Indiana Geology Gallery

IMPORTANT NOTICE: All photos are copyrighted by Raymond Wiggers. If you are an educator or student and would to like to use any of these images, e-mail me and let me know how the images will be used. Please also credit me as the photographer. I ask that all companies, organizations, and government agencies contact me about my fees for the use of my photos, and about obtaining higher-quality versions on CD-ROM. Thanks for your understanding and compliance with the law.

To go directly to a particular locale shown in this gallery, click on its name below:

- Indiana Dunes State Park (Porter County)

- Lieber State Recreation Area (Owen County)

- Miami County

- Newton County

- Orange County

- Shades State Park (Fountain, Montgomery,

& Parke Counties)

- Spring Mill State Park (Lawrence County)

- Wabash County

1. Aeolian transport. Wind-driven sand flies, skips, stumbles, and jumps southward across the park's beach parking lot. For the past few thousand years, the prevailing westerly and northwesterly winds have been a big factor in the gradual migration of shore sand to the southern end of the Lake Michigan basin. This is certainly a major reason that dunes here and at neighboring Indiana Dunes National Lakeshore are much loftier than any found along the Illinois coast.

12. This odd hump of dolostone is one of my favorite geologic landmarks, because it was one of the first I explored as a Purdue University geology undergrad. Known as Hanging Rock, it's a small Silurian reef exhumed and partially eroded away by the Wabash River, near Lagro. The Silurian Period (438-408 million years ago) was a time of extensive reef formation in the Midwest. At this point in earth history, the world's sea level was considerably higher than it is today.

6. The Newton County Stone Quarry at Kentland. Note how the strata of Silurian dolostone on the quarry's east side are dipping very steeply in that direction. The strata on the western side dip steeply in that direction. What's going on? Everywhere else in this area, the rock layers are horizontal or almost so. For many years, this site was described as a "cryptovolcanic feature" -- and was thought to be the result of some sort of volcanic event in a region distinguished by its singular lack of vulcanism for the last 1.5 billion years. But certain types of evidence, including the discovery of "shatter cone" structures, strongly suggests that this is a major astrobleme, or meteorite impact site, instead. Still, the landscape is achingly flat here, and there is no crater to be seen. Can you figure out why?

5. The Seven Pillars, along the Mississinewa River southeast of Peru. These graceful forms were sculpted and dissolved out of the Silurian Wabash Formation dolostone by the rushing waters of this Wabash River tributary -- a testament to the power of lateral erosion and chemical weathering.

3. Cataract Falls, a separate section of the State Recreation Area, is one of southwestern Indiana's scenic and geologic gems. Here at the Lower Falls, Mississippian limestone is both jointed and pitted with potholes created by the turbulence and mechanical abrasion of the local stream, Mill Creek. (The limestone-colored baseball cap in the center was placed there for scale.) Potholes are fas-cinating features found at a number of waterfalls and former waterfalls in the Midwest.

10. Shades State Park is well named. Even on the sunniest summer's day, you may need a flashlight to see the rock faces clearly, due to the dense tree canopy overhead. But the park also has an impressive roster of geologic attractions. This one, the view of Sugar Creek from a high bluff, reveals a sight not often encountered in the Midwest -- a braided stream. Instead of forming one discrete channel at any one time, the water takes several paths that wind through the abundant gravel deposits.

2. Just a little east if the first photo, along the Lake Michigan shore. The border between the beach proper and the rampart of the high dunes is abrupt and dramatic. The next time you visit this or any other beach, take along a hand lens or magnifying glass and examine a handful of sand carefully. It has an amazing story to tell you. Different minerals may be present, and their degree of rounding and polish or abrasion can reveal much about their travels and origins.

4. A view of the Upper Falls, just upstream from the previous shot. As is often the case in the Midwest, the layers of Mississippian-Period limestone at this locale are horizontal, indicating that there has not been significant , strata-tilting disturbance of the Earth's crust in this region for the past 320 million years. (For an exception to this rule, see Photos 6 and 7, below.)

11. One of the best places to see a karst (limestone solution) landscape is in southern Indiana. One of the most popular attractions in this park is Donaldson Cave. It has formed in the same Salem Limestone Formation of Mississippian age that is the source of the famous Bedford or Indiana Limestone used in building construction. See also my Architectural Geology Gallery.

8. It's one thing to lose a set of car keys, but to lose a river , , , This spot along Route 37 used to be a streambed, but its stream, fittingly named the Lost River, has in this stretch been diverted underground through connecting solution channels. After traveling (as the crow flies) about nine miles west in this subterranean fashion, it reemerges at the site shown in the following photo.

9. The Orangeville Rise. At this secluded spot in the hilly, unglaciated expanse of Orange County, the Lost River re-turns to the sunlit world. Karst topography is the result of rainwater and groundwater --which both tend to be mildly acid -- slowly but relentlesly dissolving the limestone bedrock. Another typical karst landform, sinkholes, are also common in this area.

Would you like to learn more about the geology of this diverse and fascinating state? Check out my Courses, Tours, and Lectures Pages for educational events focused on the

Earth science of Indiana.