One of the most fascinating studies of the planet Mars includes that of the Martian meteorites. Read on to learn more about the composition and structure of these rock formations.
The surface of the planet of Mars is mostly made up of basalt. This is a grey to black volcanic rock. Basalt is also found on the Earth’s surface.
It is a result usually of rapid-cooling lava. The basalt on the surface of Mars is thought to possibly be more silica-rich than that of the basalt on earth-similar to the andesitic stones on earth (or that of silica glass). The surface of Mars is covered largely with iron oxide dust. This dust is as fine in consistency as talcum powder.
There are a total of 34 Martian meteorites in all. Martian meteorites are divided into three groups of what are referred to as achonandritic (stony) meteorites. These are said to be very rare. The three types of achonandritic meteorites that exist on Mars are called shergottites (25 in all) nakhlites (7 in all) and chassignites (2 in all).
The isotopes of Martian meteorites are believed to be consistent among each other. However, they are inconsistent with those of Earth. Often times the collection of Mars Meteorites is referred to as the SNC group for short.
Not all meteorites that have landed on Earth are from Mars. Among the ones that originate from Mars include the first Shergottite, which landed in India in 1865. This was particular meteorite was simply named the Shergotty Meteorite. The ALH84001 was the most famous shergottite that fell, due to the fact it contains microscopic fossil remains of bacteria-like life forms.
These fossils, however, as of the year 2005 have been though of as not necessarily being an indicator of life. Instead it was conclude that these fossils were thought of as earthly biofilms. The ALH84001 is much older than the others of the SNC meteorite group, which have originated from Mars.
All meteorites that come from Mars are known as igneous rock. This means that they are formed by molten lava that cools and solidifies. Sometimes this rock crystallizes and sometimes it does not. They either form below or above the surface. A similar process happens on Earth as well, but Martian meteorites are of a slightly different composition, as already mentioned earlier.
Some of the meteorites on Mars (particularly the shergottites) consist of hydrated carbonates and sulfates. These have been thought of as being exposed to water before they were injected into space.
The Nakhlites of Mars have their own unique properties as well. They contain the same igneous rock, but these are very rich in augite. These meteorites also contain olivine crystals. Nakhlites were sad to have fallen to earth within the last 10,000 years, and also have been affected by water.
The first chassignite, named the Chassigny meteorite, was known to have landed in France in 1815. One other chassignite has been found as well. This one is known as the Diderot, or the NWA 2737. It was found in North-West Africa in the year 2000. The basic mineral composition of chassignites consists largely of oxygen isotopes.
Most SNC meteorites are considered to be quite young according to geologic standards. Scientists believe as a result of studying these that volcanic activity only existed in Mars a few hundred million years ago. This amount would seem not very fathomable to most humans, however, and some would suggest that the time period of volcanic activity would be considerably less than that.
Other discoveries of Martian meteorites that have fallen to earth have been made. Study and research have lead many scientists to believe that life exists on mars, at least in microscopic form. This very possibility is being researched and studied even today.