Geosystems and Geoenvironment (Nov 2023)
Detrital zircon U–Pb ages for the lower Cambrian Mantou Formation in Liaoning, northeastern China: Implications for sediment provenance and the early Palaeozoic palaeogeographic position of the North China Craton with respect to East Gondwana
Abstract
The early Palaeozoic palaeogeographic position of the North China Craton (NCC), including with respect to Gondwana, remains subject to debate. Detrital zircon chronology of lower Palaeozoic strata in the NCC should give insights into this scientific problem. Previous studies have reported zircon U–Pb ages for lower Palaeozoic clastic rocks from the western, southern, and eastern margins of the NCC. However, data remain limited for western Liaoning Province, northeastern China, in which representative Cambrian–Ordovician strata are well exposed. Data from this region should provide valuable constraints on the early Palaeozoic palaeo-location of the NCC, including with respect to Gondwana. Here we report laser-ablation–inductively coupled plasma–mass spectrometry detrital zircon ages from siltstone–mudstone of the Cambrian Mantou Formation in the Xingcheng area of Liaoning Province. Our new age determinations reveal two major source areas for the Mantou Formation: (1) the northeastern margin of East Gondwana, which yields zircons with ages of 1300–1000 and 600–510 Ma; and (2) the palaeo-highlands of the western NCC, which yields zircons of ca. 2500 and ca. 1800 Ma. Combining these new results with previously published data from lower Palaeozoic strata in the NCC, age spectra for the NCC exhibit dominant age peaks at ca. 2.5, ca. 1.9, ca. 1.0, and ca. 0.5 Ga, similar to those for Cambrian–Ordovician strata in northern India, western Australia, and Antarctica. Therefore, the NCC is interpreted to have been located close to East Gondwana during the early Palaeozoic. Integrating evidence from palaeobiogeography, palaeomagnetism, and detrital zircon geochronology, the NCC is inferred to have been situated near the boundary between northern India and western Australia during the early Cambrian–Middle Ordovician.
