Date:

SwRI-led team discovers lull in Mars’ giant impact history

From the earliest days of our solar system’s history, collisions between astronomical objects have shaped the planets and changed the course of their evolution. Studying the early bombardment history of Mars, scientists at Southwest Research Institute (SwRI) and the University of Arizona have discovered a 400-million-year lull in large impacts early in Martian history.

This discovery is published in the latest issue of Nature Geoscience in a paper titled, “A post-accretionary lull in large impacts on early Mars.” SwRI’s Dr. Bill Bottke, who serves as principal investigator of the Institute for the Science of Exploration Targets (ISET) within NASA’s Solar System Exploration Research Virtual Institute (SSERVI), is the lead author of the paper. Dr. Jeff Andrews-Hanna, from the Lunar and Planetary Laboratory in the University of Arizona, is the paper’s coauthor.

- Advertisement -

“The new results reveal that Mars’ impact history closely parallels the bombardment histories we’ve inferred for the Moon, the asteroid belt, and the planet Mercury,” Bottke said. “We refer to the period for the later impacts as the ‘Late Heavy Bombardment.’ The new results add credence to this somewhat controversial theory. However, the lull itself is an important period in the evolution of Mars and other planets. We like to refer to this lull as the ‘doldrums.'”

The early impact bombardment of Mars has been linked to the bombardment history of the inner solar system as a whole. Borealis, the largest and most ancient basin on Mars, is nearly 6,000 miles wide and covers most of the planet’s northern hemisphere. New analysis found that the rim of Borealis was excavated by only one later impact crater, known as Isidis. This sets strong statistical limits on the number of large basins that could have formed on Mars after Borealis. Moreover, the preservation states of the four youngest large basins — Hellas, Isidis, Argyre, and the now-buried Utopia — are strikingly similar to that of the larger, older Borealis basin. The similar preservation states of Borealis and these younger craters indicate that any basins formed in-between should be similarly preserved. No other impact basins pass this test.

“Previous studies estimated the ages of Hellas, Isidis, and Argyre to be 3.8 to 4.1 billion years old,” Bottke said. “We argue the age of Borealis can be deduced from impact fragments from Mars that ultimately arrived on Earth. These Martian meteorites reveal Borealis to be nearly 4.5 billion years old — almost as old as the planet itself.”

The new results reveal a surprising bombardment history for the red planet. A giant impact carved out the northern lowlands 4.5 billion years ago, followed by a lull of approximately 400 million years. Then another period of bombardment produced giant impact basins between 4.1 and 3.8 billion years ago. The age of the impact basins requires two separate populations of objects striking Mars. The first wave of impacts was associated with formation of the inner planets, followed by a second wave striking the Martian surface much later.

- Advertisement -

SOUTHWEST RESEARCH INSTITUTE

- Advertisement -

Stay Updated: Follow us on iOS, Android, Google News, Facebook, Instagram, Twitter, Threads, TikTok, LinkedIn, and our newsletter

spot_img
Mark Milligan
Mark Milligan
Mark Milligan is a multi-award-winning journalist and the Managing Editor at HeritageDaily. His background is in archaeology and computer science, having written over 8,000 articles across several online publications. Mark is a member of the Association of British Science Writers (ABSW), the World Federation of Science Journalists, and in 2023 was the recipient of the British Citizen Award for Education, the BCA Medal of Honour, and the UK Prime Minister's Points of Light Award.
spot_img
spot_img

Mobile Application

spot_img

Related Articles

Significant multi-period discoveries in Delbrück-Bentfeld

An archaeological excavation in Delbrück-Bentfeld, a town in the east of North Rhine-Westphalia, Germany, has unearthed nearly 400 features of archaeological interest that span several centuries.

Excavation confirms the origin of Sheffield Castle

Archaeologists excavating the former site of Sheffield Castle site have confirmed that an artificial mound within the castle interior is a motte dating back to the earliest phase of the castle’s construction.

WWII bunker unexpectedly discovered during forest clearance works

A WWII bunker has been discovered during forest clearance works for the S17 Piaski–Hrebenne expressway in eastern Poland.

Salvage project reveals 500 years of Veracruz history

An archaeological salvage project in Veracruz, Mexico, has uncovered more than five centuries of the city’s urban development and everyday life.

Aerial photographs indicate an enormous Avar-Era cemetery

An analysis of aerial photographs has led to the discovery of a previously unknown Avar-era cemetery on the outskirts of Tatabánya, Hungary.

Excavations reveal a vast Roman villa complex

Archaeologists from Inrap have revealed a vast Roman villa complex during excavations in Auxerre, France.

Unprecedented Roman discovery in Ireland

Archaeologists have made an unprecedented Roman discovery during excavations at Drumanagh in north Dublin.

Exquisite marble sarcophagus unearthed near Caesarea

Archaeologists from the Israel Antiquities Authority (IAA), working on behalf of the Caesarea Development Corporation, have unearthed an exquisitely sculptured marble sarcophagus near the coastal city of Caesarea, Israel.