Presented the last Tuesday of each month, March through October, 6:30 - 8:00 p.m.
Petroglyph Pláticas presentations continue our mission of providing education about the history and archaeology of Mesa Prieta and the Northern Rio Grande Valley and contextualizing the petroglyphs on Mesa Prieta. Presented on the last Tuesday of each month through October at the Northern Rio Grande National Heritage Center north of Alcalde, the gatherings provide an opportunity for learning as well as socializing.
The newly discovered high concentrations of rock varnish-like surfaces on Mars opens up new possibilities for habitability on that planet. Rock varnish is a thin (micron-scale), dark brown or black, often shiny layer on rock surfaces that forms in arid regions all over the Earth. Its dark appearance comes from the presence of manganese- and iron-oxides that make up ~30% of its composition. Despite its ubiquity on the Earth, the formation mechanism of varnish is not well understood. Microorganisms occupy crevices, pores and layers within rock varnish and it is probable that the concentration of manganese in many rock varnishes is mediated by microbial activity. However, the relationship between microbes and varnish remains a source of long-standing controversy that has important implications for our understanding of how life on Earth has evolved to capture and harness energy. Additionally, signatures of life that may be present in rock varnish on Mars cannot be definitively identified without first being identified on Earth. In this presentation, Dr. Yeager will discuss historical research on rock varnish, the current state of knowledge (Earth and Mars) and the aims of our research program.