Chapter 1: Overview of Mount Sharp's Formation

Recent research has unveiled that both water and wind played significant roles in shaping Aeolis Mons, commonly known as Mount Sharp, which is located within Gale Crater on Mars.

IMAGE: A depiction of Curiosity's journey over the past decade, overlayed on an angled view of Gale Crater. The rover landed at Bradbury Landing, marked by a star on the map, in July 2022. CREDIT: NASA

Launched a decade ago, NASA's Curiosity rover has traversed more than eighteen miles across the Martian landscape, meticulously collecting data in pursuit of evidence of flowing water. The rover's landing site, Gale Crater, is an ancient impact structure that formed at least 3.5 billion years ago, rich in sediments that provide vital insights into Mars' wetter history, particularly regarding Mount Sharp at its center. As Curiosity approached and ascended the slopes of this mountain, it captured detailed images of sedimentary layers likely formed by water-induced erosion from ancient lake deposits.

With a height of approximately 1,300 feet, Mount Sharp's layers reflect millions of years of sediment accumulation, consisting of both sand and mud. Curiosity has not only documented these geological formations but also collected rock and soil samples for analysis using its onboard instruments. To date, over 700 scientific papers have been published, revealing evidence of Mars’ ancient, potentially habitable, wet environment.

IMAGE: A view of the Maria Gordon Notch cliff face taken on Sol 3324 (Dec. 12, 2021). CREDIT: NASA

In a recent publication in the Journal of Geophysical Research: Planets, lead author Jessica Watkins and her team have introduced new findings indicating that water is not the sole agent of erosion responsible for the terrain’s current shape. Co-author John Grotzinger explains that, unlike Earth, where rainfall dramatically sculpts landscapes, Mars' erosion is primarily driven by wind, which has acted over millions to billions of years, subtly shaping the Martian surface.

Section 1.1: Comparing Erosional Forces on Mars and Earth

There are key distinctions between the processes that shape landforms on Mars and those on Earth. Much of Earth's geological activity is influenced by plate tectonics. For instance, when two continental plates collide, such as those forming the Himalayas, they create uplift that results in mountain ranges. Concurrently, rivers carve through rock, forming deep canyons, while earthquakes and volcanic activity continuously reshape the landscape.

IMAGE: This image, captured by the HiRISE camera, displays distinct alternating bands of tone and brightness within the Murray Formation. These outcrops are common throughout the formation, though the origins of the banding remain unclear. They may signify aqueous processes occurring during or after sediment deposition. CREDIT: NASA/JPL-Caltech

In contrast, while the InSight lander has recorded numerous minor marsquakes, no tectonic activity has been detected on Mars. Instead, wind erosion is the primary force shaping the Martian surface. With an atmosphere that is only one percent as thick as Earth's, many in the planetary science community have historically underestimated the impact of wind erosion on Mars. Although wind may seem less significant today, evidence suggests it played a crucial role in the planet's geological history. As highlighted in a press release, the 300-meter thick Murray formation—composed of water-formed sediments—has been eroded from the top down. Additionally, the sediments above exhibit cross-bedding indicative of ancient sand dunes, shaped by wind, suggesting a landscape that transitioned from a wet environment to one resembling a desert.

By examining the various phases of erosion, scientists gain a deeper understanding of Mars' changing environment. As Grotzinger observes, this knowledge enhances our comprehension of Mars as a whole and will aid in interpreting data from the Perseverance rover.

Chapter 2: Insights from Mars Exploration

As we anticipate the Mars Sample Return mission, which aims to bring back samples from Jezero Crater, both Curiosity and Perseverance continue to contribute valuable scientific insights.

The first video, "Daily Space 15 September 2022: Mount Sharp, Mars, Shaped by Water and Wind," explores how water and wind have sculpted Mount Sharp, showcasing stunning visuals and expert commentary.

The second video, "Curiosity at Mars' Mount Sharp - Take an amazing imagery tour," offers a breathtaking visual journey of Curiosity’s findings and highlights the rover’s pivotal role in uncovering Mars' geological secrets.

For more in-depth information, refer to the following resources:

• Caltech press release
• Curiosity Celebrates 10 Years on Mars (NASA)
• “Burial and Exhumation of Sedimentary Rocks Revealed by the Base Stimson Erosional Unconformity, Gale Crater, Mars,” Jessica A. Watkins et al., 2022 June 8, JGR: Planets

This article was originally produced for the Daily Space podcast/YouTube series. For ongoing updates from Dr. Pamela Gay, Erik Madaus, and the team, visit DailySpace.org.