File:Flint-knapped spearpoint (Flint River Chert, Oligocene; near Albany, Georgia, USA) 1.jpg
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Summary
[edit]DescriptionFlint-knapped spearpoint (Flint River Chert, Oligocene; near Albany, Georgia, USA) 1.jpg |
English: Flint-knapped spearpoint from the Oligocene of Georgia, USA. (~11.3 centimeters tall)
Knapper: Ronnie Miller "Flint" is sometimes used as a lithologic term by modern geologists, but it is a synonym for chert. Flint and chert are the same - they are cryptocrystalline, quartzose sedimentary rocks. Rockhounds often assert that flint is high-quality while chert is low-quality. Some geologists assert that "flint" implies a biogenic origin and "chert" implies a chemical origin. Many cherts do have a chemical origin - chert nodules are moderately common in some limestone units. The nodules form during diagenesis - pre-existing silica components in the carbonate sediments are dissolved, mobilized, and reprecipitated as chert masses. Some cherts do have a biogenic origin - for example, radiolarian cherts (rich in radiolarian microfossils) or spicular cherts (rich in siliceous sponge spicules). Seen here is a knapped spearpoint - it's a modern replica. The rock is "Flint River Chert", derived from the "Flint River Formation" in Georgia. Oligocene-aged fossils have been reported from the fossiliferous chert component of the unit. Stratigraphy: chert clast in the "Flint River Formation", Oligocene Locality: unrecorded/undisclosed site at or near the town of Albany, southern Georgia, USA |
Date | |
Source | https://www.flickr.com/photos/47445767@N05/51431118322/ |
Author | James St. John |
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This image was originally posted to Flickr by James St. John at https://flickr.com/photos/47445767@N05/51431118322. It was reviewed on 7 September 2021 by FlickreviewR 2 and was confirmed to be licensed under the terms of the cc-by-2.0. |
7 September 2021
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current | 14:40, 7 September 2021 | 1,613 × 3,786 (3.74 MB) | Ser Amantio di Nicolao (talk | contribs) | Uploaded a work by James St. John from https://www.flickr.com/photos/47445767@N05/51431118322/ with UploadWizard |
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Camera manufacturer | Canon |
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Camera model | Canon PowerShot D10 |
Exposure time | 1/60 sec (0.016666666666667) |
F-number | f/9 |
ISO speed rating | 80 |
Date and time of data generation | 18:01, 4 September 2021 |
Lens focal length | 7.23 mm |
Width | 4,000 px |
Height | 3,000 px |
Bits per component |
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Pixel composition | RGB |
Orientation | Normal |
Number of components | 3 |
Horizontal resolution | 180 dpi |
Vertical resolution | 180 dpi |
Software used | Adobe Photoshop Elements 18.0 (Macintosh) |
File change date and time | 23:15, 6 September 2021 |
Y and C positioning | Co-sited |
Exif version | 2.21 |
Date and time of digitizing | 18:01, 4 September 2021 |
Meaning of each component |
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Image compression mode | 3 |
APEX shutter speed | 5.90625 |
APEX aperture | 6.34375 |
APEX exposure bias | −0.66666666666667 |
Maximum land aperture | 3.34375 APEX (f/3.19) |
Metering mode | Pattern |
Flash | Flash fired, compulsory flash firing, red-eye reduction mode |
Supported Flashpix version | 1 |
Color space | sRGB |
Focal plane X resolution | 16,460.905349794 |
Focal plane Y resolution | 16,483.516483516 |
Focal plane resolution unit | inches |
Sensing method | One-chip color area sensor |
File source | Digital still camera |
Custom image processing | Normal process |
Exposure mode | Manual exposure |
White balance | Auto white balance |
Digital zoom ratio | 1 |
Scene capture type | Standard |
Lens used | 6.2-18.6 mm |
Date metadata was last modified | 19:15, 6 September 2021 |
Unique ID of original document | D7AE1840B274ABD5BF0BC3A722E73DE9 |