In　this　paper,　we　investigate　the　concentration　and　cavitation　phenomena　of　Riemann　solutions　for　the　generalized　Chaplygin　gas　equations　in　the　presence　of　flux　approximation.　The　concentration　and　cavitation　are　fundamental　and　physical　phenomena　in　fluid　dynamics,　which　can　be　mathematically　described　by　delta　shock　waves　and　vacuums　(or　constant　density　states),　respectively.　The　main　objective　of　this　paper　is　to　rigorously　investigate　the　formation　of　delta　shock　waves　and　constant　density　states　and　observe　the　concentration　and　cavitation　phenomena.　First,　the　Riemann　problem　for　the　generalized　Chaplygin　gas　equations　under　the　flux　approximation　is　solved　constructively.　Although　the　system　is　strictly　hyperbolic　and　its　two　characteristic　fields　are　genuinely　nonlinear,　the　delta　shock　wave　arises　in　Riemann　solutions.　The　formation　of　mechanism　for　delta　shock　wave　is　analyzed,　that　is,　the　1-shock　wave　curve　and　the　2-shock　wave　curve　do　not　intersect　each　other　in　the　phase　plane.　Second,　it　is　rigorously　proved　that,　as　the　pressure　vanishes,　the　Riemann　solutions　for　the　generalized　Chaplygin　gas　equations　under　the　flux　approximation　tend　to　the　two　kinds　of　Riemann　solutions　to　the　transport　equations　in　zero-pressure　flow　under　the　flux　approximation,　which　include　a　delta　shock　wave　formed　by　a　weighted　delta-measure　and　a　constant　density　state.