Zealandia: What is the Interest of Having a New Continent?

The purpose of the research paper published in the Journal of the Geological Society of America (GSA Today), with a broad readership, was to propose a name for a “new” continent: Zealandia. The fact that a new continent could have been “discovered” undoubtedly explains the fact that this scientific research has gone beyond the realm of specialized journals and been picked up by general public opinion.

Specifically, the paper proves the existence of a large area in southeast Australia with the following characteristics:

  • An elevated bathymetry (shallow water layer)
  • A rock composition with a high content in SiO2 and low seismic wave speeds.
  • From the geological standpoint, there are two types of crust: oceanic and continental.
  • The outermost shell of the earth, known as the lithosphere, is divided into 14 large sections or lithospheric plates that include oceanic and/or continental crust.

All this has been known for over 50 years, and in this time great strides have been made in our knowledge of the processes occurring at the limits between the plates, the transition between the continental and oceanic crust, and the mechanisms causing continents to open up and new oceanic crust to form ( known as “rifting”).

In this article, the authors describe the data that confirm the continental nature of the crust in the proposed area, and give an idea of its dimensions (4.9 km2), large enough to be considered an independent continent rather than a micro-continent or a fragment of a continent. The authors themselves admit that this is not a sudden discovery, but a gradual process made possible by the acquisition of accumulated data, particularly over the last ten years. The proposal is that the scientific community should refer to Zealandia as a continent.

Why the interest in defining a new continent? The key lies in sovereignty

The question that immediately comes to mind is why this designation is necessary. This classification is important for numerous fields of natural science. Most of the data supplied by the article’s authors come from works of marine geology and geophysics conducted in the last ten years, within the work submitted to the UN’s Commission on the Limits of the Continental Shelf (known by its initials CLCS).

Defining a new continent would imply expanding the dominance of certain states beyond its emerging territory / Image: Pixabay

Defining a new continent would imply expanding the sovereinty of certain states beyond its emerging territory / Image: Pixabay

The geological limits between the continental and oceanic crust–although sometimes indistinct–are based on well-defined geological (technical) criteria. However, the designation of “continent” depends on other criteria. The term “continent” tends to be geographic, and basically refers to “each of the large extensions of land separated by oceans”. This geographic definition can be modified by historical or cultural criteria: from the purely geographic point of view, Eurasia is a continent, although some authors separate Europe and Asia based on historic and cultural criteria. The reason for the importance surrounding the application of the term “continent” concerns the interest of many states in expanding their domains beyond their emerged territory. To understand this aspect, we need to take another look at how states’ sovereignty extends beyond their coastlines, without losing sight of the fact that 75% of the planet is covered by seas and oceans.

The legal question: the law of the sea

States progressively lose their sovereignty from their coastline toward the open sea, and this sovereignty is ceded to all the countries of the world, as decreed by the United Nations Convention on the Law of the Sea. The following zones are defined from the coastline toward the open sea:


Diagram of the different areas of sovereignty in the seas and oceans regulated by the Law of the Sea (United Nations). Source: Ministry of Defense

  • Territorial sea: from the straight baselines (joining the capes, approximately) up to 12 miles. States have rights of sovereignty over its airspace, waters, the seabed and marine subsoil.
  • Exclusive Economic Zone: From 12 miles to 200 miles. States have rights of sovereignty for the exploration and exploitation, conservation and administration of natural resources, both living and nonliving, in the waters, the seabed and the marine subsoil. These two zones are common to all coastal states, and their limit is the presence opposite its coasts of another state, when the Exclusive Economic Zone is then limited to the “equidistance between the baselines”.
  • Continental shelf. The sovereignty of a state can be extended beyond 200 miles to a maximum of 350 miles, to what is known as the “continental shelf”. In this zone the state has sovereignty rights for the exploration and exploitation of natural resources, both living (sedentary species) and nonliving, in the seabed and marine subsoil. In this case there is a payment for exploitation beyond 200 miles.
  • The zone. The limit of the shelf marks the start of the zone of international waters (United Nations).

To request the extension of their sovereignty beyond 200 miles, states must submit information on the limits of “their” continental shelf beyond 200 marine miles to the Commission on the Limits of the Continental Shelf. This documentation is examined by the Commission in the UN, which is formed by 21 technicians chosen for five years by the member states of the Convention, and specializing in geology, geophysics and hydrography, to guarantee a fair geographic representation and technical capability. The scientific and technical data were established in 1999 (CLCS/11).

Once the documentation has been submitted, the Commission issues recommendations to the coastal states with regard to the determination of the outer limits of their continental shelf. The limits of the shelf ultimately determined by a coastal state based on these recommendations are definitive and obligatory.

Political and economic repercussions

The political and economic repercussions of extending the continental shelf are enormous, particularly in regard to prospecting for hydrocarbons and mineral resources. As an example, we need look no further than the so-called “war for control of the Arctic” between the coastal nations (Russia, US, Canada, Denmark, Norway), which has been exacerbated by the gradual merging of the polar ice cap, and is primarily driven by the vast estimates of oil and gas reserves.

 Límites espaciales propuestos para el 'nuevo continente' Zelandia (modificado de Mortimer et al., 2017, doi: 10.1130/GSATG321A.1). NC, Nueva Caledonia; WTP, Meseta de Torres del Oeste; CT, Fosa de Cato; Cf, Islas Chesterfield; L-Isla de Lord-Howe; N Isla de Norfolk; K, Islas Kermadec; Ch, Islas Chatham; B, Islas Bounty; An, Islas Antípodas; Au, Islas Auckland; Ca, Isla de Campbell. Proyección Mercator

Spatial limits proposed for the “new continent” of Zealandia (modified from Mortimer et al., 2017, doi: 10.1130/GSATG321A.1). Mercator Projection

Whether an underwater mountain range is described as “continental” or “oceanic” therefore has a huge repercussion, as this classification implies the possibility of using a criterion such as that of 100 miles from the line of the 2500 m isobath. If this criterion were to be applied to an oceanic state like Iceland, it could extend its domains over vast areas along its oceanic mountain ranges.

In conclusion, there is no doubt that the use of the term “continent” or the adjective “continental” cannot not be applied lightly. It is not surprising that New Zealand is seeking to have this term accepted by the international community so it can be considered a “continent”. A glance at the map in this text shows that if New Zealand is not considered an archipelago state, it can obtain an extension of its continental shelf beyond the equidistance with Australia or New Caledonia. This increase in its sovereignty definitely has far-reaching political and economic ramifications that justify its efforts to seek the adoption of a nomenclature based on the scientific data that have been in the public domain for decades. However, this claim will not alter the fact that New Zealand is not a continent in geographic, historic and cultural terms, despite that fact it has a continental crust from a geological point of view.

Find the full and original article in the website of the Foundation madri+d

Dr. Alfonso Muñoz Martín
Full Professor in the Department of Geodynamics of the Faculty of Geological Sciences of the UCM