EXCLUSIVE

Carmen Argenziano -- who's perhaps best known from "Stargate SG-1" -- has died ... TMZ has learned.

Argenziano passed away Sunday, according to his personal appearance agency, Event Horizon Talent. His agent, who books him for conventions, confirms to TMZ that Argenziano had, in fact, died ... but the circumstances of his death remain unclear for now.

The Pennsylvania-born actor has starred in tons of TV shows and movies over the course of his 5-decade career, including "The Rockford Files," "Lou Grant," "Heartbeat," "Booker," "L.A. Law," "Melrose Place," "Sisters," "CSI: NY," "The Young and the Restless" and, of course, 'SG-1' ... where he played Jacob Carter from 1998 to 2005.

Argenziano also has lots of smaller roles in big productions like "Columbo," "Police Story," "The Godfather: Part II," "CHiPs," "The Greatest American Hero," "The A-Team," "Cheers," "Crime & Punishment," "ER," "Walker, Texas Ranger," "House" ... and many, many more. The man has 227 acting credits to his name on IMDb.

Argenziano is survived by his children.

He was 75.