Sample preparation for carbonate fine-fraction stable-isotope data: A total of 444 bulk sediment samples, taken at ~30 cm spacing from the Mossy Grove Core (MGC), were processed at the University of Birmingham. The sediment was sieved over a 20 µm stainless steel mesh, with the fine fraction passing through the sieve captured on ultra-fine-grade filter paper and air dried. The sediment residue (>20 µm) was then transferred to 50 ml centrifuge tubes and organic matter within this fine fraction removed by overnight reaction with 5% sodium hypochlorite (NaClO) solution. The sample was then spun down at 4,500 rpm (6,800 × g) and the supernatant discarded. The sample was then washed 2-3 times with de-ionized water – each wash consisting of resuspension, agitation and then centrifuging and discarding of the solution as above - until a neutral pH was established. Samples were then weighed to provide sufficient sample mass for sample analysis.The stable carbon (δ13C) and oxygen (δ18O) isotope analysis of 444 fine-fraction sediment samples prepared at the University of Birmingham were performed at the British Geological Survey, Keyworth, UK on a dual inlet, gas source, isotope ratio mass spectrometer. The carbonate analysis method involves reacting the carbonate sample with anhydrous phosphoric acid to liberate CO2. All data are reported against Vienna Pee Dee Belemnite standard (VPDB). Calibration of the in-house standard with NBS-19 shows the analytical precision is < ±0.01‰ for both isotope ratios.