The Pacific Ocean stands out as the largest ocean on our planet. More than five times wider than our moon. What accounts for the vastness of the Pacific Ocean?
This ocean covers approximately 63 million square miles (163 million square kilometers) and comprises over 30% of the Earth’s surface, capable of accommodating all continents within the Pacific Basin, according to the National Oceanic and Atmospheric Administration (NOAA). The Pacific Ocean also contains more than half of the world’s free water and is home to the deepest areas of our planet, reaching over 36,000 feet (11,000 meters) deep, notably in the Mariana Trench, as highlighted by NOAA.
Historically, the Pacific Ocean derived from the ancient sea known as Pantalassa, which was the Earth’s sole sea at one time. This ocean existed during the time when the Earth’s continents were united as a supercontinent, Pangaea.
“Pantalassa was the proto-Pacific,” stated Suzanne Neuer, founding director of the Maritime Futures School at Arizona State University, in an interview with Live Science. “The Pacific Ocean essentially represents the remnants of Pantalassa.”
It spans the seas and continents of both the past and present, dictated by the movements of tectonic plates, enormous rock slabs forming the Earth’s surface. These plates are constantly shifting, sometimes colliding, and at other times separating. Approximately 230 million years ago, such movements initiated the rifting of Pangaea.
“North America and Eurasia started to drift apart from what would become South America and Africa, along with Antarctica and Australia,” explained Adrian Lamb, an assistant professor of geoscience at Binghamton University, to Live Science.
Related: Do the Pacific and Atlantic Oceans mix?
Eventually, Pangaea fragmented, giving rise to the Atlantic Ocean as gaps appeared between the continents. “The Atlantic Ocean expands by about 2-3 centimeters, or roughly an inch per year,” noted Neuer. “While that seems minimal, over millions of years, it accumulates significantly.”
Pantalassa shrunk as the continents that formed Pangaea drifted apart. In a subduction zone, when these continental plates slid over the oceanic plates of Pantalassa, it resulted in the formation of a “Ring of Fire,” an area renowned for its volcanic activity and earthquakes, as explained by Neuer.
A study conducted in 2016 published in Science Advances indicated that approximately 200 million years ago, the Pacific Plate—responsible for underlining the Pacific Ocean—originated at the intersection of three tectonic plates under Pantalassa: Faralon, Phoenix, and Izanagi.
“Today’s closest comparisons to what transpired in the Pacific Ocean can be observed at a distant triple junction in East Africa, where the Nubian, Somali, and Arabian plates meet,” said Lamb. “However, at the East African junction, these plates haven’t managed to separate. The triple junction in the Pacific Ocean successfully formed these three plates into the Pacific Plate.”
As the Pacific Plate expanded, the older plates were displaced. The Izanagi plate was pushed beneath Asia, while much of the Faralon Plate was subducted beneath North America, leaving remnants off the west coast. “The Phoenix Plate remains a small segment between the southern tip of South America and the Antarctic Peninsula, known as the Drake Passage,” explained Rum.
While the Pacific Ocean holds the title of the largest ocean globally, as the Atlantic Ocean expands, it also “shrinks,” according to Lamb. Nonetheless, the Atlantic Ocean, spanning 41 million square miles (106 million square kilometers), remains significantly smaller than the Pacific. Furthermore, projections from modeling research predict the Atlantic will begin to decrease in size in approximately 20 million years.
For Lamb, the Pacific remains unmatched, stating, “The Pacific Ocean is the most extraordinary ocean basin of all.”
Source: www.livescience.com