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Browsing by Author "Osinski, Gordon R."

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    Constraining the shock conditions experienced by Haughton crystalline basement rocks: a combined Raman spectroscopy and electron backscatter diffraction study of Anomaly Hill zircons
    (2020) Walton, Erin L.; Jurak, Haley A. M.; Timms, Nick E.; Osinski, Gordon R.
    Haughton is a 23-km diameter impact structure on Devon Island, Canada [1, 2]. The target stratigraphy comprised ~1880 m of Lower Paleozoic sedimentary rocks, unconformably overlying the Precambrian Canadian Shield [2]. Near the centre of the structure, is a location characterized by negative gravimetric and positive magnetic anomalies, known as “Anomaly Hill” [3]. Highlyshocked, pumice-like lithic clasts are abundant at this locale, and include gneissic and carbonaterich clasts [4, 5]. In this study, we examined 20 zircon grains from a single crystalline clast collected at Anomaly Hill, to reveal microstructures at the micrometer to nanometer scale. Earlier work on Haughton zircons [6] did not incorporate EBSD, and so, is missing a wealth of information to facilitate the identification of key microstructures including FRIGN (former reidite in granular neoblasts) zircon, non-FRIGN granular textures, neoblasts versus sub-grain rotation formation of subdomains, and various dissociation textures, as described in [7, 8]. The goal of our study is to constrain the shock conditions experienced by crystalline basement rocks at Haughton using zircon, a mineral that is increasingly recognized as a sensitive shock indicator.
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    Shock conditions experienced by Haughton crystalline basement rocks: A combined raman spectroscopy and electron backscatter diffraction study of a sample from Anomaly Hill
    (2019) Walton, Erin L.; Timms, Nick E.; Jurak, Haley A. M.; Osinski, Gordon R.
    Haughton is a 23-million year old impact structure with an apparent crater diameter of 23-km, formed in mixed target rocks of the Canadian High Arctic on Devon Island [1]. At the time of impact, the target stratigraphy comprised 1880 meters of Lower Paleozoic sedimentary rocks unconformably overlying granulite-facies tonalitic and granitic gneisses of the Precambrian Canadian Shield. A location near the center of the structure, characterized by strong negative gravimetric and positive magnetic anomalies, has been coined “Anomaly Hill” [3]. Highly shocked lithic clasts resembling pumice are particularly abundant at this locale, including carbonate-rich and gneiss clasts [4, 5]. In this study, a hand specimen from Anomaly Hill was investigated using an array of advanced analytical techniques. The goal is to constrain shock conditions experienced by Haughton crystalline basement rocks and their post-shock evolution.