The Surface Structure of the Haughton Impact Crater, Devon Island, Canada

Abstract

Abstract— Recent geological and structural investigations support the existing descriptions of the Haughton structure being a dome‐like structure. The central area represents the central uplift and is formed by blocks of rocks belonging to the oldest part of the Devon Island Paleozoic sediment cover. The orientation of the blocks partly reflects this dome‐like structure. The morphologically defined “inner ring” is a structurally distinct zone, predominated by gypsum beds of the Bay Fiord Formation. These beds dip 30 to 40° outward and are asymmetrically folded. The outer radius of this ring is 5 to 5.5 km. A 1 to 1.5 km broad zone follows outward of more chaotically orientated blocks of rocks, which may be considered a megablock‐zone. The next ring‐like zone is strongly faulted (“faulted annulus”) and obviously represents the downfaulted, once uplifted crater rim. Within this structural annulus, a marked asymmetry of the crater structure is expressed by the attitude of the faulted blocks. The structure of the northern and eastern segments of the faulted annulus differ substantially from those of the southern and western segments. This asymmetry may reflect heterogeneities in the pre‐crater geology or a low angle impact. No evidence was found in support of the theory that the Haughton structure represents a multiring structure.