Mount Erebus

Mount Erebus is a remarkable geological feature located on Ross Island in Antarctica. It is the southernmost active volcano on Earth. This means it is the closest erupting volcano to the South Pole. It stands as the second-highest volcano in Antarctica, following the dormant Mount Sidley. The mountain is also the second most prominent mountain on the continent. It serves as the highest point on Ross Island. This island is actually the sixth-highest island on Earth.

Geologically, Mount Erebus is classified as a polygenetic stratovolcano. This means it was built by many different eruptive events over a long time. The structure of the volcano is divided into two distinct parts. The bottom half of the mountain is shaped like a broad shield. The top half is a steep stratocone.

The oldest parts of the volcano consist of nonviscous basanite lavas. These lavas formed the wide platform shield at the base. More recent eruptions produced thicker phonotephrite and trachyte lavas. The upper slopes are now dominated by steeply dipping tephritic phonolite lava flows. These flows often create large-scale levees.

The volcano is famous for its unique eruptive activity. It is currently the world's only erupting phonolite volcano. The summit contains a persistent, convecting phonolitic lava lake. This is a pool of liquid rock that stays active. It is one of only five such long-lasting lava lakes on Earth. This lake has been present in the inner summit crater since at least the early 1970s. The volcano undergoes Strombolian eruptions. These are eruptions that occur from the lava lake or from subsidiary vents.

Because these eruptions are relatively low-level, scientists can study them closely. They can stand only hundreds of metres from the active vents.

The summit area is complex and contains several distinct features. There is a conspicuous break in the slope at 3,200 metres above sea level. This break marks a summit plateau that represents a caldera. A caldera is a large crater formed by a massive collapse. This specific caldera was created by an explosive VEI-6 eruption. That massive event occurred approximately 18,000 years ago. In the center of this caldera sits a small, steep-sided cone. This cone is made of decomposed lava bombs and large anorthoclase crystals. These crystals are often called Erebus crystals.

Humans have studied Mount Erebus for a long time. Captain James Clark Ross discovered the volcano on January 27, 1841. He named it after his ship, the HMS Erebus.

In 1908, members of Sir Ernest Shackleton's party achieved the first ascent of the summit crater rim. In 1992, scientists used a robot named Dante I to explore the interior. Dante I was an eight-legged robotic explorer. It was designed to collect gas samples and measure temperatures. This was one of the first times a robotic platform was used in Antarctica. Scientists also use seismometers to listen to the volcano. By studying seismic waves, they have mapped the complex plumbing system of the magma.

Mount Erebus also hosts strange environments called ice fumaroles. These are ice towers that form around gases escaping from vents. These vents create dark ice caves in the polar environment. These caves are very important for the study of astrobiology. Astrobiology is the study of how life might exist on other planets. Inside these caves, life is very sparse. Most organisms there are chemolithoautotrophic. This means they get all their energy from chemical reactions with rocks. They do not need sunlight or other lifeforms to survive.

They use carbon dioxide fixation to live. This makes the caves a perfect place to study how life survives in extreme conditions.

There are also surprising chemical discoveries at the volcano. Researchers found that Mount Erebus emits about 80 grams of gold vapor every day. This vapor eventually condenses into microscopic gold particles. These particles can be found up to 1,000 kilometres away. This was the first time scientists documented gold condensing from volcanic emissions. However, the volcano also has a tragic history. On November 28, 1979, Air New Zealand Flight 901 crashed into the mountain. This accident killed all 257 people on board. The crash happened during a whiteout, which is a phenomenon where visibility is lost.

This event led to many lawsuits and changed how sightseeing flights operate in Antarctica.