The mysterious desert varnish
2006/10/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria
Several rocks and canyons of the deserts are varnished. This varnish is very persistent, so the drawings made previously in the Baroque rocks have remained until today.
The scientists believed that the varnish was produced by microorganisms that inhabited the rocks. Now, however, the micropaleontologists of Imperial College London have given a new explanation. The varnish has been analyzed using high resolution electron microscopes and spectroscopy, showing that it is mostly composed of sylphs.
Silica can be dropped from the atmosphere or filtered from the rock itself and is transformed into varnish through a process. In this process, over time, silica breaks down into a gelatinous material and then hardens.
In addition, researchers have found that varnish preserves remnants of organic matter of the past as amino acids, fragments of DNA, etc. The analysis of the varnish allows to know the evolution of the climate. The process of forming the varnish is really long and allows to analyze the climate for millions of years.
However, other scientists do not rule out the participation of microorganisms in the process of creating the varnish. In addition to silica, there are other elements in the varnish that consider the participation of microorganisms essential for their formation.
