SCIENCE

New findings have shed light on how some of Stonehenge’s monoliths were extracted and transported. (Nat Geo News)

Use our resources to learn more about stone quarries, or test yourself on your knowledge of Stonehenge with today’s 5-question Quick Quiz.

Teachers, scroll down for a short list of key resources in our Teachers’ Toolkit, including today’s quick quiz and MapMaker Interactive map.

Discussion Ideas

• The new archaeological discovery at Stonehenge concerns the origins of the monument’s bluestones. What are bluestones?
  • “Bluestone” is a generic term for many types of rocks, including igneous (basalt), sedimentary (limestone and sandstone), and metamorphic (slate). Bluestones are often used as building materials, and generally have a slate-blue tint.

• What are Stonehenge’s bluestones?
  • At Stonehenge, “bluestone” is a generic term for all rocks that had to be transported to the site. For this reason, bluestones are also called “foreign” or “imported” stones. The most common bluestone at Stonehenge is spotted dolerite.
    • Learn more about spotted dolerite, a type of basalt, here.
    • The other major type of rock used at Stonehenge are the giant sandstone sarsens. Take a look at this map from the good folks at British Archaeology for a terrific (literal) overview of the rocks at Stonehenge.

• How did scientists determine that Stonehenge’s bluestones came from Welsh quarries at Pembrokeshire Coast National Park?
  • Cooperation! According to the Council for British Archaeology, “Geologists have known since the 1920s that the bluestones were brought to Stonehenge from somewhere in the Preseli Hills, but only now has there been collaboration with archaeologists to locate and excavate the actual quarries from which they came.”
    • Geology: “The [Welsh stones] are volcanic and igneous rocks with precise geological signatures that match the inner horseshoe of smaller rocks at Stonehenge. Geologists have shown that this region of Wales is the only part of the British Isles that contains a particular type of rock—spotted dolerite—common in the bluestones.”
    • Archaeology: “Archaeologists have uncovered stone tools, dirt ramps and platforms, burnt charcoal and chestnuts, and an ancient sunken road that was likely the exit route from the quarry.”

• How did ancient miners quarry and transport the bluestones?
  • To extract the rocks at the quarry, “[t]hey only had to insert wooden wedges into the cracks between the pillars and then let the Welsh rain do the rest by swelling the wood to ease each pillar off the rock face,” says Dr. Josh Pollard of the University of Southampton. “The quarry-workers then lowered the thin pillars onto platforms of earth and stone, a sort of ‘loading bay’ from where the huge stones could be dragged away along trackways leading out of each quarry.”
  • To move the bluestones to Stonehenge, “[a]rchaeologists think that workers used a combination of ropes, levers, and a fulcrum to position the stones on top of wooden sledges that were carried or slid downhill.”
    • Here’s a replica sledge and sarsen at Stonehenge, and here’s how one might have worked. (Keep in mind that the sledges did not have wheels—wheels hadn’t been invented yet.)

• Carbon dating of ashes and chestnuts (a popular Neolithic snack) at the Welsh quarries indicates the bluestones were extracted about 3400 BCE, but the bluestones didn’t get put up at Stonehenge until 2900 BCE. (FYI, the giant sarsens didn’t go up for another 500 years, in about 2500 BCE.) Did it really take ancient engineers 500 years to drag the stones 200 kilometers (125 miles)?
  • Unlikely. “It could have taken those Neolithic stone-draggers nearly 500 years to get them to Stonehenge, but that’s pretty improbable in my view. It’s more likely that the stones were first used in a local monument, somewhere near the quarries, that was then dismantled and dragged off to Wiltshire.” (The race is on to find that ancient Welsh monument.)

TEACHERS’ TOOLKIT

Nat Geo: New Discovery Solves One Mystery of Stonehenge’s Construction

Council for British Archaeology: Stonehenge quarries found 140 miles away in Wales

Nat Geo: Stonehenge Quick Quiz

Nat Geo: Where Were Stonehenge’s Quarries? map

Nat Geo: What is a quarry?