Stratigraphic and U‐Pb SHRIMP Detrital Zircon Evidence for a Neoproterozoic Continental Arc, Central China: Rodinia Implications

Abstract The Bikou terrane of central China is located within the southwest Qinling Mountains along the northwest margin of the Yangtze Plate. The terrane consists of a volcanic assemblage, the Bikou Group, and a correlative volcaniclastic turbidite sequence, the Hengdan Group. U‐Pb SHRIMP detrital zircon dating of 181 grains collected from the Hengdan Group indicates ages from ca. 850 to 700 Ma, with a peak near 770 Ma. Given the predominance of volcanic, single‐cycle zircons within the Hengdan Group and the thick succession of coarsening‐upward volcaniclastic marine sediments, the sequence is best interpreted as a fore‐arc basin. This interpretation is supported by previous U‐Pb SHRIMP and conventional U‐Pb zircon dating performed within the Bikou Group that indicates subduction‐related magmatism persisted from at least ca. 850 to as recently as 700 Ma. Together, these data indicate that the Bikou terrane is a fragment of a Neoproterozoic continental arc system and that the Yangtze Plate was bordered by...