If you like aerial imagery at all, download this extension for your Chrome web browser: Earth View from Google Maps.
It drops you into a new and beautiful aerial image every time you open a new tab, and even lets you link to the Google Map view so you can pan around and see what's nearby. Amazing. Definitely the best thing that's ever happened to Chrome.
I just got this image of complex folding in Australia and it made my day.
I came across this little gem of a fault propagation fold last year while driving back from Washington DC along Corridor H (Highway 48) in eastern West Virginia.
If you don't know or remember what a fault propagation fold is, it's a thrust-related fold where part of the displacement on the fault goes into faulting new rock ahead of the fault tip, and part of the displacement goes into folding, or bending the layers above the thrust.
In this particular outcrop, the thrust ramp has propagated along cross beds in the Tuscarora Sandstone. This complicates the classic fault propagation fold geometry that we might see with originally horizontal stratigraphy (as shown in the image above), but it's still a fault propagation fold. What's nice here is that it's possible to match beds that were cut by the thrust and see that displacement decreases toward the fault tip: a diagnostic feature of fault propagation folds. The fault tip is also visible in outcrop.
In the 3D image below, click through the annotations to see how the thrust has propagated up-section. There are several other fault related folds in the view. Can you find them? Try clicking the full screen button on the bottom right for the full view.
(This will work best in Chrome or Firefox, but possibly not as well in Internet Explorer).
This is a press release about some funding I received from NRCCE to study fractures in shale outcrops to develop a "fracability index" and relate fractures in outcrop to those in the subsurface.
Here's my first attempt at creating a 3D outcrop. Changing spatial perspective is very important in structural geology, and models like this can open up new ways of visualizing and analyzing geology. In this case, I'd like to document fracture sizes and scaling in 3D (more on that below)
The Devonian Helderberg Group is exposed along large roadcut on Highway 48. These predominantly limestones were deposited in an epeiric sea that existed between the Taconic highlands to the southeast and the Cincinatti and Algonquin arches to the west (Smosna, 1988). The unit has been evaluated as a possible seal for CO2 sequestration purposes associated with the Burger electric power plant (Lewis, et al. 2009).
My interests in digitizing the outcrop are mainly in testing the photogrammetry technique for the purposes of documenting fracture network geometries in 3D. This outcrop is actually fascinating to view from different angles, because several different fracture sets come into view depending on how we rotate the model.
The 3D Outcrop