© Petrolab Limited Plate 1 : (Sample ref removed) A General view of sample (porosity shown by yellow dye) B Quartz dissolution C Clay matrix D Carbonate cement A – Plane polarised reflected light B, C & D – Cross polarised transmitted light B A C D 500 µm 250 µm 250 µm 250 µm quartz feldspar clay matrix dissolution contact clay matrix feldspar carbonate