Nd, Sr, and Pb isotopic data are presented for modern tills in the Byrd and Nimrod Glaciers of East Antarctica.

The isotopic data demonstrate that the tills are primarily the product of erosion of immediately adjacent basement rocks.

Fine-grained tills are the product of communition of coarse-grained sedimentary material at most locations.

LGM tills in the central Ross Sea likely contain detritus delivered by the Byrd and Nimrod Glaciers.

LGM tills show no evidence of preferential erosion of specific rock units by ice traversing the Transantarctic Mountains.