Complex sentence: Various mechanisms have been proposed to explain the cause of Heinrich events, most centring around the activity of the Laurentide ice sheet, although there has been speculation that the unstable West Antarctic Ice Sheet may play a triggering role.
Split into simpler sentences: Various mechanisms have been proposed to explain the cause of Heinrich events. Most center around the activity of the Laurentide ice sheet, but others suggest that the unstable West Antarctic Ice Sheet played a triggering role.