GIA New York Science Talks Series: What Natural Diamonds Can Tell Us About How Continents Are Formed

Rough diamond, yellow in color

Rough diamond from Zimmi in West Africa, near the Sierra Leone-Libera border. It contains a sulfide inclusion with compositions that give clues to how the West African continent formed. Photo by Karen Smit/GIA

Cratons, the oldest foundations of Earth’s continents, have survived for more than 2.5 billion years. Understanding cratons and the geology of how our continents formed is one part of discerning what made life on Earth possible.

The majority of Earth’s diamond forms below the Earth’s stable cratons and have ages that span most of Earth’s history. For this reason, the tiny mineral grains trapped inside a diamond can reveal details about the conditions under which a diamond and its host rock formed in Earth’s earliest times.

Researchers at GIA studied sulphide mineral inclusions in diamonds from West Africa and found that the sulphide inclusions have sulphur compositions that could only have originated in Earth’s oldest atmosphere prior to the rise of oxygen. Prior to 2.5 billion years ago, before there was abundant oxygen in the atmosphere, there was the ability for sulphur in the atmosphere to become isotopically fractionated.

This fractionated sulphur signature can be used as a tracer for geological processes that operated before 2.5 billion years ago and through which continents obtained their long-term stability, leading to the conditions that sustain life today.

Dr. Karen Smit will discuss how diamond research provides insight into the geological processes – deep mantle subduction of the oceanic lithosphere – that created the stable foundation of today’s continents.

Event Info

The event is free and open to the public. Doors open at 4:30 p.m. Please arrive early since security check-in will be required and could take up to 30 minutes. Wine will be served. 

Registration is required (register below) and closes on February 18. ​Seating is limited.

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