File:Boyle Formation over the Estill Shale (Devonian over Silurian; Drowning Creek West roadcut, Madison County Kentucky, USA) 2.jpg
Original file (1,280 × 935 pixels, file size: 1.15 MB, MIME type: image/jpeg)
Captions
Captions
Summary[edit]
_2.jpg&action=edit§ion=1){kind=link}
| Description |
English: Wallbridge Unconformity in Kentucky, USA.
The cliff-forming rocks in the middle and upper parts of the picture are cherty limestones of the Middle Devonian Boyle Formation. The gray rocks at the bottom of the picture are the Lower Silurian Estill Shale (also known as the Crab Orchard Shale). The entire Upper Silurian and Lower Devonian are missing at the contact, representing about 40 to 50 million years. The Boyle-Estill contact is a megasequence boundary called the Wallbridge Unconformity - it's the Tippecanoe-Kaskaskia Megasequence boundary. Regionally recognizable packages of sedimentary rocks bounded by major unconformities are known as megasquences, or Sloss sequences (named after geologist L.L. Sloss, 1913-1996). The bounding unconformities were caused by erosion during regressions. Continental margins have more complete sedimentary successions, whereas craton interiors have more incomplete successions. The names for North America's megasequences are (from oldest to youngest): Sauk, Tippecanoe, Kaskaskia, Absaroka, Zuni, and Tejas. Stratigraphy: Casey Member of the Boyle Formation (Middle Devonian) over the Estill Shale (Lower Silurian) Locality: Drowning Creek West outcrop - roadcut along the northern side of Route 52, ~1.2 miles west of Drowning Creek, far-eastern Madison County, east-central Kentucky, USA |
| Date | |
| Source | https://www.flickr.com/photos/47445767@N05/52889240497/ |
| Author | James St. John |
Licensing[edit]
_2.jpg&action=edit§ion=2){kind=link}
- 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@N05/52889240497. It was reviewed on 12 May 2023 by FlickreviewR 2 and was confirmed to be licensed under the terms of the cc-by-2.0. |
File history
Click on a date/time to view the file as it appeared at that time.
| Date/Time | Thumbnail | Dimensions | User | Comment | |
|---|---|---|---|---|---|
| current | 13:20, 12 May 2023 | | 1,280 × 935 (1.15 MB) | Ser Amantio di Nicolao (talk | contribs) | Uploaded a work by James St. John from https://www.flickr.com/photos/47445767@N05/52889240497/ with UploadWizard |
You cannot overwrite this file.
File usage on Commons
There are no pages that use this file.
_2.jpg&oldid=831135147){kind=link}