SHRIMP U–Pb ages of zircons from the Lengshuikeng ore field, North Wuyi Mountains, South China: Implications for dating volcaniclastic rocks

A new study challenges the long-standing debate on the age of volcanic rocks in the Lengshuikeng Ag–Pb–Zn ore field, North Wuyi Mountains, South China. Using SHRIMP zircon U–Pb dating, researchers identified two distinct populations of zircons—autocrystic and xenocrystic—in ignimbrites and tuffs from the region. The autocrystic zircons indicate that these pyroclastic rocks formed during the Early Lower Cretaceous (~140 Ma), while xenocrystic zircons suggest earlier granitic intrusions in the Early Upper Jurassic (155–159 Ma). This finding resolves conflicting age estimates and highlights the complexity of interpreting zircon ages in volcaniclastic rocks, where younger U–Pb dates may not always reflect the true formation or eruption age if juvenile or vitric pyroclasts are absent or scarce.

Wu, J.-H., Guo, H.-F., Yang, D.-G., Wang, K.-X., Wei, C.-X., & Guo, J.-L. (2020). SHRIMP U–Pb ages of zircons from the Lengshuikeng ore field, North Wuyi Mountains, South China: Implications for dating volcaniclastic rocks. Island Arc, 29(1). Portico. https://doi.org/10.1111/iar.12347