porphyry at the Beiya deposit is derived from partial melting of amphibole-rich lithologies in the upper part of the thickened juvenile lower crust beneath the Yangtze Craton, while the post-mineralization biotite-monzonite porphyry is derived from the basal, and volatiles-poor, part of the juvenile lower crust. 相似文献