China’s Arctic Expedition Maps 25 Million Years of Seabed
China’s 16th Arctic Ocean expedition has completed a geophysical survey of the eastern Gakkel Ridge, obtaining for the first time a continuous record of lithospheric evolution spanning 25 million years along one of the world’s slowest-spreading mid-ocean ridges, according to Xinhua News Agency, reporting from aboard the icebreaker Xuelong 2 on 25 September 2026.
The survey, announced as a “series of breakthrough progress and new discoveries,” marks a significant step in China’s expanding polar research program and adds a rare long-timescale dataset to one of the least-understood regions of the global ridge system.
The Breakthrough at the Gakkel Ridge
Mid-ocean ridges are the birthplace of new oceanic crust, where molten material rises to form fresh seafloor that then spreads outward. The spreading rate measures how quickly new crust forms and separates on each side. The Gakkel Ridge, stretching under the Arctic Ocean, is among the slowest-spreading ridges on Earth, with a full spreading rate of less than 20 millimetres per year.
That slowness is precisely what makes it scientifically valuable. Because the ridge spreads so gradually, a comparatively short survey line can capture an unusually long stretch of geological history. The expedition’s survey line ran 100 kilometres and recorded roughly 25 million years of lithospheric evolution, the news agency reported.
“The results of this observation of the eastern Gakkel Ridge show that the morphological evolution of the relevant lithosphere is significantly faster than traditional model predictions,” said expedition team member Jiang Jie.
A Decade of Chinese-Led Ridge Research
The survey is part of the China-led Arctic Mid-Ocean Ridge International Joint Expedition Plan, known as JASMInE, which China launched in 2021 during its 12th Arctic scientific expedition. Through continuous multi-voyage surveys, the program has proposed a new dynamic mechanism for the formation of globally typical ultra-slow-spreading mid-ocean ridges.
The 16th expedition’s findings build on an earlier landmark study. In August 2024, the journal Nature published research led by Li Jiabiao, an academician of the Chinese Academy of Engineering at the Second Institute of Oceanography under the Ministry of Natural Resources, which found that magma activity at ultra-slow-spreading ridges varies extremely strongly, with crust up to 9,000 metres thick in some areas. That result overturned the long-held view that such ridges are “extremely magma-poor,” according to a report in China Science Daily.
The 2024 work also proposed that global ridge systems are governed by a dual mechanism of active and passive mantle upwelling — a theory that challenges classical models of ocean-crust accretion and suggests the extremely variable, locally voluminous magmatism seen at the Gakkel Ridge may be the rule rather than the exception.
New Tools for Harsh Ice Conditions
A major part of the expedition’s significance lies in the technology it demonstrated. To overcome the technical bottleneck of geophysical operations in high-latitude, dense-ice areas, China developed domestically manufactured equipment — including strongly-coupled ocean-bottom seismometers and long-period ocean-bottom electromagnetic instruments — and conducted large-scale demonstration applications in the Arctic Ocean for the first time.
“The successful implementation of the survey marks a leap forward in China’s technical capability to carry out joint seabed seismic and electromagnetic detection in high-latitude dense-ice areas of the Arctic,” said Shen Zhongyan, head of the Xuelong 2 geophysics group.
Hints of Hidden Hydrothermal Fields
Beyond the geological survey, the expedition carried out full-profile CTD hydrological observations at five stations on the eastern Gakkel Ridge. The team found significant and large-scale temperature inversion phenomena at every station, a pattern suggesting that large hydrothermal fields may exist in the area — or that the observation sites lie close to seabed hydrothermal discharge points.
“This observation filled a gap in in-situ hydrological observations of this region, providing on-site observational evidence for finding large submarine hydrothermal fields and studying ridge structure-fluid interactions,” said Chen Hongxia, captain of the Xuelong 2 ocean team. The data, she added, will help researchers better explore the development mechanism of hydrothermal activity in ultra-slow-spreading mid-ocean ridges.
An Expedition Four Ships Strong
The 16th Arctic expedition set sail from Dalian in Liaoning Province on 3 July 2026, organized by the Ministry of Natural Resources. It is China’s first Arctic expedition in the opening year of the 15th Five-Year Plan and is expected to conclude in early October, according to Liaoning Daily.
Four vessels are taking part: the icebreakers Xuelong and Xuelong 2, the North China Sea Bureau’s Jidi, and the research vessel Tansuo 3. The mission focuses on global climate change and its impacts, exploring frontier questions including the Gakkel Ridge accretion mechanism and the dynamic evolution of oceanic crust, while conducting collaborative operations with scientists from Russia, Germany and other countries.
“Currently, driven by global warming, the Arctic natural ecological environment is undergoing rapid and profound changes, with trends such as sea ice melting intensifying,” said Wang Jinhui, leader of the 16th Arctic Scientific Expedition. “Continuing to carry out comprehensive Arctic expeditions is an important basic support for responding to global climate change and promoting sustainable development in the Arctic region.”
Why It Matters
Jiang Jie framed the broader stakes of the work in terms of fundamental Earth science and the Arctic system as a whole. “Continued research on the Arctic mid-ocean ridge helps reveal the deep dynamic mechanisms of plate tectonic movement,” he said. “In addition, mid-ocean ridges are gathering places for material and energy exchange; related research will help us better understand the evolution characteristics of Arctic Ocean currents, ecosystems, and element cycles.”
The Gakkel Ridge has long been considered one of the last pieces of the plate-boundary puzzle because its ice cover makes undersea seismic detection exceptionally difficult. The 2024 Nature study’s authors described the region as “the last puzzle piece” for observing plate-boundary dynamics, and noted that operations were conducted in waters with more than 80 percent ice cover and average working depths exceeding 3,500 metres.
What to Watch
The full scientific results of the 16th expedition have yet to be published in peer-reviewed form, and the announced findings remain subject to independent scrutiny. The expedition is scheduled to wrap up in early October, with further analysis of the Gakkel Ridge dataset expected afterward.
For now, the survey adds a substantial new record to an area where data has been scarce, and it reinforces a shift in thinking about how the slowest-spreading ridges on the planet actually behave — a question whose answer could reshape models of how Earth’s crust is built.