Tuesday, February 27, 2007

Cultivation of maize and manioc in Panama dated back to 7,800 years ago

Ancient people living in Panama were processing and eating domesticated species of plants like maize, manioc, and arrowroot at least as far back as 7,800 years ago – much earlier than previously thought – according to new research by a University of Calgary archaeologist.

One of the most hotly debated issues in the discipline of archaeology is how and why certain human societies switched from hunting and gathering to producing their own food through agriculture. Dr. Ruth Dickau, a post-doctoral researcher in the U of C's department of archaeology, has used a new technique called starch grain analysis to recover microscopic residues of plants directly off the stone tools that people were using in Panama 3,000 to 7,800 years ago. "These results add to the growing evidence that the earliest beginnings of farming were not centred in arid highland regions like central Mexico and the Peruvian Andes as once believed, but in the lowland areas and humid forests of the American tropics," Dickau says.
The point here is the food intersection: maize and manioc in a single place like Panama. Maize was the major staple in Mexico, Central America and Western South America while manioc was in Eastern South America. This intersection suggest a interesting point of study around Panama regarding the settlement pattern and path into the Americas (LL).

http://www.eurekalert.org/pub_releases/2007-02/uoc-pof021507.php

Wednesday, February 21, 2007

Tulor a 3000 year-old Neolithic village in Chile

Deep within the wind-swept Atacama desert in northern Chile, the remnants of a forgotten civilization rise from the sand. At first the ruins are barely visible, just small ridges that cast short shadows. But where the sand has been stripped away, circular clay structures can be clearly seen. These are the 3,000-year-old remains of Tulor, one of the oldest and best-preserved Neolithic villages in South America. But a natural climate change around 300 AD caused the river dried up and within a few hundred years, the village was abandoned. Once deserted, the sand moved in. It covered the village in dunes, protecting it for nearly three millenia until it was discovered and partially unearthed in 1958. But now, half a century later, the sand that once protected the village is destroying it. Harsh desert winds and occasional rain are threatening to reduce the site to nothing.

How old are we? Some archaeologist are digging into our past in between 40.000 to at least 15.000 years old. Are those limits realistic or we are not found our "Lucy in the Sky". In my humble opinion, is a matter of time and lucky.

More information at
http://www.theage.com.au/news/World/Winds-ravage-Neolithic-village-in-Chile/2007/02/12/1171128860149.html

Friday, February 16, 2007

The enigmatic Antikythera mechanism

The Antikythera Mechanism is the earliest bronze geared device ever found.

It's been more than two millennia (2200 years old!) since a large ship went down off the coast of the Greek island of Antikythera, and more than a century since a sponge diver discovered the ship's valuable cargo, which included bronze and marble statues, pottery, and glass and silver vases. But only now have researchers deciphered one of the wreck's--and classical archaeology's--most enigmatic artifacts: a corroded collection of bronze and wood fragments known as the Antikythera Mechanism.

From early on, archaeologists identified pieces of inscribed gear wheels within the corroded lump, which led to the consensus that it was some sort of astronomical device.

But how exactly did it work, and for what had it been used? Could such a sophisticated device have been created more than 1,400 years before similar objects were known to exist anywhere else in the world?

Currently, the multinational Antikythera Mechanism Research Project (AMRP), led by mathematician and filmmaker Tony Freeth, used innovative imaging technology to answer these questions.

Considered to be the oldest known mechanical calculator, the device was used to track the movements of the moon and the sun (and possibly the planets around Earth) and to predict the dates of future eclipses. According to scientists, no earlier geared mechanism of any sort has ever been found.

For my point of view, Greeks knew that the earth was rounded. They should have known the planets movements so most of the post-medieval discoveries were actually a rediscovery. This mechanism probably confirms the idea that Columbus had read or hears Greek tales (written about 1500 years ago) about the earth roundness and the existence of other continents. America perhaps? L.L.

More information at http://www.hpl.hp.com/news/2006/oct-dec/antikythera.html and http://www.archaeology.org/0703/abstracts/antikythera.html

Wednesday, February 14, 2007

Radio Carbon dating basis


Radio Carbon dating: a summary of the method and simplified definitions.

Radio Carbon analysis is used primary to understand how old is an object found in a specific excavation layer. Let’s see how its works:

During normal life, we incorporate carbon molecules into our tissues and bones by eating food or taking air from the atmosphere. This carbon molecules exist in three molecules (variation) called 12C, 13C and 14C. The latest is a natural radioactive molecule or unstable isotope that we also catch on the air or food and is today in our bodies (so you are in part radioactive!). Our body keep all three types of carbon molecules in a stable proportion, lets say 98% for 12C, 1% for 13C and very little for 14C (less than 1/1000000%) and this proportion is the same during all of our life.


Once we die the 14C isotopes' proportion start to dacay. 14C radioactive isotopes decay or transform from 14C to 14N (Nitrogen) in a constant rate. Every 5568 years the 14C amount existing in the organic compound is reduced to the half. Scientist can measure how old is a carbonated sample if they know the amount of 14C present in comparison with its normal proportion during life. If we found that only the half of 14C molecules is present, then the sample has approximately 5568 years old, for instance.

Note that archaeologists need to find a carbonated sample (charcoal, wood, shell, animal or human bone, etc.) to be able to date the layer or the object. Archaeologist can not date ceramic or stones in this way.

Radio Carbon dating is used for objects in between approximately 200 to 50.000 years old with and error or deviation of about +/- 100 years or less. Samples usually require a minimum of 100 grams to be used as a valid sample. Others methods require few grams like AMS technology (Accelerator Mass Spectrometry) but it is quite expensive.






Tuesday, February 13, 2007

San Valentin's Days in Archaeology


A pair of skeletons from the European Neolithic period (5000 to 6000 years old) were discovered outside Mantua, about 40km (25 miles) south of Verona, Italy.
The pair, almost certainly a man and a woman, are thought to have died young as their teeth were mostly intact, said chief archaeologist Elena Menotti.
"I've been doing this job for 25 years. I've done digs at Pompeii, all the famous sites, but I've never been so moved because this is the discovery of something special," she said.

Monday, February 12, 2007

First Venezuelan: coming by coastal route

First Venezuelan: coming by coastal route

A study of the oldest known sample of human DNA in the Americas suggests that humans arrived in the New World relatively recently, around 15,000 years ago. The DNA was extracted from a 10,300-year-old tooth found in a cave on Prince of Wales Island off southern Alaska in 1996. The sample represents a previously unknown lineage for the people who first arrived in the Americas. The findings, published last week online in the American Journal of Physical Anthropology, shed light on how the descendants of the Alaskan caveman might have spread.

Brian Kemp, a molecular anthropologist who sequenced the DNA, said the discovery underlines the importance of genetic research in understanding human migration.
"I think there's a lot of information in these old skeletons that's going to help us clarify the timing of the peopling of the Americas and perhaps where Native Americans originated in Asia," said Kemp, a research associate at Vanderbilt University in Nashville, Tennessee.

This migration probably occurred at least 15,000 years ago—the oldest human remains discovered so far are 13,000 years old—but some scientists have proposed that the first Americans arrived up to 40,000 years ago.
But where did these coastal migrants come from?
DNA samples of people living in Japan and northeast Asia show some of the genetic mutations found in the cave-tooth and Chumash samples.

Finally, are the first Venezuelan linked to the cave-tooth and Chumash samples?

Initial clues based on Sinodont dentition (a group of carateristics usually identify on asian and Native American people) found in some Venezuelan skeleton (L.Lemoine & Camilo Tapia) suggest a link to the first Venezuelan lineage. A DNA test is probably the latest tool to clarify this interesting point.
http://news.nationalgeographic.com/news/2007/02/070202-human-migration.html

Friday, February 9, 2007

Tips for collecting Radio Carbon samples in Archaeology

The following is a modest collection of tips for collecting Radio Carbon and AMS samples coming for my personal experience:

Samples collected at the field :

  • Be sure you are selecting a sample from the layer you want to know the absolute date

  • Select the sample with bigger volume (carbon, bone, shell with bigger size)

  • Select samples without or with a minimum penetrated roots, ants or any other penetrating things

  • Pack samples with plenty aluminium foil and put inside double labeled plastic zip-bag

  • Include all information about position, layer, test pit or trench information outside the bag

  • Take a record as usual (photo, diagrams, notebook info, etc)

Samples selection by type

Skeleton (collagen) samples:

- On skeleton samples I recommend a sample from a massive bone (femur, tibia, etc) by making a transverse cutting rather than to take a small bone (ribs, hand, etc).

- Alternatives: we have options like a teeth that also provide a good opportunity or an articular foot bone.

- All option should include the cortex rather than porous broken bones

- From all type of samples, human bones are the most confident type of sample. They are just the man or woman who lived just there or food eaten at that moment! other samples are always indirect or associated.

Carbon Samples:

- Take samples with a minimum or without root penetration where is possible. Try Radio Carbon dating instead AMS when you suspect root or mold penetration. Radio Carbon work averaging the content versus AMS that select a part of the sample making possible a big error if the sample took a big part of a modern root.

-Take the carbon samples with fine tools

- Don't worry if you have to take the sample at naked hand but be sure you use aluminium foil

- Carbon are the second option in confidence for dating context. Reason? carbon can be move by up and down by natural animals (worn, ants, etc) and usually are subject to mold and root penetration into the porous matrix making impossible its removing. Bones are relative more easy to remove at the laboratory.

Shell Samples:

- Shell are easy to identify and clean. Only take few of then with reasonable size.

- Shell are less confident that the others two type. Why? shell could be used by human or surviving on the grown for centuries or even thousand of years and then finally discarded on the context. On the other hand, in my personal opinion, some labs appear to by uncalibrated for tropical shells, making dating looks older than actually is (some cases a thousand of years older tan a sample from human bone in the same layer).