What are missing continents, and are we finding so many?
Continents are Earth’s seven primary landmasses that are large.
However, geoscientists have another take on this. They consider the type of rock a feature is made of, rather than much of its surface is above sea level. In the discovery of continents, we’ve noticed an increase in the past few decades. Most of them have been mountains or plateaus made from crust hidden under sea level, from our perspective.
1 instance is Zealandia, the world continent which extends underwater from New Zealand. Many smaller continents, known as microcontinents, have also recently been found submerged in the eastern and western Indian Ocean. But why, with so much geographic knowledge at our hands, are we still discovering lost continents at the 21st century?
To the research vessel RV Investigator, we undertook a voyage in August to explore a potential lost continent at a remote portion of the Coral Sea. The region is home to some large underwater plateau Queensland, called the Louisiade Plateau, which represents a major gap in our knowledge of Australia’s geology. It could be a continent which broke away from Queensland. Or it could have formed because of a massive volcanic eruption taking place around the same time. We’re not sure, since nobody had recovered stones from there until – until today.
Lab work during the next few years will provide us answers that are certain.
There are mountains and plateaus below sea level scattered across the seas, and these have been mapped from distance. They are. Not all of features that are submerged qualify as lost continents. Most are made from materials different from what we normally think of continental stone, and are formed by enormous outpourings of magma.
A fantastic example is Iceland which, despite being the size of the North Island of New Zealand, is not regarded as continental. It is made up of rocks deposited meaning it’s relatively young in geological terms.
Finding the samples is challenging, to say the least. A lot of the seafloor is covered in soft, gloopy sediment that obscures the solid rock beneath. We utilize a sophisticated mapping system to look for slopes around the seafloor, that are inclined to be free of sediment. Then we send samples to be grabbed by a metallic rock-collecting bucket. The more we sample the oceans’ depths and explore, the more likely we will be to find continents.