Lawver & Gahagan (1998; 2003) hypothesized, based on sea level records and the isostatically adjusted bedrock surface of Antarctica, the existence of a Trans-Antarctic Seaway linking the Ross Sea and the Weddell Sea, between the Antarctic peninsula and the Ellsworth Mountains, in the Paleogene.
Has any other evidence confirming or infirming the existence of such a seaway been found since then? If so, do we have an idea of when it opened and closed?
Lawver, L. A., Gahagan, L. M., 1998. Opening of Drake Passage and and its impact on Cenozoic ocean circulation. In Crowley, T. C. & Burke, K. C., Tectonic boundary conditions for climate reconstructions, Oxford monographs on geology and geophysics, 39: 212-227.
Lawver, L. A., Gahagan, L. M., 2003. Evolution of Cenozoic seaways in the circum-Antarctic region. Palaeogeography, Palaeoclimatology, Palaeoecology, 198: 11-37.