BEIJING – Using a self-developed model, Chinese scientists have discovered the origin of global seamounts and recreated their subduction history over the past 270 million years.
According to their study published in the journal Nature Geoscience, the formation and evolution of both linearly extending seamount chains and scattered isolated seamounts are closely linked to asthenosphere thermal activities driven by the uplift of mantle plumes from the core-mantle boundary.
Latest surveys reveal that there are more than 40,000 seamounts in almost every ocean basin, randomly scattered throughout the world’s ocean plates.
Read also: Nature Index: China is the world’s largest contributor to high-quality research
The traditional hotspot hypothesis suggests that high-temperature mantle plumes originating from the top of the Earth’s core trigger the melting of rocks beneath the drifting plates, thus forming long chains of submarine volcanoes in areas such as the Hawaiian Islands.
However, only a limited number of seamount ranges, more than 50 of them, echo this hypothesis. This reveals a significant mismatch between the hotspot model and the actual quantity, size and spatial distribution of global seamounts.
This raises a crucial question: Do all seamounts originate from hotspots and mantle plumes? If so, how can so few hotspots produce so many seamounts scattered around the world?
Read more: Chinese astronomers have discovered evidence linked to the star clusters in Andromeda’s halo
The researchers used a global data assimilation model to replicate the hotspot locations of present-day mantle plumes and the thermal structure of the asthenosphere. They also predicted the spatiotemporal evolution of major hotspots such as Hawaii and their corresponding deep mantle plumes.
In the Pacific, for example, during the early phase of mantle plume ascent, a large amount of hot plume material accumulated beneath the emerging Pacific plate, creating a broad thermal anomaly in the asthenosphere, according to the study.
During subsequent evolution, mantle plumes can detach from the root within the lower mantle or the middle part of the mantle transition zone, generating secondary mantle plumes. This increased the number of shallow hotspots and provided the conditions for the formation of additional seamount ranges.
Liu Lijun, a researcher at the Institute of Geology and Geophysics of the Chinese Academy of Sciences, said this mechanism provides a unified framework for the formation of seamounts within plates around the world, greatly expanding the classical mantle plume hypothesis.
The simulation was conducted on the new generation of the Tianhe supercomputer at the National Supercomputer Center in Tianjin, northern China.
