We present an abundance analysis based on high resolution spectra of 10 stars selected to span the full range in metallicity in the Ursa Minor dwarf spheroidal galaxy .
We find [ Fe/H ] for the sample stars ranges from -1.35 to -3.10 dex .
Combining our sample with previously published work for a total of 16 luminous UMi giants , we establish the trends of abundance ratios [ X/Fe ] as functions of [ Fe/H ] for 15 elements .
In key cases , particularly for the \alpha -elements , these trends resemble those for stars in the outer part of the Galactic halo , especially at the lowest metallicities probed .
The neutron capture elements show a r -process distribution over the full range of Fe-metallicity reached in this dSph galaxy .
This suggests that the duration of star formation in the UMi dSph was shorter than in other dSph galaxies .
The derived ages for a larger sample of UMi stars with more uncertain metallicities also suggest a population dominated by uniformly old ( \sim 13 Gyr ) stars , with a hint of an age-metallicity relationship .

In comparing our results for UMi , our earlier work in Draco , and published studies of more metal-rich dSph Galactic satellites , there appears to be a pattern of moving from a chemical inventory for dSph giants with [ Fe/H ] \lesssim - 2 dex which is very similar to that of stars in the outer part of the Galactic halo ( enhanced \alpha /Fe relative to the Sun , coupled with subsolar [ X/Fe ] for the heavy neutron capture elements and r -process domination ) , switching to subsolar \alpha -elements and super-solar s -process dominated neutron capture elements for the highest [ Fe/H ] dSph stars .
The combination of low star formation rates over a varying and sometimes extended duration that produced the stellar populations in the local dSph galaxies with [ Fe/H ] > -1.5 dex leads to a chemical inventory wildly discrepant from that of any component of the Milky Way .

We note the presence of two UMi giants with [ Fe/H ] < -3.0 dex in our sample , and reaffirm that the inner Galactic halo could have been formed by early accretion of Galactic satellite galaxies and dissolution of young globular clusters , while the outer halo could have formed from those satellite galaxies accreted somewhat later .