The recent discovery by Chinese researchers of the formation of global seamounts through a self-developed model has sparked intriguing insights into the geological processes shaping our planet. This breakthrough challenges conventional theories and opens up new avenues for understanding the Earth's complex dynamics.
The study, published in Nature Geoscience, reveals that the evolution of both linearly extending seamount chains and scattered isolated seamounts is intimately linked to the thermal activities of the asthenosphere. These activities are driven by the upwelling of mantle plumes from the core-mantle boundary, a phenomenon that has long been associated with the formation of hotspots.
However, the conventional hotspot hypothesis, which suggests that high-temperature mantle plumes trigger melting of rocks beneath drifting plates, has been questioned. Only a limited number of seamount chains, over 50, align with this hypothesis, creating a significant mismatch between the model and the actual distribution of seamounts.
This discrepancy raises a critical question: Are all seamounts formed by hotspots and mantle plumes? The answer lies in the researchers' innovative approach. By using a global data assimilation model, they replicated current mantle plume hotspot locations and asthenosphere thermal structure, predicting the spatiotemporal evolution of key hotspots like Hawaii.
In the Pacific region, the study highlights a fascinating process. During the early stage of mantle plume upwelling, hot plume material accumulates beneath the young Pacific plate, creating a broad thermal anomaly in the asthenosphere. This accumulation sets the stage for the formation of seamounts.
Furthermore, the researchers discovered that mantle plumes can split from the root within the lower mantle or the middle part of the mantle transition zone, generating secondary mantle plumes. This process increases the number of shallow hotspots and provides the conditions necessary for the formation of additional seamount chains.
Liu Lijun, a researcher at the Institute of Geology and Geophysics, Chinese Academy of Sciences, emphasizes the significance of this mechanism. It offers a unified framework for understanding the formation of intraplate seamounts worldwide, expanding the classical mantle plume hypothesis. The simulation, conducted on the Tianhe supercomputer, reinforces the team's findings.
This discovery not only challenges existing theories but also opens up new avenues for exploration. It prompts us to reconsider the role of mantle plumes in shaping our planet's geology. As we delve deeper into these findings, we may uncover even more fascinating insights into the Earth's dynamic processes.
