A young Washington-based undergraduate student Katie Wall, aged 21, has been looking for evidence that water influences crystal formation in basalt. Basalt is a dark volcanic rock found a lot in Washington and Oregon. She used this prevalent rock as a comparison to rock observations made by the rover Curiosity on Mars.
Firstly, Wall and her fellow researchers came up with a method to quantify the texture of volcanic rock using an index called ‘groundmass crystallinity’. According to Wall the texture of volcanic rock is like the texture of a chocolate chip cookie, it varies according to method of cooking and cooling. “We were interested in the cookie dough part of the cookie,” she said.
When liquid volcanic rock hits water it rapidly cools and flash freezes to form mostly glass. When there is no water it takes longer to cool and crystals form. The body of the rock is the dough and the chocolate chips are the crystals. Using an X-ray diffraction machine on Washington University campus, Wall analyzed basalt samples from all over the world and compared it to the volcanic rock analyzed by the Curiosity rover on mars.
Unfortunately, she discovered that all the rocks analyzed by Curiosity were similar in structure the volcanic rocks on earth that had not formed in the presence of water. This indicated that there was no water on Mars at the time of formation of any of the analyzed rocks. However, Wall has still made a great achievement as this same method can be used to look for water elsewhere.
Written by Caroline Steel.