image BXO50.jpg
track, Sadgill to Gatescarth, Longsleddale, Westmorland, NY40 -- Rock, hand specimen of a igneous rock, Andesite lava with amygdales, infilled vesicles, from the track from Sadgill to Gatescarth Pass, Longsleddale, Westmorland, 2012.
Ordovician; Borrowdale volcanic group.
The vesicles are gas bubbles which came out of solution in the lava when pressure reduced as it erupted from the volcano. Later material permeated through the rock and desposited minerals in the holes, forming 'amygdales'.
(photo . .2012)