New observations of the opal silica deposits discovered in 2007 by the Spirit rover in the Gusev crater, endorse that there was once a hot spring on Mars.
The origin and age of the opal silica deposits discovered by the Spirit rover adjacent to the Home Plate feature in the Columbia Hills crater in Gusev is still debated, partly due to its proximity to sulfur-rich soils.
The processes related to smoking activity and hot springs and / or geysers are the main candidates. It is known that both processes produce opal silica on Earth, but with differences in composition, morphology, texture, and stratigraphy.
In the new research, a team led by Steven W. Ruff of the University of Arizona State incorporates new and existing observations from the Home Plate region with field and laboratory work observations to address competing hypotheses.
The results, which include new evidence for a thermal water vent mound( (hot spring found on Mars) ), “demonstrate that a volcanic hydrothermal system that manifests activity from thermal / geyser and fumaric sources best explains opal silica rocks and sulfur-rich proximal materials, respectively” . Opal silica rocks are most likely sinter deposits derived from the activity of hot springs.
.According to the study, published in the journal Astrobiology, stratigraphic evidence indicates that its deposition occurred before the location of volcanic deposits comprising Home Plate and nearby ridges. “Because sinter deposits throughout geological history on Earth preserve evidence of microbial life, they are a key objective in the search for ancient life on Mars,” they stress.