Abstract: The 23 km-diameter, ca. 24 Ma Haughton Dome impact structure in the Canadian Arctic on Devon Island, Nunavut (89deg41’W, 75deg22’N) occurred within a two layered target composed of a shallowly-dipping ~1700 m thick succession of Paleozoic limestones and evaporates overlying ca.1.9 Ga high grade gneisses [1, 2]. Within the structure a well preserved impact melt bearing breccia unit contains a variety of shocked clasts from the pre-impact sediments and basement gneisses [3]. Due to their high l…