  In this letter we report the detection of a strong and extremely blueshifted
X-ray absorption feature in the 1 Ms Chandra spectrum of CXO CDFS
J033260.0-274748, a quasar at z = 2.579 with L_2-10keV ~ 4x10^44 ergs/s. The
broad absorption feature at ~ 6.3 keV in the observed frame can be fitted
either as an absorption edge at 20.9 keV or as a broad absorption line at 22.2
keV rest frame. The absorber has to be extremely ionized with an ionization
parameter \xi ~ 10^4, and a high column density N_H >5x10^23 cm^-2. We reject
the possibility of a statistical or instrumental artifact. The most likely
interpretation is an extremely blueshifted broad absorption line or absorption
edge, due to H or He--like iron in a relativistic jet-like outflow with bulk
velocity of ~ 0.7-0.8 c. Similar relativistic outflows have been reported in
the X-ray spectra of several other AGNs in the past few years.
