A possible multiple impact crater site in southwestern Nova Scotia, Canada
LE3 .A278 2010
Pufahl, Peir K.
Bachelor of Science
Earth & Environmental Sciences
An approximately 0.4 km diameter elliptical structure was identified in southwestern Nova Scotia in 1987 during a regional airphoto survey. The structure was confirmed as an impact crater in 2009, and was named the Bloody Creek structure ( BCS). In addition to the main crater, a cluster of discontinuous arcuate scarps located approximately 1 km north of the BCS was identified. These arcuate scarps have been called the North Group. This study has identified these arcuate scarps as possible impact crater remnants, suggesting the impactor fragmented upon entry into the atmosphere producing a crater field. Evidence for impact origin is based on an integrated analysis of geomorphic, geophysical and petrographic data collected in the summer, fall and winter of 2009. Analyses of aerial photos revealed discontinuous arcuate scarps and flat depressed inner floors. Geophysical surveys confirmed the negative relief feature of the structures. The craters are infilled with lacustrine sediment and peat. Thin- section analysis of samples collected proximal to the crater rim document shock metamorphic features that include kink bands in feldspar and biotite and planar microstructures ( PMs) in quartz and feldspar. The PMs consist of rare planar fractures ( PFs) in both quartz and feldspar and possible planar deformation features ( PDFs) in quartz. Of these features, the PDFs are considered uniquely diagnostic of shock metamorphism.
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