AUTHOR=Dong Leilei , Bai Xin , Song Mingchun , Wang Runsheng 

TITLE=Crustal thickness of the Jiaodong Peninsula in the Mesozoic: Implications for the destruction of the North China Craton

JOURNAL=Frontiers in Earth Science

VOLUME=Volume 11 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/earth-science/articles/10.3389/feart.2023.1171456

DOI=10.3389/feart.2023.1171456

ISSN=2296-6463

ABSTRACT=The North China Craton (NCC) underwent extensive and widespread crustal reworking (or decratonization) during the Mesozoic. However, how the decratonization operated is not well understood. Zircon compositions are widely used to reconstruct the crustal thickness in the scientific community. In this study, we sampled thirteen magmatic rocks in the Jiaodong Peninsula and used zircon Eu/Eu* to put constraints on the crustal thickness of the Jiaodong area and reveal decratonization processes in the Mesozoic time. Reconstructed crustal thickness using zircon Eu/Eu* is about 70 km in the Jurassic, and this value turns to be 89 km at around 130 Ma, after which the crustal thickness drops to 30–40 km at ca. 110 Ma. These results are generally in compatible with or slightly higher than the calculation results using whole-rock La/Yb proxy for the Jurassic and ~130 Ma rocks. Crustal thickness estimated using whole-rock La/Yb proxy for the ~110 Ma rocks is thicker than 70 km, which is not consistent with the geological fact and the result given by zircon proxy. The whole-rock proxy failed in estimating crustal thickness because of amphibole fractionation for the ~110 Ma rocks. The crustal thickening from Jurassic to ~130 Ma was probably related to westward subduction of Paleo-Pacific slab. The thinning of the crust during 130 to 110 Ma is not a rapid process but occurs more slowly than expected, which might be explained by chemical erosion process rather than a mechanical delamination model. The chemical erosion was most likely induced by rollback of the subducting slab and upwelling of the asthenosphere.