Radiocarbon dates show the origins of megalith graves and how they spread across Europe

How did European megalith graves arise and spread? Using radiocarbon dates from a large quantity of material, an archaeologist at the University of Gothenburg has been able to show that people in the younger Stone Age were far more mobile than previously thought, had quite advanced seafaring skills, and that there were exchanges between different parts of Europe.

Radiocarbon dates show the origins of megalith graves and how they spread across Europe
The megalithic grave Dolmen de Fontanaccia, Corsica
[Credit: Bettina Schulz Paulsson]

Bettina Schulz Paulsson’s study has been published in the Proceedings of the National Academy of Sciences. With the aid of modern technology, she has been able to answer a question which has occupied researchers for over a hundred years: How and where did megalith graves arise?
Today, there are approximately 35,000 megaliths – ancient monuments constructed from one or more blocks of stone – that remain all across Europe. Most of them come from the Neolithic period (the final part of the Stone Age) and the Copper Age (the transition period between the Neolithic period and the Bronze Age) and are concentrated in coastal areas.

Radiocarbon dates show the origins of megalith graves and how they spread across Europe
The Dolmen di Sa Coveccada megalithic grave, Sardinia
[Credit: Bettina Schulz Paulsson]

The question scientists have long been asking is whether the tradition of constructing megalith graves spread across Europe from a single point of origin, or if this tradition arose at different locations, independent of each other.
More than 2,400 radiocarbon dates

Bettina Schulz Paulsson, who is an archaeologist at the University of Gothenburg, has analysed more than 2,400 radiocarbon dates from megalithic, pre-megalithic and contemporaneous non-megalithic sites throughout Europe, which she collected over a 10-year period in the research literature and on field trips.

Radiocarbon dates show the origins of megalith graves and how they spread across Europe
A megalithic enclosure on Er Lannic Island in the Gulf of Morbihan in Brittany, France
[Credit: Loic Venance/AFP — Getty Images]

The earliest megalith graves arose 6,500 years ago over a period of 200-300 years in Northwest France, along the Atlantic coast of the Iberian Peninsula, and in the Mediterranean region.
Pre-megalithic structures were found only in Northwest France. Megalith graves emerge on the Iberian Peninsula, in the British Isles and in France in the first half of the 5th millennium BCE, and in Scandinavia during the second half of the same millennium.

Radiocarbon dates show the origins of megalith graves and how they spread across Europe
A Megalithic grave on the north coast of Brittany [Credit: Bettina Schulz Paulsson]

In the early 20th century, researchers such as Oscar Montelius and Gordon Childe assumed that the megaliths had developed in one region (although they disagreed on where) and then spread from there. But apart from these two, until now the scientific community had thought and assumed that the construction of megalith monuments developed independently in five separate regions.
Diffused via sea routes

For the first time, Bettina Schulz Paulsson’s study establishes that this practice was not developed in and then spread from different places independently of each other – and also where the first ones were constructed.

Radiocarbon dates show the origins of megalith graves and how they spread across Europe
The stone circle Ring of Brodgar on the Orkney Islands, Scotland
[Credit: Bettina Schulz Paulsson]

“My results show that Northwest France was where Europe’s first megalith graves arose and that the megalith tradition then gradually diffused in largely three phases. All in all, the results indicate that there was great mobility via sea routes,” says Bettina Schulz Paulsson.

“This is the first time that this has actually been shown. The distribution of these graves suggests that the megalith tradition was diffused via sea routes. The maritime skills and technologies of megalithic societies appear to have been more advanced than previously thought,” says Bettina Schulz Paulsson.

Source: University of Gothenburg [February 14, 2019]

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NASA’s InSight Prepares to Take Mars’ Temperature

NASA — InSight Mission patch.

Feb. 14, 2019

Image above: NASA’s InSight lander set its heat probe, called the Heat and Physical Properties Package (HP3), on the Martian surface on Feb. 12. Image Credits: NASA/JPL-Caltech/DLR.

NASA’s InSight lander has placed its second instrument on the Martian surface. New images confirm that the Heat Flow and Physical Properties Package, or HP3, was successfully deployed on Feb. 12 about 3 feet (1 meter) from InSight’s seismometer, which the lander recently covered with a protective shield. HP3 measures heat moving through Mars’ subsurface and can help scientists figure out how much energy it takes to build a rocky world.

Equipped with a self-hammering spike, mole, the instrument will burrow up to 16 feet (5 meters) below the surface, deeper than any previous mission to the Red Planet. For comparison, NASA’s Viking 1 lander scooped 8.6 inches (22 centimeters) down. The agency’s Phoenix lander, a cousin of InSight, scooped 7 inches (18 centimeters) down.

«We’re looking forward to breaking some records on Mars,» said HP3 Principal Investigator Tilman Spohn of the German Aerospace Center (DLR), which provided the heat probe for the InSight mission. «Within a few days, we’ll finally break ground using a part of our instrument we call the mole.»

HP3 looks a bit like an automobile jack but with a vertical metal tube up front to hold the 16-inch-long (40-centimeter-long) mole. A tether connects HP3‘s support structure to the lander, while a tether attached to the top of the mole features heat sensors to measure the temperature of the Martian subsurface. Meanwhile, heat sensors in the mole itself will measure the soil’s thermal conductivity — how easily heat moves through the subsurface.

Image above: nSight’s heat probe, called the Heat and Physical Properties Package (HP3). Image Credits: NASA/JPL-Caltech/DLR.

«Our probe is designed to measure heat coming from the inside of Mars,» said InSight Deputy Principal Investigator Sue Smrekar of NASA’s Jet Propulsion Laboratory in Pasadena, California. «That’s why we want to get it belowground. Temperature changes on the surface, both from the seasons and the day-night cycle, could add ‘noise’ to our data.»

The mole will stop every 19 inches (50 centimeters) to take a thermal conductivity measurement of the soil. Because hammering creates friction and releases heat, the mole is first allowed to cool down for a good two days. Then it will be heated up by about 50 degrees Fahrenheit (10 degrees Celsius) over 24 hours. Temperature sensors within the mole measure how rapidly this happens, which tells scientists the conductivity of the soil.

If the mole encounters a large rock before reaching at least 10 feet (3 meters) down, the team will need a full Martian year (two Earth years) to filter noise out of their data. This is one reason the team carefully selected a landing site with few rocks and why it spent weeks choosing where to place the instrument.

Image above: An artist’s concept of InSight’s heat probe, called the Heat and Physical Properties Package (HP3), annotates various parts inside of the instrument. Image Credits: NASA/JPL-Caltech/DLR.

«We picked the ideal landing site, with almost no rocks at the surface,» said JPL’s Troy Hudson, a scientist and engineer who helped design HP3. «That gives us reason to believe there aren’t many large rocks in the subsurface. But we have to wait and see what we’ll encounter underground.»

However deep it gets, there’s no debating that the mole is a feat of engineering.

«That thing weighs less than a pair of shoes, uses less power than a Wi-Fi router and has to dig at least 10 feet [3 meters] on another planet,» Hudson said. «It took so much work to get a version that could make tens of thousands of hammer strokes without tearing itself apart; some early versions failed before making it to 16 feet [5 meters], but the version we sent to Mars has proven its robustness time and again.»

About InSight

JPL manages InSight for NASA’s Science Mission Directorate. InSight is part of NASA’s Discovery Program, managed by the agency’s Marshall Space Flight Center in Huntsville, Alabama. Lockheed Martin Space in Denver built the InSight spacecraft, including its cruise stage and lander, and supports spacecraft operations for the mission.

A number of European partners, including France’s Centre National d’Études Spatiales (CNES) and the German Aerospace Center (DLR), are supporting the InSight mission. CNES and the Institut de Physique du Globe de Paris (IPGP) provided the Seismic Experiment for Interior Structure (SEIS) instrument, with significant contributions from the Max Planck Institute for Solar System Research (MPS) in Germany; the Swiss Federal Institute of Technology (ETH Zurich) in Zurich, Switzerland; Imperial College London and Oxford University in the United Kingdom; and JPL. DLR provided the Heat Flow and Physical Properties Package instrument, with significant contributions from the Space Research Center (CBK) of the Polish Academy of Sciences and Astronika in Poland. Spain’s Centro de Astrobiología (CAB) supplied the wind sensors.

For more information about InSight, visit: https://mars.nasa.gov/insight/

Seismic Experiment for Interior Structure (SEIS): https://mars.nasa.gov/insight/mission/instruments/seis/

Heat Flow and Physical Properties Probe (HP3): https://mars.nasa.gov/insight/mission/instruments/hp3/

InSight Mars Lander: https://www.nasa.gov/mission_pages/insight/main/index.html

Images (mentioned), Text, Credits: NASA/Tony Greicius/JPL/Andrew Good.

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