Posted on 02/15/2017 8:36:43 AM PST by fishtank
Lake Sediments Record Climate Change At Cahokia
INDIANAPOLIS, INDIANA
National Public Radio reports that climatologist Broxton Bird of Indiana University-Purdue University Indianapolis and colleagues analyzed layers of calcite crystals interspersed with layers of mud on the bottom of Indianas Martin Lake in order to learn about historic rainfall levels at Cahokia. The study suggests that beginning in the 900s, the Central Mississippi Valley received more rain than usual. And carbon isotopes found in skeletons at Mississippian cities indicate that people ate a lot of corn. That comes at right around 950, and thats around the time the population at Cahokia explodes, Bird said. Then around A.D. 1200, at a time of increased worldwide volcanic activity, the weather pattern in North America shifted. We switch to profound drought at A.D. 1350, Bird explained. According to the climate record in the Martin Lake sediments, the drought lasted for 500 years. Archaeological evidence suggests that palisades were built at Cahokia after A.D. 1250, villages were burned, and skeletal remains show signs of decapitations and other injuries.
(Excerpt) Read more at archaeology.org ...
There are also some Indian mounds near Germantown, Ohio, as well as a great pair on Mt. Maria Carey.
I used to be an archaeologist. I really dig articles like this.
Not rigged- Cahokia went from being the major artisanal and trading center of the Southeast to abandoned about 1300 AD.... It sits on what is arguably some of the richest soil on Earth, in a flood-prone bottomland where corn grows fabulously well, so it would take something like a major drought to cause their agriculture to collapse. It would have to be prolonged because the resources in that area - fish, wetland wildife and flora, deer from the uplands nearby, would take a great deal of time to be consumed- their trading network stretched from the Gulf Coast to the Rockies and East Coast and in the north, Wisconsin, so if one area experienced a poor season or two there would be some way to provide for themselves. They also built granaries against short term crisis, so whatever happened to them was not just losing one year’s crop to a drought.
This isn’t a case where the archeologist is claiming their SUVs caused global climate change...this is a case where a series of events caused normal weather patterns to change in ways the people were unable to adjust to.
Could be their government- under an emperor and noble elite of sorts- was too centralized to deal with the calamity and very likely the people gave up on them when they couldn’t deliver, and revolted or broke up and went their separate ways.
The fits rather well with the Choctaw-Chickasaw origin stories of when they were one people, forced to wander, and separated.
500 years takes the drought to 1850. In reading up on great plains\midwest droughts, the whole 19th century was considered dry with periods of drought.
The prior century as a whole was considered wet.
Which makes me wonder how Cahokia was in a 500 year drought ?
Here’s an older article with some different spin.
My research says it started around 1327 and lasted for 361 years and 4 months.........
Yes... Cahokia had already risen and fallen by DeSoto’s time, though other Mississippian fiefdoms continued without it.
Mt St Helens was tiny.
Ohio is an archaeologist’s dream. Not just Mississippians but Hopewell and Adena mounds, too.
Ohio’s Flint Ridge chert has appeared all over, including Cahokia, which has its own Mill Creek and Burlington chert.
1200 to 1700. Cahokia was long gone before getting through the 500 years.
Not that “500 year drought” means there was a uniform drought affecting all localities for precisely 500 years; it means a widespread drought. Here and there, there could have been even short heavy rains, but insufficient to make much of a difference, or ill-timed. Some areas would fare better than others... in that region there’s a notable difference in temp depending on which side of the Mississippi you live on, or whether you live in the bottoms or on the highlands beyond the bluffs.
Once dried out that bottomland clay would be rock hard and if they did get a cloudburst now and then, it’d drain away before soaking in. It would take prolonged rain to soften it up. The clay there is called “gumbo” and it is rich and black when wet but pancakes with deep fissures when dry, very hard to work it dry. The sand ridges would be easier to work but even drier and not very fertile. Upland loes would blow away as it blew in. In fact, that tan-brown upland loess along the bluffs and interior of Illinois blew in from the far west in the first place, millions of years ago.
Wise liberals told me climate change all started during the evil industrial revolution.
Has the story changed yet again?
Wise liberals told me climate change all started during the evil industrial revolution.
Has the story changed yet again?
No. They found it was easier to change the history books...
Oh.
I didn’t know that!
thank you. please do more of these. I really loved sunken_civ’s posts. I would love it if you did more of these.
Doesn’t sound like they weren’t able to adjust. Sounds like they moved on to greener (wetter) pastures.
The problem was they were in St Louis.
It was a bad place back then too.....
The interesting thing is that the vikings began their expansion in 800 AD at the beginning of the medieval warming period that lasted to about 1300. The last of the viking settlements in greenland were abandoned in 1400 when the little ice age in europe started.
Interestingly, the Mayan culture’s decline started about 800 AD as well because the rains stopped. and didn’t start again for about 500 years.
this looks better researched than the drought theory.
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