Fig. 7.

EBSD band contrast image of hydrothermally altered T. transversa shell. Alteration occurred at 175 °C for 28 days and was carried out in simulated burial fluid. Shell areas where the original fibre morphology was distorted by alteration (yellow rectangle) can be observed close to regions where the shell microstructure was little affected (white rectangle). Note that amalgamation of fibres occurred occasionally (white arrows).