Zealandia, the eighth continent of Earth, was mostly submerged beneath the sea. A dedicated team of international geologists and seismologists has meticulously crafted an updated map of Zealandia, utilising invaluable data extracted from dredged rock samples recovered from the ocean floor.
Their comprehensive findings have been published in the journal Tectonics, shedding profound insights into the distinctive geological history of Zealandia.
Zealandia was once a component of the ancient supercontinent Gondwana, which emerged approximately 550 million years ago, encompassing all the landmasses in the southern hemisphere.
Key Findings
- Studies indicate that about 83 million years ago, geological forces divided the supercontinent Gondwana. This event led to the formation of the continents we see today.
- The division also resulted in the creation of Zealandia, another continent that is currently submerged under the ocean.
- Zealandia is estimated to be 94% underwater, while the remaining 6% forms what we know as New Zealand and nearby islands.
- The recently enhanced map not only displays the position of the magmatic arc axis of the Zealandia continent but also highlights other significant geological features.
- Zealandia, an underwater continent, is not as thoroughly researched as other continents due to its submerged state.
- This leads to uncertainties about its shape and structure.
- A group of researchers aimed to improve Zealandia’s maps in this recent study.
- Their method involved examining rock and sediment samples collected from the ocean floor.
- Most of these samples were obtained from drill sites.
- Some samples were also gathered from island shores in Zealandia’s vicinity.
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‘Campbell Fault’ Did Not Happen
The authors challenge the notion of a strike-slip ‘Campbell Fault’ and assert that both Zealandia and Antarctica experienced significant internal deformation. They suggest that the Campbell Magnetic Anomaly System emerged from extensive stretching between segments of Gondwana, ultimately giving rise to the seafloors surrounding Zealandia.
- Zealandia, mostly underwater, has remained largely unexplored, leading to many uncertainties about its structure.
- An international team of geologists and seismologists collected and analysed rock and sediment samples from the ocean floor and coastal islands to enhance our understanding of the eighth continent.
- They also analysed seismic data, leading to the creation of a more detailed map of this hidden continent, totalling 5 Mkm2 in size.
- Their study revealed geologic patterns suggesting a subduction zone near the Campbell Plateau, off the western coast of New Zealand.
- Previous theories of strike-slip faults were challenged as no magnetic anomalies were found in this region.
- The team suggests that the Campbell Magnetic Anomaly System was actually formed due to the stretching of Gondwana during its separation, leading to the creation of Zealandia’s lower oceanic parts.
- Chemical composition analysis and geological indicators hint that the hidden continent’s edge was pushed beneath the Campbell Plateau up to 250 million years ago, a process known as subduction.
- Interestingly, the magnetic anomalies in the region are not linked to this subduction event.