Magmatic stoping is a term that has been controversial almost since it was first mentioned over a century ago. Scientists have been arguing whether it plays an important part as an emplacement process of magma chambers, or whether it takes place at all. With growing evidence for both pro- and counterar guments the debate becomes tenser and the question raised is whether it is possible to find a unanimous answer. Magmatic stoping is often associated with the presence of xenoliths, “foreign” rocks that have been enclosed by magma. As parts of the roof or walls in the magma chamber detach, the pieces become trapped in it if they don’t have time to dissolve before the magma cools. The new cavities make room for a growing chamber and the possibility for magmatic stoping to be a volumetrically significant process is as well in discussion. The problematic starts early, beginning with the definitions of words like stoping, xenoliths, and rafts which are not unified. Natural findings of xenoliths in plutons are rare and speak against stoping but are often explained by xenoliths that possibly sunk down to the floor of magma chambers and become inaccessible for researchers. Nowadays there are several explanations to these statements that will be both presented and discussed in this thesis. A case study is also made from the Åva ring complex in Finland, and it has been shown to provide a fairly clear idea of the evidence for magmatic stoping. With remote sensing xenoliths have been mapped and measured and the results show that magmatic stoping is an abundant process and not something to be dismissed.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:uu-183409 |
| Date | January 2012 |
| Creators | Lagergren, Hanna |
| Publisher | Uppsala universitet, Institutionen för geovetenskaper |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | Självständigt arbete ; 38 |
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