[Rockhounds] Substance found in Antarctic ice may solve a martian mystery

[Kreigh Tomaszewski]

Researchers have discovered a common martian mineral deep within an ice
core from Antarctica. The find suggests the mineral—a brittle, yellow-brown
substance known as jarosite—was forged the same way on both Earth and Mars:
from dust trapped within ancient ice deposits. It also reveals how
important these glaciers were on the Red Planet: Not only did they carve
valleys, the researchers say, but they also helped create the very stuff
Mars is made of.

Jarosite was first spotted on Mars in 2004, when the NASA Opportunity rover
rolled over fine-grained layers of it. The discovery made headlines
<https://www.sciencemag.org/news/2004/03/mars-was-wet> because jarosite
needs water to form, along with iron, sulfate, potassium, and acidic
conditions.

These requirements aren’t easily satisfied on Mars, and scientists began to
theorize how the mineral could have become so abundant. Some thought it may
have been left behind by the evaporation of small amounts of salty, acidic
water. But the alkaline basalt rocks in Mars’s crust would have neutralized
the acidic moisture, says Giovanni Baccolo, a geologist at the University
of Milan-Bicocca and lead author on the new study.

https://www.sciencemag.org/news/2021/01/substance-found-antarctic-ice-may-solve-martian-mystery