Answer:
Currently the oldest insitu rock layers of terrestrial origin were discovered by Dr. Jonathan O'Neil and his colleagues, whose work published in September of 2008, revealed rocks as old as 4.28 billion years of age in Northern Quebec, along the Hudson's Bay coast, 40 km south of Inukjuak. This area is known as the Nuvvuagittuq greenstone belt. They were dated by measuring the decay of the element neodymium-142 which was present in the rock.
However this is either the oldest rock material of Earth origin or the oldest rock material found on Earth.
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