Mercury surface formed by volcanic activity and iron deficiency

The role of volcanic activity on Mercury surface formation is much greater than what scientists think. This result was obtained by multi-spectral imaging data collected by the ship MESSENGER in January 2008 during the survey of the planet near the Sun's most solar system.

The data of MESSENGER has identified and mapped the surface rocks corresponding to lava, volcanic and other geological characteristics. At the same time, the ship's toolkit also confirmed the lack of iron throughout the apparent planet in Mercury's surface rocks.

MESSENGER (short for MErcury Surface, Space ENvironment, GEochemistry, and Ranging - Mercury surface, space environment, geochemistry and classification) is the first ship to Mercury since the real Mariner 10 of NASA Three flights through the planet appeared in 1974 and 1975. MESSENGER, controlled by NASA's Applied Physics Laboratory at Baltimore's John Hopkins University, will make two flights through Mercury (October 6, 2005). 2008 and September 29, 2009) before going into orbit around the planet on March 18, 2011.

Scientists led by planetary geologist Jim Head have delineated a pea-shaped volcanic fracture (on the right and center), surrounded by a ring of light and a faint outer ring. more, to help confirm that Mercury's surface is made up of volcanic activities right from the beginning of the planet's history.Photo taken by MESSENGER spacecraft when it flew by Mercury in January 2008. (Photo: NASA / John Hopkins University Applied Physics Laboratory / Carnegie Institution, Washington)

Mercury and MESSENGER are the topics of 11 papers in a special section for the January flight in Science on July 4, 2008.

Mark S. Robinson of Arizona State University (ASU), the lead author in the paper on the publication, emphasized the data on the surface rocks of Mercury using multi-spectral colors. Robinson, a geology instructor at ASU's Space and Earth Exploration School, at the University of Social Sciences and Humanities, is also a member of the ship's geological science group MESSENGER. Besides Robinson, the multi-spectral study has 12 co-authors from other institutions.

'We have captured a half-Mercury photo that has not been discovered by Mariner 10. The panorama is still incomplete but we will receive the other half on October 6. '

In 1974-75, the orbital Mariner moved to make three passes through Mercury constrain, causing it to capture nearly half of the planet's surface. This makes the information about the rest of Mercury still empty, until the MESSENGER helps scientists fill the data this January.

Lava land

Robinson said the photographs of MESSENGER show the broad role of volcanic activity. Collisions are quite common, so when Mercury looks at it, Mercury is quite like the moon. Much of the planet's surface is formed through volcanic activity.

'For example, according to our color data, the Caloris collision basin is covered with smooth, smooth material that seems to have originated from a volcano. Compared to the shape and morphology, these mines are very similar to the flat dark areas with basalt currents on the moon. But unlike the moon, Mercury's flat soil has low iron content, so it is quite an unusual rock. '

The land of Caloris is at least 1 million square kilometers, equal to the combined areas of Arizona, Nevada and California. The size of flat land indicates the existence of a large source of magma in Mercury's outer shell.

Multi-spectral shots also show that beside the lava flow, Caloris has a 'red spot', which also seems to be related to volcanoes. 'The red spot has a wide range and sometimes lies at the center of the non-fringing subsidence. They are now the same as the explosion created by the eruption. '

In addition, there are three main stone units that stand out from the photographs of MESSENGER.

'We have re-created the new hemisphere using an image resolution of about 5km / pixel. Also on the hemisphere explored by Mariner, we saw 3 main units distinguished by color. These units consist of smooth flat areas with high reflectivity, medium convex terrain and low reflective yield materials. '

Where is iron?

Material with low reflectivity is especially difficult to understand. 'It is an important and popular stone that appears deep in the shell as well as on the surface, yet it has very little iron in silicate minerals.'

That is unusual for him. 'Normally you will meet volcanic rocks with low reflectivity with a high amount of silicate minerals. But not here. ' One possibility is that iron actually exists but is not displayed on the spectrophotometer of MESSENGER because it is filled inside the chemical structure of minerals such as ilmenite.

Solving this puzzle will help scientists explore the history of Mercury. 'If you want to understand how a planet evolves, you need to know about the minerals in its shell and layers. Unfortunately, we can't drill into Mercury for a long time. All we can do is study very detailed volcanic rocks. They will provide an understanding of the planet's floor. '

'For now, it seems that Mercury is formed without iron. But we will know more about high quality compounds that help to understand its history, when MESSENGER goes into orbit in 2011. That's when surface rocks can be studied in more detail, with the whole tools.'