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TitleIdentification of the Bloody Creek structure, a possible impact crater in southwestern Nova Scotia, Canada
 
AuthorSpooner, I; Stevens, G; Morrow, J; Pufahl, P; Grieve, R; Raeside, R; Pilon, J; Stanely, C; Barr, S; McMullin, D
SourceMeteoritics and Planetary Science vol. 44, no. 8, 2009 p. 1193-1202, https://doi.org/10.1111/j.1945-5100.2009.tb01217.x
Image
Year2009
Alt SeriesEarth Sciences Sector, Contribution Series 200080731
PublisherWiley-Blackwell
Documentserial
Lang.English
Mediapaper; on-line; digital
File formatpdf
ProvinceNova Scotia
NTS21A/14
AreaBridgetown
Lat/Long WENS-65.5000 -65.0000 45.0000 44.7500
Subjectsextraterrestrial geology; igneous and metamorphic petrology; geophysics; craters; meteorite craters; mineralogical analyses; structural analyses; alteration; metamorphism, shock; ground probing radar; geophysical surveys; Bloody Creek structure; Paleozoic; Devonian
Illustrationslocation maps; photomicrographs; profiles
Released2010 01 26
AbstractAn approximately 0.4 km diameter elliptical structure formed in Devonian granite in southwestern Nova Scotia, herein named the Bloody Creek structure (BCS), is identified as a possible impact crater. Evidence for an impact origin is based on integrated geomorphic, geophysical, and petrographic data. A near-continuous geomorphic rim and a 10 m deep crater that is infilled with lacustrine sediments and peat define the BCS. Ground penetrating radar shows that the crater has a depressed inner floor that is sharply ringed by a 1 m high buried scarp. Heterogeneous material under the floor, interpreted as deposits from collapse of the transient cavity walls, is overlain by stratified and faulted lacustrine and wetland sediments.
Alteration features found only in rim rocks include common grain comminution, polymict lithic microbreccias, kink-banded feldspar and biotite, single and multiple sets of closely spaced planar microstructures (PMs) in quartz and feldspar, and quartz mosaicism, rare reduced mineral birefringence, and chlorite showing plastic deformation and flow microtextures. Based on their form and crystallographic orientations, the quartz PMs consist of planar deformation features that document shock-metamorphic pressures <=25 GPa.
The age of the BCS is not determined. The low depth to diameter ratio of the crater, coupled with anomalously high shock-metamorphic pressures recorded at its exposed rim, may be a result of significant post-impact erosion. Alternatively, impact onto glacier ice during the waning stages of Wisconsinian deglaciation (about 12 ka BP) may have resulted in dissipation of much impact energy into the ice, resulting in the present morphology of the BCS.
GEOSCAN ID226642

 
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