A Window Into Prebiotic Worlds? USRA Scientist Shares Unique Perspective

Washington DC and Houston, TX—February 9, 2023. A perspective article published today in Science magazine's Insights section provides a unique assessment of the study by Dustin Trail and Thomas McCollom contextualizing a new calibration they built to deduce the redox state, and subsequent geochemistry, of ~3.8-billion-year-old hydrothermal fluids using isotopic anomalies within zircon minerals from Jack Hills, Australia.

Quartz-pebble metaconglomerate pulled from the Jack Hills Quartzite, Australia containing microscopic grains of the mineral zircon (ZrSiO4 - zirconium silicate). Image attribution: Quartz-pebble metaconglomerate (Jack Hills Quartzite, Archean, 2.65 to 3.05 Ga; Jack Hills, Western Australia) 2 by James St. John is licensed under CC BY 2.0

In the article “A Window Into Prebiotic Worlds?” USRA’s Dr. Laura Rodriguez, an organic geochemist at the Lunar and Planetary Institute, describes some constraints we have for the origins of life on Earth, how zircons have previously helped shape what we know about the early Earth, and discusses implications of the work by Trail and McCollom. The result that really struck Rodriguez was the fact that even though the authors found that the hydrothermal fluids were relatively more oxidized than the mantle at that time, their geochemical models suggested that a relatively oxidized environment—contrary to popular opinion—could still generate conditions conducive for prebiotic organic synthesis.

Rodriguez highlights potential applications of this work, including how the approach by Trail and McCollom could be applied to zircons from samples from Jezero Crater returned by the Mars Sample Return Campaign. Deducing the geochemistry of 3.8-billion-year-old fluids that were once present within Jezero Crater could be used to inform prebiotic studies that aim to constrain the origins of organic compounds identified in these samples and is necessary for estimating the probability that any putative biosignatures detected have abiotic or biotic origins.

To read the article, visit https://www.science.org/toc/science/current.