Effects of upper mantle wind on mantle plume morphology and hotspot track:Numerical modeling  

作　　者：Jie XIN Huai ZHANG Yaolin SHI Felipe ORELLANA-ROVIROSA 

机构地区：[1]College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China [2]Department of Ocean Science and Engineering,Southern University of Science and Technology,Shenzhen 518055,China [3]Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai),Zhuhai 519080,China [4]Beijing Yanshan Earth Critical Zone National Research Station,University of Chinese Academy of Sciences,Beijing 101408,China

出　　处：《Science China Earth Sciences》2024年第12期3881-3899,共19页中国科学（地球科学英文版）

基　　金：supported by the National Key Scientific and Technological Infrastructure project“Earth System Science Numerical Simulator Facility”(EarthLab);supported by the National Natural Science Foundation of China(Grant Nos.U2239205,41725017)。

摘　　要：A mantle thermal plume may be tilted,deflected,or even split-up by mantle lateral flows(mantle wind)during its ascent,which in turn changes the spatial distribution of various geological-magmatic responses,such as magmatic activity in the overriding plate and hotspot tracks on the surface,affecting the reliability of the constraints on absolute plate motion history.Previous research on tilted mantle plumes has focused mainly on the lower/whole mantle regions.Whether mantle plumes formed in whole/layered mantle convection suffer lateral tilt in the upper mantle,and how this affects the magmatic activity along the surface hotspot track as well as the plume-related tectonic processes,are important scientific issues in mantle thermalplume dynamics and plate tectonics theory.This study introduces a thermal Stokes-fluid-dynamics numerical model(in ASPECT software)and pyrolite parameters constrained by mineral physics data,and quantitatively analyzes the tilted/deflected morphology of upper-mantle plumes and the concomitant surface-hotspot location-evolution characteristics under the combined effects of overriding-plate-motion driven flow(Couette)and upper mantle counter-flow(Poiseuille).We find that this composite upper-mantle wind can lead to(1)Plume head-and-upper-conduit horizontal motion in the opposite direction of the overriding plate motion and also with respect to the conduit roots,such that the magmatic spacing is increased;(2)Near-periodic split-up and ascent of a laterally-moving plume conduit,whose split-up/ascent period depends mainly on the thermo-chemical buoyancy of the plume itself;and(3)Under specific conditions of thermo-chemical buoyancy of a main“parent”plume interacting with upper mantle winds,two secondary“child”plumes hundreds of kilometers apart can sprout and ascend sequentially/subsimultaneously through the upper mantle in a very short period of time(2–4 Myr).The resulting oscillating/jumping behavior of hotspot locations along the overriding plate motion direction can be used to ex

关 键 词：Hotspot track Mantle plume Upper mantle wind Absolute plate motion Plume-derived magmatism Numerical modeling 

分 类 号：P542.5[天文地球—构造地质学] P588.11[天文地球—地质学]