Integrating Phytoliths within Use-Wear/Residue Studies of Stone Tools

Archaeological Context:

The obsidian artefacts came from two sites, FRL and FAO, located in West New Britain Province, Papua New Guinea. These sites are notable for having well-defined stratigraphy and relatively long time depth. The Bitokara Mission Site (FRL) was excavated by Specht (1988). The FAO excavations were part of the larger Garua Island Project (Torrence et al, in press). Both sites have a sequence of volcanic tephras with a well-developed soil in the upper horizon of each. The volcanic events have been dated by radiocarbon. The tephras have been sourced and cross correlated by macroscopic and geochemical techniques.

Stratigraphic units have been divided into four chronological periods:

  • Older than W-K1 tephra (10,000 – 6000 BP)
  • Between W-K1 and W-K2 tephra (5900 – 3600 BP)
  • Between W-K2 and Dk tephras (3600 – 1100 BP)
  • Post-Dk tephra (1100 BP – present)

Organic preservation of macroscopic plant material is poor due to the high acidity of soils and high rainfall, but organic residue on stone artefacts was not unexpected because phytoliths are extremely resistant to decay.

Methodology:

  • 10 artefacts taken haphazardly from each arbitrary unit of 1m x 1m grid during excavation, using a metal trowel so that they were not handled in any way. With adhering soil, artefacts placed into plastic bags, air-dried, sealed and stored.
  • Analysis began with microscopic examination. Use-wear and residues assessed concurrently using high and low magnification.
  • To distinguish from post-depositional contamination, integrated analysis of residues with four main kinds of use wear is required. These are:
    • Scarring
    • Rounding
    • Polish
    • Striations
  • Surface preservation of the obsidian tools and residues present was recorded.
  • Phytoliths identified by comparison with reference collection.
  • Integrity of residue on artefact tested by comparing phytolith assemblage on surface with that of surrounding soil. If residue due to usage then there should be differences.

Results:

  • Phytolith assemblages included wide variety of grasses falling mainly within Bambusoideae and Panicoideae sub-families, herbaceous types (Compositae, Marantaceae, Cyperaceae), diverse arboreal types (Palm, Moraceae, Musaceae, Burseraceae, Annonaceae, etc) and unknown Dicotyledon types.
  • The analysis of starch grains, often from plants that do not make phytoliths (e.g. Root crops such as taro and yams), expand our knowledge of plant use. The authors were surprised to note the survival of these given the aggressive techniques of phytolith extraction. The only current explanation is that the grains were silicified in some way.
  • In a number of examples the phytolith data provided additional information on the types of plants which produced the use-wear.
  • The earliest Periods 1 and 2 appear to have been characterised by both multi-functional and single purpose tools primarily for processing starch. Hafting was common, but unretouched flakes were also used on soft, starchy plants.
  • Period 3 is characterised by change to more expedient tool use.
  • By period 4 this trend has progressed further. In the majority of cases the very sharp, unretouched obsidian flakes were grasped with bamboo leaves. There is no evidence for starch processing in this period. This is important as ethnographic accounts only refer to uses such as shaving. Shell not stone tools used in the recent past for processing starchy tubers.

Reference:

Kealhofer, L, Torrence, R and Fullagar, R. 1999. Integrating Phytoliths within Use-Wear/Residue Studies of Stone Tools. Journal of Archaeological Science 26: 527-546.

Heritage Of A Deadly Disease Pinpointed With Help From Iceland’s Genealogical Database

A collaboration of scientists from Iceland and the United States has used Iceland’s genealogical database* to trace the ancestors of patients suffering from hereditary cystatin C amyloid angiopathy (HCCAA). Analysis shows that the deadly mutation in the cystatin C gene, L68Q, derives from a common ancestor born roughly 18 generations ago, around 1550AD.

This dominantly inherited disease, which is due to a mutation in cystatin C (L68Q), strikes young adults with healthy blood pressure. The disease results in death from repeated brain haemorrhages, on average by the age of 30. The origin of the mutation causing HCCAA was previously unknown, but using DNA haplotype analysis* the scientists have shed light on the history of this autosomal dominant disease that has high penetrance in contemporary Icelanders.

The scientists found that 200 years ago, obligate carriers of the mutation lived a normal life span compared to the control population (their spouses). In carriers born around 1820, however, a trend of shortening life span began, resulting in an average life span of only 30 years in people born around 1900. This 30-year lifespan has stayed constant since then in both men and women.

At the same time, a matrilinear effect appeared whereby those who inherited the mutation from the mother died earlier. For carriers born after 1900, the difference is a loss of 9.4 years for those who inherited the mutation from their mothers rather than their fathers. Based on this information, the authors propose that the traditional diet of the nation (which in the past consisted largely of whey-preserved offal as well as meat, dried fish, and butter) “protected” the mutation carriers for almost 300 years until the Icelandic diet changed early in the early 19th century, exemplified by drastic increases in imported carbohydrates and salt.

This finding has implications for studies of Alzheimer’s disease as cerebral amyloid angiopathy (CAA) is almost universally found in Alzheimer’s patients and normal cystatin C protein is one of the proteins found in amyloid in brains of Alzheimer’s patients. Studies are underway to try to elucidate the risk factors with the hope of providing a preventive stategy for cystatin L68Q carriers.

*By deCODE Genetics

Palsdottir A, Helgason A, Palsson S, Bjornsson HT, Bragason BT, et al. A Drastic Reduction in the Life Span of Cystatin C L68Q Carriers Due to Life-Style Changes during the Last Two Centuries. PLoS Genet, 4(6): e1000099 DOI: 10.1371/journal.pgen.1000099

The Mystery of Mass Extinctions Is No Longer Murky

If you are curious about Earth’s periodic mass extinction events such as the sudden demise of the dinosaurs 65 million years ago, you might consider crashing asteroids and sky-darkening super volcanoes as culprits. However, a new study, published June 15, 2008, in the journal Nature, suggests that it is the ocean, and in particular the epic ebbs and flows of sea level and sediment over the course of geologic time, that is the primary cause of the world’s periodic mass extinctions over the past 500 million years.

Blog Carnival – Four Stone Hearth #43

The latest edition of the archaeology and anthropology blog carnival, Four Stone Hearth, is hosted by Paddy K in his own inimitable style. Check it out.

New Research Refutes Myth Of Pure Scandinavian Race

A team of forensic scientists at the University of Copenhagen has studied human remains found in two ancient Danish burial grounds dating back to the iron age, and discovered a man who appears to be of Arabian origin. The findings suggest that human beings were as genetically diverse 2000 years ago as they are today and indicate greater mobility among iron age populations than was previously thought. The findings also suggest that people in the Danish iron age did not live and die in small, isolated villages but, on the contrary, were in constant contact with the wider world.

On the southern part of the island of Zealand in Denmark, lie two burial grounds known as Bøgebjerggård and Skovgaarde, which date back to the Danish iron age (c. 0-400 BC). Linea Melchior and forensic scientists from the University of Copenhagen analysed the mitocondrial DNA of 18 individuals buried on the sites and found that there was as much genetic variation in their remains as one would expect to find in individuals of the present day. The research team also found DNA from a man, whose genetic characteristics indicate a man of Arabian origin.

Archeologists and anthropologists know today that the concept of a single scandinavian genetic type, a scandinavian race that wandered to Denmark, settled there, and otherwise lived in complete isolation from the rest of the world, is a fallacy.

“If you look at the geographic position of Denmark, then it becomes clear that the Danes must have been in contact with other peoples,” says scientist, Linea Melchior. “We know from other archeological excavations that there was a good deal of trade and exchange of goods between Denmark and other parts of Scandinavia and Europe. These lines of communication must have extended further south as one of the Danish burial grounds, which dates back to the iron age also contained the remains of a man, who appears to have been of arabian origin.

At the beginning of the Danish iron age, the roman legions were based as far north as the river Elbe (on the border of northern Germany) and it is thought that the man of arabian descent found in the burial grounds in Southern Zealand would have either been a slave or a soldier in the roman army. It is probable that he possessed skills or special knowledge, which the people in Bøgebjerggård or Skovgaard settlements could make use of, or he could have been the descendant of a female of arabian origin, who for reasons unknown, had crossed the river Elbe and settled down with the inhabitants of Zealand.

“This discovery is comparable to the findings of a colleague of mine, who found a person of siberian origin on the Kongemarke site,” continues scientist, Linea Melchior. He was buried on consecrated ground, just as the circumstances of the arab man’s burial was identical to that of the locals. The discovery of the arab man indicates that people from distant parts of the world could be and were absorbed in Danish communities.

“All of our ancestors, no matter when they arrived have contributed to our history and the development of our lifestyle,” explains Linea Melchior. “Indeed, Danish identity is more a definition of where one is physically located and lives today than a question of our past history – since we’re all originally african in origin. That we ended up in Europe was accidental, which is in itself remarkable”.

“Another interesting feature of the approximately 50 graves assessed so far on the two sites and also from other burial sites and time periods in Danish history is that none of the individuals seem to be maternally related to one another”, explains Linea Melchior. “We couldn’t see any large families buried in the same location. This suggests that in the Danish iron age, people didn’t live and die in the villages of their birth, as we had previously imagined”.

The findings have been published in the American Journal of Physical Anthropology 135:206-215 (2008.) and PLoS One 3(5): e2214.

Source: Science Daily

Greek Horse Burials

News via Past Horizons of the excavation of 16 horses and a two-wheeled chariot in a grave dating back to the Roman Empire in north-east Greece.

Bandurria may be the oldest Peruvian site

The archaelogical site of Bandurria dating back 3200 BCE (located in the province of Huaura, Lima) is considered the origin of ancient American civilization, said archaeologist Alejandro Chu Barrera, director of the Archaeological Project of Bandurria. “Several radiocarbon datings done in the United states confirmed that Bandurria dates back from 3200 BCE, while Caral dates from 2900″, said the archaeologist.

The expert mentioned that the main reason for the development of highly organized cultures along the Peruvian coast is explained in the availavility of marine resources which allowed to improve the population’s diet of the place.

Bandurria is located 140 kilometres from Lima and received this peculiar name because of a bird which inhabit this area. It was discovered by late 1973 but first excavations took place in 1977. It wasn’t until July 2005 that the site begun to be excavated by a team of archeologists and students from San Marcos National University, led by archeologist Alejandro Chu.

Source: Andina