Friday, November 21, 2014

Educational Outreach

This fall, Gwen has had several opportunities to pass along her passion by educating others about geology and anthropology. During a junior high level nature and biology trip, she explained to students how glacial erratics ended up in Central Illinois and gave a bonus lesson on the formation of igneous rock.

Glacial erratic at Forest Park Nature Center

During a homeschool co-operative, Gwen gave a presentation to the younger kids about Native American artifacts and how to collect and catalog them.
Discussing artifacts at a homeschool co-op

Presenting a three-quarter grooved stone axe to the students
 And then Gwen and her brother Ronan headed down to Dickson Mounds to help visitors make origami bats and other crafts for Going Batty! A few weeks later, both Gwen and Ronan volunteered to help with Ancient Arts in Illinois. Many opportunities to pass on their knowledge and sharpen their own skills.
Gwen at the origami station 

Ronan at the bat puppet station

Tuesday, August 26, 2014

Boxes of Rockses

Recently, Team Paleo member Katie downsized her vast collection of fossils and rocks. Most were donated by her grandfather, who is active in Peoria Academy of Science Geology Section. Contained in several large moving boxes, the collection was jumbled together with little sorting or identification. Being an avid fan of the geological field, I graciously agree to take the extra objects in the collection.

I got the collection home and hauled the ridiculously heavy boxes upstairs to a sorting table, where I laid each specimen out so I could see in entirety the rocks. Some of the objects had been bagged and labeled, while others were thrown higgledy-piggledy into tupperware containers. At this point, I knew I had to further sort and narrow down the specimens in order to make them manageable.

The rock and fossil collection when first unpacked ~ vast and jumbled

Thanks to opportunities to sort and catalog the type collection at Dickson Mounds Museum, I have had experience with sorting specimens into manageable groups for labeling and organizing. I used the same techniques I learned at Dickson Mounds to tackle my own recently acquired rock collection.

My end goal is to have everything carefully cataloged and boxed or bagged, with any duplicates, extras, or unwanted specimens in storage. I would like to eventually have a series of shelves where the specimens can be laid out without being broken or damaged. My criteria for what I would like to keep is 1. things I find interesting, 2. specimens of strange or rare minerals and fossils, and 3. some of the most common fossils and minerals, along with multiple variations of each.

~~~~~

Determining what specimens I have is part of sorting. While some specimens were labeled, others were just stuck in a box with no designation. Using my geology handbooks and research websites, I began to lengthy process of identifying the unlabeled specimens.

I'm not 100% certain what this rock is, but I think it is shale, due to the numerous layers and light color. The sample is very light-weight and chalky, of a mostly fine-grained material like silt or mud. However some layers appear to be made up of  larger grains. 

The top specimen is sandstone, which has become partially geodized. The specimen below is likely limestone, which has also become host to a geode. Both rocks are similar, however the sandstone seems to be made up of larger grains and has cross-bedding and deposits other minerals (beside the geode). Whereas the limestone is much siltier and smooth. The weight of each rock is similar.
Geodes are formed similarly to chert, where a hollow irregularity in sandstone or limestone matrix becomes filled with mineralized water. In some cases, such as in the creation of chert and jasper, the irregularity completely solidifies. In the case of geodes, quartz and other minerals form around the exterior circumference of the hollow area. In most geodes, the crystals never grow enough to completely fill the area, however there are specimens of solid geodes.

This is a GNEISS rock. (You pronounce gneiss as 'nice') Although similar in appearance to granite, gneiss has a different breaking pattern and is generally 'banded' in appearance, displaying the different layers of deposition. If you were to compare a piece of gneiss next to granite, you would see that the particles in gneiss all align in the same direction while the particles in granite are wacko skitzy all over the place. Wacko skitzy meaning muddled and chaotic. Gneiss would shear off with the grain like slices, while granite, since the particles are chaotic, it breaks in many directions at once, or in chunks and crumbles. All rock wants to break along a particle line, but with granite, the particles go in so many directions the break wanders around finding the easiest path.

Volcanic basalt- formed by lava flows and is a classic igneous rock. While hard to see in the picture, the rock has a fine crystalline structure that is often overlooked. 

After much research, I identified this as the petrified branch of a tree. While most people are accustomed to using the term 'petrified', the scientific term is 'permineralized'. Petrified means 'turned to stone, while permineralization is the process by which organic material is turned to stone. When the material is buried by sediment, mineralized water seeps over time into the organic object, replacing organic materials with minerals. In this case, the organic material was a tree branch or wood.
Another possibility is that this is a fossilized long bone, however generally fossilized bone has a porous appearance, while this specimen appears to be smooth. I will continue to research and seek a professional opinion.

Article and commentary written by Gwen McDaniel

Saturday, August 9, 2014

Lego Team Paleo

In the late hours of the night, during the goofiness that is a slumber party, Lego Team Paleo was born...


We have Emily, Katie, Dr Mike, Jen, and Gwen....

Coming soon... Lego Team Paleo Junior!

Friday, August 1, 2014

Clay Pots and Porcelain

This week, Team Paleo finished up one project and assisted with another. 

The team has been working on sorting, photographing, and organizing the museum type collection for many months. During the last two weeks, they organized a large collection of lithic points and other objects donated by another local museum. Each piece needed to find a home in the large type collection. 

Later in the day, Team Paleo got to offer a small help to a large project. Dickson Mounds has been adding an exhibition of Illinois life in the early 1800's, so the team got to unpack some of the artifacts that will be displayed. Instead of stone arrow points and earthen clay jars, the collection included steel knives and blue porcelain transferware. 


Sorting lithic points by type and placing them in large wooden drawers for the type collection.

A tiny number of the large lithic point collection to be sorted.

There is always time for some jokes and laughter in the collections room...

Our fearless leader, Dr. Michael Wiant, ponders lithic types.

The Illinois in the 1800's collection- Carefully boxed up and ready to be displayed in the new exhibit.

Early 1800's artifacts. Containers evolve from clay pots to glass and porcelain.

Team Paleo volunteer, Ronan, unpacks a box of interesting artifacts.







Friday, July 25, 2014

Last Dig Day

Often archaeologists discover most of their finds toward the end of the dig. It's a bit of a frustrating conundrum! On Gwen's last dig day, she took lots of pictures of a house the MSU team was excavating.

In a smaller pit feature, we found exposed bone, likely from a meal of a larger bird like the geese and ducks that still inhabit the nearby Emiquon Nature Preserve. Bones and scraps like this are tossed into a garbage pit where we find them today. Obviously, it is helpful to know what the people are eating, but quantity of materials also helps us know how many people may have been living there. For example, if we find large quantities of deer bones we know deer were abundant at that time. We might go further and see if they are using the bones to make tools, like needles, awls, hoes from deer mandibles and scapulae.
We also see a reddish chunk of sandstone in the lower right hand corner of the image. It was exposed to fire at one point, as the sandstone is red. 

The morning weather was unsettled and scattered showers kept hitting the site. But the clouds cleared quickly and by ten in the morning, we were enjoying sunny weather. We can continue to dig during a light rain, with the use or tarps and tents (which also keep the glaring sun off of us on hot days). But we have to 'tarp up' the dig site in heavy rain. This means we must cover every inch of the excavated area with a large tarp, using sandbags to try to seal and secure the edges. Nevertheless, rain water will still percolate into the excavation. It is, after all, a big hole in the ground. Sometimes pumps must be used to siphon the excess ground water out of the excavated areas. 

At the house, we see a cross section or profile of the excavation. Charred logs are easy to see- possibly a sign that the house building burned in a fire. Already removed from this section were 3 or 4 other charred logs. 

This is a closeup of the image above, where we saw evidence of charred logs. You can see that the soil here is yellow and lighter in color than the surrounding soil. The lighter soil is the natural floor of the house when the original residents lived there. In other words, it is ground level. All the darker dirt on top is from the plow zone or A horizon fill- this is soil, organic material, artifacts, and naturally accumulating materials that fill in where the house used to be.
Usually, these homes were built by digging a basin into the earth, then building short walls around the edges. Imagine the classic 'sunken living room' in a modern house- except the entire house is sunken. 


Here you see a large pit feature in the earliest stages of excavation. Across the approximate center is a string, which marks the diameter of the circular shape of the feature. The string provides a straight line, making it easier to know where to dig. You start by digging on one side of the string giving us a clean profile wall along the string. 
This is the same pit feature as above, but digging has commenced. Digging occurs in 10 centimeter deep increments, creating levels that are clean scraped, mapped, and photographed for documentation. The reason for going down 10 centimeters at a time is so you can see the pit feature as it progresses down. This also saves the excavators and screeners from processing clay-like b-horizon soil that is not part of the feature.

Same feature, clean scraped and ready for photography- You can faintly see the edge of the feature where the darker soil meets a lighter, yellow soil, near the upper left hand side of the photograph. So where we see this soil demarcation, the edge of the pit feature is established. 

Here is another example of bisection lines. This feature has not been excavated at the time of the photograph. 

One of the MSU students excavated this feature- a post mold with the remains of the charred post still visible. You can see the bisected profile wall clearly here. Once the feature has been photographed, the charcoal is carefully removed and wrapped in tin foil to protect the friable material. Samples are sent to the lab for analysis of the type of wood used. It could also be dated for age. 

A large fragment of decorated pottery- I found this in the pit pictured above. 

This is an exciting find- burned roofing thatch that had fallen into the pit feature we were digging. Likely to be made from grasses, thatching was used for covering the roof of a structure- probably a home. Preservation in this pit is good, as charcoal often degrades easily. 

Here we see the pit feature containing the charred roofing thatch. We can also see the straight bisection line dividing the pit in half, as well as the excavation boundaries. Each level is 10 centimeters deep, and like stairsteps. Of course, the pit would not have originally been dug in stairsteps- this is a result of careful excavation which shows the borders of the pit at each 10 centimeter level. 

A photo showing the entire excavation block in which we worked. Our pit with the charred thatch is in the center of the image. In the upper left hand side is another large pit feature- you can see that the walls are almost straight down, rather than stepped. This is because the pit is deep and cylindrical in shape, where as the charred thatch pit is more shallow and the walls are bowl shaped. However, later in the dig we discovered that what we thought was a shallow bowl ended up being a six foot deep storage pit.

Gwen at the dig. 

One large block and a screening shade to the right.



The Michigan State University students and teachers along with Dickson Mounds Museum staff