For many years now, some experts have suggested that the world is broken into more than just seven continents. Although there isn’t a universally accepted definition of a continent, Africa, Antarctica, Asia, Oceania, Europe, North America and South America have traditionally been considered as such. Since 2017, though, there have been strong claims that an eighth landmass has been overlooked by scientists for many years.
Continents are generally considered to be immense landmasses divided from one another by oceans. However, even this definition is problematic. You see, the majority of accepted continents aren’t totally detached from their neighbors at all – let alone by large expanses of water. Continents might better be described as predominately disconnected from one another, then, rather than wholly so.
In fact, Oceania and Antarctica are the only two of the traditionally accepted continents that are not connected to other landmasses. Meanwhile, North America and South America, for instance, are often considered to be two distinct continents – yet the two are joined by a thin section of territory known as the Isthmus of Panama.
That hasn’t always been the case, though. You see, North and South America were once divided from each other by waters called the Central American Seaway. Yet just under three million years ago, the emergence of the Isthmus of Panama saw the two landmasses join together. And this in turn led to increased biodiversity on both continents, as animals were subsequently able to travel between the two. This past migration is now known as the Great American Interchange.
The difficulties in defining a continent can thus be illustrated perfectly by North and South America. After all, while many think of the two entities as being separate, some people consider them as one continent referred to broadly as America. This second notion is popular in Latin American nations, in fact, as well as in European countries such as Portugal and Spain.
Europe is also difficult to define as a continent in its own right. It’s connected to Asia, and there aren’t any particular geographical divergences between the two. Taken together, then, this landmass is known as Eurasia.
Moreover, there’s a belief in some quarters that the idea of Europe as a single continent is the result of a Eurocentric view of the world. To support this argument, people point towards China and India – two considerable masses of land akin to the whole of Europe in terms of size. Yet only Europe is thought of as a continent in its own right – while India and China are not.
The boundaries defining continents can, then, be seen to be quite trivial from a geographical standpoint. And this is illustrated by the fact that some countries are considered transcontinental – that is, they are found on more than one continent. Examples of transcontinental nations that straddle both Europe and Asia are Russia, Georgia and Turkey.
Cultural and historic reasoning is, it would seem, significant in defining Europe and Asia as distinct continents. After all, they are each found on a single mass of land that isn’t divided by an ocean. And a section of people go even further than suggesting that Europe and Asia are one continent. Yes, there are some who claim that even Eurasia is an ill-considered definition.
You see, Asia is joined to Africa by the Isthmus of Suez. This section of land – which is 75 miles across – is found entirely in modern-day Egypt. As such, Egypt spans both Asia and Africa, meaning that it, too, can be defined as a transcontinental country.
The Isthmus of Suez, meanwhile, stands between the Mediterranean and the Red Sea; however, there is a water route connecting these two seas. The waterway in question is the Suez Canal, which was built between 1859 and 1869. Yet the canal is not sufficient to define Africa and Asia as separate landmasses, as canals are both small and manmade.
Given the connection between Asia and Africa by the Isthmus of Suez, then, it cannot be said that the two are entirely separate. Hence, some believe that we cannot then think of them as continents in their own right. And given Europe and Asia’s connection, the addition of Africa, too, makes for a monumental landmass.
Taken together, the landmass made up of Europe, Asia and Africa is called Afro-Eurasia. And it constitutes a considerable portion of the Earth too. Indeed, at almost 33 million square miles, Afro-Eurasia includes in excess of 50 percent of the planet’s land.
Moreover, if we take into consideration the numbers of people living on Afro-Eurasia, we can further see the significance of this landmass. Roughly speaking, some 6 billion human inhabitants can be found throughout its expanse. And this translates as approximately 86 percent of the overall population of Earth.
If Afro-Eurasia is taken as a single continent – and similarly North and South America are thought of simply as the American continent – then the traditional seven-continent standard becomes four. In this line of thinking, the world is split into the continents of America, Afro-Eurasia, Oceania and Antarctica.
It’s important, then, to understand how loose the criteria for defining continents can be. After all, this in turn can help to explain how the scientific community had for so long ignored the existence of what appears to be a continent in close proximity to Oceania. It also helps illustrate why this continent is yet to be universally accepted as such by experts within the field.
Primarily located underneath the Pacific Ocean, this particular mass of land has an approximate area of close to two million square miles. But it’s mostly found underwater. Around seven percent of the landmass sticks out from the ocean, though, and we might recognize one of these areas jutting out from the water as New Zealand.
In 1995 an American scientist by the name of Bruce Luyendyk decided to christen the landmass. He called it Zealandia. Luyendyk argued that the area is a continent in its own right – as opposed to a fragment of one or a microcontinent. However, for some time there was resistance to the American’s claim.
Indeed, it wasn’t until the publication of a research paper in 2017 that the notion of Zealandia as a continent really began to take hold. This study was presented in a journal called GSA Today – a publication from the Geographical Society of America – and argued strongly for the recognition of the continent of Zealandia.
“The identification of Zealandia as a geological continent, rather than a collection of continental islands, fragments and slices, more correctly represents the geology of this part of Earth,” the research paper reads. The paper’s authors argue that Zealandia actually sank beneath the ocean in the region of 70 million years ago. And they believe that this occurred after it split from Gondwana – an ancient supercontinent.
Like continents themselves, supercontinents are difficult to define – with various criteria in existence. However, they can generally be thought of as the unified landmasses of most of today’s continents. Gondwana was formed from what we might now recognize as Antarctica, Africa, Australia, India and South America. And it’s believed that this supercontinent divided around 100 million years before Zealandia sank beneath the waves.
What’s more, there have been a number of supercontinents throughout the history of the Earth. And they have, in fact, split up and reformed on numerous occasions over the course of millions of years. Among this collection of supercontinents, Pangaea is perhaps the most well known.
Today, Zealandia, for its part, is predominately underwater. However, some of the landmass sticks out above sea level in the form of New Zealand, the Lord Howe Island group, Norfolk Island, New Caledonia and the Elizabeth and Middleton reefs. As a whole, Zealandia boasts a similar expanse to that of the Indian subcontinent discussed earlier.
Nick Mortimer is one of the researchers who authored the paper published in GSA Today. And he believes that, even though Zealandia is found mostly underwater, it possesses enough of the characteristics needed to be thought of as a continent. As he told The Guardian in February 2017, “This is a big piece of ground we’re talking about, even if it is submerged.”
Mortimer also explained how he and his colleagues had come to conclude that Zealandia should be defined as a continent. He says that it goes back to 2002, when they first came across a bathymetric map of the area. Such maps display landmasses that have become submerged beneath water.
“That’s when the penny dropped, really,” Mortimer said. “From that point, that map was literally our road map for some crosses, just trying to get rocks out of all the four corners of Zealandia that we could, so we could prove up the geology.”
Mortimer and his fellow researchers believe that the prospect of a scientific consensus regarding Zealandia’s classification as a continent would be a positive development. Indeed, as the team pointed out in their research paper, this recognition could lead to some exciting geographical discoveries. And these in turn might result in a greater overall understanding of the Earth and the processes that formed it.
“The scientific value of classifying Zealandia as a continent is much more than just an extra name on a list,” the paper reads. “That a continent can be so submerged yet unfragmented makes it a useful and thought-provoking geodynamic end member in exploring the cohesion and breakup of continental crust.”
And understanding the processes at work in the planet’s continental crusts is also important for predicting the future of the Earth. By looking into the past of Zealandia, for instance, scientists can gather information that they are then able to apply to computer models. And from there, experts can attempt to forecast changes that are due to occur to the Earth.
However, the notion that Zealandia is a continent has, of course, been disputed by some. And yet given the vague and differing definitions of what actually constitutes a continent, this should probably come as no surprise. Christopher Scotese, a geologist from Northwestern University, is one such scientist who doesn’t accept the argument.
“My judgment is that though Zealandia is continental, it is not a continent,” Scotese told National Geographic in February 2017. “If it were emergent, we would readily identify it with [Oceania], much like we identify Greenland with North America and Madagascar with Africa.”
Many details about Zealandia also remain unclear. And yet since the release of the GSA Today research paper, there have been further investigations to help gain a better comprehension of the area. For instance, one large-scale study saw a multinational team drill through Zealandia’s seafloor.
The expedition in question took place in 2017 and involved a group of more than 30 experts from a dozen nations. Sailing on a ship called JOIDES Resolution, the scientists were at sea for over two months. The group was associated with the International Ocean Discovery Program (IODP), which seeks to examine the Earth’s past by analyzing materials found underneath the planet’s seabeds.
The team that were sent to Zealandia set about their work by drilling holes into the seafloor at six different locations. In an attempt to understand how the landmass has transformed over the course of millions of years, the experts amassed sediments from depths of in excess of 4,000 feet. And the researchers are confident that their work has culminated in positive results.
“More than 8,000 specimens were studied, and several hundred fossil species were identified,” the expedition’s co-chief, Gerald Dickens, explained to the U.S. National Science Foundation’s website in September 2017. “The discovery of microscopic shells of organisms that lived in warm shallow seas, and of spores and pollen from land plants, reveal that the geography and climate of Zealandia were dramatically different in the past.”
Scientists had previously asserted that Zealandia was underwater when it first split with Oceania and Antarctica. And the excursion’s other co-leader, Rupert Sutherland, has stated that this theory is probably correct. However, following the team’s investigations, it has become evident that other processes were also at play when it came to the way in which Zealandia was molded.
“Big geographic changes across northern Zealandia – which is about the same size as India – have implications for understanding questions such as how plants and animals dispersed and evolved in the South Pacific,” Sutherland explained. “The discovery of past land and shallow seas now provides an explanation. There were pathways for animals and plants to move along.”
Zealandia is geologically unusual, and many scientists believe its study is essential to gaining a more thorough understanding of the Earth’s continental crusts. Indeed, even some of those opposed to defining the landmass as a continent welcome analysis of the area.
“I appreciate the author’s attempt to change the definition of [a] continent, but definitions change slowly,” Scotese told National Geographic. “Consider the word ‘planet.’ Just as Pluto is almost a planet, Zealandia is almost a continent.”
This is actually an area where Scotese and the authors of the GSA Today study can agree. “If you want to name a mountain, there are certain procedures you have to go through to get it formally ratified. With this, it will just come with time,” Mortimer told The Guardian. “If Zealandia makes its way into popular culture and onto maps, that’s all the validation that we’ll seek.”