Geology of Ascension Island other volcanic islands, which only have a few mafic and felsic endmembers such as basalt or rhyolite, Ascension has a full-range from some of the most mafic to most felsic. This includes basalt, hawaiite, mugearite, benmoreite,trachyte and rhyolite. Potassium-argon dating indicates that the oldest rocks exposed above the water are one million year old rhyolites. Geologists have divided the island's mafic and felsic rocks into different named sequences and sub-divided mafic rocks based on their ratio of zirconium and niobium. The Sister's Peak region in northwest Ascension has intermediate mafic lava flows, scoria cones and mafic ash fall deposits near
Huangling Complex Craton during subduction beneath the North China Craton. As the oceanic Yangtze Craton subducted under the continental North China Craton, magmatic activities result in the formation of hydrated mafic basaltic magma. On the other hand, trondhjemites were formed in Archean, with the source from partial melting of Archean amphibolites and granulites under the continental Yangtze Craton in a high-pressure condition. They are composed of felsic minerals such as plagioclase, quartz, and Na-K-rich feldspar and minor mafic minerals biotite and hornblende. The ultramafic-mafic rocks exhibit a band within the K-feldspar-rich granites.The K-feldspar-rich granites are found in the southwestern of the Huangling