Monthly Archives: July 2015

Ancient Dental Plaque

A University of Oklahoma scientist is perfecting the art (and by art I mean science) of studying ancient dental plaque. We’ve highlighted Dr. Christina Warinner before when her research gained national recognition. Now she’s featured in a fantastic video produced by Illumina. The company describes itself as, “a leading developer, manufacturer, and marketer of life science tools and integrated systems for large-scale analysis of genetic variation and function.” 

Dr. Warinner likes to say she’s an “archaeologist of the invisible”. She studies the dental plaque from teeth that are thousands of years old. Bacteria covers that dental plaque, from that she’s able to learn all kinds of things about the person who once used that tooth. Where they lived, what they ate, whether they were healthy or not, etc…

This video is an amazing look inside the process.

What’s a Graptolite?

Remember that Golden Spike? (Click here or scroll down one story.) It marks a boundary between two geologic time spans. In a nutshell, it’s where and when (geologically speaking) a  species makes its debut in the geologic record.
The Oklahoma spike is where Diplacanthograptus caudatus was found. It was a small aquatic animal called a Graptolite that floated around thanks to ocean currents.
Kyle Hartshorn with Dry Dredgers sent along some pictures of Graptolites that were found in Oklahoma. They’re tiny and look like pencil marks in the rock. Hartshorn told me, “Graptolites came in a variety of shapes: long and thin, short and wide, wishbone shaped, spiraled, and more.  There were quite a few forms at the places we went.”
Courtesy: Kyle Hartshorn

Courtesy: Kyle Hartshorn

Courtesy: Kyle Hartshorn

Courtesy: Kyle Hartshorn

Courtesy: Kyle Hartshorn

Courtesy: Kyle Hartshorn

This pic below is of a conodont. It was an small creature that kind of looked like an eel. The conodont below is the yellow-orange speck inside the circle. That circle is about the size of a dime and was drawn around the fossil to help spot it. Conodonts are extremely hard to spot with the naked eye.

Courtesy: Kyle Hartshorn

Courtesy: Kyle Hartshorn

These images are why I can’t help but examine rocks when I’m outside. You never know what you’re going to find, fossils can be all shapes and sizes!!

A Golden Spike in Oklahoma Marks the Spot

A Golden Spike in Oklahoma marks a geologic boundary that has the attention of scientists across the world. The picture below shows what’s called the Katian Golden Spike. It’s been placed near Atoka (about 45 miles southeast southwest of McAlester).

The Katian Golden Spike near Atoka. Courtesy: Dry Dredgers

The Katian Golden Spike near Atoka. Courtesy: Dry Dredgers

So what’s up with a big gold spike being hammered into the rocks? Well, long story short- it marks the beginning of a span of geologic time. This particular spike represents the start of the Upper Ordovician Katian Stage. The Ordovician Period is a span of time that lasted from about 485-million years ago to 443-million years ago. The Katian Stage was the second to last stage of the Ordovician. It lasted about 8-million years.

The spike marks a Global Boundary Stratotype Section and Point or GSSP. The location for a spike is determined by the first appearance of a particular species in the geologic record. In the case of the Katian Golden Spike, it marks the first place where Diplacanthograptus caudatus was found…a small aquatic animal that just floated around.

Kyle Hartshorn is with Dry Dredgers, “the oldest continuously-operating fossil club in North America”. He was also part of a group that recently toured Oklahoma’s geology and placed the spike in Atoka. He says these kinds of fossils look like little zippers or feathers, “These floating colonial animals were widely distributed by ocean currents, making them excellent tools for stratigraphic correlation.  Other wide-ranging planktonic fossils are also found at the site, including conodonts (teeth-like structures from tiny lamprey-like primitive fish) and chitinozoans (little sac-shaped fossils of unknown origin).”

The placement of a Golden Spike is mostly ceremonial, according to Hartshorn, but it does help scientists who do research there in the future. There are Golden Spikes placed around the world but only six , including the Katian Spike in Atoka, are in the United States.