Nido Formation

The Nido Formation is a stratigraphic unit of Neogene age in northwestern British Columbia, Canada.

Naming
The Nido Formation takes its name from Nido Creek, a stream flowing northeast from the eastern flank of Mount Edziza into Nuttlude Lake. Nido means "white man" in the Tahltan language.

Geology
The Nido Formation has a volume of 127 km3, making it the second most voluminous geological formation of the Mount Edziza volcanic complex after the Armadillo Formation. It overlies the Raspberry, Armadillo and Little Iskut formations, all of which are Miocene in age. Also underlying the Nido Formation are pre-Tertiary rocks of the Stikinia terrane. Overlying the Nido Formation are the Spectrum, Pyramid, Ice Peak, Edziza and Big Raven formations which are of Pliocene age and younger.

Two subunits comprise the Nido Formation, namely the Tenchen Member and the Kounugu Member. Both members are separated by the Armadillo Highlands in the middle of the Mount Edziza volcanic complex. The Tenchen Member forms a lava field north of the Armadillo Highlands while the Kounugu Member forms a lava field south of the highlands.

The Nido Formation consists of alkali basalt and hawaiite lava flows that issued from multiple eruptive centres. K–Ar dating has yielded ages of 7.8 ± 0.3 million years, 5.5 ± 1.6 million years, 4.5 ± 0.3 million years and 4.4 ± 0.5 million years for Nido alkali basalt.