Likely to be asbestos??

[Chrisbrims]

Hi All - does anyone know if the black layer in pictures is likely to be asbestos/contain asbestos?
We have been renovating our house over the past couple of years and not had any asbestos problems. We are in process of relaying the kitchen floor and found this black layer under a few tiles and started to be concerned. Tiles were laid in the mid 80s.

 

[White Room]

Might be worth getting it tested if you have concerns, I now work for a housing trust who encapsulate with self leveling on all floors with black Jack or bitumen coated floors.
You say the 80s which sounds the age it could be possible.