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The Lost Riches of the Himalaya

Aerial view of several Himalayan glaciers.

Aerial view of several Himalayan glaciers.

By Lloyd White

Most of the world’s gold and copper deposits are formed at tectonic plate boundaries. It’s a pity, then, that geologists find it difficult to locate the ancient plate boundaries in the Himalayan mountains.

Lloyd White is now a postdoctoral research fellow at the Australian National University’s Research School of Earth Sciences.

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The Earth’s surface is divided into a number of tectonic plates that are constantly moving. They grind against one another, tear apart and crash into each other, triggering earthquakes and volcanic eruptions. Over time this movement also results in the formation and destruction of vast oceans such as the Indian and the Pacific, and great mountain chains such as the Himalaya and the Andes.

The world’s oceans and mountain ranges take many millions of years to form because the tectonic plates move at about the rate at which your fingernails grow. Geologists are able to understand more about the rates of these processes by determining the age of rocks, which can be dated if they contain fossils of a known age or by measuring the relative amounts of certain isotopes produced by the radioactive decay of minerals trapped in the rock.

Fossils can provide very useful information about how old a rock is, but they are only found in some sedimentary and metamorphic rocks. For the other sedimentary, igneous and metamorphic rocks we must use isotopic dating to get a precise measurement of a rock’s age.

Over the course of my PhD project I have dated the age of rocks and minerals from the Himalayan mountain chain to determine how they were emplaced, deposited or deformed. It is important to understand how the plate boundaries have evolved over time as this is...

The full text of this article can be purchased from Informit.