New stable carbon isotope data (δ¹³C_carb and δ¹⁸O_carb) from the Lower–Middle Ordovician is presented from petroleum exploration well Olympic 1 in the Canning Basin, Western Australia. Olympic 1 continuously cored 319.53 m of sedimentary strata, from the basal part of the Willara Formation through the majority of the Nambeet Formation. This cored section comprises carbonate and siliciclastic deposits that constitute the primary fill sequence of the Canning Basin. Previous studies report CA-IDTIMS dates between 479.37 ± 0.16 Ma and 470.18 ± 0.13 Ma from bentonite beds within the Nambeet Formation and lower Willara Formation in Olympic 1. Four conodont biozones ranging from the Paroistodus proteus conodont Biozone (upper Tremadocian) to the Jumudontus gananda Biozone (upper Floian to lower Dapingian) have been identified from the same interval. The new carbon isotope data from the Olympic 1 core are superimposed on this robust framework to provide context for Tremadocian to Dapingian stable isotope trends for Australia.

Three positive δ¹³C_carb excursions are identified in the Olympic 1 δ¹³C_carb isotope curve, which are correlated to the global generalized δ¹³C curve. The highest of these occurs in the basal Willara Formation, immediately above a CA-IDTIMS radioisotopic date of 470.18 ± 0.13 Ma within the upper Floian to lower Dapingian J. gananda conodont Biozone. The second falls in the upper Nambeet Formation, immediately above a middle Floian CA-IDTIMS radioisotopic date of 472.82 ± 0.13 Ma, and within the Oepikodus communis conodont Biozone. The oldest positive excursion occurs in the lower Nambeet Formation, immediately above a CA-IDTIMS radioisotopic date of 479.37 ± 0.16 Ma, and within the upper Tremadocian P. proteus conodont Biozone.

Correlation of the Olympic 1 δ¹³C_carb curve to Lower-Middle Ordovician δ¹³C_carb curves from the Great Basin USA, Argentine Precordillera, Western Newfoundland and South China confirms the global distribution of dissolved inorganic carbon preserved in the geological record. This integrated record may be a useful reference for constraining the timing of major oceanographic events, and a key to establishing better links between the sedimentary successions of Western Australia and the larger Ordovician world.