“Longer periods of hydrothermal activity will generate extended windows of opportunity for prebiotic chemical reactions to occur, life to develop, and micro-organisms to thrive and propagate beyond their point of origin,” Pickersgill said in a study published in Communications Earth & Environment.
Fathoms below and eons ago
Hydrothermal systems created by other impacts are all over the planet. Although these systems are considered habitable because of heat and nutrients, signs of life have been hard to find, and linking the timing of an impact to processes that contributed to the flourishing of life is even harder. Microbes have only been found to colonize eight of the 70 underwater impact craters with hydrothermal activity.
What Pickersgill and her team wanted to find out was whether the Chicxulub impact could have created habitable conditions, so she analyzed rock samples to figure out when there was the highest chance of habitability. The work doesn’t answer whether the hydrothermal system in that crater was actually inhabited.
The researchers delved into how long the impact crater brought about temperatures and additional conditions that would have been ideal for attracting and holding on to life. Habitable conditions that endure for long periods allow more time to attract organisms that build colonies around a hydrothermal vent.
To determine the duration of the Chicxulub hydrothermal system, Pickersgill recovered samples at the site, drilling 1 km down. She then took radioisotopic measurements of feldspar samples recovered from the site. Feldspar contains potassium, and the decay of that potassium into argon can give an idea as to how old the rock is. Lunar rocks and volcanic formations have been dated this way.