Carbonatite ring-complexes explained by caldera-style volcanism

نویسندگان

  • Magnus Andersson
  • Alireza Malehmir
  • Valentin R. Troll
  • Mahdieh Dehghannejad
  • Christopher Juhlin
  • Maria Ask
چکیده

Carbonatites are rare, carbonate-rich magmatic rocks that make up a minute portion of the crust only, yet they are of great relevance for our understanding of crustal and mantle processes. Although they occur in all continents and from Archaean to present, the deeper plumbing system of carbonatite ring-complexes is usually poorly constrained. Here, we show that carbonatite ring-complexes can be explained by caldera-style volcanism. Our geophysical investigation of the Alnö carbonatite ring-complex in central Sweden identifies a solidified saucer-shaped magma chamber at ~3 km depth that links to surface exposures through a ring fault system. Caldera subsidence during final stages of activity caused carbonatite eruptions north of the main complex, providing the crucial element to connect plutonic and eruptive features of carbonatite magmatism. The way carbonatite magmas are stored, transported and erupt at the surface is thus comparable to known emplacement styles from silicic calderas.

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منابع مشابه

3D Structure and Emplacement of the Alnö Alkaline and Carbonatite Complex, Sweden Integrated Geophysical and Physical Property Investigations

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عنوان ژورنال:

دوره 3  شماره 

صفحات  -

تاریخ انتشار 2013