File:Dike intruding tillite (Nipissing Diabase & Gowganda Formation, Paleoproterozoic; Percival Lake roadcut, Ontario, Canada) 10 (47674714572).jpg
Original file (4,000 × 3,000 pixels, file size: 8.65 MB, MIME type: image/jpeg)
Captions
Summary
[edit]DescriptionDike intruding tillite (Nipissing Diabase & Gowganda Formation, Paleoproterozoic; Percival Lake roadcut, Ontario, Canada) 10 (47674714572).jpg |
Dike intruding tillite in the Precambrian of Ontario, Canada. This outcrop has intrusions of dark-colored mafic dikes (now metamorphosed to greenstones) in glacial tillites. The glacial deposits are part of the famous Gowganda Formation, a ~2.3 billion year old deposit in Ontario, Canada representing a very ancient Ice Age. Other glacially-deposited sedimentary rocks of Paleoproterozoic age have been reported from Wyoming, Finland, India, southern Africa, and Australia. The glaciation was likely a widespread event, and may have persisted for a long time. This ice age is hypothesized to have been triggered by decreasing levels of methane gas (CH4) in the atmosphere as oxygen gas (O2) levels increased (the methane oxidized to carbon dioxide). This lessened the effects of greenhouse warming, and resulted in climate cooling. The dikes are part of a tholeiitic gabbroic complex called the Nipissing Diabase. Specific intrusion types include dikes, sills, conical intrusions, and irregularly-shaped plutons. The major igneous minerals reported from the Nipissing Diabase are plagioclase feldspar and various types of pyroxene. Minor minerals include olivine, ilmenite, quartz, potassium feldspar, amphibole, magnetite, pyrite, and pyrrhotite (sulfides were observed in the Nipissing at this outcrop). Lithologies in the Nipissing actually range from gabbros to pyroxenites to granophyres. Regional metamorphism has reached greenschist to amphibolite grade, resulting in the presence of several common metamorphic minerals: actinolite, chlorite, epidote, amphibole, garnet, and biotite mica. Minor peperitization has occurred here. Peperites are breccia-like, clastic-textured rocks formed when magma or lava encounters wet, unlithified sediments. Stratigraphy of host rocks: Coleman Member, Gowganda Formation, lower Cobalt Group, Huronian Supergroup, Paleoproterozoic, ~2.3 Ga Geology of dikes: Nippissing Diabase, Paleoproterozoic, 2.219 to 2.220 Ga Locality: Percival Lake outcrop - roadcut on the eastern side of Route 144, opposite Percival Lake, north-northwest of the town of Cartier, Ontario, southeastern Canada (46° 45’ 47.38" North latitude, 81° 35’ 50.64" West longitude) (= stop 35 of Rousell et al. (2009) - A field guide to the geology of Sudbury, Ontario. Ontario Geological Survey Open File Report 6243, p. 165.) Some info. from: Blonde (1996) - Petrology and Metamorphism of Nipissing Diabase of May Township, Ontario. M.S. thesis. Carleton University, Ottawa, Ontario. 160 pp. See info. at: <a href="https://en.wikipedia.org/wiki/Nipissing_sills" rel="noreferrer nofollow">en.wikipedia.org/wiki/Nipissing_sills</a> |
Date | |
Source | Dike intruding tillite (Nipissing Diabase & Gowganda Formation, Paleoproterozoic; Percival Lake roadcut, Ontario, Canada) 10 |
Author | James St. John |
Licensing
[edit]- You are free:
- to share – to copy, distribute and transmit the work
- to remix – to adapt the work
- Under the following conditions:
- attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
This image was originally posted to Flickr by James St. John at https://flickr.com/photos/47445767@N05/47674714572 (archive). It was reviewed on 22 October 2019 by FlickreviewR 2 and was confirmed to be licensed under the terms of the cc-by-2.0. |
22 October 2019
File history
Click on a date/time to view the file as it appeared at that time.
Date/Time | Thumbnail | Dimensions | User | Comment | |
---|---|---|---|---|---|
current | 06:07, 22 October 2019 | 4,000 × 3,000 (8.65 MB) | Rudolphous (talk | contribs) | Transferred from Flickr via #flickr2commons |
You cannot overwrite this file.
File usage on Commons
There are no pages that use this file.
Metadata
This file contains additional information such as Exif metadata which may have been added by the digital camera, scanner, or software program used to create or digitize it. If the file has been modified from its original state, some details such as the timestamp may not fully reflect those of the original file. The timestamp is only as accurate as the clock in the camera, and it may be completely wrong.
Camera manufacturer | Canon |
---|---|
Camera model | Canon PowerShot D10 |
Exposure time | 1/200 sec (0.005) |
F-number | f/11 |
ISO speed rating | 80 |
Date and time of data generation | 10:56, 16 July 2012 |
Lens focal length | 11.614 mm |
Width | 4,000 px |
Height | 3,000 px |
Bits per component |
|
Pixel composition | RGB |
Orientation | Normal |
Number of components | 3 |
Horizontal resolution | 180 dpi |
Vertical resolution | 180 dpi |
Software used | Adobe Photoshop Elements 16.0 (Macintosh) |
File change date and time | 19:58, 28 April 2019 |
Y and C positioning | Co-sited |
Exif version | 2.21 |
Date and time of digitizing | 10:56, 16 July 2012 |
Meaning of each component |
|
Image compression mode | 3 |
APEX shutter speed | 7.65625 |
APEX aperture | 6.90625 |
APEX exposure bias | −0.33333333333333 |
Maximum land aperture | 4 APEX (f/4) |
Metering mode | Pattern |
Flash | Flash did not fire, compulsory flash suppression |
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 | Landscape |
Lens used | 6.2-18.6 mm |
Date metadata was last modified | 15:58, 28 April 2019 |
Unique ID of original document | 06C41A2C48C056D48982B1D91E3207E6 |