Scientists have “reset the clock” for the moon’s craters, meaning parts of its surface are about 200 million years older than previously thought.
Researchers from Norway and France have found a way to coordinate and recalibrate two conflicting systems for dating the surface of the moon. This new evaluation shows that large parts of the moon’s crust are about 200 million years older than previously thought and allows scientists to explain the sequence of events in the evolution of the moon’s surface.
The moon is now relatively inactive geologically, meaning that the craters from asteroids and comets that have bombarded the moon throughout time have not been eliminated; Earth receives a similar barrage throughout time, but Earth’s surface motions mask these effects.
Presenting the work at the Goldschmidt Geochemistry Conference in Lyon, Professor Stephanie Werner (of the Center for Planetary Habitability, University of Oslo) said, “Looking at the traces of these impacts on the moon shows what the Earth would be like without the geological churning of plate tectonics happening here on Earth. What we’ve done is show that large parts of the lunar crust are about 200 million years older than previously thought.”
The work based on this presentation is scheduled to be published as two articles in the The Planetary Science Journal.
Researchers know that the standard method of measuring the age of the moon’s surface—a process known as crater counting—gives different results than those found when examining rocks from the Apollo missions, especially in bright areas. of the month, the Highlands.
“We decided we needed to reconcile these differences, and that meant correlating the individually dated Apollo samples to the number of craters in the sample site’s surrounding area—in fact, resetting the crater clock. We also correlated them against spectroscopy data from various lunar missions. , especially the Indian Chandrayaan-1, to ascertain which Apollo sample belonged to the surface where we counted the craters. It’s a lot of work, we started this project in 2014. We knew that by doing this we could resolve the discrepancy and push the age of the moon’s surface up to 200 million years.”
As an example, the age of the Imbrium Basin, filled with Mare Imbrium (seen above left of the moon), which was probably created by the collision of an asteroid impactor around the size of Sicily, dates back from 3.9 billion years . ago, to 4.1 billion years ago. The researchers emphasize that this does not change the estimates of the age of the moon itself, only the estimate of its surface. The new dating system changes the ages of all parts of the moon’s surface—not identically, but with the oldest surfaces showing significant changes.
Professor Werner said, “This is an important difference. It allows us to push back in time an intense period of bombardment from space, which we already know happened before the great volcanic activity that formed in the patterns of the ‘man in the moon’-the horse. volcanic fields including Mare Imbrium. As it happened on the moon, the Earth almost certainly suffered from this early bombardment, too.”
Prof. Audrey Bouvier (University of Bayreuth, Germany) said, “The moon provides unique records of early bombardment history. We have had three successful lunar sample return programs (Apollo, Luna, and Chang’e) related to rocks in their In sampling locations on the moon. By combining the latest spacecraft observations with the impacts recorded on lunar rocks, Prof. Werner and his colleagues have pushed hard in records of heavy bombardment to terrestrial planets.
“Such a heavy bombardment period must have affected the origin and early evolution of life on Earth and possibly on other planets such as Mars. Bringing back rock samples from Jezero Crater on Mars is the next giant leap in the search for signs of ancient life on another planet in the solar system, and when.”
Conference Abstract 15810 Lunar Time Travels—Introduction to a Revised Cratering Chronology Model Stephanie C Werner, Benjamin Bultel, Tobias Rolf.
Bultel, B., SC Werner (2023) Sample-Based Spectral Mapping Around Landing Sites on the Moon—Lunar Time Scale Part 1. The Planetary Science Journalin the press.
Werner, SC, B. Bultel, T. Rolf (2023) Review and Revision of the Chronology of Lunar Cratering—Lunar Time Scale Part 2. The Planetary Science Journalin the press.
Presented at the Goldschmidt Conference
Citation: Revised cratering chronology moon model shows parts of crust 200 million years older than thought (2023, July 13) retrieved 13 July 2023 from https://phys.org/news/ 2023-07-cratering-chronology-moon-crust- milion.html
This document is subject to copyright. Except for any fair dealing for the purpose of private study or research, no part may be reproduced without written permission. Content is provided for informational purposes only.