Pieces of Laurentia in East Antarctica

East Antarctica figures prominently as a central cratonic piece in reconstructions of the Neoproterozoic supercontinent Rodinia, yet these fits variously position East Antarctica next to (so-called SWEAT fit), or distant from, the western margin of Laurentia. Paleomagnetic poles are lacking for East Antarctica during the time period between assembly at about 1.3-1.1 Ga and subsequent breakup by 700-650 Ma, and there is uncertainty about the reliability and/or applicability of data from Laurentia and Australia. Despite controversial paleomagnetic results, several lines of geologic, age and isotopic evidence from the central Transantarctic Mountains provide a reasonable Rodinia fit between East Antarctica and western Laurentia: (1) similar Nd-isotope crustal age provinces; (2) similarity of ~1.7 Ga crustal events; (3) provenance link between ~1.4 Ga detrital zircons in Antarctic rift-margin strata and Mesoproterozoic A-type granites in Laurentia; (4) associated 1.8-1.6 Ga detrital zircons in these same strata; and (5) similarity in ages of rift-margin formation, by 668 Ma in East Antarctica and ~717-685 Ma in western Laurentia. New isotopic and age data further support such a fit: (6) ~1.4 Ga Antarctic-margin detrital zircons have ÎõHf(i) values (-2 to +7) that match those of coeval A-type Laurentian granites; and (7) a newly discovered A-type rapakivi granite boulder in glacial till at Nimrod Glacier has a U-Pb zircon age of ~1440 Ma and ÎõHf(i) = +7, indicating the presence of Mesoproterozoic granites beneath the East Antarctic ice sheet. We suggest that these detrital-mineral and rock clasts represent distinctive pieces of Laurentia in East Antarctica, providing further support for a Rodinia connection. These two areas thus share similar crustal, rift- margin, and sedimentary histories, and there are several lines of lithologic correlation strengthened by distinctive age and isotopic signatures. From these integrated geological, isotopic and geochronological datasets we also infer that some significant part of the East Antarctic shield is comprised by Paleoproterozoic orogenic belts punctuated with geochemically and temporally distinctive ~1.4 Ga A-type rapikivi granites. Although various other Rodinia geometries have been suggested, none appear as geologically compelling as the modified SWEAT model.