 They were emplaced and crystallized at around 3 billion years ago.Meanwhile, the parent rocks of the metamorphosed sedimentary rocks, including amphibolite, paragneiss and quartzite, were deposited.In Qixia of eastern Shandong, a local magmatic event 2.9–2.85 billion years ago formed the igneous parent rocks of tonalitic-trondhjemitic-granodioritic gneisses.