  We present the results of the combined analysis of three XMM-Newton EPIC
observations of the northern rim of the Vela SNR. The three pointings cover an
area of ~10 pc^2 (at 250 pc) behind the main shock front and we aim at studying
with high resolution the spatial distribution of the physical and chemical
properties of the X-ray emitting plasma on this large scale. We produce
count-rate images and equivalent width maps of the Ne IX and Mg XI emission
blends. We also perform a spatially resolved spectral analysis of a set of
physically homogeneous regions. We reveal physical and chemical inhomogeneities
in the X-ray emitting plasma. In particular, we find large variations of the O,
Ne, Mg, and Fe abundances. In some bright knots we also find unexpectedly
enhanced Ne and Mg abundances, with values significantly larger than solar. Our
results support a possible association of a few X-ray emitting knots with
previously undetected residuals of stellar fragments (i. e. shrapnels)
observed, in projection, inside the Vela shell.
