Magmatic evolution of the Andean Eastern Cordillera of Colombia during the Cretaceous: Influence of previous tectonic processes

作者：Vasquez Monica^*; Altenberger Uwe; Romer Rolf L; Sudo Masafumi; Manuel Moreno Murillo Juan

来源：Journal of South American Earth Sciences, 2010, 29(2): 171-186.

DOI：10.1016/j.jsames.2009.02.003

• Intraplate magmatism
• Cretaceous
• Extension
• Radiogenic isotopes
• Ar-dating
• Colombia

The Eastern Cordillera of the Colombian Andes represents an inverted Cretaceous basin where Cretaceous magmatism is characterized by rare mafic dykes and sills. We use (40)Ar/(39)Ar, Sr-Nd-Pb isotopes, as well as major and trace elements analyses of Cretaceous intrusions from both flanks of the Eastern Cordillera in combination with structural data to document the complex evolution of the basin. Magmatism, which is diachronous and geochemically diverse, seems to be related to mantle melting beneath the most subsiding segments of each sub-basin during enhanced extensional tectonics. The mafic intrusions display two different compositional series: an alkaline one with OIB-like pattern and a tholeiitic one with MORB-like features. This indicates at least two diverse mantle sources. Trace-element patterns suggest that the intrusions were emplaced in an extensional setting. (40)Ar/(39)Ar dating on primary plagioclase and hornblende provides plateau ages between similar to 136 and similar to 74 Ma.
The geochemical and temporal diversities show that the emplacement of the magmas was tectonically controlled, each sub-basin reflecting an individual subsidence event.

• 出版日期2010-3