Compare these two basalts. One is an example of a basalt flow, the other of a pillow basalt. Pillow basalts erupt underwater and cool instantaneously around their margins, while basalt flows cool more gradually, and fractures may break the flow up into discrete cooling columns.
3D model of Outcrop A
3D model of Sample B
Which basalt formed as part of a flow? (A or B)
Which basalt is more likely to be associated with oceanic sediments? (A or B)
Now take a look at this outcrop (which we can call outcrop C) from Washington state’s Columbia River flood basalt province.
3D model of Outcrop C:
What characteristics does it display?
How would you interpret the story of its formation?
The image below links to a KMZ file (3.76 MB) that can be used as a basis for a Canadian Rockies virtual field experience (VFE). The VFE consists principally of embedded GigaPan imagery, but there are also some regular-resolution photographs and two geologic base maps, one for western Alberta, and one for eastern British Columbia. There are 85 total GigaPans in this trip, arranged in chronological order of principal themes.
Summary: The Canadian Rockies are a world-class example of a fold-and-thrust belt. The geologic story begins in the Neoproterozoic with sedimentary deposition that continued until the Cretaceous, with most exposed sedimentary rocks being Paleozoic in age. Notable in particular is the Cambrian section, which includes the soft-bodied fossils of the Burgess Shale. Deformation associated with the accretion of exotic terranes west of the Rocky Mountain Trench during the Laramide Orogeny folded, cleaved, and faulted these strata toward the Western Interior Seaway. During the Pleistocene, extensive glaciation sculpted the landscape into a classic suite of alpine glacial geomorphological features. Many glaciers still exist, and can be viewed from the excellent roadways of the Canadian national park system. Recently, episodes of catastrophic flooding have dramatically altered low-lying valley regions, especially in the Canmore and Evan Thomas area. All of these features can be seen in whole or in part using this VFE platform.
Here’s a video preview of the trip:
Questions, suggestions, critique, and comment should be directed to Callan Bentley.
Users are welcome to modify the VFE to suit their needs. If you develop any ancillary assignments or student worksheets, please share them here.