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We report results from an exploratory study implementing a new probe ofGalactic evolution using archival Hubble Space Telescope imaging observations.Precise proper motions are combined with photometric relative metallicity andtemperature indices, to produce the proper motion rotation curves of theGalactic bulge separately for metal-poor and metal-rich Main Sequence samples.This provides a "pencil-beam" complement to large-scale wide-field surveys,which to-date have focused on the more traditional bright Giant Branch tracers.  We find strong evidence that the Galactic bulge rotation curves drawn from"Metal-rich" and "Metal-poor" samples are indeed discrepant. The "Metal-rich"sample shows greater rotation amplitude and a steeper gradient against line ofsight distance, as possibly a stronger central concentration along the line ofsight. This may represent a new detection of differing orbital anisotropybetween metal-rich and metal-poor bulge objects. We also investigate selectioneffects that would be implied for the longitudinal proper motion cut often usedto isolate a "pure-bulge" sample. Extensive investigation of synthetic stellarpopulations suggest that instrumental and observational artifacts are unlikelyto account for the observed rotation curve differences. Thus, propermotion-based rotation curves can be used to probe chemo-dynamical correlationsfor Main Sequence tracer stars, which are orders of magnitude more numerous inthe Galactic Bulge than the bright Giant Branch tracers. We discuss briefly theprospect of using this new tool to constrain detailed models of Galacticformation and evolution.

Chemically-dissected rotation curves of the Galactic Bulge from Main Sequence proper motions