Deep Time: A One-Sentence Summary

 

John McPhee, with his characteristic elegance, once observed (in Annals of the Former World) that he could summarize Earth’s geological history - or, at least, the processes that drove it - with a single sentence: “The summit of Mount Everest is marine limestone.” The highest single point on the Earth’s surface once lay below the Tethys Ocean, where 400 million years ago the remains of tiny creatures drifted to the sea bottom and cemented together. A third of a billion years later, in the Eocene Epoch, the Indian tectonic plate pushed northward into the Eurasian Plate. It moved with such force that it drove the collision zone, including Everest’s limestone, toward the stratosphere, and formed the highest mountain chain in the world.

 

The former Tethys seabed. (Source: Wikimedia)

The resulting Himalayan Mountains are so voluminous, massive and full of heat-generating isotopes that they are, in fact, melting.

 

Some of my readers might observe that this is old news to them. I dare say it is, since I’m describing events that are more than 40 million years old, but I present it as my beau ideal of summarizing one’s own work.