LBNL: New Evidence for a Water-Rich History on Mars

[bystander]

New Evidence for a Water-Rich History on Mars
Lawrence Berkeley National Laboratory | 2017 Mar 06

[img3="Naturally formed crystals of the mineral whitlockite, which is rare on Earth,
are visible in this sample on display at Canada’s Royal Ontario Museum.
(Credit: Wikimedia Commons)"]https://upload.wikimedia.org/wikipedia/ ... n18-09.jpg[/img3][hr][/hr]

Mars may have been a wetter place than previously thought, according to research on simulated Martian meteorites conducted, in part, at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab).

In a study published today in the journal Nature Communications, researchers found evidence that a mineral found in Martian meteorites -- which had been considered as proof of an ancient dry environment on Mars -- may have originally been a hydrogen-containing mineral that could indicate a more water-rich history for the Red Planet.

Scientists at the University of Nevada, Las Vegas (UNLV), who led an international research team in the study, created a synthetic version of a hydrogen-containing mineral known as whitlockite.

After shock-compression experiments on whitlockite samples that simulated the conditions of ejecting meteorites from Mars, the researchers studied their microscopic makeup with X-ray experiments at Berkeley Lab’s Advanced Light Source (ALS) and at Argonne National Laboratory’s Advanced Photon Source (APS).

The X-ray experiments showed that whitlockite can become dehydrated from such shocks, forming merrillite, a mineral that is commonly found in Martian meteorites but does not occur naturally on Earth.

“This is important for deducing how much water could have been on Mars, and whether the water was from Mars itself rather than comets or meteorites,” said Martin Kunz, a staff scientist at Berkeley Lab’s ALS who participated in X-ray studies of the shocked whitlockite samples.

“If even a part of merrillite had been whitlockite before, it changes the water budget of Mars dramatically,” said Oliver Tschauner, a professor of research in the Department of Geoscience at UNLV who co-led the study with Christopher Adcock, an assistant research professor at UNLV.

And because whitlockite can be dissolved in water and contains phosphorous, an essential element for life on Earth -- and merrillite appears to be common to many Martian meteorites -- the study could also have implications for the possibility of life on Mars. ...

Shock-Transformation of Whitlockite to Merrillite and the Implications for Meteoritic Phosphate - C. T. Adcock et al

• Nature Communications 8:14667 (06 Mar 2017) DOI: 10.1038/ncomms14667

[neufer]

<<Merrillite is a calcium phosphate mineral with the chemical formula Ca₉NaMg(PO₄)₇. It is an anhydrous, sodic member of the whitlockite group. The mineral is named after George P. Merrill (1854–1929) of the Smithsonian Institution. Merrill had described the mineral from four meteorites in 1915: the Alfianello, Dhurmsala, Pultusk, and Rich Mountain meteorites. The mineral was not recognized as distinct from whitlockite, however, by the IMA until 1975. Merrillite is a very important constituent of extraterrestrial rocks. It occurs in pallasites, lunar rocks, martian meteorites, and many other meteorite groups.>>

<<Whitlockite can be found at many sites in the human body, but is particularly concentrated in calcified tissues, such as embryonic and adult bone. The highest concentrations of whitlockite appear in the weight bearing area of the femoral head. Traces of whitlockite have also been found in tuberculous lesions, urinary calculi and even prostatic deposits. Whitlockite can also be found in the oral cavity, where it is a primary component of dental calculi and salivary stones.>>