BY PETER J. SMITH
Departmentof Earth Sciences
Milton Keynes, U.K.
" Even as the final parts (south China and Cimmeria) were coming together to complete the construction of Pangea, the supercontinent was undergoing incipient rifting (leading to breakup) in eastern North America, in northwest and east Africa, and here. There was a major turning point 230 million years ago, when because of the first major loss of heat from the reservoir beneath Pangea there was a change from icehouse to greenhouse conditions, the fall in sea level was reversed, and there were singular points in other global indices.
J.J. Veevers, "Middle/Late Triassic (230±5 Ma) singularity in the stratigraphic and magmatic history of the Pangean heat anomaly," Geology, 17,784-7, September1989. (Macquarie University, Sydney, Australia)
" Radioactive fallout from the very unfortunate Chernobyl reactor accident has produced a valuable time stratigraphic marker in the Greenland ice sheet. However,...