NEW EVIDENCE FOR GONDWANALAND

Press, Volume CII, Issue 30234, 12 September 1963, Page 6

NEW EVIDENCE FOR GONDWANALAND

“East Antarctica (the Ross Dependency and its neighbourhood) can truly be considered a part of Gondwanaland,” the geological system of rocks, hundreds of millions of years old, believed by some to indicate the former existence of a huge eontinemit or group of continents which included parts of Australia, South America, South Africa, and India as well as Antarctica. This is said by Mr G. W. Grindley, of the Geological Survey, Department of Scientific and Industrial Research, in the second special Antarctic issue of the “New Zealand Journal of Geology and Geophysics.”

The Antarctic coal-meas-ures do not necessarily indicate a formerly mild or warm climate there, Mr Grindley says. Formations indicating periglacial climates (climates of areas in the . neighbour. .od of glaciers) are found among the Permian coal-measures in the Beardmore glacier area. Mir Grindley started this in an article describing his wonk in the Queen Alexandra range, which lies between the Beardmore and Nimrod glaciers in the southern part of the dependency. He quotes also in support of his contention the results of other geologists’ work in the region.

Differences between Ant arotaca and the other south' enn continents indicate ir general that Antarctica wai cooler and therefore presumably nearer the pole that they were at the time tc which the rock sequences refer. Nevertheless, Mi Grindley says, similaritiei between the records in India and East Antarctica, a’ any rate, require some displacement of the poles oi continents, or both, since th< two regions are now separated by 90 deg. of latitude “Further, more decisive evidence is required.” Similarities between the

rock records od East Antairctica and one or more of trie other regions of Gondwanaiand include a marine transgression in the Devonian period, a sequence of quartz arenites including in the case of Antarctica trie remains of Devonian fishes and lycopod stems, glacial tillite from trie widespread Late Palaeozoic glaciation already recognised in other southern continents, postglacial shales, coal measures containing cool-temperate Glossopteris fauna (a characteristic fauna of unknown botanical affinities), glacial varves among Permian coalmeasures (such varves are often found in glacier-fed lakes), Triassic plant beds with the Dicroidium flora which succeeded the Gloesopteris type, and Jurassic basalts. Differences between the Antarctic sequences and those of the other parts of Gondwanaland include the relative rarity of red hotdeserrt or monsoon-land sediments in Antarctica in the Triassic period (the upper part of the Gondwana sequences), the absence of reptile fossils in Antarctica, and the occurrence of a Jurassic or Cretaceous glaciation 1 in the McMurdo sound region but not repeated in the other conitiinents.