Эрдэмтэд Ангараг гаригийн Alba Mons галт уулын хажуугаас илэрсэн устөрөгчийн хлоридын хийн импульс нь гаригийн гүнд геологийн идэвхжил үргэлжилж буйг илтгэж байж магадгүй хэмээн таамаглаж байна.
Европын сансрын агентлагийн ExoMars Trace Gas Orbiter хөлөг сүүлийн хэдэн жилийн хугацаанд Ангараг гаригийн хойд хагас бөмбөрцгөөс устөрөгчийн хлоридын хийн огцом ялгаралт илрүүлжээ. Дэлхий дээр ийм төрлийн хий нь галт уулын магма гүний даралтаас чөлөөлөгдөх үед ялгардаг байна. Судлаачид уг хий нь Alba Mons галт уулын энгэр дэх хагарал бүхий хэсгээс гарч байгааг тогтоосон бөгөөд эдгээр хагарал нь гадаргын доорх магмын урсгалтай холбоотой байж болзошгүй гэж үзэж байгаа юм.
Гэсэн хэдий ч энэхүү таамаглалыг эцсийн дүгнэлт гэж үзэхэд эрт байна. Устөрөгчийн хлорид нь уур амьсгалын нөлөөгөөр, тухайлбал мөс уурших үед ялгардаг тохиолдол байдаг тул хийн гарал үүсэл нь тодорхойгүй хэвээр байна. NASA-гийн InSight хөлгийн авсан газар хөдлөлтийн мэдээллээр тухайн бүс нутагт магмын идэвхжилийн тодорхой шинж тэмдэг бүртгэгдээгүй байгаа нь уг асуудлыг илүү төвөгтэй болгож байна.
Зарим эрдэмтдийн үзэж буйгаар тус галт уулын доорх идэвхжил нь магма болон усны аль алиных нь нөлөөлөл байх магадлалтай аж. Хэдийгээр Ангараг гаригийг геологийн хувьд нам гүм гариг гэж үздэг ч эдгээр ажиглалт нь гаригийн дотоод дулаан болон галт уулын үйл ажиллагааны талаарх эрдэмтдийн мэтгэлцээнийг дахин сэргээж байна. Галт уул судлаач Трэйси Греггийн тэмдэглэснээр, гариг эрхэс нь нарийн төвөгтэй бүтэцтэй тул ирээдүйд ямар ч үйл явц өрнөхийг үгүйсгэх аргагүй юм.
Дэлгэрэнгүйг эх сурвалжаас харах
↓Эх сурвалжийг нээх ↓
Pulses of a pungent gas keep rising from the flank of the Red Planet’s biggest volcano, and scientists can’t explain them away yet. The finding, reported in Science Advances, hints that Mars could still harbor molten rock beneath its surface. It isn’t proof, though, and the researchers say so themselves.
Earth has around 40 volcanoes erupting at any given moment, and Venus is generally thought to have lava-spewing mountains of its own. Mars, once blanketed in active volcanoes, has gone quiet, and nobody has seen definitive signs of eruptions there.
But a quiet planet is not necessarily a geologically dead one. These new observations feed a longstanding debate: how do relatively small planets like Mars retain enough internal heat to fuel volcanic activity and, perhaps, sustain conditions favorable to microbial life?
A Gas That Shouldn’t Be There
The European Space Agency’s ExoMars Trace Gas Orbiter has spent the past few years picking up bursts of hydrogen chloride, a gas the article compares to vinegar mixed with a dangerously strong toilet cleaner. On Earth, volcanoes can emit it when rising magma decompresses.
Most Martian hydrogen chloride isn’t volcanic, however. It’s tied to the planet’s weather. During the warmer southern spring and summer, the gas pervades the southern sky, partly released as ice vaporizes. When colder autumn arrives, it sticks to falling ice and is dragged to the surface.
The north should behave differently, because Mars’s orbit is less circular than Earth’s, and northern summer coincides with a distant stretch of the orbit, so there’s no intense vaporizing-and-freezing cycle there. Yet Alexander Trokhimovskiy of the Russian Space Research Institute, a member of the team behind the study, says they “identified several very unusual detections” in the northern hemisphere. The HCl arrives in distinct, sharp pulses.
Fissures on Alba Mons
Those pulses keep coming from one location. “These observations occur in the same place: the northern flank of the Alba Mons volcano,” says Kevin Olsen, an atmospheric physicist at the University of Oxford and a co-author. Alba Mons covers roughly the area of the contiguous United States and is covered in youthful lava flows, a sign of recent geologic activity.
Using orbital imagery, the team spotted a series of fissures on that flank, each around 330 feet long. As explained by the co-author Daniel Mège of the Polish Academy of Sciences, such features “are thought to be associated with vertical magma sheets.” The researchers speculate that molten rock below may be releasing the gas. It’s only detected in summer, since winter ice blankets the ground and keeps it trapped.
Why Nobody’s Calling It Yet
Despite these clues, the researchers are not yet willing to conclude that there is ongoing volcanic activity. They cannot confirm that the hydrogen chloride comes precisely from the fissures they observed. As Olsen points out, “the nature of the source is unknown.”
Seismic data adds another wrinkle. NASA’s InSight lander never recorded convincing magmatic signals from Alba Mons or the wider Tharsis province. Its seismometer did detect odd marsquakes in Elysium Planitia, which suggested fluid moving underground.
“Some folks think it’s magma; others think it’s water,” says Tracy Gregg, a volcanologist at the University at Buffalo. “I think it might be both.”
She wasn’t involved in the study, but she notes that Tharsis hosted the planet’s largest and likely longest-lived magma chambers, which would take a long time to cool, degas and freeze solid. Even if magma is the source, nobody is forecasting an eruption.
”Planets are big, complicated bodies and unpredictable things can always happen,” she says, adding that: “In volcanology, we’ve learned to never say never.”
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