File:Asteroid tsunami in the Gunflint 1,850 my.jpg
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Summary
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| Description |
Natural history story written in 1.85 billion year old iron formation. The most impressive feature of a two day geology tour was this chaotically folded Sudbury Impact Layer in the Gunflint Iron Range as dished out by ~36,000 mph, ~10 mile-wide asteroid abruptly encountering our planet, 480 miles (770 km) east of here. Way back then, this outcrop was an unsuspecting tidal mudflat consisting of vertically-stacked horizontal layers made of alternating fine-grained iron oxide and white silica gel. Without the black-and-white contrast of these layers, the chaotic folding caused by the asteroid impact would be much less apparent. The Sudbury Impact Layer seems to form the topmost layer of every iron range hereabouts. The SIL is rarely exposed at surface but it has been drilled in various places throughout Minnesota, Wisconsin, Michigan and northwestern Ontario. The evidence, so far, points to the Sudbury impact event terminating the wet, soft sediment accumulation of iron formation throughout this modest-sized Proterozoic sedimentary basin. The once-continuous iron formation of Proterozoic age now consists of five "iron ranges". About a trillion tons of iron have been recovered across a span of 150 years from many iron mines with Minnesota's outstanding Mesabi Iron Range still producing today. |
| Date | |
| Source | Asteroid tsunami in the Gunflint, Stop 12 |
| Author | Mike Beauregard from Nunavut, Canada |
| Camera location |  | View this and other nearby images on: OpenStreetMap |  |
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This image was originally posted to Flickr by subarcticmike at https://flickr.com/photos/31856336@N03/27206234405. It was reviewed on 21 August 2016 by FlickreviewR and was confirmed to be licensed under the terms of the cc-by-2.0. |
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| Date/Time | Thumbnail | Dimensions | User | Comment | |
|---|---|---|---|---|---|
| current | 20:49, 22 August 2016 | | 3,600 × 2,170 (3.86 MB) | Tillman (talk | contribs) | Cropped 13 % vertically using CropTool with lossless mode. |
| 04:12, 21 August 2016 |  | 3,600 × 2,487 (4.25 MB) | Tillman (talk | contribs) | Transferred from Flickr via Flickr2Commons |
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