Lead (Pb) isotope measurements are performed in the ferromanganese crust PS75/247-2, dredged on the southern flank of Haxby Seamount in the Pacific sector of the SO, using laser ablation coupled to a MC-ICP-MS (LA-MC-ICP-MS). The measurement is targeted at the bulk sample in this crust. We used smaller laser spot sizes (each integrating about 8 kyr of growth) to resolve glacial-interglacial cyclic Pb isotope variations in the youngest part of our record. We also used larger laser spot sizes to integrate a sampling interval of approximately 40 kyr of growth (i.e., one early Pleistocene glacial cycle) in order to detect long-term changes beyond orbital cyclicity throughout the past 20 Ma. In order to verify the laser ablation-based Pb isotope data, the Pb isotope compositions of samples from 10 different depths in crust Haxby was also analysed by conventional solution-based method. The depth in the sample list represents the distance from the measurement spot to the sample surface.Pb isotope is a sensitive water mass tracer and our data reveal that the Antarctic Circumpolar Current (ACC) has experienced five stable circulation states since the early Miocene which were separated by four major transitions observed at 17.5-14.6, 12, 10 and 5 Ma. According to our data the modern ACC configuration formed 5 million years ago, likely in response to the closure of the Panama Seaway. Our data also show that changes in the latitudinal position of the ACC were linked to the middle Miocene waxing and waning of the Antarctic ice sheets, which emphasizes the ACC's critical role as a key control of Antarctic glaciation.