Stone Age America, Pyramids and the Big Muddy
Towering pyramids and ceremonial plazas are the hallmarks of ancient Mesoamerican urban building, yet the oldest examples that call to mind this familiar style are found nearly 1000 kilometers to the north in the muddy bayous of Louisiana. Five millennia ago, Native Americans began to build high mounds of earth flanked by flat plazas that resemble the classic architecture of the Maya and the Aztec. Surprisingly, new dating efforts reveal that the first great period of mound building nearly occurred 5,000 years ago—nearly 2,000 years before the first cities appeared in Mexico, and before the Giza pyramids in ancient Egypt. Stranger still is what brought this golden age of prehistoric Native American culture to an end: a five century long spell of massive floods in the lower Mississippi Valley.
Ancient conical mounds found dotting the lower Mississippi Valley were long considered to be no older than 1000 years or so. But in the 1970s and '80s, some archaeologists were puzzled by radiocarbon dates from some of the sites. These readings placed the time of the mound builders in the Middle Archaic period—which ended around 3000 BC. Most dismissed these readings as erroneous but then, in the 1990s, local archaeologists carefully reexamined the evidence.
Louisiana state archaeologist Joseph Saunders published a paper in the September 19th, 1997, issue of Science that claimed Native Americans went on a building spree across the lower Mississippi Valley, from about 3700 BC. to 2700 BC. They left behind mysterious rectangular blocks of heated clay, thousands of spear points, and giant mounds, some of which can still be seen today. The paper's abstract states the author's conclusion:
An 11-mound site in Louisiana predates other known mound complexes with earthen enclosures in North America by 1900 years. Radiometric, luminescence, artifactual, geomorphic, and pedogenic data date the site to over 5000 calendar years before present. Evidence suggests that the site was occupied by hunter-gatherers who seasonally exploited aquatic resources and collected plant species that later became the first domesticates in eastern North America.
Toward the end of the Archaic Period in eastern North America, earthen mound construction, extensive long-distance trade, and technological developments reached a zenith among the hunter-gatherers of the Poverty Point culture. Built about 1500 BC, Poverty Point is a striking example of Late Archaic mound-builder construction (c. 2500 BC - 1000 BC). It consists of a complex more than a mile square, where six earthwork crescent ridges were built in concentric arrangement, interrupted by radial aisles.
Poverty Point is not the only impressive site left behind by the ancient Americans. Named after its largest site, Cahokia, located in south-western Illinois, bears testimony to the culture that flourished throughout the Mississippi Valley between 900 and 1450 AD.
Cahokia Mounds circa 1150AD, painting by William R. Iseminger.
Now, a recent news focus article in that same journal, “Does North America Hold the Roots of Mesoamerican Civilization?,” asks the question, did ancient settlements in what is now Louisiana lay the foundation for the great cities of Mesoamerican civilization? This article is a follow up on Andrew Lawler's 2011 article, “America's Lost City,” which described the unexpected size and organization of the ancient city of Cahokia, near modern day St. Louis.
Cahokia proper was the only pre-Columbian city north of the Rio Grand, and it was large even by contemporary European and Mesoamerican standards. In 1250 AD, Cahokia was larger than London, drawing immigrants from hundreds of kilometers around to live, work, and participate in mass ceremonies.
Cahokia Mound State Historic site in Illinois.
Saunders' work in the 1990s included a site near a bayou west of Monroe, called Hedgepeth, that contained 16 mounds including a conical earthen structure 8 meters high and some 33 meters in diameter. That site was radiocarbon dated to approximately 3000 BC. Another site called Frenchman's Bend, north of Monroe, proved to be of a similar age and radiocarbon dates put Watson Brake, south of Monroe, at 3500 BC. In the decade and a half since that key paper, a dozen other Middle Archaic mounds have been identified.
The state of Louisiana is campaigning for World Heritage status for Poverty Point, a significant settlement during the second great burst of mound building, which began about 1600 BC and lasted for nearly 600 years. Located on a bayou east of Monroe, the site includes a giant mound second only to that at Cahokia in size. But here is where things get interesting. Archaeologists have identified a 500-year gap in occupation within many areas of the Lower Mississippi Valley and pronounced cultural differences between Poverty Point and later inhabitants of the region. What could have caused the gap? Moreover, what prompted the archaic inhabitants of the Mississippi Valley to build great mounds in the first place?
Mound building could be seen as a natural response to the capricious nature of the Mississippi River, whose course tends to wander and floods frequently even in modern times, despite the best efforts of the Army Corps of Engineers to tame it. But the 500 year gap in meaningful habitation would require something more destructive than an occasional inundation. Now scientists think they have found an ecological smoking gun.
Recent studies in northeast Louisiana have identified evidence of catastrophic flooding and large-scale changes in the Mississippi River system between 1000 BC and 500 BC. These floods now have been implicated in the dissolution of the Poverty Point culture approximately 1000 BC. They are also believed to be linked to the cultural break between the Middle Archaic and later inhabitants. Evidence of flooding during this interval has also been found at Jaketown, where the earliest Poverty Point occupation has been deeply buried by sediment. In some areas of the site, these archaeological deposits are found as deep as 12 feet below the modern ground surface
Did the ancient inhabitants of the Mississippi Valley influence the pyramid building cultures of Mesoamerica? John Clark, a Mesoamerican specialist at Brigham Young University, thinks so. He states: “We need to look to Louisiana as a source.” In Central America many cultures built great cities, some of which were still inhabited when the Spanish Conquistadors invaded the New World in the 15th Century. Others we know only from their impressive ruins.
Reproduction of Tenochtitlan, the capital of the Aztec Empire.
The early inhabitants of North America, however, left behind no such impressive stone monuments to their thriving civilization. According to Lawler: “Mesoamericans may have used the plaza-and-pyramid innovation to help create a more complex social organization and to jump-start urban life. But in the Mississippi River valley, this didn't happen.”
Regardless of the possible impact of Middle Archaic period North Americans on their Central American cousins, one thing regarding life near the early Mississippi is clear—something extraordinary bad happened in the lower Mississippi Valley around 3,000 years ago. For several hundred years, there were no mounds built. Finally, in the early centuries AD, a third and final period of mound building began, this time centered in the Ohio River valley, culminating in Cahokia. Now the cause of the blank period has been identified by recent geoarchaeological research in northeast Louisiana.
Tristram R. Kidder of Washington University in St. Louis, Missouri, suggests that large-scale floods and river instability, along with cooler temperatures, may have rendered sites like Poverty Point uninhabitable. Coring in the Gulf of Mexico has lately confirmed that large floods, some episodes extending over decades, dumped enormous quantities of sediment into the gulf for half a millennium. That's right, it was climate change that wiped out the flourishing civilization that once filled the Mississippi Valley. The only thing surprising about this is that some people find it surprising.
Nature has visited a long string of disasters on human civilizations: Minoan civilization declined as a result of a volcanic eruption on the island of Thera; the Harappan Civilization in the greater Indus Valley met a mysterious demise in the mid second millennium BC, perhaps due to flooding; the Olmec inhabited the tropical lowlands of south-central Mexico until suddenly disappearing, climate change is suspected; the Khmer Empire of Southeast Asia died when their water supply became unreliable; and so it goes. Of course, now the entire world is threatened by anthropogenic global warming.
NASA photography of the flooding Big Muddy.
Just imagine the clamor that would ensue if the Mississippi began another 500 year period of great and persistent flooding. The know nothing talking heads of the news media would breathlessly ask what terrible fate humanity has wrought, while the agenda driven purveyors of junk science would sagely nod and say that we were warned—and it would all be pure bovine excreta. For, as the inhabitants of the Mississippi Valley found out to their great dismay 3,000 years ago, nature is cruel and uncaring, and gives not one whit about her children. This is, of course, because nature is not a being. Nature is a collection of processes—geological, ecological and biological—that man with great hubris thinks he can control. Piffle! The Big Muddy rolls on today as it did then, as last year's spate of flooding proves.
The Earth and its accidental passengers are beginning another new year—2012 AD as westerners figure such things. And despite predictions by prophets both unlamentedly dead and regrettably alive, the world will probably not end anytime soon. But you can count on Earth's climate changing, because it is always changing.
Being beyond humankind's control, many of the changes will be viewed as disasters by one group or another on this world. Fortunately for them they have the IPCC and climate change alarmists to tell them who to blame for nature's capriciousness. The inhabitants of Poverty Point didn't have the comfort of confessing their profligate use of fossil fuels or the modern lament, “if only we hadn't bought all those big SUVs!”
Be safe, enjoy the interglacial and stay skeptical.
From Louisiana to Ohio, the remains of the mound builders can be found.