Situated in Chad, Trou au Natron presents a unique volcanic landscape that appears to manifest as a spectral visage when observed from space. Comprehensive studies conducted through satellite imagery and scientific expeditions have contributed to our understanding of its complex geological past.
The unusual appearance of this “face” in the northern region of Chad has been shaped by historical volcanic activities as well as current salt deposits originating from thermal springs.
Viewed from an aerial perspective, the volcanic pit and soda lake known as Trou au Natron, which is approximately 1,000 meters (3,300 feet) deep, gives the impression of an eerie face peering upwards. This remarkable image was captured on February 12, 2023, by an astronaut stationed on the International Space Station.
The periphery of the facial resemblance is partially delineated by shadows produced by the border of a caldera—a specialized form of a volcanic crater created either through a violent eruption or the caving in of the surface into a depleted magma chamber. The features resembling “eyes” and a “nose” are cinder cones—steep, cone-shaped hills that form around volcanic vents. These cinder cones are believed to have formed relatively recently in geological timescales, potentially within the last few million to a few thousand years.
The photograph taken by an astronaut aboard the International Space Station on February 12, 2023, showcased the profound depths of the volcanic pit and soda lake of Trou au Natron located in northern Chad.
Surrounding the area that mimics a “mouth” is a mineral crust composed of a specific salt called natron—a compound consisting of sodium carbonate, sodium bicarbonate, sodium chloride, and sodium sulfate. This crust originates from the evaporation of thermal spring water and the rise of mineral-laden steam from the geothermally active zone.
Located to the southeast of Tarso Toussidé, a vast volcanic feature replete with fumaroles and an active stratovolcano, Trou au Natron is one of the numerous volcanic summits within the Tibesti Mountains. It has been the site of several relatively recent eruptions, although these have been inadequately documented and researched.
The isolated location of Trou au Natron presents significant challenges for scientific exploration. Nonetheless, analyses of rock and fossil specimens gathered in the 1960s suggest that a glacial lake once filled Trou au Natron to a considerable depth around 14,000 years ago. A 2015 expedition headed by German scientist Stefan Kröpelin collected fossilized aquatic algae samples estimated to have formed approximately 120,000 years ago.
Satellite data have supplemented gaps in our understanding. Researchers from the University of Cambridge utilized data from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensor aboard NASA’s Terra satellite to construct a preliminary timeline of the region’s volcanic activity. The formation of Trou au Natron is identified as one of the most recent significant geological events, partitioned into six phases of activity.
The image, identified as ISS068-E-53507, was obtained using a Nikon D5 digital camera with a 500-millimeter focal length. The photograph was supplied by the ISS Crew Earth Observations Facility and the Earth Science and Remote Sensing Unit at the Johnson Space Center. A member of the Expedition 68 crew captured this image, which has been cropped and processed to enhance contrast and remove lens artifacts. The International Space Station Program supports this laboratory activity as a part of the ISS National Lab, with the aim of assisting astronauts in capturing invaluable Earth imagery for both scientific and public benefit, and making these images widely accessible online.
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Frequently Asked Questions (FAQs) about Trou au Natron
What is Trou au Natron and where is it located?
Trou au Natron is a unique volcanic pit and soda lake situated in northern Chad. It is notable for its appearance, which resembles a ghostly face when viewed from an aerial or orbital perspective.
What makes Trou au Natron appear like a face?
The features that contribute to the face-like appearance of Trou au Natron include the shadows cast by the rim of a caldera, which form the outline of the “face,” and cinder cones that resemble “eyes” and a “nose.” Additionally, a mineral crust made of natron outlines the “mouth.”
How was the remarkable image of Trou au Natron captured?
The striking image of Trou au Natron was captured on February 12, 2023, by an astronaut aboard the International Space Station using a Nikon D5 digital camera with a 500-millimeter focal length.
What geological features are present in Trou au Natron?
The geological features include a caldera, cinder cones, and a mineral crust of natron. These features have been formed through past volcanic activities and the deposition of salt from thermal springs.
What challenges do scientists face in studying Trou au Natron?
One of the primary challenges is the site’s remote location, making it difficult to access for research. Despite these challenges, some studies have been conducted, including rock and fossil sampling, to shed light on its geological history.
What additional research has been conducted on Trou au Natron?
Apart from on-site expeditions, researchers from the University of Cambridge have analyzed satellite data from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensor on NASA’s Terra satellite to piece together a rough timeline of the region’s volcanic activity.
How old is Trou au Natron?
Based on fossil samples and rock analyses, Trou au Natron’s most recent significant geological activities are estimated to have occurred within the last few million to a few thousand years.
What are the scientific implications of Trou au Natron?
Trou au Natron serves as an important case study for understanding complex geological processes, including volcanic activities and mineral deposition. Its isolated location and unique features make it a subject of ongoing scientific interest.
Who was responsible for the astronaut photograph?
The photograph was provided by the ISS Crew Earth Observations Facility and the Earth Science and Remote Sensing Unit at the Johnson Space Center. It was taken by a member of the Expedition 68 crew.
How is Trou au Natron connected to the broader geological context of the Tibesti Mountains?
Trou au Natron lies southeast of Tarso Toussidé, a large volcanic feature within the Tibesti Mountains. It is one of several volcanic peaks in the region and is the source of several relatively recent—though poorly documented—eruptions.
More about Trou au Natron
- Geological Features of Trou au Natron
- Astronaut Photography from the International Space Station
- Calderas and Cinder Cones: An Introduction
- The Tibesti Mountains: A Geological Overview
- Satellite Observations and Geology
- Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER)
- ISS Crew Earth Observations Facility
- Earth Science and Remote Sensing Unit at the Johnson Space Center
- Volcanic Activity in the Tibesti Mountains
- Mineral Composition of Natron
10 comments
Epic photo from the ISS! Kudos to the astronaut who snapped it. It’s like the Earth is looking back at us.
Loved the bit about the German researcher collecting samples from way back. The historical context adds a whole new layer to this.
So what happens if the volcano erupts? Does the face change? Would be cool to keep track of this over time.
this is mind-blowing! Who knew geology could be this interesting. Really puts things in perspective, y’know?
Interesting, but how sure are we about all this? Science is always updating, so who knows what they’ll find next.
This is so unique but it also reminds us how we need to protect such natural wonders. Hope it stays untouched.
Love how detailed the article is. satellite data, expeditions, everything’s in there. But would’ve liked more on the methods used for geological dating.
Trou au Natron just got added to my bucket list. Even if its remote, gotta see this wonder in person!
Wow, never thought a volcano could look like a face from space. Nature’s full of surprises, huh?
its amazing to know something this cool is in my country. Puts Chad on the map for something other than politics.