Mars has granite that contains the elements essential for life

A recent study sheds light on Mars’s ancient past, revealing how variations in crustal thickness influenced the planet’s magmatic evolution and hydrology.

This research challenges long-standing assumptions about Mars, and suggests that the thick crust under its southern highlands supported granitic magmas and underground aquifers billions of years ago.

Evolution of Mars’s dynamic crust

Led by Cin-Ty Lee of Rice University, the study uncovers the role of Mars’s southern highlands – where crustal thickness reached up to 80 kilometers (50 miles) during the Noachian and early Hesperian periods (3-4 billion years ago).

Advanced thermal modeling revealed that radioactive heating in these thick crustal regions caused partial melting in the lower crust, and produced felsic magmas like granites.

“Our findings indicate that Mars’s crustal processes were far more dynamic than previously thought,” said Lee.

“Not only could thick crust in the southern highlands have generated granitic magmas without plate tectonics, but it also created the thermal conditions for stable groundwater aquifers – reservoirs of liquid water – on a planet we’ve often considered dry and frozen.”

The research team used advanced computer models to simulate the conditions of the Martian crust during its ancient epochs, focusing on three critical factors: radioactive heat generation, mantle heat flow, and crustal thickness.

Granite formation on Mars

Radioactive elements in the crust naturally decayed, releasing heat over time, while additional warmth from the planet’s mantle contributed to heating the crust from below.

In areas where the crust exceeded 50 kilometers (31 miles) in thickness, this combination of factors led to partial melting of the lower crust. This process generated granitic magmas, which are rich in silica.

Stable underground water reservoirs

The heat flow from the thick crust also supported stable underground water reservoirs, or aquifers, beneath a frozen surface layer. These aquifers extended several kilometers below the surface, retaining liquid due to the sustained warmth in the thick crustal regions.

Occasionally, volcanic eruptions or asteroid impacts may have disrupted these underground reservoirs, causing water to emerge onto the surface in episodic flooding events.

The interplay between heat, crust dynamics, and water highlights a much more geologically active and hydrologically dynamic Mars than previously believed. The findings have major implications for the planet’s potential habitability.

Significance of granite on Mars

The research debunks the assumption that granites are unique to Earth’s plate tectonics and water recycling processes.

“Granites aren’t just rocks; they’re geological archives that tell us about a planet’s thermal and chemical evolution,” said Rajdeep Dasgupta.

“On Earth, granites are tied to tectonics and water recycling. The fact that we see evidence for similar magmas on Mars through deep crustal remelting underscores the planet’s complexity and its potential for hosting life in the past.”

Hidden beneath basaltic flows in the southern highlands, these granites offer crucial insights into Mars’s geological history.

Ancient water and implications for habitability

The study suggests that Mars’s southern highlands may have been more hospitable to life in the past than scientists once believed.

Granitic magmas formed in these regions of the Martian crust are known to contain elements essential for life, such as potassium and phosphorus.

Additionally, the presence of stable underground water reservoirs beneath the highlands adds another layer when considering potential habitability. These liquid water aquifers, protected beneath a frozen surface layer, could have provided a stable environment for microbial life to exist.

The combination of these factors significantly changes how we view Mars’s potential to support life, offering new insights into the planet’s past environments.

Roadmap for future exploration

The southern highlands present a promising target for future Mars missions. Large craters and fractures in this region could expose hidden granitic rocks or ancient water reservoirs.

“Every insight into Mars’s crustal processes brings us closer to answering some of the most profound questions in planetary science, including how Mars evolved and how it may have supported life,” noted study co-author Kirsten Siebach.

”Our research provides a roadmap for where to look and what to look for as we search for these answers.”

A more complex Red Planet

This study paints a picture of Mars as a more dynamic and complex planet than previously imagined.

The interplay of thick crustal regions, granitic magmas, and underground aquifers highlights a planet rich in geological and hydrological processes.

These discoveries could reshape our approach to studying Mars and our assessment of whether it could have hosted life in the distant past.

The study is published in the journal Earth and Planetary Science Letters.

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