Genesis of the Baiyangping Cu–Co and Pb–Zn Mineralizations in Lanping Basin, SW China

Jiaxuan Zhu,Hongyu Duan,Lijun Liu,Qiaoxin Li,Jinlong Qian,Qi Chen,Rong Hu,Lifei Yang,Kangxing Shi

doi:10.3390/app12042129

Abstract

The Oligocene to Miocene Baiyangping Cu–Co and Pb–Zn mineralization was deposited during the collision of the India and Asia continents. The mineralization is hosted in veins in faulted carbonate and clastic rocks, which act as fluid pathways. A detailed fluid-inclusion analysis and C–O–S isotopic study are reported, focusing on the origin of the mineralizing fluids and mineralizing processes. The microthermometry of fluid inclusions hosted in quartz and carbonates indicate that the fluid peak temperature for both Cu–Co and Pb–Zn mineralizations ranges from 160 to 200 °C and from 120 to 160 °C, respectively. During these metallogenic hydrothermal events, salinity evolved from 2.7 wt% NaCl equiv to 24.8 wt% NaCl equiv. The δ34S values measured on sphalerite and tennantite range from +5.2‰ to +9.5‰, which indicates that sulfur originated from a reservoir characterized by thermochemical sulfate reduction (TSR). The C–O isotopic values obtained from the carbonate samples suggest that the fluid mainly originates from basinal brines. The combination of C and S isotopic values of the Cu–Co and Pb–Zn mineralization indicate the sedimentary source of the basin. Mineralization is controlled by faults, thermochemical sulfate reduction, and the physicochemical conditions of the fluid.

Highlights

The classification of sediment-hosted Pb–Zn deposits consists of Mississippi Valleytype (MVT), vein-type, or clastic-dominated deposits
To distinguish the coexistence and precipitation mechanisms involved in the formation of sediment deposits, we chose to study the Baiyangping Cu–Co–Pb–Zn metallogenic district in the Mesozoic to Cenozoic Lanping Basin of SW China [15,16,17,18]
The primary fluid inclusions consisted of two phases, including a liquid phase and vapor bubbles hosted in quartz, calcite, dolomite, and gypsum

Summary

Introduction

The classification of sediment-hosted Pb–Zn deposits consists of Mississippi Valleytype (MVT), vein-type, or clastic-dominated deposits. Sediment-hosted Pb–Zn deposits are major sources of Pb and Zn and significant sources of Ag and Ge, whereas Cu mineralization is generally rare yet economically important [1,2,3,4,5]. Land of Namibia; in the Goodsprings district of Nevada, America; and in the Leeuwbosch and Thabazimbi district of Cornwall [11,12,13,14] The rarity of such types of sediment-hosted deposits appears to reflect a more complex genesis, which deserves detailed studies. The mineralization is widespread in the central part of the basin, which is located within the eastern part of the Indian–Asian collisional zone (Figure 1)

Methods

Results

Discussion

Conclusion