<Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (June 2012) (Learn how and when to remove this template message) </Td> </Tr> <P> The oldest dated rocks on Earth, as an aggregate of minerals that have not been subsequently broken down by erosion or melted, are more than 4 billion years old, formed during the Hadean Eon of Earth's geological history . Such rocks are exposed on the Earth's surface in very few places . Some of the oldest surface rock can be found in the Canadian Shield, Australia, Africa and in a few other old regions around the world . The ages of these felsic rocks are generally between 2.5 and 3.8 billion years . The approximate ages have a margin of error of millions of years . In 1999, the oldest known rock on Earth was dated to 4.031 ± 0.003 billion years, and is part of the Acasta Gneiss of the Slave craton in northwestern Canada . Researchers at McGill University found a rock with a very old model age for extraction from the mantle (3.8 to 4.28 billion years ago) in the Nuvvuagittuq greenstone belt on the coast of Hudson Bay, in northern Quebec; the true age of these samples is still under debate, and they may actually be closer to 3.8 billion years old . Older than these rocks are crystals of the mineral zircon, which can survive the disaggregation of their parent rock and be found and dated in younger rock formations . </P> <P> The oldest material of terrestrial origin that has been dated is a zircon mineral of 4.404 ± 0.008 Ga enclosed in a metamorphosed sandstone conglomerate in the Jack Hills of the Narryer Gneiss Terrane of Western Australia . The 4.404 ± 0.008 Ga zircon is a slight outlier, with the oldest consistently - dated zircon falling closer to 4.35 Ga . This zircon is part of a population of zircons within the metamorphosed conglomerate, which is believed to have been deposited about 3.060 Ga, which is the age of the youngest detrital zircon in the rock . Recent developments in atom - probe tomography have led to a further constraint on the age of the oldest continental zircon, with the most recent age quoted as 4.374 Ga ± 0.006 . </P> <P> The oldest rock formation is, depending on the latest research, either part of the Isua Greenstone Belt, Narryer Gneiss Terrane, Nuvvuagittuq greenstone belt, or the Acasta Gneiss (on the Slave craton). The difficulty in assigning the title to one particular block of gneiss is that the gneisses are all extremely deformed, and the oldest rock may be represented by only one streak of minerals in a mylonite, representing a layer of sediment or an old dike . This may be difficult to find or map; hence, the oldest dates yet resolved are as much generated by luck in sampling as by understanding the rocks themselves . </P>

What mineral in 4 ga sandstones was dated to determine the age of the earth