GEOL 104 Lecture Notes - Lecture 8: Magma Chamber, Laccolith, Feeder
31 Oct 2017
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Lecture 8: igneous rocks pt 3- volcanic rocks. Intrusive igneous bodies: bodies of plutonic, igneous rock, formed at depth are called plutons. Plutons are studied after rock has been uplifted to earth"s surface: when it"s a magma magma chamber. If erosion continues pluton starts to be exposed at surface basalt: 2 different types of linear tabular bodies, nature of plutons, classified by: Orientation: (discordant or concordant: dykes: tabular discordant bodies, produced when magma is injected into fissures. Thickness ranges from 1 cm to 1 km: sills: tabular concordant plutons, formed when magma is injected along bedding surfaces. Horizontal sills most common, but can occur in various orientations: cross cutting = discordant (dykes) If dyke is feeding volcano = feeder dyke: parallel/ layering = concordant (sills, not all dykes reach surface intrude in rock, khumbu valley, nepal can see something intruding in limestone (skinny =
