The giant sediment-hosted finding zinc-lead deposit is located in the Lanping Basin, northwestern Yunnan Province, China. The genesis of the deposit has long been debated and the sources of the ore-forming fluids and metals are controversial. This study presents rare earth element (REE) and noble gas isotope data that constrain the origins of the ore fluids and the heat source driving the hydrothermal circulation. The early-stage sulfides are enriched in light REEs and have high Sigma REE values (30.8-94.8 ppm) and weakly negative Eu (delta Eu 0.85-0.89) and Ce anomalies (delta Ce 0.84-0.95), suggesting that the fluids were likely derived from dissolution of Upper Triassic marine carbonates with input of REEs from aluminosilicate rocks in the basin. In contrast, the late-stage sulfides have irregular REE patterns, generally low Sigma REE values (0.24-10.8 ppm) and positive Eu (delta Eu 1.22-10.9) and weakly negative Ce anomalies (delta Ce 0.53-0.90), which suggest that the ore-forming fluids interacted with evaporite minerals. The He-3/He-4 (0.01-0.04 R-a) and Ar-40/Ar-36 values (301-340) of the ore-forming fluids indicate crustal and atmospheric origins for these noble gases. These findings are in agreement with the published fluid inclusion microthermometry data and the results of H, O, C, S, Pb and Sr isotope studies. Our data, in combination with published results, support a two-stage hydrothermal mineralization model, involving early-stage basinal brines and late-stage meteoric water that acquired metals and heat from crustal sources. (C) 2017 Elsevier B.V. All rights reserved.

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