Suspected meteorite fragments in marine sediments from East Antarctica

Unusual mafic rock fragments deposited in Plio-Pleistocene-aged marine sediments were recorded at Integrated Ocean Drilling Program (IODP) Site U1359, in Wilkes Land, East Antarctica. These fragments were identified from sediment layers deposited between c. 3 and 1.2 Ma, indicating a sustained supply during this time interval. Clinopyroxenes in these basalts are Al-Ti diopside hedenbergite, uncommon in terrestrial magmatic rocks. A single strong peak in the Raman spectra of a phosphate-bearing mineral at 963 cm(-1) supports the presence of merrillite. Although not conclusive, petrological traits and oxygen isotopic compositions also suggest that the fragments may be extraterrestrial fragments affected by shock metamorphism. Nevertheless, it is concluded that the basaltic fragments incorporated in marine sediments at Site U1359 represent ice-rafted material supplied to the continental rise of East Antarctica, probably from the bedrocks near the proximal Ninnis Glacier. Further studies on Plio-Pleistocene sediments near Site U1359 are required to characterize the unusual mafic rocks described.