Chinese scientists have made a groundbreaking discovery in understanding the formation of global seamounts, challenging long-held beliefs about their origin. Using a self-developed model, they have not only identified the source of these underwater mountains but also traced the subduction history of the past 270 million years. This research, published in the prestigious journal Nature Geoscience, sheds light on the intricate relationship between the Earth's mantle and the creation of seamounts.
The study reveals that the formation of both linearly extending seamount chains and scattered isolated seamounts is closely tied to the thermal activities of the asthenosphere. These activities are driven by the upwelling of mantle plumes from the core-mantle boundary. This finding challenges the conventional hotspot hypothesis, which suggests that high-temperature mantle plumes trigger melting of rocks beneath drifting plates, forming long chains of submarine volcanoes.
While the hotspot hypothesis explains the formation of some seamount chains, such as the Hawaiian Islands, it falls short when considering the vast number and diverse distribution of seamounts worldwide. Over 40,000 seamounts are scattered across nearly every ocean basin, and only a limited number of seamount chains align with the hotspot model. This discrepancy raises a critical question: Do all seamounts originate from hotspots and mantle plumes?
To address this, researchers developed a global data assimilation model to replicate current mantle plume hotspot locations and asthenosphere thermal structure. They predicted the spatiotemporal evolution of key hotspots like Hawaii and their corresponding deep mantle plumes. In the Pacific region, for instance, the study reveals that during the early stage of mantle plume upwelling, a large volume of hot plume material accumulated beneath the young Pacific plate, creating a broad thermal anomaly in the asthenosphere.
As the mantle plumes evolved, they could split from the root within the lower mantle or the middle part of the mantle transition zone, generating secondary mantle plumes. This process increased the number of shallow hotspots and provided conditions for the formation of additional seamount chains. This mechanism offers a unified framework for the formation of intraplate seamounts worldwide, substantially expanding the classical mantle plume hypothesis.
The implications of this research are far-reaching. It not only provides a new understanding of the formation of seamounts but also challenges existing geological models. It raises questions about the role of mantle plumes in shaping the Earth's surface and the potential for additional mechanisms contributing to seamount formation. Furthermore, it highlights the importance of advanced modeling techniques in unraveling complex geological processes.
In my opinion, this study is a significant step forward in our understanding of the Earth's geological history. It demonstrates the power of scientific inquiry to challenge established theories and uncover new insights. The use of advanced modeling techniques and the collaboration between Chinese scientists and international journals like Nature Geoscience showcase the potential for global scientific cooperation. As we continue to explore the mysteries of our planet, such groundbreaking discoveries will undoubtedly shape our understanding of the Earth's past and present.
