Close your eyes and imagine this place 260 millions years ago!.
You are on the bottom of an intra-continental sea with extinct animals swimming around you: fish, ammonites, coral, etc. Suddenly in this quiet underwater environment, lights appear, thick columns of smoke and air bublles begin to rise from the bottom of the sea towards the distant sea surface.Red lava with a 1,000-1,250°C temperature begins to rise from the depths of the earth and spread over the ocean floor...
Pillow basalt
You have just witnessed the birth of an underwater volcano! Submarine volcanoes exist also today in many parts of the Earth's oceans and are mainly located near areas of tectonic plate formation, known as mid-ocean ridges. 80 percent of the volcanic eruptions on Earth take place in the ocean. Most of these volcanoes are thousands of feet deep, and difficult to find.The pressure of the water stops submarine volcanoes from blowing their tops. Instead, they ooze basaltic, runny lava out like toothpaste being pushed out of a tube. As the volcano erupts, the lava is pushed out along the sea bottom. As there is a large difference in temperature between the lava and the water, the surface of the emergent tongue cools very quickly, forming a skin. The tongue continues to lengthen and inflate with more lava, forming a lobe, that resembles a pillow in shape until the pressure of more magma pushing forward becomes sufficient to rupture the skin and start the formation of a new pillow. Geologists call this formation “pillow lava” which is characteristic of submarine volcano activities. This “pillow lava” makes up the site in front of you which is today at an altitude of more than 300m and not anymore at the bottom of a deep ocean!
Cao Bang Geopark
