Million year time scale magnetic record in Mars' Blueberries deduced from Earth's Navaho sandstone (Utah) concretions?
Abstract
Terrestrial Fe-oxides (e.g., hematite, goethite, and magnetite) form cemented concretions from aqueous diagenetic solution in sandstones. We discovered that magnetic record of a concretion from the Jurassic Navajo Sandstone, Utah, contain, at least, three magnetic reversals.
Reversals allow for the first time evaluation of the time scale on which iron concretions form. The similarities of terrestrial and Mars concretions supports that similar formation process time scales may occur during the formation of Mars Blueberries found by the Mars rover Opportunity.
Magnetic reversals on Earth last order of millions years. We conclude that Utah concretion formed on the millions of years' time scale.
Similarity of the Utah's concretions to the Mars blueberries suggests that Mars concretion may contain magnetic record on the similar time scale, possible recording the once existing magnetic dynamo on Mars.