Ancient globular clusters contain multiple stellar populations identified by variations in light elements ( e.g. , C , N , O , Na ) .
Although many scenarios have been suggested to explain this phenomenon , all are faced with challenges when compared with all the observational evidence .
In this Letter , we propose a new scenario in which light element variations originate from nucleosynthesis in accretion discs around black holes .
Since the black holes form after a few Myrs , the cluster is expected to still be embedded in a gas rich environment .
Through a simplified accretion model , we show that the correct light element anti-correlations can be produced .
Assuming a Kroupa stellar initial mass function ( IMF ) , each black hole would only have to process { \approx } 300 M _ { \odot } of material in order to explain multiple populations ; over a period of 3 Myr this corresponds to \sim 10 ^ { -4 } M _ { \odot } yr ^ { -1 } ( similar to the estimated accretion rate for the x-ray binary SS 433 ) .