Mysterious Platinum Signatures Beneath Greenland’s Ice

Beneath the depths of Greenland’s ice sheets lie puzzling chemical signatures that have sparked widespread scientific debate. The discovery of a sharp increase in platinum concentrations, dated to around 12,800 years ago, has supported the theory of Earth’s collision with a comet or meteor at that time.

Ice Chemistry Analysis

In new research, a more conventional explanation has been presented: these mysterious platinum signatures may have been caused by a volcanic eruption in Iceland rather than from space. This explanation revisits an old theory suggesting that the platinum spike might have been the result of a cosmic impact.

The significance of this discovery lies in its timing, coinciding with the onset of the planet’s last great cooling period, known as the Younger Dryas event. This period lasted from about 12,870 to 11,700 years ago and saw a significant drop in temperatures across the Northern Hemisphere.

Diverse Hypotheses

Traditional explanations for this event included the release of massive amounts of freshwater from melting ice sheets in North America. This influx disrupted ocean circulation, affecting temperatures. However, other researchers have suggested the event might have been caused by a comet or asteroid impact over North America.

In 2013, researchers discovered a rise in platinum concentrations in ice samples from the Greenland Ice Sheet Project. The ratio of platinum to the radioactive element iridium was also unusual, as space rocks typically contain high levels of iridium, which was absent in the ice.

Recent Research

It was proposed that the unusual ice chemistry could have been caused by the eruption of the Laacher See volcano in Germany, known for its unconventional geochemistry and occurring around the same period. However, analysis confirmed this hypothesis was incorrect because German volcanoes did not contain sufficient platinum.

In contrast, analysis showed that the platinum spike occurred 45 years after the start of the Younger Dryas, making it unlikely to have triggered the cooling period.

The Volcanic Role

Research indicated that Icelandic volcanoes could produce fissure eruptions lasting years, matching the 14-year duration of the platinum increase. During the melting period preceding the Younger Dryas, volcanic activity in Iceland increased significantly due to reduced pressure on the Earth’s crust.

Underwater or subglacial eruptions can interact with water in ways that explain the unusual chemistry. Seawater can strip away sulfur compounds while concentrating other elements like platinum in volcanic gases.

Conclusion

Due to the timing mismatch, the mechanism responsible for the platinum increase was not the cause of the Younger Dryas onset. However, research suggests that large volcanic eruptions may have accelerated climate cooling during that period. Understanding past climate triggers is crucial for predicting future events.