David Grinspoon Quote
A few times, all the world’s land surface has clumped together into one giant supercontinent, surrounded by one global ocean. Even supercontinents drift, and 450 million years ago the planet was put out of sorts when the supercontinent Gondwana drifted down over the South Pole. As this one and only huge continent completely froze over, the ice and snow piled up, miles thick. So much of the world’s water became locked into these colossal drifts that sea level plummeted. During several million years in this strange configuration, there were multiple glaciations punctuated with more mild interglacials. Both sea level and ocean chemistry fluctuated sharply, dooming many species dependent upon the disappearing and changing coastal environments. This caused the Ordovician–Silurian extinction, probably the second-most extreme mass extinction in Earth history. It seems that the perpetrator was just a series
A few times, all the world’s land surface has clumped together into one giant supercontinent, surrounded by one global ocean. Even supercontinents drift, and 450 million years ago the planet was put out of sorts when the supercontinent Gondwana drifted down over the South Pole. As this one and only huge continent completely froze over, the ice and snow piled up, miles thick. So much of the world’s water became locked into these colossal drifts that sea level plummeted. During several million years in this strange configuration, there were multiple glaciations punctuated with more mild interglacials. Both sea level and ocean chemistry fluctuated sharply, dooming many species dependent upon the disappearing and changing coastal environments. This caused the Ordovician–Silurian extinction, probably the second-most extreme mass extinction in Earth history. It seems that the perpetrator was just a series