History of the Moine Thrust in 2 square metres of folded rock at Glencoe Lochain
OneMinuteGeology
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History of the Moine Thrust in 2 square metres of folded rock at Glencoe Lochain
2 055 просмотров · 3 года назад
OneMinuteGeology
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2 055 просмотров · 3 года назад
You can really tell a lot from small pieces of rock if you know what you are looking for. Here at Glencoe Lochain, slates and schists of Dalradian age (around 700 millioin years) have been beautifully folded in assymetric ductile folds. The shape and orientation of the folds is consistent with the regional stress field which was operating during the Caledonian Orogeny, brought on by the closure of the Iapetus Ocean around 450 million years ago. The orientation of the fold axes align very closely with the Moine Thrust Belt, which is the most obvious regional feature produced by Iapetus closure and this means that the same compressive stress orientation produced both these cm-scale folds and the Moine thrust. The assymetry of these folds also imply that the land to the South and East was overriding the land to the North and West, also consistent with the Moine system. It is remarkable how much you can infer from small-scale features and when they agree with the regional scale features of similar age it means that you are likely to have correctly imterpreted both sets of features.