Friday, August 09, 2013

On Chert

Out around Joplin, down in the Osage Plains, rest very rare natural communities in Missouri. Based on chert bedrock, chert glades are among the rarest glades in the state. Field verification remains an integral part of our ongoing glade mapping project which is now, several years after launching, coming to an end. The methodology is a little complex, but I've finally become relatively well versed in it. But the field verification is vital to accuracy.

Among the discoveries we've made during this process, the most exciting is finding hundreds of sandstone glades, some of them vast in scale. Likely one of the most depressing discoveries we made earlier this month. There are very, very few intact chert glades. All of the signatures were there on the infrared, the topography, the leaf off aerial photos, but on the ground, they weren't glades at all but slag heaps, big mounds of cherty sandy substance, the remains of mining. I'm unclear what has been mined all over the chert country, but Galena is a nearby town. It's really quite sad to see so much destruction of chert glades out in the equally destroyed chert prairie country (though I did see a pretty nice little privately owned chert prairie near a big factory of some sort). High quality prairies remain quite rare, and becoming increasingly rare with the onslaught of poor management, but high quality chert glades possibly even more so. There is, however, an effort underway in Missouri to reclassify natural communities, a project that is making natural community classification unnecessarily complex and based not in any real science, but on pronouncement. I was told recently that in the heart of dolomite glade country, around Niangua Basin where historic grazing degraded glades to chert rubble overburden, that these are "chert glades." They are dolomite glades with chert rubble. This new classification system is pretty shaky, frankly, and creates a mess of natural communities that were so aptly described in Nelson's Terrestrial Natural Communities of Missouri, the system accepted by most ecologists worth their salt.

A quick visit to the chert falls allowed me to meet C. asteroides which was actually pretty common on the chert slabs. I wonder what a quality chert glade looked like 200 years ago before the age of extraction began.

3 comments:

Ana said...

Hi Alllison,

We have an area of our farm that looks quite unusual and distinct. Wondering if it could be chert. Are these maps you compiled available to the public? How would I identify a chert glade? We are located south of Ava.

Thank you,

Ana

Allison Vaughn said...

Hi Ana, The glade map is now public, and I'll post the link for download. Tons of glades around Ava, but mostly dolomite. The chert formations are in the Joplin area and extends into parts of Arkansas around Eureka Springs. Let me get that link --you can see if we mapped the glades on your property. The Protem quadrangle around Ava has the largest population of dolomite glades in Missouri!

Allison Vaughn said...

Here's the link to the public glade map of Missouri:
http://gcpolcc.databasin.org/maps/4a84fba3e73e43f3988d1eea3e090f14

You should be able to scroll in to see your family's property...