Instead of spewing lava, it spews mud. Is this kind of volcano "not doing its job"?

Question: Volcanoes spew out lava, but what spews out mud?

Answer: Mud volcanoes!

Mud volcanoes are indeed a real natural phenomenon. In addition to being a natural landscape, mud volcanoes also have their own unique value.

Are mud volcanoes volcanoes?

Mud volcanoes, also known as false volcanoes and ice volcanoes, are formed when mud and gas are ejected from the ground at the same time and accumulate. They have a similar or similar structure to ordinary volcanoes. Their appearance is mostly conical hills or basins. There are often depressions at the tip of the hill, from which mud and gas are intermittently ejected.

Image source: Pixabay

Just like a volcano has structures such as magma chamber, magma channel, crater, volcanic cone, etc., a mud volcano also has structures such as mud layer, mud channel, vent, etc. However, no matter how much it looks like a volcano, it is not a true volcano.

How are mud volcanoes formed?

Scientists believe that the formation of mud volcanoes is related to earthquakes, the state of deep sediments and gas content, fault activity, and artificial drilling. The eruption of mud volcanoes requires three conditions: the distribution of loose mudstone layers underground to provide the source of mud required for the eruption; the presence of a huge pressure difference that causes gas to flow out and drive mud to erupt; and the presence of channels required for mud eruption, such as faults, anticline axes, drilling, etc.

The formation of some mud volcanoes is related to real volcanic activity. When the volcanic activity stops, the magma below the volcano that originally erupted magma is exhausted or the magma reservoir loses contact with the underground magma. There is previously buried silt or hot spring activity under the volcano. These materials are ejected to the surface along with volcanic gases, forming mud volcano activity. The mud volcano in Yellowstone National Park in the United States is a typical volcano of this type.

Image source: Pixabay

There are also mud volcanoes developed on the seabed. Some scientists believe that the formation of mud volcanoes on the seabed is related to the sedimentation rate and lateral compression. The faster sedimentation rate and lateral compression of the continental margin will cause the fluid to pierce the mud bottom splitter, allowing the fluid to migrate upward along faults or cracks or leak to the seabed, forming the mud volcanoes that people see.

There are many ways for mud volcanoes to erupt. There are mud overflow eruptions, where gas carries mud and erupts over the surface, gradually accumulating into a cone or dome-shaped landform. There are pool-shaped mud crater eruptions, where the groundwater carried by the gas accumulates into a pool and flows out from an overflow gap. The solid matter ejected is relatively small, and the outer edge of the vent is slightly higher than the surrounding surface, presenting a gentle shield shape. There are violent eruptions, where the underground high-pressure gas suddenly bursts out and carries a large amount of mud volcano breccia to the surface.

The mud ejected by mud volcanoes contains more than 60 trace elements, including a variety of minerals. However, the causes of mud volcanoes around the world are different, and the types of minerals are also different. Some mud volcanoes can even eject minerals such as illite, quartz, montmorillonite, and kaolinite, while some mud volcanoes eject large amounts of methane, methane, hydrogen sulfide and other gases.

Where are the mud volcanoes?

There are mud volcanoes in many places around the world. The Baku region of Azerbaijan has the most mud volcanoes in the world. At the same time, Baku is also a famous oil producing area with a vast oil reserve belt. One of the largest mud volcanoes in the world, the Ottoman Bozdag Mud Volcano, is located here. In 2018, this huge mud volcano erupted, and the magma it spewed reached a height of two to three hundred meters, which was very shocking. The Makran Mud Volcano in Iran and the Buza Mud Volcano in Romania are also relatively famous mud volcanoes, and the mud volcano group in Yellowstone Park in the United States is a world-famous mud volcano group.

There are numerous land mud volcanoes distributed in Xinjiang, Tibet, Taiwan and other places in my country, and there are also some submarine mud volcanoes on the seabed in the northern waters of the South China Sea.

In 2002, the Wusu Mud Volcano in Xinjiang erupted. The active Wusu Mud Volcano at that time showed many mud springs and mud pools. They were mostly circular, ranging from a few centimeters to a few meters, and were distributed in hillsides and valleys with a radius of about half a square kilometer. The mud in these mud springs and mud pools was bubbling, as if it was boiling. Today, the Wusu Mud Volcano Group has become the largest mud volcano group discovered in my country. The materials ejected from the mud craters of the Wusu Mud Volcano Group contain a large amount of barium, copper, zinc and other trace elements, which have high physical therapy and beauty value.

There is also a famous mud volcano attraction in Xinjiang, my country, called Dushanzi Mud Volcano. It is located in Dushanzi District, Karamay City, Xinjiang, China, about 1 km west of the south side of the district. Dushanzi is one of the birthplaces of China's petroleum industry and an important petrochemical base in Xinjiang. Its name comes from this mud volcano.

Three million years ago, this mud volcano was at the peak of its activity, erupting continuously and accumulating into a mud mountain. Because the mountain is isolated in the Tianshan Mountains, the locals called this area Dushanzi.

There are two theories about the possible cause of the Dushanzi mud volcano eruption and the possible cause of the eruption is the Dushanzi fault.

First, the Dushanzi Fault cuts through the already formed natural gas reservoir during its activity, causing underground high-pressure natural gas to violently erupt along the fault surface; second, the Dushanzi Fault cuts through the gas source layer, and the natural gas generated in the gas source layer migrates upward along the fault surface and gathers into a natural gas reservoir at a location with better sealing and shielding conditions. When the pressure of the gas reservoir rises to exceed the maximum limit of the sealing and shielding, the high-pressure natural gas in the gas reservoir will violently erupt along the fault surface.

Dushanzi volcano has been erupting for millions of years, and its geological activity is now in its final stage, with mostly intermittent eruptions.

The crater of Dushanzi volcano is located on a peak in the north of Dushanzi. There are two main craters, about 100 meters apart. The larger one is about 60 centimeters in diameter and more than 1 meter above the ground. The crater is filled with viscous mud, which is gray-green and has a slight smell of oil. Mud bubbles keep bubbling outward, and the collected mud overflows along the opening on the southwest side. The gushing mudflow forms a cone-shaped hill on the surface, with a bottom diameter of more than 10 meters and cracked mud blocks on the surface.

Walk into the Dushanzi mud volcano and feel the charm of the mud volcano brought by the majestic geological movement.

Dushanzi Mud Volcano not only has a majestic body, but also has the blessing of Danxia landform. The colorful peaks and gurgling mud seem to give it breath and life. In this kingdom of Danxia landform, being in it is like walking into a fantasy foreign land.

The geological movement of the Dushanzi mud volcano also brought oil. The Dushanzi Oilfield is one of the earliest and largest oilfields in my country, and it also gave life to the energy city of Karamay. If you have friends traveling to Xinjiang, you can consider visiting the different scenery of the mud volcano!

Source: Chongqing Science and Technology Museum

Author: Yi Jingkun, majoring in geography at Southwest University.

Review experts: Huang He, Li Chunli, Chen Tao, Xu Xiaoping

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