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Fyddai haenau rhywbeth-neu’i-gilydd yn gwneud y tro, os nad oes term cydnabyddedig? Beth fyddai’r ffordd orau o ddisgrifio’r haenau hyn? From: Gareth Jones Sent: Monday, January 23, 2012 1:33 PM To: [log in to unmask] Subject: flow banding Termau daeareg ydy’r cyd-destun. Dyma’r diffiniad: Flow banding is a geological term to describe bands or layers that can sometimes be seen in rock that formed from the substance molten rock or magma. Flow banding is caused by friction of the viscous magma which is in contact with a solid rock interface, usually the wall rock to an intrusive chamber or if the magma is erupted, the surface of the earth across which a lava is flowing. The friction and viscosity of the magma causes phenocrysts and xenoliths within the magma or lava to slow down near the interface and become trapped in a viscous layer. This forms laminar flow, which manifests as a banded, streaky appearance. A oes term cydnabyddedig os gwelwch yn dda?