At IMAGE 2026, which will be held in Houston from 17–20 August, Doug Wyatt of the NASA Ames Research Center and I will be convening a special session entitled “Exploration, Mineral Science, and Mining of the Moon, Mars, and Asteroids,” with support from AAPG’s Astrogeology Committee.
We’d love to read/review your research on this topic! The abstract submission deadline is March 15. Please submit your presentations and abstracts. I look forward to seeing you in Houston!
For now, we will look at some recent research on “celestial geology.” Happy reading!
Rasoul Sorkhabi
Editor, Core Elements
The Geologic History of Mars
Artsiom P with elements furnished by NASA/Shutterstock.com
An article by M. Kolkas in The Professional Geologistoffers a nice review of the geologic and climatic history of Mars. Let’s take a look.
How we know what we know: Our knowledge of Martian geology comes mainly from NASA missions, including:
Mars orbiters: Mars Global Surveyor (launched in 1996), Mars Odyssey (2001), Mars Reconnaissance Orbiter (MRO, 2005)
Mars landers: Viking (1975), Phoenix (2008), InSight Lander (2018)
Mars rovers: Spirit (2003), Opportunity (2003), Curiosity (2011)
Internal Structure of Mars
Like Earth, Mars is divided into core, mantle, and crust, but in its own way:
Crust: Basalt covered with regolith rich in iron oxide metals, roughly 60 kilometers thick. The iron oxide is what gives Mars its nickname, the Red Planet.
Upper Mantle (between depths of 60–1,070 kilometers): Mainly olivine-pyroxene-garnet assemblage
Mars tectonic-climatic evolution: Four stages are identified:
Pre-Noachian (4.6 to 4.1 billion years ago. Ga): A period of intense meteoritic bombardment and craters, volcanism, and crustal deformation. The Northern Lowlands were formed by 4.1 Ga.
Noachian (4.1 to 3.7 Ga): This period was characterized by extensive volcanic activity, meteoritic bombardment, and craters. Major basins formed, including the Argyre, Hellas, Isidis, and Utopia.
Hesperian (3.7 to 3.0 Ga): During this time, there were some impact events, extensive volcanism, rifting, widespread precipitation and fluvial activity, and basin fill. There was a wet and warm climate, particularly during the Late Hesperian.
Amazonian (3.7 Ga to present): There has been volcanism and fluvial activity, particularly during the Early Amazonian. There are polar layered deposits and diminished meteorite impact.
Glaciation:
From the Late Hesperian through the Amazonian, Mars experienced alternating glacial and interglacial periods.
This is evident from U-shaped valleys, tillite sediments, and landscape striations.
Volcanic activity: Although Martian volcanoes formed billions of years ago, some volcanoes in two regions show signs of recent activity:
The Tharsis volcanic province, which covers about 25 percent of the Martian surface. Notable examples include: Tharsis Montes and Olympus Mons (shield volcanoes); Tholi and Patera (small domal volcanoes).
The Elysium volcanic province is several thousand kilometers west of Tharsis.
This week, discover how PaleoScan™ provides a stratigraphically consistent framework that improves time‑shift analysis and supports more reliable interpretation of reservoir fluid movement.
How Gaia revealed the Milky Way galaxy: “On January 15, 2025, the Gaia spacecraft took its last image. Then the craft ran a final round of engineering tests, fired its thrusters to leave Earth behind, and slipped into an orbit around the Sun, finally turning off on March 27.”
This is the opening of a feature article in the January 2026 issue of Astronomy.
Here we pay homage to Gaia in the first year of its retirement by reflecting on its biography and services.
A spacecraft called Gaia:
The European Space Agency (ESA) launched Gaia on December 19, 2013.
Gaia was ten meters wide and equipped with solar panels and two telescopes.
After a 30-day journey, it reached 1.5 million kilometers from Earth and settled at the Earth-Sun Lagrange 2 Point (L2).
L2 is the common orbital destination for space telescopes because of the very dark (and cold) views of space.
What did Gaia find?
Gaia measured the position and distance of two billion stars, mainly in the Milky Way, and created the most precise 3D map of our galaxy.
The Milky Way’s spiral is not flat but warped. Gaia measured the shape and precession period of the warp and found that the warp wobbles in less than 700 million years. This is unexpectedly fast and indicates a Milky Way collision with another galaxy —most likely the Sagittarius Dwarf Galaxy.
Gaia mapped some 40 dwarf galaxies orbiting just beyond the Milky Way. Long considered satellite galaxies that had settled around the Milky Way, Gaia found that many of these dwarf galaxies are encountering the Milky Way for the first time because they have high speeds.
The Large Magellanic Cloud, a dwarf galaxy near the Milky Way, is 10 percent more massive than previously thought, indicating a central black hole.
Data releases:
Scientists are still analyzing the hundreds of terabytes of data that Gaia sent to Earth.
Scientists release this information in stages. Data release 4 will take place in 2026 (covering 5.5 years of Gaia’s service) and release 5 in 2030.
An artist's impression of the Plato spacecraft. Photo credit: ESA/ATG Europe/Wikimedia Commons
In January 2027, the ESA will launch Plato (Planetary Transit and Oscillations of Stars) on an Ariane 6 rocket. Four years later, it plans to launch another mission, Ariel.
Plato 2027:
Plato will be placed at L2, like the previous spacecraft: COROT (2007 by ESA), Kepler (2009, NASA), Gaia (2013, ESA), TESS (2018, NASA), JWST (2021, NASA).
Plato will search for exoplanets using the transiting technique—when a planet passes in front of its star from the spacecraft’s perspective, it blocks a fraction of the star’s light.
Ariel will focus on infrared spectrometric analysis of the atmospheres of more than 1,000 known exoplanets identified by the transiting technique.
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