1887
PDF

Abstract

Koegel Fontein is a 30 km diameter anorogenic igneous complex that intruded Namaqualand gneisses during the initial phase of break-up of Africa and South America. It is notable for the presence of quartz porphyry dykes that formed from low-δ18O magmas. Many of the igneous rocks show petrographic evidence for alteration and have had their δ18O values lowered by fluid-rock interaction at high temperatures. Partial melting and/or assimilation of this material produced the low- δ18O magmas. Whole-rock δD and δ18O values indicate equilibrium with meteoritc water with a δ18O value around -10 ‰, which is abnormally negative given the relatively low latitude at the time of intrusion. A combination of an elevated volcanic edifice and the ‘continental effect’ is the most likely explanation.

Loading

Article metrics loading...

/content/papers/10.3997/2214-4609-pdb.241.curtis_paper
2009-09-16
2024-03-29
Loading full text...

Full text loading...

http://instance.metastore.ingenta.com/content/papers/10.3997/2214-4609-pdb.241.curtis_paper
Loading
This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error