Given that we have started our unit on rocks…it got me thinking large-scale: Stonehenge.
Stonehenge is a prehistoric monument in the English county of Wiltshire. According to Britannia History, Stonehenge is a national icon that symbolized “mystery, power and endurance.” Of the many mysteries surrounding Stonehenge, its original intended purpose is one of them. Researchers have “speculated that it was a temple made for the worship of ancient earth deities. It has been called an astronomical observatory for marking significant events on the prehistoric calendar. Others claim that it was a sacred site for the burial of high-ranking citizens from the societies of long ago” (Britannia History). Another unanswered question surrounding this monument is that of who built Stonehenge. Some theories attribute the creation of the monument to people of the late Neolithic period (around 3000 BC), while others cite the Druids (Britannia History).
Stonehenge is made up of an inner ring and an outer ring. The inner ring is made up of small blue stones; the stones of the inner ring of Stonehenge are made of dolerite, which is a dark,medium-grained igneous rock. The dolerite rocks of Stonehenge “weigh up to 4 tons each, and about 80 stones were used [in total]” (Britannia History). Given the immense size of these blue stones, I found it astonishing that they are believed to from the Prescelly Mountains, located roughly 240 miles away. There are extensive theories on how these immense stone traveled so far without sophisticated tools and technologies.
The outer ring of this impressive engineering feat is comprised of sarsen stones, which are sandstone blocks found in abundance on the Salisbury Plain (Britannia History). These sarsen stones weigh as much as 50 tons each (Briannia History). These 50 ton sandstone blocks are believed to have come from 20 miles away!
A relatively recent BBC article (December 2011) mentioned that scientists have claimed for the first time that they can pinpoint the “precise origin of some of the rocks at Stonehenge” (BBC). Interestingly, a keeper of geology at the National Museum of Wales and a professor at Leicester University have been working together for nine months to collect and identify rock samples from “rock outcrops in Pembrokeshire to try to find the origins of rhyolite debitage rocks that can be found at Stonehenge” (BBC).
For a little background information, rhyolite is a pale fine-grained volcanic rock. In other words, it is an igneous felsic rock; it is a relatively common volcanic rock and has the same chemical equivalent as granite (Rhyolite).
The two geological researchers undertook the task of detailing the mineral content and texture of rocks; this process is also known as petrography (BBC). Amazingly, “they found that 99% of the samples could be matched to rocks found in this particular set of outcrops” (BBC). The scientists mentioned that identifying the source of the rocks is the first step in addressing the question (or better said, mystery) of transport.
Reading about the recent findings regarding Stonehenge has really enlightened me to the powers of Geological research; they mystery of Stonehenge is slowly being unraveled.
Work Cited:
“Stonehenge Rocks- Pembrokeshire Link Confirmed.” BBC News. 19 Dec. 2011. Web. 23 Feb. 2013. .
“Stonehenge.” Britannia History. Web. 23 Feb. 2013. .
“The Rock.” Rhyolite. Web. 23 Feb. 2013. .
ENVR 102:: Introduction to Geology:: Blog 
How utterly fascinating! I wonder if we will unravel this historical mystery? I am amazed that scientists have not been able to pinpoint a more definitive explanation what group of people built it or even if its creation happened over a large period of time. If it is a burial ground it would be very easy date the bodies. Is it off limits for excavation? In my mind if the nature of the use monument is explained and we date the possible bodies in the burial mounds we could at least explain what technologies they had……