Tectonically asymmetric Earth:From net rotation to polarized westward drift of the lithosphere

作     者：Carlo Doglioni Eugenio Carminati Mattia Crespi Marco Cuffaro Mattia Penati Federica Riguzzi 

作者机构：Dipartimento di Scienze della TerraSapienza Universita di Roma DITS-Area di Geodesia e GeomaticaSapienza Universita di Roma Istituto di Geologia Ambientale e GeoingegneriaCNR MOX-Dipartimento di MatematicaPolitecnico di Milano Istituto Nazionale di Geofisica e VulcanologiaSez.CNTRomeItaly 

出 版 物：《Geoscience Frontiers》 (地学前缘（英文版）)

年 卷 期：2015年第6卷第3期

页      面：401-418页

核心收录：

学科分类：070904[理学-构造地质学] 0709[理学-地质学] 07[理学] 

基　　金：Research supported by Sapienza University of Rome and Miur-Prin2011 

主　　题：Asymmetric plate tectonics Plate motions Westward drift Mantle convection 

摘      要：The possibility of a net rotation of the lithosphere with respect to the mantle is generally overlooked since it depends on the adopted mantle reference frames, which are arbitrary. We review the geological and geophysical signatures of plate boundaries, and show that they are markedly asymmetric worldwide. Then we compare available reference frames of plate motions relative to the mantle and discuss which is at best able to fit global tectonic data. Different assumptions about the depths of hotspot sources （below or within the asthenosphere, which decouples the lithosphere from the deep mantle） predict different rates of net rotation of the lithosphere relative to the mantle. The widely used no-net-rotation （NNR） reference frame, and low （〈0.2°-0.4°/Ma） net rotation rates （deep hotspots source） predict an average net rotation in which some plates move eastward relative to the mantle （e.g., Nazca）. With fast （〉1°/Ma） net rotation （shallow hotspots source）, all plates, albeit at different velocity, move westerly along a curved trajectory, with a tectonic equator tilted about 30° relative to the geographic equator. This is consistent with the observed global tectonic asymmetries.