Figure 4. Carbon and oxygen isotopic profiles from late Holocene specimens of Aequipecten opercularis. Specimen name is indicated in the lower left hand corner of each plot, together with the corrected radiocarbon date for that shell. Specimen SP1 is from the Inner Silver Pit; other specimens are from the Sole Pit. Oxygen isotope profiles are represented by solid black lines; carbon by dashed blue lines. The umbonal area was broken off in specimen PB1; shell height is therefore related to the ventral margin in this specimen. Solid triangle in SP1 indicates position of prominent growth ring as shown in Figure 3. The horizontal line on each profile indicates an arbitrary boundary between "summer" and "winter" (using ¹⁸O = 0.79, equivalent to a temperature of 13°C, as the transition), as referred to in the text.