Earthly rocks point way to water hidden on Mars

[Judi Lynn]

Date:
July 29, 2021
Source:
Penn State
Summary:
A combination of a once-debunked 19th-century identification of a water-carrying iron mineral and the fact that these rocks are extremely common on Earth, suggests the existence of a substantial water reservoir on Mars, according to a team of geoscientists.


A combination of a once-debunked 19th-century identification of a water-carrying iron mineral and the fact that these rocks are extremely common on Earth, suggests the existence of a substantial water reservoir on Mars, according to a team of geoscientists.

"One of my student's experiments was to crystalize hematite," said Peter J. Heaney, professor of geosciences, Penn State. "She came up with an iron-poor compound, so I went to Google Scholar and found two papers from the 1840s where German mineralogists, using wet chemistry, proposed iron-poor versions of hematite that contained water."

In 1844, Rudolf Hermann named his mineral turgite and in 1847 August Breithaupt named his hydrohematite. According to Heaney, in 1920, other mineralogists, using the then newly developed X-ray diffraction technique, declared these two papers incorrect. But the nascent technique was too primitive to see the difference between hematite and hydrohematite.

Si Athena Chen, Heaney's doctoral student in geosciences, began by acquiring a variety of old samples of what had been labeled as containing water. Heaney and Chen obtained a small piece of Breithaupt's original sample, a sample labeled as turgite from the Smithsonian Institution, and, surprisingly, five samples that were in Penn State's own Frederick Augustus Genth collection.

After multiple examinations using a variety of instruments including infrared spectroscopy and synchrotron X-ray diffraction, a more sensitive, refined method than used in the mid-19th century, Chen showed that these minerals were indeed light on iron and had hydroxyl — a hydrogen and oxygen group — substituted for some of the iron atoms. The hydroxyl in the mineral is stored water.

More:
https://www.sciencedaily.com/releases/2021/07/210729122123.htm