  The genesis and chemical patterns of the metal poor stars in the galactic
halo remains an open question. Current models do not seem to give a
satisfactory explanation for the observed abundances of Lithium in the galactic
metal-poor stars and the existence of carbon-enhanced metal-poor (CEMP) and
Nitrogen-enhanced metal-poor (NEMP) stars. In order to deal with some of these
theoretical issues, we suggest an alternative explanation, where some of the
Pop. III SNe are followed by the detonation of their neutron stars
(Quark-Novae; QNe). In QNe occurring a few days to a few weeks following the
preceding SN explosion, the neutron-rich relativistic QN ejecta leads to
spallation of 56Ni processed in the ejecta of the preceding SN explosion and
thus to "iron/metal impoverishment" of the primordial gas swept by the combined
SN+QN ejecta. We show that the generation of stars formed from fragmentation of
pristine clouds swept-up by the combined SN+QN ejecta acquire a metallicity
with -7.5 < Fe/H] < -1.5 for dual explosions with 2 < t_delay (days) < 30.
Spallation leads to the depletion of 56Ni and formation of sub-Ni elements such
as Ti, V, Cr, and Mn providing a reasonable account of the trends observed in
galactic halo metal-poor stars. CEMP stars form in dual explosions with short
delays (t_delay < 5 days). These lead to important destruction of 56Ni (and
thus to a drastic reduction of the amount of Fe in the swept up cloud) while
preserving the carbon processed in the outer layers of the SN ejecta. Lithium
is produced from the interaction of the neutron-rich QN ejecta with the outer
(oxygen-rich) layers of the SN ejecta. A Lithium plateau with 2 < A(Li) < 2.4
can be produced in our model as well as a corresponding 6Li plateau with
6Li/7Li < 0.3.
