2023-09-28 11:00:06
An international team demonstrates that rocks from the hydrothermal system formed following the Rochechouart asteroid impact, around 200 million years ago, contain traces of the atmosphere of this era in Earth’s history (The history of the Earth covers approximately 4.6 billion years…).
Artist’s impression of an asteroid crashing into Earth.
© Freepik
Following the evolution of the composition of the Earth’s atmosphere means studying the whole (In set theory, a set intuitively designates a collection…) of the geological history of our planet (A planet is a body celestial orbiting around the Sun or another star of…). However, geological samples that have trapped atmospheric signals are extremely rare. An international team of researchers led by Guillaume Avice (IPGP-Université Paris (Paris is a French city, capital of France and the capital of the region…) Cité, CNRS), in collaboration with the University (Une university is a higher education establishment whose objective is the…) of Queensland (Australia), the University of Lorraine (The University of Lorraine is a grouping of establishments…) and the Museum of natural history (The process of observation and systematic description of nature begins from…) of Vienna (Austria), demonstrates that rocks coming from the hydrothermal system formed following the asteroid impact of Rochechouart (France), around 200 million years ago, contain traces (TRACES (TRAde Control and Expert System) is a veterinary health network of…) of the atmosphere (The word atmosphere can have several meanings:) of this era of the history of the Earth.
Agate nodule (concretion of layers of silica) formed by the circulation of fluids in the crater (For the crater of volcanic origin, see Volcanic crater For the crater of origin…) of Rochechouart. Red bar = 1 cm.
© Avice et al., EPSL 2023
Fluid inclusions contained in Rochechouart samples. Some contain a liquid phase (liq.) and a gas phase in the form of a bubble (vap.). The largest inclusion is twenty micrometers wide.
© Avice et al., EPSL 2023
The measured elemental and isotopic compositions of rare gases reveal an almost pure atmospheric signal, the age of which is confirmed by the argon-argon dating method.
Impact craters are therefore new targets for studying the evolution of the Earth’s atmosphere over the long term, thus leading to a better understanding of future variations and in particular climate change.
Reference
G. Avice, MA Kendrick, A. Richard, L. Ferrière,
Ancient atmospheric noble gases preserved in post-impact hydrothermal minerals of the 200 Ma-old Rochechouart impact structure, France, Earth and Planetary Science (Latin scientia, “knowledge”) is, according to the dictionary…) Letters, Vol. 620, 2023,
DOI: 10.1016/j.epsl.2023.118351.
1696017482
#evolution #earths #atmosphere #studied #impact #craters
