Illustration about Illustration of the different tree stumps on a white background. Illustration of dendrochronology, everyday, grow - 38652930
New research in dendrochronology and environmental climate change by using AMS/CFAMS radiocarbon dating and stable isotope analysis
What a treat it was to talk with primatologist and biological anthropologist Craig Stanford. If you’re a regular listener of ReWild Yourself podcast, you probably know how deeply fascinated I am with the great apes. I think they give us a window into understanding ourselves biologically, into understanding our wildness and even help us to glimpse into our origins. Craig — author of sixteen books and over one hundred scholarly and popular articles — has studied chimpanzees extensively, studying their hunting behavior in Tanzania in collaboration with Dr. Jane Goodall, studying chimps and mountain gorillas in Uganda and more. He takes us on a journey to the meeting place of primatology and anthropology. He breaks down the social behaviors of some of the great apes, focusing on chimps and bonobos, and shares some of his controversial findings on the popularized "peaceful bonobo" research. This interview provides context to many of the themes we discuss on this podcast and was my favorite of the season. If you’re interested in ReWilding, I think you’ll find our conversation fascinating.
Dendrochronology
Dendrochronology, the study of tree rings. Picture from A Concise Weather Guide.
What dendrochronology can tell us about sunspots, jet streams, pirates and gardening
It's called dendrochronology, the study of data culled from the growth patterns of trees. And it can tell us a lot.
Furniture maker Jason Breen embraces the ethos of Vermont -- he works the land, finds inspiration in nature, and even dabbles in dendrochronology. Get to know him on our blog.
This chronometric technique is the most precise dating tool available to archaeologists who work in areas where trees are particularly responsive to annual variations in precipitation, such as the American Southwest.Developed by astronomer A. E. Douglass in the 1920s, dendrochronology—or tree-ri
archaeological timescale, also called archaeological chronology, chronology that describes a period of human or protohuman prehistory. Some archaeological timescales are based on relative dating techniques, such as stratigraphy, which illuminate a sequence of change. Others are based on chronometric (absolute) methods such as carbon-14 dating and dendrochronology that derive a specific date from a specific item or sample (as of carbon). Most also include geographic information, as change generally varies over space as well as time. The scales of time and space considered vary depending upon the purpose of the archaeological chronology: a timescale describing the development of a locale
In 2000-2003, a ‘royal’ burial site in Tuva Republic, Siberia, dating to early Scythian times, was excavated by a joint German-Russian research program. Thousands of gold articles were discovered in the wooden chamber of ‘royal’ burial no. 5, dated to the late 7th century BC. The majority of these ornaments are decorated in the Scythian animal style. The study of the technological aspects reveals the variety of manufacturing techniques and designs employed for these extremely rich ornaments, and provides an insight into the complexity of the art of the early Scythian goldsmiths at the end of the 7th century BC. This paper aims to present the large variety of distinct processes used in the manufacture of these gold artefacts. The technical expertise and the equipment at the disposal of the Early Iron Age craftsmen can be inferred from tool marks and analysis of surface structures. The early date of these finds, demonstrated by a combination of radiocarbon and dendrochronology, supports the assumption that this particular, sophisticated style of early Scythian metal work originated in the Tuva region.
Charlotte Pearson's eyes scanned a palm-sized chunk of ancient tree. They settled on a ring that looked "unusually light," and she made a note without giving it a second thought. Three years later, and armed with new methodology and technology, she discovered that the light ring might mark the year that the Thera volcano on the Greek island of Santorini erupted over the ancient Minoan civilization. The date of the eruption, which is one of the largest humanity has ever witnessed, has been debated for decades. The Santorini Caldera is what's left behind from the Thera eruption [Credit: Steve Jurvetson] Pearson, a University of Arizona assistant professor of dendrochronology and anthropology, is lead author of a paper, published in the Proceedings of the National Academy of Sciences, in which she and her colleagues have used a new hybrid approach to assign calendar dates to a sequence of tree rings, which spans the period during which Thera erupted, to within one year of a calendar date. This allows them to present new evidence that could support an eruption date around 1560 B.C. Filling the Gaps "In every tree ring, you have this time capsule that you can unpack," Pearson said. Trees grow in accordance with the conditions of their local environment. Each year, trees produce a new layer of concentric growth, called a tree ring, which can record information about rainfall, temperature, wildfires, soil conditions and more. Trees can even record solar activity as it waxes and wanes. When a sequence of rings from trees of various ages are overlapped and added together, they can span hundreds or thousands of years, providing insight about past climate conditions and context for concurrent civilizations. Charlotte Pearson points to the light tree ring that could mark the year of the Thera eruption [Credit: Mikayla Mace]"The longest chronology in the world stretches back 12,000 years. But in the Mediterranean, the problem is that we don't have a full, continuous record going back to the time of Thera," Pearson said. "We have recorded the last 2,000 years very well, but then there's a gap. We have tree rings from earlier periods, but we don't know exactly which dates the rings correspond to. This is what's called a 'floating chronology.'" Filling this gap could help pin down the Thera eruption date and paint a climatic backdrop for the various civilizations that rose and fell during the Bronze and Iron ages, which together spanned between 5,000 and 2,500 years ago. "Until you can put an exact year on events on a scale that makes sense to people - one year - it's not quite as powerful," Pearson said. "This study is really about taking (my co-author and tree ring lab research professor) Peter Kuniholm's chronology that he's put together over 45 years of work and dating it in a way not possible before. Most importantly, it is fixed in time, just as if we had filled our tree ring gap." A Hybrid Approach Since the inception of the UArizona Laboratory of Tree-Ring Research in 1937, an assortment of tree ring samples from all over the world accumulated in less-than-ideal conditions beneath Arizona Stadium. But since the completion of the university's upgraded Bryant Bannister Tree Ring Building in 2013, the curation team, led by Peter Brewer, has been relocating, organizing and preserving samples for future research. "This is the collection that founded the field of tree ring research, and it's by far the world's largest," Brewer said. "Researchers come from all over to use our collection." "It's just crammed full of the remains of ancient forests and archaeological sites, which no longer exist, and it contains wood samples that were fundamental in the growth of the discipline of dendrochronology," Pearson said. The tree rings that make up the Gordian chronology were sourced from timbers that made up the tomb casing in the Midas Mound Tumulus at Gordion in Turkey [Credit: Richard Liebhart]The collection includes timbers from the Midas Mound Tumulus at Gordion in Turkey - a giant tomb of a man that was likely Midas' father or grandfather. From timbers like these, Kuniholm has been building a tree ring chronology from the Mediterranean for nearly a half century. Together, Kuniholm's record from the B.C. period spans over 2,000 years, including trees growing downwind of the Thera eruption, making it key to the team's research. Despite the length of this chronology, it remained undated. To pin it down, the team decided to try something new. When cosmic rays from space enter the Earth's atmosphere, neutrons collide with nitrogen atoms to create a radioactive version of carbon, called carbon-14, which spreads around the planet. All other life on Earth, including tree rings, pick up the carbon-14, and because tree-rings lock away a measurement of carbon-14 for each year that they grow, they hold patterns showing how it changed over time. These patterns of carbon-14 in tree rings around the world should match. Pearson and her team used the patterns of carbon-14 captured in the Gordion tree rings to anchor the floating chronology to similar patterns from other calendar dated tree ring sequences. "It's a new way to anchor floating tree ring chronologies that makes use of the annual precision of tree rings," Pearson said. To validate their findings, the team turned to the calendar-dated rings of high-elevation bristlecone pines from western North America that lived at the same time as the Gordion. Charlotte Pearson holds the tree sample containing the light ring that might mark the date of the Thera eruption [Credit: Mikayla Mace]"When there are large volcanic eruptions, it often scars bristlecone by freezing during the growing season, creating a frost ring," said second author Matthew Salzer, research scientist at the tree ring laboratory. "Then we compared the dates of the frost rings with what was going on in the Mediterranean trees, which respond to volcanoes by growing wider rings. And it worked. It showed that the wide rings in the Mediterranean chronology occurred in the same years as the frost rings in the bristlecone. We took that to be confirmation that the dating was probably correct." The team then thought to use a new piece of technology in the lab called the X-ray fluorescence machine to scan the wood for chemical changes. "We scanned the entire period across when Thera is known to have happened," Pearson said, "and we detected a very slight depletion in calcium, right where I saw this lighter ring years ago." While it's a slight fluctuation, it is significant and only occurs at one point in the years around 1560 B.C. "We put that in the paper and tentatively suggest it's a possible date for Thera," Pearson said. Something changed the chemistry of the environment in which the tree grew; acid deposition from a volcano is one possibility, wildfire is another, but because the date happens to coincide with other tree ring markers for a major eruption, Pearson she says it's worthy of further exploration. "I think to do good science you have to investigate everything and keep an open mind until sufficient data comes together," Pearson said. "This is another little piece of the puzzle." Author: Mikayla Mace | Source: University of Arizona [March 30, 2020] Labels Archaeology, Earth Science, Europe, Greece, Southern Europe TANN you might also like Newer Post Older Post
Much Hadham is a lovely church being much larger than one would expect for its village setting. The church guidebook acknowledges this and points out that the site was owned by the Bishops of London since some date after 952 AD when it was gifted by Saxon Queen Ethelfleda in her will - first to her sister and her brother-in-law Brithnoth, the alderman of Essex - and then to the Bishop after her relative's deaths. I think this is same Brithnoth (spelled variously) who died leading the Saxon resistance against the Vikings at the Battle of Maldon in 991 - see my Maldon church set earlier. www.flickr.com/photos/barryslemmings/sets/72157630026001994/ to see the full set. A Bishops' Palace was built nearby and the presence of that palace, and the desire of various London bishops for a more substantial church, led to the construction of the present church which the guidebook admits would not look out of place in a well-to-do town like Ware or Hertford. The building is 121 feet long and the tower is topped with a stiletto-like thin spire called a 'Hertfordshire Spike'. Dedicated to St Andrew, the present church was almost certainly a Saxo-Norman site but nothing survives today earlier than about 1225. Frustratingly no documents survive before the 19th century as the records should have been in Fulham Palace's archives and should have been transferred to the Guildhall Library in London. Fulham Palace is the main London home of the Bishops of London. An on-site investigation has revealed three phases of construction which - for argument's sake - have been called 13th, 14th and 15th century. It is not possible to ascribe accurate dates to these phases (so far) but future dendrochronology could be used to date the roof timbers with some accuracy and might result in a clearer architectural history. The oldest part of the church is a weathered door which has now been moved inside and is thought to date to about 1225. It was moved about 100 years later and cut down to fit. Sometime after 1225 the chancel was greatly expanded and this may have been enlarged to allow the bishop and his chaplains to carry out the elaborate rituals which would not fit into a narrow Norman-style chancel. This chancel is Early English in style. Some time later the expansion of the nave was commenced (say 1240-1250) with the building of the south aisle. The first three arches on the south side set the scale for this work and may have been the work of a London mason supplied by the Bishop. This enlargement work continued until around 1280 with two more simpler arches being built on the south side. Moving into the 14th century (the Decorated style) windows were improved and the north aisle was commenced. In common with many other churches in England the Black Death, in the 1340s, would have brought a halt to any other work as a substantial proportion of the population died along with many skilled artisans. In some English churches it is possible to see where this work halted during the plague. Work at Much Hadham restarted in the Perpendicular style (1390 to 1450). The 90-foot tall west tower carries the arms of Bishop Braybrooke (died 1404) so his arms may date that work at least. Also added were the south porch, a clerestory to the nave and the enlarged east window. The main furnishings of the church such as the font, some pews, the screen and stalls also date to the 15th century. The pulpit looks like it was made from medieval material but was probably constructed during in the reign of Elizabeth I.
