PROVENANCE OF MINERAL PHASES IN THE CRETACEOUS-TERTIARY BOUNDARY SEDIMENTS EXPOSED ON THE SOUTHERN PENINSULA OF HAITI

Acid-insoluble mineral residua of tektite-bearing Cretaceous-Tertiary boundary sediments in the Beloc Formation of Haiti contain abundant sh ocked quartz and lesser amounts of shocked plagioclase. The shocked qu artz grains typically have 2 or 3 sets of planar deformation features, although grains with up to 15 sets were observed. The proportion of s hocked quartz in the boundary sediments increases with stratigraphic h eight; at least 70 +/- 11% of the quartz grains are shocked in the upp ermost stratigraphic interval. The proportion of shocked quartz throug hout the boundary sediments indicates that these grains were excavated primarily from crystalline silicate units, which may have been covere d with a small amount of porous quartz-bearing sediments. Polyhedral a nd moderately sutured margins in shocked polycrystalline quartz grains , the size of the crystal units in these grains and the presence of sh ocked plagioclase, indicate these ejecta components were excavated fro m a target with continental affinities, containing quartzites or metaq uartzites and a sialic metamorphic and/or igneous component. Other evi dence suggests the target may also have contained a significant amount of calcium carbonate and/or sulfate. The large size and amount of sho cked quartz grains deposited in Haiti indicate the crater from which t hey were excavated was produced in the proto-Caribbean region.