Question: I'm just throwing this out there for discussion/answering:

If person A sat in a chair all his life, in a house on earth (let's say 100 years),
and person B flew around in earth's atmosphere at let's say 1000km/h or 1000mph (which ever is easiest to comprehend) for 100 years. 

Would there be a time difference for those people at the end of their life? would person B's clock have ran slower than person A, as person B was traveling at a speed closer to the speed of light, or is this speed too slow to be relevant?

Answer: 
As I understand it regular fusion in a star takes light elements as input and the output is heavier elements and energy. There are several potential steps in the regular process, e.g:

* Hydrogen fusing to helium **and producing energy** which keeps the star from collapsing.
* After a lot of hydrygen is spent and helium has collected in the center of the star the hydrogen fusion reactions tapers off. The star shrinks. **Pressure and heat increase in the core**. The core starts burning helium.
* Repeat for heavier elements. E.g. up to oxygen/carbon.

Now I stressed a few points in the regular process:

* "and producing energy": The reaction is endothermic. If you needed to add energy instead then processes tend not to work or much slower.
* Add to that that fusing iron does **not** produce energy. Lighter element than iron/tin produce energy if fused. Heavier elements produce energy when split. Iron/Ni is the most stable element.
* "Pressure and heat increase in the core": There is no fusion to produce heat, but you can increase pressure by just adding a lot of mass. If you add enough mass then you will get very dense iron. At some point the mass gets big enough to that it is not merely resisted by the electric charges of the charged iron aton cores, but also by the pressure of electrons. (See [Degenerate matter](https://en.wikipedia.org/wiki/Degenerate_matter)).  

Add enough and you might get neutronium rather than heavier elements.

> 
> To be plain, I am not talking about stellar fusion or whether there is enough latent
>  energy to continue fusion at an already existing core. I want to know if there was 
>  enough collective mass in the debris field, could the field itself, coalesce to the
>  point where the heavy elements will fuse. 
> 
> 
> 

Well, yes and no. Add enough and it will change to a neutron star or beyond. I guess you could consider that a technical yes with a single star sized atom. It also feels as if I am playing word games.

Everything I have read (but I am not a physic person) seems to say that fusion stops. You will get very many iron atoms close to each other. Statistically I guess some might fuse and thereby cool the coalicing mass of iron. But intuition tells me that most will stay iron. Add more and it just gets denser and denser until it become energytically advantageous to capture elctrons and change to neutronium. (which, though very heavy/dense) is the opposite. It goes to element 0, not to classic 'heavier' elements.
As I understand it, iron will not be able to fuse with iron no matter how much of it you have gravitationally bound. Instead to fuse iron atoms together requires a supernova.