  During protoplanetary disk formation, dust grains located in the outer disk
retain their pristine icy composition, while solids in the inner stellar-heated
disk undergo volatile loss. This process may have left a fossil record in Solar
System material showing different nucelosynthetic imprints that have been
attributed to different degrees of thermal processing. However, it remains
unclear how a large mass fraction of thermally-processed inner-disk pebbles is
produced and how these grains are subsequently transported throughout the disk.
In this work we numerically investigate the evolution in time of a
two-component pebble disk, consisting of pristine pebbles and those that
underwent ice sublimation. We find that stellar outbursts exceeding 1000 times
the solar luminosity are efficient in thermally altering, through ice
sublimation, a large mass fraction of pebbles (around 80%). After the
establishment of this initial radial dust composition gradient throughout the
disk, the subsequent mixing and inward drift of pristine outer-disk pebbles
alter the inner disk bulk composition from processed to more unprocessed in
time. Therefore, if processed pebbles without ice mantles have an isotopic
composition similar to ureilite meteorites from the inner Solar System,
inner-disk minor bodies forming from the early pebble flux (<1Myr) will be
isotopically ureilite-like, while later-formed bodies will be increasingly
admixed with the signature of the late incoming CI chondrite-like unprocessed
pebbles. This appears to be largely consistent with the trend seen between the
accretion age of different meteoric classes and their different stable isotope
composition anomalies (in $\mu$54Cr, $\mu$48Ca, $\mu$30Si, $\mu$58Ni), but
further work may be needed to explain the role of isotopically anomalous
refractory inclusions and anomaly trends in other elements.
