West African proximity of the Avalon terrane in the latest Precambrian

Considerable debate surrounds the Late Neoproterozoic paleogeographic posit ion of the Avalon terrane, specifically whether it was adjacent to West Afr ica or Amazonia. New paleomagnetic results from upper Neoproterozoic rocks in the Avalon terrane challenge the latter position. Samples collected from the ca. 580-570 Ma. Marystown Group in the southern part of the Burin peni nsula of Newfoundland, Canada, yield high-temperature magnetic components, including dual-polarity directions, which are considered to be primary, on the basis of positive fold and agglomerate tests. The resultant tilt-correc ted inclination is 53 degrees, representing a paleolatitude of deposition o f 34 degrees + 8 degrees/-7 degrees for the Marystown Group. Given the like lihood that Amazonia and Laurentia were still juxtaposed around 580-570 Ma, the Marystown Group results reveal that the paleolatitude of Avalon is sig nificantly lower than would be expected if it was part of Amazonia. In fact , Avalon was separated from northern Amazonia by at least 1100 km at ca. 58 0 Ma. If West Africa was juxtaposed to Amazonia, opposite Laurentia, by thi s time, these results place Avalon at the same paleolatitude as the norther n margin of the West African craton.