Jan 18, 2025 11:46 PM
Antarctic ice melt may fuel eruptions of hidden volcanoes
https://eos.org/research-spotlights/anta...-volcanoes
EXCERPT: Climate change is causing the ice sheet to melt, raising global sea levels. The melting is also removing the weight over the rocks below, with more local consequences. Ice sheet melt has been shown to increase volcanic activity in subglacial volcanoes elsewhere on the globe. Coonin et al. ran 4,000 computer simulations to study how ice sheet loss affects Antarctica’s buried volcanoes, and they found that gradual melt could increase the number and size of subglacial eruptions.
The reason is that this unloading of ice sheets reduces pressure on magma chambers below the surface, causing the compressed magma to expand. This expansion increases pressure on magma chamber walls and can lead to eruptions.
Some magma chambers also hold copious amounts of volatile gases, which are normally dissolved into the magma. As the magma cools and when overburden pressure reduces, those gases rush out of solution like carbonation out of a newly opened bottle of soda, increasing the pressure in the magma chamber. This pressure means that melting ice can expedite the onset of an eruption from a subglacial volcano.
Eruptions of subglacial volcanoes may not be visible on the surface, but they can have consequences for the ice sheet. Heat from these eruptions can increase ice melting deep below the surface and weaken the overlying ice sheet—potentially leading to a feedback loop of reduced pressure from the surface and further volcanic eruptions.
The authors stress that this process is slow, taking place over hundreds of years. But that means the theorized feedback could continue even if the world curtails anthropogenic warming. Antarctica’s ice sheet was much thicker during the last ice age, and it is possible that the same process of unloading and expansion of magma and gas may have contributed to past eruptions... (MORE - details)
PAPER: https://doi.org/10.1029/2024GC011743
Why is one half of Mars so different to the other? ‘Marsquakes’ may have just revealed the answer
https://theconversation.com/why-is-one-h...wer-246575
EXCERPTS: Mars is home to perhaps the greatest mystery of the Solar System: the so-called Martian dichotomy, which has baffled scientists since it was discovered in the 1970s.
The southern highlands of Mars (which cover about two-thirds of the planet’s surface) rise as much as five or six kilometres higher than the northern lowlands. Nowhere else in the Solar System do we see such a large, sharp contrast at this scale.
What caused this dramatic difference? Scientists have been split on whether it resulted from external factors – such as a collision with a huge, moon-sized asteroid – or internal ones, such as the flow of heat through the planet’s molten interior.
In new research published in Geophysical Research Letters, we analysed marsquakes detected by NASA’s Insight lander, located near the border separating the two sides of the dichotomy. Studying how the marsquake vibrations travel revealed evidence that the origin of the Martian dichotomy lies deep inside the red planet.
[...] This temperature difference between the two halves of the dichotomy supports the idea that the split was caused by internal forces on Mars, not some external impact.
The full explanation of why is quite complex. To simplify, scientists have made models of how the dichotomy could have formed based on an initial unevenness in the crust of Mars way back in time.
At one point, Mars had moving tectonic plates like Earth does. The movement of these plates and the molten rock beneath them could have created something like the dichotomy – which was then frozen in place when the tectonic plates stopped moving to form what scientists call a “stagnant lid” on the planet’s molten interior.... (MORE - missing details)
https://eos.org/research-spotlights/anta...-volcanoes
EXCERPT: Climate change is causing the ice sheet to melt, raising global sea levels. The melting is also removing the weight over the rocks below, with more local consequences. Ice sheet melt has been shown to increase volcanic activity in subglacial volcanoes elsewhere on the globe. Coonin et al. ran 4,000 computer simulations to study how ice sheet loss affects Antarctica’s buried volcanoes, and they found that gradual melt could increase the number and size of subglacial eruptions.
The reason is that this unloading of ice sheets reduces pressure on magma chambers below the surface, causing the compressed magma to expand. This expansion increases pressure on magma chamber walls and can lead to eruptions.
Some magma chambers also hold copious amounts of volatile gases, which are normally dissolved into the magma. As the magma cools and when overburden pressure reduces, those gases rush out of solution like carbonation out of a newly opened bottle of soda, increasing the pressure in the magma chamber. This pressure means that melting ice can expedite the onset of an eruption from a subglacial volcano.
Eruptions of subglacial volcanoes may not be visible on the surface, but they can have consequences for the ice sheet. Heat from these eruptions can increase ice melting deep below the surface and weaken the overlying ice sheet—potentially leading to a feedback loop of reduced pressure from the surface and further volcanic eruptions.
The authors stress that this process is slow, taking place over hundreds of years. But that means the theorized feedback could continue even if the world curtails anthropogenic warming. Antarctica’s ice sheet was much thicker during the last ice age, and it is possible that the same process of unloading and expansion of magma and gas may have contributed to past eruptions... (MORE - details)
PAPER: https://doi.org/10.1029/2024GC011743
Why is one half of Mars so different to the other? ‘Marsquakes’ may have just revealed the answer
https://theconversation.com/why-is-one-h...wer-246575
EXCERPTS: Mars is home to perhaps the greatest mystery of the Solar System: the so-called Martian dichotomy, which has baffled scientists since it was discovered in the 1970s.
The southern highlands of Mars (which cover about two-thirds of the planet’s surface) rise as much as five or six kilometres higher than the northern lowlands. Nowhere else in the Solar System do we see such a large, sharp contrast at this scale.
What caused this dramatic difference? Scientists have been split on whether it resulted from external factors – such as a collision with a huge, moon-sized asteroid – or internal ones, such as the flow of heat through the planet’s molten interior.
In new research published in Geophysical Research Letters, we analysed marsquakes detected by NASA’s Insight lander, located near the border separating the two sides of the dichotomy. Studying how the marsquake vibrations travel revealed evidence that the origin of the Martian dichotomy lies deep inside the red planet.
[...] This temperature difference between the two halves of the dichotomy supports the idea that the split was caused by internal forces on Mars, not some external impact.
The full explanation of why is quite complex. To simplify, scientists have made models of how the dichotomy could have formed based on an initial unevenness in the crust of Mars way back in time.
At one point, Mars had moving tectonic plates like Earth does. The movement of these plates and the molten rock beneath them could have created something like the dichotomy – which was then frozen in place when the tectonic plates stopped moving to form what scientists call a “stagnant lid” on the planet’s molten interior.... (MORE - missing details)