New view offers alternative history of how precious metals sank into the planet’s core
There’s a new twist to the story of how Earth’s most precious metals, including gold and platinum, got to where they are in the planet.
Some 4.6 billion years ago, space rocks pummeling the infant Earth kept it hot and molten. As the nascent planet grew bigger, a new study suggests, the heat and pressure kept precious metals trapped within its upper layers rather than allowing them to sink into the newly forming core. Later, chemical reactions involving sulfur pulled the metals down deep.
The work illuminates not only what happened during the Earth’s early years, but also why gold, platinum and related metals are so scarce in its upper layers today (SN: 8/6/16, p. 22).