megalith Archives - ATLANTIS RISING THE RESEARCH REPORT

by Stephanie Baum

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The Dordogne region of southern France is home to over 200 caves decorated with colorful Paleolithic art, but little is known about how old it is. Due to its coloration with iron- or manganese-oxide-based material, radiocarbon dating of the art has not been possible, and it has been generally thought to have been created during the Magdalenian Period, which occurred between 12,000 and 17,000 years ago.

Now, a research team from the Center de Recherche et de Restauration des Musées de France has reported the first discovery of black carbon-based art in Dordogne’s Font-de-Gaume cave, portending new opportunities for both radiocarbon dating and reevaluation of existing art in this cave and others throughout the region.
The team’s findings, titled “First discovery of charcoal-based prehistoric cave art in Dordogne,” are published in Scientific Reports (https://www.nature.com/articles/s41598-023-47652-1).
In late February 2020, the team discovered the charcoal-based drawings in the cave’s main galleries. The cave is informally known as “Bison Cave” owing to its 80 depictions of bison, along with others of deer, horses, mammoths, and other images. Animals comprise approximately two-thirds of all the Font-de-Gaume cave’s art, with tectiforms representing the remaining third.
While some of the bison are depicted in two or more shades including ranges of black to brown and red to yellow, others are done primarily in black and red, or only black. In 1902, Henri Moissan—who won the 1906 Nobel Prize in Chemistry—used coloring matter samples from the art to determine components of iron and manganese oxide. However, the Font-De-Gaume cave is now a protected UNESCO World Heritage site, and only in very rare cases is sampling by authorities permitted.
Because of this, researchers have turned to non-invasive analytical methods. The researchers in this study used both visible-light and infrared photography, superimposition of the visible-light and infrared images, portable X-ray fluorescence (pXRF) and portable micro-Raman spectroscopy to generate their data. These methods revealed carbon-based drawings beneath others known to have been created with pigments of iron and manganese oxide.By superimposing visible-light and infrared images captured from the same vantage point, the team created false color infrared photography (FCIR) images. The camera and filter they used to capture the infrared images permitted radiation wavelength only above 900 nm. Using software to combine these with green and red layers of visible-light images generated FCIR images and enabled differentiation of various materials used in the creation of the images.
The use of micro-Raman spectroscopy allowed the team to detect carbon-based compounds within the images, as well as to identify specific mineralogical phases of the iron and manganese oxide-based pigments. This spectroscopy method also made it possible to identify images specifically created with charcoal-black-based compounds as opposed to other carbon-based materials.
Looking ahead, the discovery of charcoal-based figures in the Font-de-Gaume cave heralds new opportunities for specific radiocarbon dating, improvement of creation phase knowledge, and perhaps even precise inter-regional comparison.

https://www.nature.com/articles/s41598-023-47652-1

AR #73

“20,000 Years to Paint?

A team of archaeologists, geologists and historians has found that the Menga dolmen represents one of the greatest engineering feats of the Neolithic. In their study, published in Scientific Reports, the group used new technology to learn more about the stone that was used to create the ancient burial site and to explore how wood and rope would have been used in its construction.

The Menga dolmen is an ancient burial mound located near Antequera, Málaga, Spain. Is usually dated to approximately 5,700 years ago and is one of the largest known megalithic structures to be built in Europe. It was built into the top of a hill using large stones, the largest of which weigh more than 100 tons. In this new effort, the research team took a closer look at the composition of the stones used to build the burial mound, where they came from and how they were transported.
To learn more about the makeup of the stones, the research team used petrographic and stratigraphic analysis techniques, which showed that the stones were mostly calcarenites, a type of detrital sedimentary rock. In the modern age, they are known as soft stones due to their fragility. According to the researchers, such a soft type of rock would have been difficult to transport without causing damage—a finding that suggests a certain level of engineering sophistication.
Moving and placing such large stones, they concede, would have involved massive planning and engineering, particularly for the capstone, which, as its name implies, was laid across the top of the chamber to serve as a roof. The researchers say it weighs approximately 150 tons. They point out that placing such large rocks would have involved the use of scaffolds and ropes, and transporting them would have required level roads.
The research team also states that the burial ground was built in such a way as to point in a desired direction. Its position aligns with nearby mountains in a way that creates complex light patterns inside the chamber. They also found that the early engineers had devised a way to place stones at the edges of the burial chamber in interlocking fashion to channel away water seepage as a means of preventing erosion.
More information: José Antonio Lozano Rodríguez et al, The provenance of the stones in the Menga dolmen reveals one of the greatest engineering feats of the Neolithic, Scientific Reports (2023). https://www.nature.com/articles/s41598-023-47423-y