检索结果-南通市图书馆

The Farallon-Aluk ridge collision with South America:Implications for the geochemical changes of slab window magmas from fore- to back-arc

引用

Geoscience Frontiers 2013年第4期4卷 377-388页

作者： Eugenio Aragón Lucio Pinotti Fernando D'Eramo Antonio Castro Osvaldo Rabbia Jorge Coniglio Manuel Demartis Irene Hernando Claudia E.Cavarozzi Yolanda E.Aguilera Centro de Investigaciones Geologicas(UNLP-CONICET) 1 N°644(1900) La Plata.Buenos Aires.Argentina Facultad de Ciencias Naturales y Museo Universidad Nacional de la Plata122 y 60s/n.(1900).La PlataBuenos AiresArgentina Departamento de Geologia.Universidad Nacional de Rio Cuarto.(UNRC-CONICET).Ruta 36 km 601.Rio Cuarto.Cordoba.Argentina Departamento de Geologia.Universidad de Huelva.21071 Huelva.Spain Instituto de Geologia Economica Aplicada.Universidad de Concepcion.Concepcion.Chile Departamento de Geologia.Universidad Nacional de Rio Cuarto.(UNRC-CONICET) Ruta 36 km 601.Rio Cuarto.CordobaArgentina Centro de Investigaciones Geologicas(UNLP-CONICET).1 N°644.(1900) La Plata.Buenos Aires.Argentina Facultad de Ciencias Naturales y Museo.Universidad Nacional de la Plata.122 y 60 s/n.(1900).La PlataBuenos Aires.Argentina Facultad de Ciencias Naturales y Museo.Universidad National dela Plata.122 y 60 s/n(1900)La Plata.Buenos Aires.Argentina Direccion de Aplicacion de Imagenes Satelitarias(M.O.S.P.).58 e/ 7 y 8.piso 2.1900 La Plata.Buenos Aires.Argentina

The collision of a divergent ocean ridge may evolve into two end cases： in the continuity of ocean-floor subduction, or in the detachment of the subducted plate. The northern Patagonia active plate margin has the unique situation that in Cenozoic time it has been subjected to two divergent ridge collisions, each one representing one of the end members. The Neogene Antarctica-Nazca divergent ridge collision evolved as a continuous ocean-floor subduction system, promoting a magmatic hiatus at the arc axis, the obduction of part of the ridge ocean-floor in the fore-arc, and basaltic volcanism in the back-arc. In contrast, the Paleogene Farallon-Aluk divergent ridge collision evolved into a transform margin, with the detachment and sinking of the Aluk plate and the development of a large slab window. As in the previous case, this collision promoted a magmatic hiatus at the arc axis, but the tectono-magmatic scenario changed to postorogenic synextensional volcanism that spread to the former fore-arc （basalt, andesite, rhyolite） and former back-arc （bimodal ignimbrite flare-up, basalt）. Geochemistry of this slab window synextensional volcanism shows more MORB-like basalts towards the former fore-arc, and MORB-OIB-Iike basalts towards the former back-arc. Instead, an isolated undeformable crustal block in the former back-arc, with an ＂epeirogenic＂ response to the slab window and extensional regime, was covered by OIB-type basalts after uplift. Major elements show that slab window basalts reach TiO2 values up to 3 wt%, as compared with the top value of 1.5 wt% of arc magmas. Besides, the MgO with respect to （FeOt ＋ A1203） ratio helps to distinguish slab window magma changes from the former fore-arc to the former back-arc and also with respect to the ＂epeirogenic＂ block. Higher contents of HFS elements such as Nb and Ta also help to distinguish this slab window from arc magmas and also, to distinguish slab window magma changes from the former fore-arc to the former back-arc and ＂epeirogenic＂ block settings. The isotope co

关键词： andesactive ridge collisionsubduction-transform transitionslab window volcanismsynextensional calc-alkalinebimodal volcanism

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：