Dark Bilious Vapors

Apropos of Len's prior post -- I’ve been working my way through “Collapse” by Jared Diamond this summer. But it’s been a slow read, not because I’ve been too busy, nor because it’s too difficult to read. More because each chapter is a story of a society (or group of tribes / cities /states) that failed. It’s rather sad and so it’s hard to just buzz through it and each segment deserves some thought and consideration before just skipping to the next.

What is captivating, in part though, is the incredibly weird and amazing science used to determine the characteristics and conditions of these past places and observations about what probably led to their demise. And some of the techniques are as fascinating as they are startling. Take this one about "Middens" and analyzing the Ancient Native American Anasazi (Chaco Culture National Historical Park and Mesa Verde Park in New Mexico):

”The other major environmental problem besides water management involved deforestation as revealed by the method of packrat midden analysis. For those of you who (like me…) have never seen packrats, don’t know what middens are, and can’t possibley imagine their relevance to Anasazi prehistory, here is a quick crash course in midden analysis:

In 1849, hungry gold miners crossing the Nevada desert noticed some glistening balls of a candy like substance on a cliff; licked or ate the balls and discovered them to be sweet tasting, but then they developed nausea.

Eventually it was realized that the balls were hardened deposits made my small rodents, called packrats, that protect themselves by building nests of sticks, plant fragments, and animal dung gathered in the vicinity, plus food remains, discarded bones,, and their own feces. Not being toilet trained, the rats urinate in their nests, and sugar, and other substances crystallize from their urine as it dries out, cementing the midden into a brick like consistency. In effect the hungry miners were eating dried rat urine laced with rat feces and rat garbage.
…
Crystallized urine prevents the material in the midden from decaying. By identifying the remains of dozens of urine encrusted plant species in amidden, a paleobotanist can reconstruct a snapshot of the vegetation growing near the midden at the time the rats were accumulating it, while zoologists can reconstruct something of the fauna from insects and vertebrate remains. In effect, a packrat midden is a paleontologist’s dream: a time capsule preserving a sample of the local vegetation, gathered within a few dozen yards of the spot within a period of a few decades, at a date fixed by radio carbon dating.
…
in 1975, paleontologist Julio Betancourt happened to visit Chaco Canyon …and submitted samples of those middens for radio carbon daing. When the dates came back from the radiocarbon lab, Julio and Tom were astonished to learn that many of the middens were over a thousand years old.

That serendipitous observation triggered an explosion of packrat midden studies. Today we know that middens decay extremely slowly in the Southwest’s dry climate. If protected from the elements under an overhang or inside a cave, midden can last 40,000 years, far longer than anyone would have dared to guess.

Karen on 08.09.05 @ 06:17 AM CST