Molybdenite Re-Os isochron age of the Huoshenmiao Mo deposit in Luanchuan of Henan Province and its geological implications

The Huoshenmiao skarn Mo deposit in the Luanchuan ore district is a medium-sized Mo deposit discovered in recent years. The Mo orebodies are mainly hosted in Huoshenmiao intrusion and Sanchuan marble. In order to determine the age of mineralization, the source of molybdenum and the relationship with the Nannihu-Sandaozhuang and the Shangfanggou Mo deposits, the authors selected six molybdenum-bearing samples of different ore-forming types for precise dating through ICP-MS molybdenite Re-Os isotopic measurement, and the results yielded model ages ranging from 146.1Ma±2.0Ma to 148.1Ma±2.1Ma, a weighted average age of 147.01Ma±0.95Ma, and an isochron age of 145.7Ma±3.9Ma, implying that the Huoshenmiao Mo deposit was formed in late Jurassic, whereas the Re values of molybdenum vary in the range of 39×10-6～65.4×10-6, indicating that they were derived from mixed crust and mantle sources. The Huoshenmiao and Nannihu-Sandaozhuang as well as Shangfanggou Mo deposits were produced by the second magmatic activity of the late Jurassic in the Luanchuan ore district. The discovery of the Huoshenmiao Mo deposit provides the basis in the search for mineral resources in the west of the Luanchuan ore district.