2024-03-13 23:43:49
A giant volcano and a possible buried glacial ice sheet have been discovered in the eastern part of Mars’ Tharsis volcanic province, near the planet’s equator.
Repeatedly photographed by spacecraft orbiting Mars since Mariner 9 in 1971, but deeply eroded beyond easy recognition, the giant volcano had been hidden in plain sight for decades in one of the most iconic regions of Mars, on the edge between the strongly fractured labyrinths of Noctis Labyrinthus and the monumental canyons of Valles Marineris.
Provisionally designated as “Noctis volcano” pending an official name, the structure is centered at 7° 35′ S, 93° 55′ W. It reaches 9,022 meters high and spans 450 kilometers wide. The gigantic size of the volcano and its complex history of modifications indicate that it has been active for a long time. In its southeastern part is a recent, thin volcanic deposit beneath which there is probably still glacial ice.
This combined discovery of a giant volcano and a possible discovery of glacial ice is significant, as it points to an exciting new location to study the geological evolution of Mars over time, search for life, and explore with robots and humans in the future.
“We were examining the geology of an area where we had found the remains of a glacier last year when we realized we were inside a huge, deeply eroded volcano,” Dr. Pascal Lee, a planetary scientist at the Institute, said in a statement. Seti and the Mars Institute based at NASA’s Ames Research Center and lead author of the study, presented at the Lunar and Planetary Science Conference held in The Woodlands, Texas.
Several clues, taken together, reveal the volcanic nature of the jumble of stratified mesas and canyons in this eastern part of Noctis Labyrinthus. The central summit area is marked by several raised mesas that form an arc, reaching a regional high and descending from the summit area. The gentle outer slopes stretch 225 kilometers away in different directions.
Near the center of the structure you can see a caldera remnant, the remains of a collapsed volcanic crater that once housed a lava lake. Lava flows, pyroclastic deposits (made of volcanic particulate materials such as ash, pumice, and tephra), and hydrated mineral deposits occur in several areas within the structure’s perimeter.
“This area of Mars is known to have a wide variety of hydrated minerals spanning a long period of Martian history. A volcanic environment for these minerals has long been suspected. Therefore, it may not be too surprising to find a volcano here,” explained Sourabh Shubham, a graduate student in the Department of Geology at the University of Maryland and co-author of the study. “In a sense, this great volcano is a long-sought ‘smoking gun’.”
In addition to the volcano, the study reports the discovery of a large area of 5,000 square kilometers of volcanic deposits within the volcano’s perimeter, featuring a large number of low, rounded and elongated, blister-shaped mounds. This “blistered terrain” is interpreted as a field of “rootless cones,” mounds produced by the explosive release of vapor or vapor swelling when a thin layer of hot volcanic materials rests on a surface rich in water or ice.
The Noctis volcano has a long and complex history of modification, possibly by a combination of fracturing, thermal erosion, and glacial erosion. Researchers interpret the volcano to be a vast shield formed by layered accumulations of pyroclastic materials, lavas and ice, the latter a result of repeated accumulations of snow and glaciers on its flanks over time.
As fractures and faults developed, particularly in connection with the uplift of the broader Tharsis region on which the volcano sits, lavas began to rise from different parts of the volcano, causing thermal erosion and removal of large amounts of buried ice and the catastrophic collapse of entire sections of the volcano.
Subsequent glaciations continued its erosion, giving many canyons within the structure their current distinctive shape. In this context, the “relict glacier” and the possible buried ice sheet around it could be remains of the last episode of glaciation that affected the Noctis volcano.
EUROPA PRESS
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