The invention relates to a thermoplastic membrane (e.g. film, fluid barrier, and the like) which is formed from a blend of: a) a first polymer component (FPC), wherein said FPC comprises a propylene-ethylene copolymer containing from 80 to 93 percent by weight of units derived from propylene, and having a melting point derived from stereoregular polypropylene sequences, as determined by differential scanning calorimetry (DSC), in the range of from 25° C. to 70° C., and a heat of fusion of from 2 J/g to 25 J/g; b) an inorganic filler; c) a processing oil, and d) optionally, a second polymer component (SPC), wherein said SPC is a stereoregular polypropylene containing less than 7 percent by weight of units derived from ethylene or alpha-olefin monomer containing from 4 to 8 carbon atoms and having melting point, as determined by DSC, greater than 130° C., and a heat of fusion greater than 80 J/g.