A comparison of methods of strain determination in rocks from southwest Dyfed (Pembrokeshire) and adjacent areas

A variety of methods devised in the last twelve years for measuring two-dimensional strain ratios have been applied to the same deformed oolitic limestone from southwest Dyfed. Their relative merits are discussed. A graphical method for studying relative locations of marker objects is described and its application to a variety of rocks illustrated. It is shown to have theoretical and practical advantages, while giving values of two-dimensional strain ratios comparable with those of other methods.