The petrology of the basic and intermediate rocks of upper Swat, Pakistan
- 1 March 1973
- journal article
- research article
- Published by Cambridge University Press (CUP) in Geological Magazine
- Vol. 110 (3) , 285-300
- https://doi.org/10.1017/s0016756800036116
Abstract
Summary: A series of metamorphosed (amphibolite facies) basic and intermediate igneous rocks from upper Swat, Pakistan, is described, with seven chemical analyses. The rocks intrude ?Palaeozoic metasediments and are partially bordered by other, later, intrusive and volcanic rocks. The group, now represented by, from S–N, epidote amphibolites, amphibolites, noritic and hypersthene gabbros, and quartz diorites, is considered to be derived from a series of plagioclase hypersthenites, norites, hypersthene gabbros, and hypersthene diorites. Variation diagrams are used to show that the series forms a differentiated sequence; FMA and lime-alkali diagrams suggest that it is similar to the rocks of the Garabal Hill–Loch Fyne area of Scotland. Some of the mineralogy of the group is briefly discussed, with five chemical analyses. A K/Ar age determination gives 67 Ma; thus the rocks probably derive from an early Himalayan (Alpine) tholeiitic basalt magma.Keywords
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