ADVENTURES WITH ROCKS (TM): CANNONBALLS, POTTERY, AND OLD PLANTS

One of the most intriguing places we have been this summer is the Badlands of North Dakota. It also was a place that held many surprises for people like us who love rocks. We have been to the Badlands in South Dakota, in Utah, and in Nebraska, but the Badlands of Western North Dakota were different. Here in this arid grassland, where buttes of multicolored layers of sedimentary rock and volcanic tuff rise majestically above lush prairie, there are abundant examples of how diverse and fascinating rocks can be.

View of Badlands, South Unit

The Paleocene landscape in the North Dakota of 60
million years ago was swampy bottom-land covered with thick vegetation and dense forests of sequoia, bald cypress, and other water-loving trees. Ancient rivers carried sediments of mud, sand, and silt off of the newly forming Rocky Mountains and deposited them in layers. Volcanoes in Montana and Idaho erupted and spewed huge amounts of ash into the swamps and rivers of Paleocene North Dakota. It was during these conditions that some of the most interesting rocks that I have ever seen were formed. And that’s saying something, because I sure have seen a lot of interesting rocks in my lifetime.

Petrified Wood

To begin with, fossils and petrified wood erode out of badlands buttes in abundance. Some sequoia and cypress stumps that have been found here are enormous specimens over 12 feet in diameter. While petrified wood can be found in many places, a type unique to the North Dakota Badlands is called Teredo-bored because it contains the fossilized remains of holes bored in the wood by little ancient clams called Teredos.

Another interesting formation is the layer of lignite coal that is found throughout the badlands. Lignite coal is younger, geologically speaking, than harder, higher grade bituminous coal. It is the lowest rank of coal with the lowest energy content. It is formed from peat and plants, like other coals, but lignite coal is formed at shallower depths and with less heat and pressure than other coals. It is softer than bituminous coal and has a higher moisture content. It is also volatile. It burns easily

Lignite Coal Vein (black streak)

and has a tendency to spontaneously combust. Lightning strikes and prairie fires often ignite seams of lignite coal.

This tendency of lignite coal to combust creates another of the curious types of rock found in the North Dakota Badlands – a reddish rock called scoria. Scoria is baked and fused clay, shale, and sandstone. Scoria forms in thick layers or massive chunks of fused pieces of sandstone and clay. These reddish layers and masses of baked material formed in areas where seams of lignite coal burned. The heat
produced from the burning coal baked nearby sediments into a natural

Scoria (Clinker) Outcrop

form of brick. Scoria is also called clinker, probably due to the fact that the pieces clink like pottery when they hit against each other. In fact, broken pieces of scoria look, feel, and sound like pottery shards.

By far the most interesting rocks we saw in the North Dakota Badlands were large spherical formations called Cannonball Concretions. Concretions are hard, compact masses of sedimentary rock formed when a mineral precipitation occurs around some type of nucleus, similar to how layers of minerals build up around a center core to form a pearl. Many shapes and sizes of concretions exist in the world, but the ones in North Dakota known as Cannonball Concretions are among the more unusual ones. Cannonball Concretions are made up of dissolved minerals of calcium carbonate cemented

Cannonball Concretions

with siderite, or iron carbonate. Cannonballs up to three feet or more in diameter can be found in several places in Western North Dakota. The wide variety of shapes of concretions is based on composition and cementing agent of the concretion, as well as the composition and hardness of the enclosing sediment. The Cannonballs are able to form in an enormous spherical shape because the soft bentonite clay sediment in which they form did not constrain the growth in any way.

There are several different ways to explore the rugged badlands of North Dakota, however the easiest way is to visit Theodore Roosevelt National Park. The South Unit is just off of Interstate 94 and Hwy 85, near Belfield. There are two sections of the South Unit: The Painted Canyon Overlook and the main area of the park. Painted Canyon offers a Visitor Center, expansive views of the Badland wilderness, and access to trailheads that take the visitor down into the canyon. The main section of the South Unit is a few miles west of Painted Canyon near Medora. The South Unit of the Park has a scenic drive, many trailheads, access to backcountry trails, 4-wheel drive roads and wilderness areas. There is a very nice campground in the park, but it is first-come, first-served and it typically fills up quickly. There is a both a tent camping area and a section with pull-through sites for larger RV's.

The North Unit of the Park is approximately 65 miles north of the South Unit on Hwy 85. While similar in

geology, the North Unit is different than the South Unit and worth exploring as well. There are many opportunities to experience some of the very unique rock formations, like the Cannonball Concretions, up close on some of the trails or just off the road. The North Unit offers several hiking trails, backcountry and wilderness experiences, and a scenic drive which begins in the canyon and ends up on the rim with expansive views of the badlands below. There is also a small campground located inside the North Unit with both pull-through and back-in spaces. Both the North and South Units offer Ranger Progams and the South Unit provides a ranger-guided tour deep into the heart of the wilderness to visit the Petrified Forest- a unique geological area consisting of some of the largest petrified trees in the world.

There are also abundant opportunities to see wildlife in both the north and the south unit. We saw several herds of wild horses, buffalo, and antelope, as well as deer. There are also quite a few prairie dog towns, some of which are right along the road providing excellent opportunities to sit and enjoy the antics of these cute little creatures. Because of the abundance of vegetation and trees, birds, butterflies, and the like abound as well.

Theodore Roosevelt National Park is truly a natural and geological

Buffalo in the Missouri River

treasure, and well worth the trip to this remote section of the United States. Whether just traveling through, or spending several days, the North Dakota Badlands holds spectacular surprises for all who visit. To get more information on Theodore Roosevelt National Park go to their website here. For more information on Rockhounding sites in the North Dakota Badlands go here.

Meanwhile, to follow all our adventures, and to see all our new exciting products, go to our website RocksInMyHead.com. From there you can access Facebook, Twitter, Pinterest, Flickr, and more! We will be open in Quartzsite at A37 in Rice Ranch in November, but you can also order by phone, email, or online! And don't forget, Life is Short! Go outside and Play.