The westward lithospheric drift,its role on the subduction and transform zones surrounding Americas:Andean to cordilleran orogenic types cyclicity  

作　　者：Eugenio Aragon Fernando D'Eramo Marco Cuffaro Carlo Doglioni Eleonora Ficini Lucio Pinotti Silvina Nacif Manuel Demartis Irene Hernando Tomas Fuentes 

机构地区：[1]Centro de Investigaciones Geologicas,Universidad Nacional de La Plata,Argentina [2]Instituto de Ciencias de La Tierra,Biodiversidad y Ambiente(ICBIA).Departamento de Geología,Universidad Nacional de Río Cuarto(UNRC-CONICET),Ruta 36 Km 601,Río Cuarto,Cordoba,Argentina [3]Istituto Geologia Ambientale e Geoingegneria-CNR,Italy [4]Dipartimento de Scienzedella Terra,Universita La Sapienza,Italy [5]Instituto Geofísico Sismologico F.Volponi,Universidad Nacional de San Juan,Argentina

出　　处：《Geoscience Frontiers》2020年第4期1219-1229,共11页地学前缘（英文版）

摘　　要：We investigate the effect of the westerly rotation of the lithosphere on the active margins that surround the Americas and find good correlations between the inferred easterly-directed mantle counterflow and the main structural grain and kinematics of the Andes and Sandwich arc slabs.In the Andes,the subduction zone is shallow and with low dip,because the mantle flow sustains the slab;the subduction hinge converges relative to the upper plate and generates an uplifting doubly verging orogen.The Sandwich Arc is generated by a westerly-directed SAM(South American) plate subduction where the eastward mantle flow is steepening and retreating the subduction zone.In this context,the slab hinge is retreating relative to the upper plate,generating the backarc basin and a low bathymetry single-verging accretionary prism.In Central America,the Caribbean plate presents a more complex scenario:(a) To the East,the Antilles Arc is generated by westerly directed subduction of the SAM plate,where the eastward mantle flow is steepening and retreating the subduction zone.(b) To the West,the Middle America Trench and Arc are generated by the easterly-directed subduction of the Cocos plate,where the shallow subduction caused by eastward mantle flow in its northern segment gradually steepens to the southern segment as it is infered by the preexisting westerly-directed subduction of the Caribbean Plateau.In the frame of the westerly lithospheric flow,the subduction of a divergent active ridge plays the role of introducing a change in the oceanic/continental plate’s convergence angle,such as in NAM(North American)plate with the collision with the Pacific/Farallon active ridge in the Neogene(Cordilleran orogenic type scenario).The easterly mantle drift sustains strong plate coupling along NAM,showing at Juan de Fuca easterly subducting microplate that the subduction hinge advances relative to the upper plate.This lower/upper plate convergence coupling also applies along strike to the neighbor continental strike slip fault systems wher

关 键 词：Lithospheric drift Converging hinge Diverging hinge Slab rollbakc TERRANES 

分 类 号：P542[天文地球—构造地质学]