Fig. 3: Zircon U–Pb–Hf–O isotope features of Cretaceous igneous rocks from the Comei LIP.

a Zircon U–Pb isotopic data for N-MORB-like gabbros from Cona area. Error ellipses represent 1σ; MSWD—mean square of weighted deviates. b Histogram of zircon δ18O values for the N-MORB-like gabbros from the Cona area, showing a quasi-normal distribution with an average value below the typical mantle zircon range (light gray area)70. c Zircon δ18O vs. 206Pb/238U age for N-MORB-like gabbros from the Cona area. Green points represent single spots, with 2 standard deviation bars indicating repeated measurements. Light gray area denotes the typical mantle zircon range. Light green arrow highlights the first-order negative covariation trend. (d) εHf(t) vs. 206Pb/238U age for zircon grains in the Cretaceous igneous rocks from the Comei LIP. Symbols follow Fig. 2.