Clovis in the sky with diamonds

On Saturday, both the BBC Science section and Science Daily had a story about a recent study of nanodiamonds at Clovis sites in North America published in Science (abstact below). The jist of the study is that there was a "celestial event" that caused the Younger Dryas and that this led to the demise of Megafauna and the Clovis culture in North America. This event or series of events may have been similiar to the Tunguska explosion in Siberia that occurred in 1908. I haven't read the article yet so I can't comment on it at this point but an interesting hypothesis, nonetheless. I do however, have a problem with extraterrestrial events to explain mass extinctions. There is one evolutionary universal and that is extinction, plus there would appear to be some different rates of demise for the megafauna and the Younger Dryas occurred globally, so it would be interesting to see if other sites of similiar dates from the Old World had similiar sediment layers or even if Tunguska in Siberia had a similiar soil profile.

Nanodiamonds in the Younger Dryas Boundary Sediment Layer

D. J. Kennett,^1* J. P. Kennett,² A. West,³ C. Mercer,⁴ S. S. Que Hee,⁵ L. Bement,⁶ T. E. Bunch,⁷ M. Sellers,⁷ W. S. Wolbach⁸

We report abundant nanodiamonds in sediments dating to 12.9 ± 0.1 thousand calendar years before the present at multiple locations across North America. Selected area electron diffraction patterns reveal two diamond allotropes in this boundary layer but not above or below that interval. Cubic diamonds form under high temperature-pressure regimes, and n-diamonds also require extraordinary conditions, well outside the range of Earth's typical surficial processes but common to cosmic impacts. N-diamond concentrations range from 10 to 3700 parts per billion by weight, comparable to amounts found in known impact layers. These diamonds provide strong evidence for Earth's collision with a rare swarm of carbonaceous chondrites or comets at the onset of the Younger Dryas cool interval, producing multiple airbursts and possible surface impacts, with severe repercussions for plants, animals, and humans in North America.

Day 97: Natural History Museum (6/26/2008)

Jennifer and I both have school meetings on Thursdays for a writing class we are taking. Rather than have the kids hang out in my cramped office we headed to the KU Natural History Museum to

learn about grasshopper love -


Check out this famous Bison antiquus skeleton - this is an ancient bison that was found in western Kansas with a Folsom point under its shoulder plate. Herein began the cracks in Hrdilkca's idea that Native Americans were recent immigrants to the New World.


Have the boys take their picture with a polar (tolar) bear.

See how we measure up to chimpanzees.

P365 D55: Juligalpa Archaeological Musem

We stopped in Juligalpa to check out this archaeological museum that has a number of pre-Combian statues from the Chontales department in Nicaragua. Two of which are 8 meters tall. This was to see whether or not these effigies look more Chibchan and were made by people inhabiting the isthmo-Colombian area or were they made by Mesoamerican populations. This has important implications for understanding a number of concepts regarding the movement of people during pre-Columbian times. Based on my general observations and my colleaque who has worked as an archaeologist in Central America belief that are more Chibchan in origin but there is a general lack of context on exactly where these object come from.

Maya Manioc

ScienceDaily is reporting the discovery of ancient manioc cultivation site in El Salvador, this site is important is because it was previously unknown how the large Maya cities (like Tikal or Copan) were able to support their populations on only beans and corn. Manioc is an excellent source of nutrition and would have been useful in feeding a large number of people. I do have some issues with this article, it does not refer to an article (if there is one, it would be nice to know), which means the discovery may not have been published in a scientific venue. This seems to be increasingly common among archaeological sites. This is unfortunate because there may be issues with the site and its impact. The other thing is manioc is a South American domesticate so there had to be some interaction between groups through trade 1,400 years ago.

This discovery does go a long when in increasing our understanding of agriculture in Mesoamerica. There is often a misconception regarding the complexity of agricultural development in the region, where new dates have pushed back to approximately 8,000 to 10,000 years before present for a number of new world domesticates in South America including arrowroot, squash, gourds (Cooke, 2005) and years for maize (Pipererno et al. 2007). This places the origins of agriculture near the early domesticates in the old world. This is actually an exciting area of study and I'm sure several new discoveries will come out over the next decade.

References

Cooke R. 2005. Prehistory of Native Americans on the Central American Land Bridge: colonization, dispersal, and divergence. J Archaeological Res 13:129–187.

Piperno DR, Moreno JE, Iriarte J, Holst I, Lachniet M, Jones JG, Ranere AJ, Castanzo R. 2007. Late Pleistocene and Holocene environmental history of the Iguala Valley, Central Balsas Watershed of Mexico. PNAS. 104(29)11874-81.