Audio News for April 7 to April 13, 2013
Welcome to the Audio News from Archaeologica! I'm Laura Pettigrew and these are the headlines in archaeological and historical news from April 7th to April 13th, 2013.
Dating methods combine to tie Maya dates to European calendar
Original Headline: Maya Long Count calendar and European calendar linked using carbon-14 dating
In our first story, the Maya are famous for their complex, intertwined calendar systems, and now one calendar, the Maya Long Count, is calibrated to the modern European calendar.
According to Douglas J. Kennett, professor of environmental archaeology at Penn State University, the Long Count calendar fell into disuse before European contact in the Maya area. The Long Count could be tied to the modern European calendar using known historical and astronomical events, but researchers looking at how climate affects the rise and fall of the Maya began to question how accurately the two calendars really correlated.
The most popular method in use is the Goodman-Martinez-Thompson or GMT correlation, initially put forth by Joseph Goodman in 1905 and subsequently modified by others. In the 1950s, scientists tested this correlation using early radiocarbon dating, but the large error range left open the validity of GMT. The new research looked for an independent source of corroboration, as described in the current issue of Scientific Reports. The solution was to combine additional new carbon-14 dates with a calibration using tree growth rates. The results verify the GMT correlation.
The Long Count calendar counts days from a mythological starting point. The date is comprised of five components, each of which combines a multiplier times 144,000 days – Bak'tun, 7,200 days – K'atun, 360 days – Tun, 20 days – Winal, and 1 day – K'in. In the standard Mayan notation these are shown separated by dots.
According to Kennett, one reason archaeologists want to place the Long Count dates into the European calendar is to understand when things happened in the Maya world relative to events elsewhere. Correlation also allows a comparison of the rich historical record of the Maya with other sources of environmental, climate and archaeological data calibrated using the European calendar.
The samples came from an elaborately carved wooden lintel from a temple in the ancient Maya city of Tikal, Guatemala, that carries a carving and dedication date in the Maya calendar. This same lintel was one of three analyzed in the previous carbon-14 study.
Researchers measured tree growth by tracking annual changes in calcium uptake by the trees, which is greater during the rainy season.
The amount of carbon-14 in the atmosphere is incorporated into a tree's growth. Atmospheric carbon-14 changes through time and during the Classic Maya period oscillated up and down.
The new research team took four samples from the lintel and used annually fluctuating calcium concentrations evident in the incremental growth of the tree to determine the true time distance between each by counting the number of elapsed rainy seasons. The researchers used this information to fit the four radiocarbon dates to the wiggles in the calibration curve. Wiggle-matching the carbon-14 dates provided a more accurate age for linking the Maya Long Count dates to the European calendars.
These calculations were complicated by known differences in the atmospheric radiocarbon content between the northern and southern hemisphere.
According to Kennett, the Maya area lies on the boundary such that the atmosphere is a mixture of the southern and northern hemispheres that changes seasonally. Scientists had to factor that into the analysis.
The researcher's results indicate that the GMT was on the right track for linking the Long Count and European calendars. This means that Maya events can now be compared to other environmental, climatic and archaeological datasets from this and adjacent regions with greater certainty. The research also underscores the important role of climate change in the development and demise of the Maya civilization.
Giant stone cairn found submerged below Sea of Galilee
Original Headline: Mysterious Stone Structure Discovered Beneath Sea of Galilee
In Israel, a massive monumental stone structure discovered beneath the waters of the Sea of Galilee has archaeologists puzzled about its purpose and when it was built.
The mysterious structure is cone shaped, made of unfinished basalt cobbles and boulders, and weighs an estimated 60,000 tons, heavier than most modern-day warships.
Measuring nearly 10 meters high, with a diameter of about 70 meters, it is almost twice the size of the outer stone circle of Stonehenge, although not as high as the tallest stones at Stonehenge. It appears to be a giant cairn, rocks piled on top of each other. Structures like this are known from elsewhere in the world and are sometimes used to mark burials. Researchers have not yet determined the purpose of this massive underwater pile, however.
The structure was first detected in the summer of 2003, during a sonar survey of the southwest portion of the sea. Since then divers have been down to investigate, and the mystery is described in the latest issue of the International Journal of Nautical Archaeology.
Close inspection by the scuba team revealed that the structure is made of basalt boulders up to 1 meter long with no apparent construction pattern. The boulders have natural faces with no signs of cutting or chiseling. Similarly, there is no sign of arrangement or walls that delineate this structure.
The investigation has confirmed two things. First, that it is definitely human-made. Second, that it was originally built on land, and later covered by the Sea of Galilee as the water level rose. The shape and composition of the submerged structure does not resemble any natural feature. Therefore, they conclude that it is human-made and might be termed a cairn.
Underwater archaeological excavation is needed so scientists can find associated artifacts and determine the structure's date and purpose, the researchers said.
According to Yitzhak Paz, of the Israel Antiquities Authority and Ben-Gurion University, it could date back more than 4,000 years. The logical possibility is that it belongs to the third millennium BC, because there are other megalithic phenomena from that time found close by. According to Paz, those sites are typically associated with fortified settlements.
Several megalithic structures found close to the Sea of Galilee are more than 4,000 years old. One is the monumental site of Khirbet Beteiha, located 30 kilometers northeast of the submerged stone structure. It comprises three concentric stone circles, the largest of which is 56 meters in diameter.
If the idea of a third-millennium BC date proves correct, it would put the structure about a mile to the north of a city that researchers call "Bet Yerah" or "Khirbet Kerak."
During that era, the city was one of the biggest sites in the region. According to archaeologist Raphael Greenberg, Khirbet Kerak was the most powerful and fortified town in Israel at that time, covering 30 hectares and holding up to 5,000 inhabitants.
Researchers hope to conduct more underwater surveys soon and to begin excavating the structure, in search of artifacts that will help determine its date with more certainty.
New analysis shows pottery started with Ice Age hunter-gatherers cooking fish
Original Headline: Pottery reveals Ice Age hunter-gatherers' taste for fish
A pioneering new study by the University of York shows that hunter-gatherers living in glacial conditions produced pots for cooking fish, which is the earliest direct evidence for the use of ceramic vessels.
Writing in the journal Nature, scientists from the UK, the Netherlands, Sweden, and Japan carried out chemical analysis of food residues in pottery up to 15,000 years old from the late glacial period of Japan, the oldest pottery so far investigated. It is the first study that directly addresses the often-posed question of why humans made pots.
The research team was able to determine the use of a range of hunter-gatherer Jomon (joe-MOAN) ceramic vessels through chemical analysis of organic compounds extracted from charred surface deposits. The samples analyzed are some of the earliest found in Japan, long recognized as one of the first centers for ceramic innovation, and come from the end of the Late Pleistocene, a time when humans were adjusting to changing climates and new environments.
Until recently, ceramic container technologies have been associated with the arrival of farming, but we now know they were a much earlier hunter-gatherer adaptation, though the reasons for their emergence and subsequent widespread uptake are poorly understood. The first ceramic containers must have provided prehistoric hunter-gatherers with attractive new ways for processing and consuming foods, but until now, virtually nothing was known about how early pots were used, or for what.
The researchers recovered lipids from the charred surface deposits of the pottery and found that most of the compounds in those fats came from the processing of freshwater or marine organisms. Stable isotope data support the lipid evidence, and suggest that the majority of the 101 charred deposits, analyzed from across Japan, were derived from high levels of aquatic foods.
According to the study’s leader, Dr. Oliver Craig, of the Department of Archaeology and Director of the BioArCh [BYE-oh-ark] research center at York, foragers first used pottery as a revolutionary new strategy for the processing of marine and freshwater fish, but perhaps most interesting is that this fundamental adaptation emerged over a period of severe climate change.
The reliability and high abundance of food along shorelines and riverbanks may well have provided the initial thrust for an investment in producing ceramic containers, perhaps to make the most of seasonal gluts or as part of elaborate celebratory feasts and could be linked to a reduction in mobility.
This initial phase of ceramic production probably paved the way for further intensification in the warmer climate of the Holocene when we see much more pottery on Japanese sites.
This study demonstrates that researchers can analyze organic residues from some of the world's earliest ceramic vessels. It opens the way for further study of hunter-gatherer pottery from later periods to clarify the development of what was a revolutionary technology.
Easter Island statue reveals more through digital imaging
Original headline: Archaeologists Shine New Light On Easter Island Statue
Archaeologists in the UK at the University of Southampton have applied digital imaging technology on an Easter Island statue and in the process learned more about its history.
James Miles, Hembo Pagi and Dr Graeme Earl at Southampton’s Archaeological Computing Research Group worked with with Mike Pitts, archaeologist and editor of British Archaeology, to get a very close look at the statue in London’s British Museum.
The statue, called Hoa Hakananai'a, is one of the giant moai that have made Easter Island famous. It came to England in 1869 and the presumed date of its carving is about AD1200. This statue is especially interesting because its back is marked by complex carvings, which now can be recorded by imaging technology in fine detail.
One interpretation of Easter Island history has it that around AD1600 the islanders faced an ecological crisis and stopped worshipping their moai. The people then turned to a new birdman religion, or cult that involved a ritual focused on collecting the first egg of migrating birds from a nearby rocky islet called Motu Nui. The group whose champion swam to the islet and then back with the egg gained sacred status for a year.
Hoa Hakananai'a apparently survived this change in religions, as the islanders moved it into a stone hut and covered its back in rock engravings thought to be motifs of the birdman cult. Thus, it may represent the transition from the cult of the moai to the cult of the birdman.
The research team employed two different techniques to examine Hoa Hakananai'a: with the first, Photogrammetric Modeling; they ttook hundreds of photos from different angles to generate a high-res 3D computer model of the statue. The second technique was Reflectance Transformation Imaging, which scans a virtual light source across the surface of the object’s digital image and amplifies the difference between light and shadow to bring out details otherwise invisible.
The results were fascinating. One remarkable outcome is the realization that one of the two carved bird beaks is short and round, not long and pointed as previously thought. Now, the two bird figures on the back are recognized as male and female, revealing a narrative story in the entire composition relevant to the birdman cult. The team also came to realize that this statue is one of the few on Easter Island that did not stand on a platform beside the shore. Now, the researchers believe that it always stood in the ground, where it was found, on top of a 300 metre cliff.
According to Mike Pitts, the tapering base of the statue suggests that it never was thinned to make it fit into a pit, as often suggested. Instead, it base more likely is part of the original boulder or outcrop from which it was carved. As it is displayed in the British Museum, it leans slightly to the left, but that apparently is because it was incorrectly placed into its support pedestal when it was set up for viewing back in the Nineteenth Century.
That wraps up the news for this week!
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I'm Laura Pettigrew and I'll see you next week!