page_title: Nuvvuagittuq Greenstone Belt
section_title: Geology
hierarchical_section_title: Nuvvuagittuq Greenstone Belt / Geology
caption_attribution_description: English: An outcrop of metamorphosed volcanosedimentary rocks from the Porpoise Cove locality, Nuvvuagittuq supracrustal belt, Canada. Some of these rocks have Sm/Nd ages in excess of 4.0 Ga and may be the oldest rocks on Earth.
context_page_description: The Nuvvuagittuq Greenstone Belt is a sequence of metamorphosed mafic to ultramafic volcanic and associated sedimentary rocks located on the eastern shore of Hudson Bay, 40 km southeast of Inukjuak, Quebec. These rocks have undergone extensive metamorphism, and represent some of the oldest rocks on Earth.
  Two papers dating the age of the Nuvvuagittuq Greenstone Belt have been published. One paper gave an age of ca. 3,750 million years ago, while the other gave an age of ca. 4,388 mya. In March 2017, the age of the Nuvvuagittuq Greenstone Belt was still unresolved.
  In March 2017, a published report gave evidence for fossils of microorganisms in these rocks, which would be the oldest trace of life yet discovered on Earth.
context_section_description: The Nuvvuagittuq Greenstone Belt contains 3 major components:
  Cummingtonites, metamorphic amphiboles, which form most of the belt
  Mafic and ultramafic sills that intrude the amphibolites
  Banded iron formations, sedimentary rock that formed in sea water
  The cummingtonite amphibolite that dominates the belt is unusual that sections of the rock have a grayish-beige color, compared to the dark green of common amphibolites, giving it the nickname "faux-amphibolite". The cummingtonite amphibolite displays gneissic foliation, with cummingtonite, quartz, biotite and plagioclase feldspar being the primary components. The cummingtonite amphibolites range from garnet-rich to garnet-poor and are interpreted to be highly metamorphosed volcano-sedimentary rocks.
  Ultramafic and gabbroic sills appear commonly on the northern portion of the belt. These sills range from 5 to 30 m (16 to 98 ft) in width, and have serpentine and talc rich interiors with amphibole rich margins. They represent a significant intrusion event in the history of the NGB.
  The banded iron formation can be traced continuously across the northern portion of the belt. The formation is composed mainly of quartz, magnetite, and grunerite.
caption: An outcrop of metamorphosed rock from Nuvvuagittuq
exif: {}