کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4692200 1636784 2013 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Insights into extensional events in the Betic Cordilleras, southern Spain: New fission-track and U–Pb SHRIMP analyses
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات فرآیندهای سطح زمین
پیش نمایش صفحه اول مقاله
Insights into extensional events in the Betic Cordilleras, southern Spain: New fission-track and U–Pb SHRIMP analyses
چکیده انگلیسی


• Extensional tectonics in the Betic Cordilleras has been dated.
• Two periods of extension of Oligocene and Miocene ages are identified.
• Dolerite dykes, related to lithospheric delamination, intruded in Oligocene time.
• A time span of 10 m.y. between the chain's collapse and the HT metamorphism is fixed.

A combination of the U–Pb SHRIMP and zircon fission-track analyses has been used to constrain the age and evolution of the extensional tectonics in the Betic Cordilleras, southern Spain. The studied rocks are dolerite dykes intruded in the Malaguide Complex and in the underlying Los Reales nappe and their country rocks. The dykes are grouped in two nearly perpendicular systems, characterized by N–S strikes in the Los Reales nappe and E–W strikes in the Malaguide Complex. Two periods of extension have been identified. The age of the older event, ranging from ~ 33 to 25 Ma, is constrained by the intrusion of the dykes (33 Ma) and the joint cooling of the Los Reales–Malaguide domain from 25 Ma onwards. This event is associated with the structural emplacement of the Malaguide Complex over the Los Reales nappe, along a brittle–ductile extensional detachment and is tentatively ascribed to the tectonic collapse of the orogenic belt. A minimum time span of 10 m.y. is established between the onset of the extensional collapse and the widespread Aquitanian HT-LP metamorphism. In the present geographic frame, the kinematics of this event is characterized by a change from an E–W extension at lower levels (Los Reales nappe) to a N–S extension in upper levels (Malaguide Complex). A younger extensional event of Miocene age (~ 18 Ma) has been deduced based on the fission-track analysis within the “calizas alabeadas” member of the Malaguide Complex.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Tectonophysics - Volume 603, 9 September 2013, Pages 179–188
نویسندگان
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