Parallelization of priority queue-based algorithms
Two old, but, I think, still very useful resources:


M.T.Goodrich, M.R.Ghouse, and J.Bright. Sweep Methods for Parallel Computational Geometry. Algorithmica (1996), 15:126-153. - closely related to what you are asking about, download for free: link.
S.G.Akl, K.A.Lyons. Parallel Computational Geometry. Prentice-Hall, 1993 - monograph about first ten years of research in parallel computational geometry. In the Chapter Four they say: "The plane sweep technique appears to be inherently sequential", but nevertheless refer to a number of parallel sweeping algorithms. Please see: link.