  Protoplanetary disks are dust-rich structures around young stars. The
crystalline and amorphous materials contained within these disks are variably
thermally processed and accreted to make bodies of a wide range of sizes and
compositions, depending on the heliocentric distance of formation. The
chondritic meteorites are fragments of relatively small and undifferentiated
bodies, and the minerals that they contain carry chemical signatures providing
information about the early environment available for planetesimal formation. A
current hot topic of debate is the delivery of volatiles to terrestrial
planets, understanding that they were built from planetesimals formed under far
more reducing conditions than the primordial carbonaceous chondritic bodies. In
this review, we describe significant evidence for the accretion of ices and
hydrated minerals in the outer protoplanetary disk. In that distant region
highly porous and fragile carbon and water-rich transitional asteroids formed,
being the parent bodies of the carbonaceous chondrites (CCs). CCs are
undifferentiated meteorites that never melted but experienced other physical
processes including thermal and aqueous alteration. Recent evidence indicates
that few of them have escaped significant alteration, retaining unique features
that can be interpreted as evidence of wet accretion. Some examples of
carbonaceous chondrite parent body aqueous alteration will be presented.
Finally, atomistic interpretations of the first steps leading to water-mediated
alteration during the accretion of CCs are provided and discussed. From these
new insights into the water retained in CCs we can decipher the pathways of
delivery of volatiles to the terrestrial planets.
