  The Vela Molecular Ridge is one of the nearest intermediate-mass star forming
regions, located within the galactic plane and outside the solar circle. Cloud
D, in particular, hosts a number of small embedded young clusters. We present
the results of a large-scale map in the dust continuum at 1.2 mm of a ~ 1deg x
1deg area within cloud D. The main aim of the observations was to obtain a
complete census of cluster-forming cores and isolated (both high- and low-mass)
young stellar objects in early evolutionary phases. The bolometer array SIMBA
at SEST was used to map the dust emission in the region with a typical
sensitivity of ~ 20 mJy/beam. This allows a mass sensitivity of ~ 0.2 Msun. The
resolution is 24 arcsec, corresponding to ~ 0.08 pc, roughly the radius of a
typical young embedded cluster in the region. The continuum map is also
compared to a large scale map of CO(1-0) integrated emission. Using the
CLUMPFIND algorithm, a robust sample of 29 cores has been obtained, spanning
the size range 0.03 - 0.25 pc and the mass range 0.4 - 88 Msun. The most
massive cores are associated both with red IRAS sources and with embedded young
clusters, and coincide with CO(1-0) integrated emission peaks. The cores are
distributed according to a mass spectrum ~ M^{-alpha} and a mass-versus-size
relation ~ D^{x}, with alpha ~ 1.45 - 1.9 and x ~ 1.1 - 1.7. They appear to
originate in the fragmentation of gas filaments seen in CO(1-0) emission and
their formation is probably induced by expanding shells of gas. The core mass
spectrum is flatter than the Initial Mass Function of the associated clusters
in the same mass range, suggesting further fragmentation within the most
massive cores. A threshold A_V ~ 12 mag seems to be required for the onset of
star formation in the gas.
