  The SKA PAthfinder Radio Continuum Surveys (SPARCS) are providing deep-field
imaging of the faint (sub-mJy) extra-galactic radio source populations through
a series of reference surveys. One of the key science goals for SPARCS is to
characterize the relative contribution of radio emission associated with AGN
from star-formation (SF) in these faint radio source populations, using a
combination of high sensitivity and high angular resolution imaging over a
range of spatial scales (arcsec to mas). To isolate AGN contribution from SF,
we hypothesise that there exists a brightness temperature cut-off point
separating pure AGN from SF. We present a multi-resolution (10-100 mas) view of
the transition between compact AGN and diffuse SF through a deep wide-field
EVN+e-MERLIN, multiple phase centre survey of the centre of the Northern SPARCS
(SLOAN) reference field at 1.6 GHz. This is the first (and only) VLBI
(+e-MERLIN) milliarcsecond angular resolution observation of this field, and of
the wider SPARCS reference field programme. Using these high spatial resolution
(9 pc - 0.3 kpc at z ~ 1.25) data, 11 milliarcsecond-scale sources are detected
from a targeted sample of 52 known radio sources from previous observations
with the e-MERLIN, giving a VLBI detection fraction of ~ 21%. At spatial scales
of ~ 9 pc, these sources show little to no jet structure whilst at ~ 0.3 kpc
one-sided and two-sided radio jets begin to emerge on the same sources,
indicating a possible transition from pure AGN emissions to AGN and
star-formation systems.
