We detect the optical afterglow and host galaxy of GRB 070714B .
Our observations of the afterglow show an initial plateau in the lightcurve for approximately the first 5 to 25 minutes , then steepening to a powerlaw decay with index \alpha = 0.86 \pm 0.10 for the period between 1 to 24 hours post burst .
This is consistent with the X-ray light-curve which shows an initial plateau followed by a similar subsequent decay .
At late time , we detect a host galaxy at the location of the optical transient .
Gemini Nod & Shuffle spectroscopic observations of the host show a single emission line at 7167 Ã which , based on a grizJHK photometric redshift , we conclude is the 3727 Ã [ O II ] line .
We therefore find a redshift of z = 0.923 .
This redshift , as well as a subsequent probable spectroscopic redshift determination of GRB 070429B at z = 0.904 by two other groups , significantly exceeds the previous highest spectroscopically confirmed short burst redshift of z = 0.546 for GRB 051221 .
This dramatically moves back the time at which we know short bursts were being formed , and suggests that the present evidence for an old progenitor population may be observationally biased .