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In one of the most terrifying articles I have ever read, planetologists show that ancient Mars suffered repeated huge eruptions from supervolcanoes that buried a huge region in ash up to a mile deep, and that these eruptions are linked to vast calderas in a specific location on the planet.
These supervolcanoes erupted between 1000 to 2000 times over a period of 500 million years, an apocalyptic era in the Martian past called the end of the Noachian / beginning of the Hesperian, about 3.7 billion years ago. To give you an idea of how deep this period was, this period was a transition from warmer, wetter Mars to the dry, cold desert we see today. It was a time of vast global change.
Arabia Terra is a huge region on Mars, measuring up to 4,500 kilometers in diameter (about as wide as the continental United States) and terribly ancient. It is an area of high altitude (high altitude) which is strongly eroded. It’s also littered with small and large craters, almost … almost – all impacts of asteroids and comets billions of years ago.
The northern part of Arabia Terra is where it meets Acidalia Planitia, a vast lowland plain. There have been suggestions of volcanic deposits in this area in the past, but the problem with this is that the area is huge, suggesting really huge volcanic activity, and no volcanic vents have been identified that could be related to these. eruptions.
In a recently published paper, planetologists searched for evidence of supervolcano activity – where a single explosive event erupts over 1,000 cubic kilometers of matter. To give you an idea of the scale, the eruption of an Indonesian volcano in 1257 AD caused extensive regional damage and left traces on Earth; this eruption was about 7.5 cubic kilometers of material. Martian supereruptions were well over 100 times larger.
They used observations of the region’s cliffs by NASA’s Mars Reconnaissance Orbiter to look for evidence of volcanic activity. The wind would carry the shattered ash through the area, where it would have settled in layers as further eruptions occurred. Cracks in the surface that opened after the eruptions can reach a mile or more in depth, exposing these layers, and the spectra taken can then be used to identify the minerals in those layers.
They found seven locations across Arabia Terra that were structurally and mineralogically distinct, where the cliff layers showed evidence of huge deposits from ash eruptions. This is not very surprising, but it is the quantity and distribution that is convincing: the thickness of the volcanic stratification appears to be the greatest (about 1 km deep) centered on a large area in the northern part of ‘Arabia Terra, and thins as it moves away. , about 100 meters deep to several thousand kilometers.
Be careful, a deposit barely 100 meters deep still buried a 30-story building, so these are incredibly huge eruptions, capable of dropping so much material on a continent.
Scientists searched for potential supervolcanoes in this area where the deposits were thickest and found several potential culprits that had previously been identified as possible. boilers – the depression that forms in a volcano after an eruption causes it to collapse – in work done earlier by a team of scientists. Some of these features include Eden Patera, Oxus Patera, Ismenia Patera, and Semeykin Crater (little boat means “flat” because they are wide and deep bowls). The craters themselves are tens of kilometers wide, and the surrounding flanks can be well over 100. They are huge structures.
How much material has exploded in total? This is the part that gave me shivers: they estimate the total deposits in the area to be more than 10 millions cubic kilometers. Ten. MILLION. That’s enough to bury the entire United States under a mile of material. The whole country. Including Alaska.
After a supervolcano eruption, the collapse leaves a large depression on the surface. They found that the average paternal depression was about 3,300 cubic kilometers. Assuming this is the volume of a given eruption and taking into account the density of the magma and tephra (rock and ash) blown out, scientists find that it would take 1,000 to 2,000 such eruptions during this 500 million year period of activity to create the deposits seen in Arabia Terra.
And that’s when my brain shot out of my head and started spinning around in circles screaming incoherently.
This is roughly the same eruption cycle length (a few hundred thousand years between events) as the Yellowstone supervolcano, and in volume roughly the same eruptive size in a single event as well. I’ve read quite a bit about what a supereruption of Yellowstone would do (for example, in Colorado where I live it would drop about a yard of ash), and to think it happens a thousand times is more than my brain can. manipulate. It’s too much.
And I know, it’s kind of funny for someone who’s used to thinking about supernovae and gamma-ray bursts that eclipse such a supervolcano into quantum nonexistence. But these are distant cosmic events, internalized in the form of numbers more than in real terms. A volcanic eruption is something that is more on a human scale, although it dominates it to the highest degree. The visceral impact is much greater.
I have observed Mars countless times with the naked eye and through a telescope, and I have read so many articles about its past and present nature that I have lost track of it. But I still need that kick in the pants every now and then, that reminder that Mars is a whole world, capable of marvels and magnificent panoramas and fascinating scientific discoveries and also violence on an almost incomprehensible scale.
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