Work

Geology of the central uplift of the Kamestastin Lake impact structure, Labrador, Canada

Year: 2026

Type: article

Abstract: The ~28 km Kamestastin (Mistastin) Lake impact structure is a relatively well‐preserved and well‐exposed complex impact structure. The central uplift of this structure is accessible as two islands in the middle of Kamestastin Lake. We present an updated, detailed geological map and description of Horseshoe and Bullseye islands that provides increased accuracy and detail of the target rock outcrop and contact locations. In addition, we document six occurrences of impact melt‐poor breccia dikes and one occurrence of impact melt rock on Horseshoe Island for the first time. The impact melt rock outcrop is proposed to be a remnant of a veneer of impact melt on the original central peak, and the impact melt‐bearing breccia dikes to have had a dynamic emplacement mechanism. We also carried out the first detailed, systematic shock study of the central uplift. Planar deformation features in quartz and diaplectic feldspar glass suggest local peak shock pressure of up to 45 GPa. These shock pressures are higher than the peak pressures recorded in the central uplifts of similarly sized impact structures. We suggest that this difference is due to the minimal erosion of the central uplift at the Kamestastin Lake impact structure.

Source: Meteoritics and Planetary Science

DOI: 10.1111/maps.70184

Authors: A. C. Singleton, G. R. Osinski

Institution: Western University

Language: English

Topic: Astro and Planetary Science

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,300

Funders: Canadian Space Agency, Natural Sciences and Engineering Research Council of Canada