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Strong, delayed X-ray line emission is detected in the afterglow of GRB030227, appearing near the end of the XMM-Newton observation, nearly twentyhours after the burst. The observed flux in the lines, not simply theequivalent width, sharply increases from an undetectable level (<1.7e-14erg/cm^2/s, 3 sigma) to 4.1e-14 erg/cm^2/s in the final 9.7 ks. The lineemission alone has nearly twice as many detected photons as any previousdetection of X-ray lines. The lines correspond well to hydrogen and/orhelium-like emission from Mg, Si, S, Ar and Ca at a redshift z=1.39. There isno evidence for Fe, Co or Ni--the ultimate iron abundance must be less than atenth that of the lighter metals. If the supernova and GRB events are nearlysimultaneous there must be continuing, sporadic power output after the GRB of aluminosity >~5e46 erg/s, exceeding all but the most powerful quasars.Comment: Submitted to ApJL. 14 pages, 3 figures with AASLaTe

Delayed Soft X-Ray Emission Lines in the Afterglow of GRB 030227