Australia is a compact continent that has few major islands, inlets or embayments and a coastline of a bit less than 20,000 km.
The ratio of shore length to land area of about 1 km of coast for every 390 km off the north coast are the only major islands.
These changes in the isotopic ratios may indicate distinct events or particular phases within one event.
At that time, all complex multicellular organisms lived in the sea, and of them, about 100 marine families covering about 49 percent of genera (a more reliable estimate than species) of fauna became extinct (Rohde 2005).
By the time the water table gets close to the surface it has passed through these salt layers and so causes salinisation in the root zone and eventually at the surface, which makes the land useless for agriculture.