Plutonium-based.
Its plutonium was produced at Hanford site.
Figure 1. Source.
Video 1. Trinity Test Preparations by AtomicHeritage (2016) Source. Appears to be a compilation of several videos, presumably each with their own separate LA-UR, though these are not noted. Credited: "Video courtesy of the Los Alamos National Laboratory Archives", TODO how to search that archive online?
Video 2. Trinity: Getting The Job Done. Source. Good video, clarifies several interesting technical points: