Weathering images — where each one came from

Every file here is reproduced under a licence that permits it. The licence is named in the caption on the page as well, because attribution that lives only in a repository is not attribution. Retrieved 2026-09-03 from Wikimedia Commons.

If you add one: check the licence on the Commons page yourself, look at the image, and record it here. A picture that shows the wrong mechanism is worse than no picture — see the note on Minnesota at the end.

corestones-lost-creek-colorado.jpg

Granite corestones and joint-bounded blocks, Lost Creek Wilderness, Colorado.

• Photographer: Adam Baker
• Licence: CC BY 2.0
• Source: https://commons.wikimedia.org/wiki/File:Boulders,_Lost_Creek_Wilderness.jpg
• Processing: resized to 1600 px wide, re-encoded at JPEG quality 82.

corestones-vedauwoo-wyoming.jpg

Turtle Rock, Vedauwoo — weathered Sherman Granite, Medicine Bow-Routt National Forest, Albany County, Wyoming.

• Photographer: Carol M. Highsmith, for the Library of Congress
• Licence: public domain (Highsmith dedicated the collection to the public)
• Source: https://commons.wikimedia.org/wiki/File:Vedauwoo_Turtle_Rock,_a_towering_pile_of_weathered_Sherman_Granite_that_is_the_cornerstone_of_a_3.2-mile_trail_in_the_Medicine_Bow-Routt_National_Forest_between_Laramie_and_Cheyenne_on_the_Albany_LCCN2015632858.tif
• Library of Congress catalogue: https://lccn.loc.gov/2015632858
• Processing: rendered from the master TIFF at 1600 px wide, JPEG quality 82.

corestone-formation-usgs.jpg

“Weathering of joint blocks and stages in the formation of corestones” — the mechanism this exercise models, drawn.

• Source publication: Huber, N.K., 1987, The geologic story of Yosemite National Park: U.S. Geological Survey Bulletin 1595, 64 p. https://doi.org/10.3133/b1595
• Licence: public domain (work of the U.S. Geological Survey)
• Source: https://commons.wikimedia.org/wiki/File:Weathering_of_joint_blocks_and_stages_in_the_formation_of_corestones.jpg
• NOTE: the Commons credit calls this “Professional Paper No. 1595”. That is wrong — 1595 is a Bulletin, confirmed against the USGS publication record and its DOI. The citation above is the corrected one; do not copy Commons’.
• Processing: resized to 1280 px wide, JPEG quality 82.

weathering-rinds-galicia.jpg

Concentric spheroidal weathering rinds in granite, Estaca de Bares, A Coruña, Galicia, Spain. A coin gives the scale.

• Photographer: Wikimedia Commons user PePeEfe
• Licence: CC BY-SA 3.0
• Source: https://commons.wikimedia.org/wiki/File:Concentric_spheroidal_weathering_in_granite.JPG
• Processing: re-encoded at JPEG quality 82; not resized (1024 px original).

Considered and rejected

• Morton Outcrops Scientific and Natural Area, Minnesota (Morton Gneiss, CC BY-SA 4.0, Tim Kiser). Rejected after looking at it. The outcrop is glacially scoured, so its roundness is ice, not weathering — the opposite of what this page teaches. Southwestern Minnesota’s crystalline exposures are generally stripped rather than deeply weathered, which is why the search for a corestone photograph there came up empty on Commons.