资源环境科技发展态势分析平台

It has been proposed that hot spot tracks are caused by moving rigid plates above relatively stationary hot spots. However, the fixity of hot spots remains under debate. Here, we perform 3-D very high resolution (<25 km laterally) global mantle convection models with realistic convection vigor to investigate the lateral motion of mantle plumes. We find that the lateral motion of plumes beneath the Pacific plate is statistically similar to that beneath the Indo-Atlantic plates. In the past 80 Ma, the majority (>90%) of plumes move laterally with an average speed of 0-20 mm/year under the no-net-rotation reference frame, and there are a small portion (similar to 10-20%) of plumes whose lateral motion is less than 5 mm/year. The geodynamic modeling results are statistically in a good agreement with the hot spot motions in the last 5 Ma estimated from observation-based kinematic models. Our results suggest a small-to-moderate (0-20 mm/year) lateral motion of most plume-induced hot spots.

Plain Language Summary The intraplate volcanic islands on the Earth's surface often form progressively aged hot spot tracks. The hot spot tracks have been proposed to be caused by moving rigid plates above relatively stationary plumes. However, it remains unclear how fast mantle plumes move laterally. Here, very high resolution 3-D global mantle convection models are performed to quantify the lateral motions of all long-lived plumes. The models show that while the number, location, and lateral motion of individual plumes are rather model dependent, the majority (>90%) of plumes move laterally at a speed of 0-20 mm/year with only a small portion (similar to 10-20%) of plumes being relatively stationary with a lateral motion less than 5 mm/year. The lateral motions of Pacific plumes and Indo-Atlantic plumes are statistically similar. Importantly, the results of plume motions are statistically in an excellent agreement with the motions of observed hot spots. The results have important implications for understanding the formation of hot spot tracks and the dynamics of mantle plumes.