Scientists believe the asteroid that killed the dinosaurs created a warm, moist sanctuary for life deep below the ocean, and they say it endured far longer than anyone had expected.
Some 66 million years ago, an asteroid struck Earth near what is now the Yucatan Peninsula, causing tsunamis and releasing hot debris that wiped out non-avian dinosaurs and many other species. The collision also generated a hydrothermal system below the surface that endured for 8 million years.
The Collision That Made the System
When the asteroid struck, it generated sufficient force to bend rock well beneath the surface. The subterranean consequences descended as deep as 35 kilometers, and among them was the melting of massive quantities of rock. Once that melted rock came into contact with seawater, it became porous, and as warm water then sank into those pores, a hydrothermal system took shape.
A jet of heated liquid rushed into a remote part of the frigid deeps, and that heat might have drawn small living things and perhaps other kinds of creatures that were otherwise finding it hard to endure.
Drilling Samples in 2016
In 2016, researchers drilled for samples in the impact zone. They studied the types of rock that had formed as a result of the asteroid strike, gaining insight into what happened in the immediate and long-term aftermath of this cataclysmic event.
A New Look at the Data
A separate research group, led by geologist and planetary scientist Annemarie Pickersgill of the SUERC Center for Isotope Sciences at the University of Glasgow, has now reviewed those rock samples. They aimed to build a stronger case for how the hydrothermal system developed and how long it operated.
The new findings show that the duration and size of this hydrothermal system beneath the Yucatán Peninsula were both underestimated. Scientists had believed it existed for about 2 million years, yet the revised study uncovered signs that it persisted in those depths for at least four times longer.
The Scale of Underestimation
| Previous Estimate | New Analysis |
|---|---|
| Duration | 2 million years |
| Actual duration | At least 8 million years |
| Depth of effects | Not specified |
| Depth of effects | 35 kilometers down |
The contrast is plain to see. What was believed to be a system that had endured for two million years has now been shown to have lasted at least four times longer than that.
What Life Might Have Found There
Many living things find warmth and isolation to be favorable circumstances, and the hydrothermal system would have supplied both. Catastrophe was raging above ground, but beneath the water, microorganisms had reason to prosper. These tiny life forms are known for thriving in extreme settings, and the warm pockets produced by the impact could have served as a haven for some of Earth’s most durable species.
The region where the system lay sat apart within the freezing depths, and that isolation may have kept it separate from the disorder at the surface.
What We Know and Don’t Know
No proof is given here that life existed on Mars. What the study shows instead is that the setting was suitable and that the setup lasted for a very long time. The question of whether anything ever lived there still stands unanswered, and it is a matter that later research may take up.
The results also prompt inquiry into how life endures through sudden calamities. Since a hydrothermal system has been found to last for 8 million years following an asteroid strike, the endurance of these systems merits closer examination.
The Delight of It
It is strange indeed: an event that destroyed nearly all life upon the Earth also produced a warm, moist refuge beneath the ocean where some living thing might have endured for millions of years.
The findings point to a system that went beyond what researchers had expected in both size and endurance. This is a striking result, one that offers a view into a realm few of us will ever witness.
Source material: “Dinosaur-killing impact crater might have been teeming with life,” Ars Technica.
Get the Notebook.
The day's best stories and every fresh verdict, in plain English, in your inbox by seven. One email a day, no more.