  The collapsar engine behind long-duration gamma-ray bursts extracts the
energy released from the rapid accretion of a collapsing star onto a
stellar-massed black hole. In a collapsing star, this black hole can form in
two ways: the direct collapse of the stellar core into a black hole and the
delayed collapse of a black hole caused by fallback in a weak supernova
explosion. In the case of a delayed-collapse black hole, the strong
collapsar-driven explosion overtakes the weak supernova explosion before shock
breakout, and it is very difficult to distinguish this black hole formation
scenario from the direct collapse scenario. However, the delayed-collapse
mechanism, with its double explosion, produces explosive nucleosynthetic yields
that are very different from the direct collapse scenario. We present
1-dimensional studies of the nucleosynthetic yields from both black hole
formation scenarios, deriving differences and trends in their nucleosynthetic
yields.
