Geochronological constraints on the formation and evolution of the Huangling basement in the Yangtze craton, South China

• Published in: Precambrian research 2020-06, Vol.342, p.105707, Article 105707
• Main Authors: Wei, Junqi, Wei, Yunxu, Wang, Jianxiong, Wang, Xiaode
• Format: Article
• Language: English
• Subjects: Archean continental nucleus; Huangling basement; Kongling complex; Proterozoic cratonization; Yangtze craton
• ISSN: 0301-9268; 1872-7433
• DOI: 10.1016/j.precamres.2020.105707

•A chronotectonic framework of the Huangling basement has been established. For the first time, we divide the magmatic events into four periods: 3.2–3.0 Ga, 3.0–2.9 Ga, 2.7–2.6 Ga, and 1.87–1.85 Ga, and the metamorphic events into two periods: 2.6–2.5 and 2.05–1.9 Ga.•The first metamorphic event (2.6–2.5 Ga) provides strong chronological evidence for the Shuiyuesi movement. The second metamorphic event (2.0–1.9 Ga) provides strong chronological evidence for Xingshan movement, which was the response of the Yangtze craton to the Columbia supercontinent.•The stable cratonization and sedimentation lasted for 500 Ma (2.5–2.05 Ga) in the Siderian and Rhyacian periods, during which thick (2500 m) sedimentary rocks were deposited and the “Great Oxidation Event” was triggered, which lead to the flourishing of organisms to provide an organic carbon source for graphite ore. The Huangling basement has the largest area and highest metamorphic grade of exposed Archean and Paleoproterozoic rocks in the Yangtze craton basement. Hence, it provides an excellent opportunity for examining the formation and evolution of the Yangtze craton. The Huangling basement consists mainly of the Kongling complex, with a chronotectonic framework established through the geochronological study of amphibolites, khondalites, ultramafic rocks, and diabase dikes. Our results indicate that magmatic events in the Huangling basement are divided into four phases; the first phase is represented by the emplacement of the intermediate–basic volcanic rocks (3.2–3.0 Ga) that formed a typical Archean greenstone belt. The greenstone belt was subsequently intruded by tonalite–trondhjemite–granodiorite rocks (3.0–2.9 Ga) and A-type granite (2.7–2.6 Ga) constituting a typical Archean granite–greenstone terrane. The granite–greenstone terrane was transformed into an Archean continental nucleus during the first metamorphism (2.6–2.5 Ga), resulting in an unconformity between Archean and Proterozoic strata. Stable cratonization and sedimentation are considered to have lasted for 500 Ma (2.5–2.05 Ga), during which sedimentary rocks with a thickness of 2500 m were deposited. Later, the sedimentary rocks were metamorphosed to form the khondalite series during the second metamorphic event at 2.05–1.9 Ga, which caused an angular unconformity between Paleoproterozoic and Mesoproterozoic strata. The Paleoproterozoic high-grade terrane and Archean continental nucleus simultaneously merged to form the Huangling basement.