Geological structure of Charity Shoal crater, Lake Ontario, revealed by multibeam bathymetry

Holcombe, Troy L.; Youngblut, Scott; Slowey, Niall C.

doi:10.1007/s00367-013-0322-6

Cited by 6 publications

(4 citation statements)

References 16 publications

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“…The concentric gullies between the exposed Paleozoic bedrock scarps are due to the alternation of more erosion-resistant dolomitic limestones, with weaker shale units within the Trenton Group. A similar pattern of glacial erosion and craig-and-tail development has been identified at the Charity Shoal structure on the lakebed of northeastern Lake Ontario (Armour, 2022;Holcombe et al, 2013).…”

Section: Postimpact Modificationsupporting

confidence: 65%

“…The structure surface morphology of Holleford crater (Figure 2a) is similar in many respects to the Charity Shoal structure, a proposed 1.2 km diameter impact structure in eastern Lake Ontario (Armour, 2022;Holcombe et al, 2013;Suttak, 2013). Both structures have a raised bedrock rim that encloses a central synformal basin with Paleozoic carbonate strata dipping radially at low angles into the basin center (Figure 2a).…”

Section: L3 -L Cambrian Clastic Sediments L1 -Mesoproterozoic Basementmentioning

confidence: 67%

“…Both structures have a raised bedrock rim that encloses a central synformal basin with Paleozoic carbonate strata dipping radially at low angles into the basin center (Figure 2a). The rim structure at Charity Shoal has been attributed to the conformal (drape) deposition of Middle Ordovician (Trenton Group) carbonate sediments over a buried impact structure followed by differential glacial erosion and plucking of dolomitic limestones (Holcombe et al., 2013). Both structures are examples of glacial craig‐and‐tail landforms, produced by erosional streamlining of Paleozoic below southwest‐flowing ice during the last (Late Wisconsinan) glaciation (Bukhari et al., 2021) (Figure 2a).…”

Section: Discussionmentioning

confidence: 99%

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3‐D geophysical modeling of a buried, simple impact crater: Holleford impact structure, Ontario, Canada

Armour,

Boyce,

Shulman

et al. 2023

Meteorit & Planetary Scien

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Holleford Crater is a deeply buried, 2.35 km diameter late Proterozoic‐early Cambrian (550 ± 50 Ma) simple impact crater located in southeastern Ontario, Canada. Exploration drilling in the 1950–60s indicated a >450 m deep, simple impact structure with an infill stratigraphy of Cambro‐Ordovician clastic and carbonate sediments and a −2.2 mGal gravity anomaly. We conducted new ground‐based geophysical surveys (magnetics, gravity) and potential field modeling to better resolve the buried impact structure depth, subsurface geometry, and postimpact modification. Geophysical surveys reveal a well‐defined ~3 mGal Bouguer gravity low and <20 nT residual magnetic anomaly over the crater basin. The lack of a well‐defined magnetic anomaly is due to the low magnetic contrast between Mesoproterozoic metasedimentary target rocks and Paleozoic infill sediments. The modeled basement surface shows a deeply buried (>400 m), eroded simple impact structure with a rim‐to‐rim diameter (D) of 1.8–2 km, a residual rim height of about 30 m and a true depth (dt) >400 m. The modeled diameter is smaller than the previous estimate (2.35 km) based on the surface outcrop pattern of Paleozoic strata, which overestimates the buried impact structure dimensions. The modeled basement surface identifies a rim breach and a possible fluvial outflow channel in the southeast impact structure rim. The channel is up to 150 m deep and 400 m in width and has morphology similar to outlet channels produced by fluvial rim dissection of terrestrial impact structures and “tadpole craters” on Mars.

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Section: Postimpact Modificationsupporting

confidence: 65%

Section: L3 -L Cambrian Clastic Sediments L1 -Mesoproterozoic Basementmentioning

confidence: 67%

Section: Discussionmentioning

confidence: 99%

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3‐D geophysical modeling of a buried, simple impact crater: Holleford impact structure, Ontario, Canada

Armour,

Boyce,

Shulman

et al. 2023

Meteorit & Planetary Scien

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“…simple impact crater (Fig. 5) as proposed by Holcombe et al (2013). Future work will include coring and sampling of crater sediments and bedrock for evidence of meteoritic material and shock metamorphic effects, and analysis of vector magnetic data collected over the crater.…”

mentioning

confidence: 99%

Seismic and Magnetic Survey of the Charity Shoal Suspected Impact Structure, Eastern Lake Ontario, Canada

Armour¹,

Boyce²,

Suttak³

2016

Geological Society of America Abstracts With Programs

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The Charity Shoal structure (CSS) is a 1.2 km diameter, bedrock-rimmed circular depression in the lakebed of northeastern Lake Ontario (Fig. 1). The CSS has been interpreted as a possible Ordovician-age simple impact crater based on multi-beam imaging of the lakebed (Holcombe et al. 2013) but the subsurface structure was not resolved. Other possible origins include a karst sinkhole, glacially erosion (e.g. kettle hole), basement structural depression or Jurassic volcanic intrusive (Suttak, 2013). Detailed magnetic and high-resolution chirp and 1.5 kHz boomer seismic (>400-line km) surveys were conducted across a 9-km 2 area to investigate the subsurface structure. Total magnetic intensity (TMI) data (Fig. 2) reveal a large (>1400 nT) magnetic anomaly centered over the crater basin and a ring-like magnetic high (40-50 nT) corresponding with the raised bedrock rim (Fig. 3). Depth to basement below the structure was estimated at 600 m using extended Euler deconvolution (Fig. 3F).

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The origins of s-forms: Form similarity, process analogy, and links to high-energy, subglacial meltwater flows

Shaw

Gilbert

Sharpe

et al. 2020

Earth-Science Reviews

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Geological structure of Charity Shoal crater, Lake Ontario, revealed by multibeam bathymetry

Cited by 6 publications

References 16 publications

3‐D geophysical modeling of a buried, simple impact crater: Holleford impact structure, Ontario, Canada

3‐D geophysical modeling of a buried, simple impact crater: Holleford impact structure, Ontario, Canada

Seismic and Magnetic Survey of the Charity Shoal Suspected Impact Structure, Eastern Lake Ontario, Canada

The origins of s-forms: Form similarity, process analogy, and links to high-energy, subglacial meltwater flows

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