Zircon trace elements and magma fertility: insights from porphyry (-skarn) Mo deposits in NE China

It has been widely accepted that magmas genetically linked to porphyry (-skarn) Cu (Mo) deposits are commonly oxidized. Recently, using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) techniques, zircon Ce 4+ /Ce 3+ , Ce N /Ce N *, Eu N /Eu N *, and Ce/Nd ratios, and magma ΔFMQ values (departure from the fayalite–magnetite–quartz oxygen buffer) based on zircon trace element compositions, have been used as proxies to quantify magma oxidation state. Here we present the zircon trace element compositions of 13 Mesozoic porphyry (-skarn) Mo deposits in NE China of various sizes to examine the relationship between magma Mo fertility and magma oxidation state. Generally, the studied deposits with > 0.3 Mt Mo have Ce 4+ /Ce 3+ > 100, Ce N /Ce N * > 100, Ce/Nd > 10, and Eu N /Eu N * > 0.3, whereas those containing