We have made observations with the Keck I telescope and HIRES at a resolution of \sim 45,000 of five nearly identical stars at the turn-off of the metal-rich globular cluster M 71 .
We derive stellar parameters and abundances of several elements .
Our mean Fe abundance , [ Fe/H ] = -0.80 { \pm } 0.02 , is in excellent agreement with previous cluster determinations from both giants and near-turnoff stars .
There is no clear evidence for any star-to-star abundance differences or correlations in our sample .
Abundance ratios of the Fe-peak elements ( Cr , Ni ) are similar to Fe .
The turn-off stars in M71 have remarkably consistent enhancements of 0.2 - 0.3 dex in [ Si/Fe ] , [ Ca/Fe ] and [ Ti/Fe ] – like the red giants .
Our [ Mg/Fe ] ratio is somewhat lower than that suggested by other studies .
We compare our mean abundances for the five M 71 stars with field stars of similar metallicity [ Fe/H ] – 8 with halo kinematics and 17 with disk kinematics .
The abundances of the alpha-fusion products ( Mg , Si , Ca , Ti ) agree with both samples , but seem a closer match to the disk stars .
The Mg abundance in M71 is at the lower edge of the disk and halo samples .
The neutron-capture elements , Y and Ba , are enhanced relative to solar in the M71 turn-off stars .
Our ratio [ Ba/Fe ] is similar to that of the halo field stars but a factor of two above that for the disk field stars .
The important [ Ba/Y ] ratio is significantly lower than M71 giant values ; the pre-cluster material may have been exposed to a higher neutron flux than the disk stars or self-enrichment has occured subsequent to cluster star formation .
The Na content of the M71 turn-off stars is remarkably similar to that in the disk field stars , but more than a factor of two higher than the halo field star sample .
We find [ Na/Fe ] = +0.14 \pm 0.04 with a spread less than half of that found in the red giants in M71 .
Excluding Mg , the lack of intracluster \alpha -element variations ( turn-off vis-a-vis giants ) suggests the polluting material needed to explain the abundance patterns in M71 did not arise from explosive nucleosynthesis , but arose in a more traditional s -process environment such as AGB stars .
The determination of light s -peak abundances should reveal whether this pollution occurred before or after cluster formation .