A complex diversity of lithologies are exposed at Haughton, reflecting the fact that the impact event punched through the entire stack of Paleozoic sediments present at the time and excavated material from a depth of over 1.7 km, biting into the gneissic basement. Some shocked formations at Haughton have retained their integrity and are now exposed as tilted or downfaulted magablocks within the structure and at its periphery. However, particularly distinctive at Haughton is the crater's allochthonous impact breccia formation, a rubble deposit resulting from the launching, airborne mixing, fallback and weak rewelding of impact-shattered fragments derived from the entire stack of excavated rocks. Thus at Haughton, (shocked) basement crystalline rocks can be now found in abundance at the surface.

The Haughton Impact Breccia

As an impact-generated rubble with thoroughly mixed fragments originating from a variety of pre-impact target horizons, at present permeated with ground-ice in a zone of continuous permafrost, the Haughton breccia formation may represent a first-order physical analog to impact crater deposits on Mars, at least to the extent that the latter may be characterized as ground-ice-rich impact-generated rubble. Ground-penetrating radar surveys at 500 MHz made across selected portions of the breccia deposits during the 1998 field season of the HMP and local excavations conducted for ground-truthing show that ground-ice in the uppermost 10 meters or so of the breccia permafrost zone is distributed uniformly rather than in any massive segregated form.

The absence of massive (meter-scale) ice segregation in the near-surface zone is consistent with the lack of any ice-cored mounds on the breccia surface at Haughton and is likely due to the coarse particle size distribution of the breccia relative to more silty substrates and its consequent high permeability. Current erosion of the breccia deposits at Haughton involves the local exposure of ground-ice and the resulting formation of active layer mudslides along slopes. The discrete active layer mudslides represent areas of seasonal ground-ice sapping and may have resulted in the formation and growth of distinctive valleys in the breccia bearing unique morphologic similarities with sapping valleys interpreted on Mars.

A Brief History of Studies at Haughton

1950s. The circular outline of Haughton Crater was first spotted on aerial photographs. H. R. Greiner of the Geological Survey of Canada visited the site briefly and suggested it was probably a salt piercement dome. He named it Haughton Dome, after the Reverand Samuel Haughton, a british naturalist who wrote the first account of the geology of the Arctic Archipelago based on observations and samples brought back by Capt. F. L. M'Clintock who sailed through Lancaster Sound (sea passage south of Devon) in the 1850s in search of the ill-fated Franklin Expedition.

1970s. Based on the isolation of the structure and its morphology, the Canadian impact geology pioneer M. R. Dence suggests that Haughton Dome might in fact be an astrobleme, i.e. an impact crater. D. W. Mason eventually revisits Haughton and finds shatter cones (fractured rocks presenting cone-shaped patterns of fracture diagnostic of impact shock), and with F. Blyth Robertson of the Geological Survey of Canada, formally confirms the nature of Haughton as an impact structure. In 1976, R. Thorsteinsson and T. Frisch carry out the first of a series of more in-depth studies of Haughton Crater led by the Geological Survey of Canada.

1980s. Several teams of geologists, geophysicists and paleobotanists from Canada, Germany and the U.S. investigate Haughton jointly under the auspices of the Haughton Impact Structure Study (HISS) Project. Their comprehensive survey of the geology of the structure leads to a landmark joint publication in the journal Meteoritics (Vol. 23, September 1988).

1990s. Haughton Crater is revisited on occasion. Beginning in 1997, the crater and its surroundings are studied as a promising Mars analog by the NASA-led Haughton-Mars Project.