Water-bearing salt crystals found in a Texas meteorite

Scientists at the NASA Johnson Space centre in Houston have discovered crystals of halite (NaCl) and sylvite (KCl) in a chondritic (rocky) meteorite which fell in the small town of Monahans, Texas in 1998. Like many other crystals found on earth, these crystals of halite have many tiny flaws and cavities, and some of the these cavities contain water. These are known as fluid inclusions.

There are two possible origins for water found in these crystals

• it may have been from water which existed in the asteroid parent body of the Texas meteorite - and then made its way to the surface of the body where it evaporated leaving the crystals behind, or
• it may have have been delivered to the surface of the asteroid from a water-bearing object - such as a comet - and again, the water would have evaporated leaving the crystals behind.

Water has not been found within minerals present in metorites examined in the past, and, according to the authors, this is the first time that anyone has had the opportunity to study and analyze a sample of water which may have existed early in the development of the solar system. Tiny amounts of strontium present in the water have been analyzed using isotopic techniques and dated at between 4.5 and 4.7 billion years.

From: Zolensky, M.E. and others, Asteroidal water within fluid inclusion-bearing halite in an H5 chondrite, Monahans (1998), Science, Vol. 285, 27 August 1999, p. 1377-1379.