A Little Bit of Color in Ancient Thera

After a brutal mile hike and an elevation gain of 369 meters, I reached Ancient Thera, one of the many reasons I wanted to visit Santorini for school. Located on the Southeast corner of Thera, the Spartan town of Ancient Thera was once used as a port for war purposes around the 9th Century BC[1]. As I walked into the ancient city, I could see the civilization, like many others, in ruins with crumbling walls and roofless structures(Fig. 1)(Fig. 2) . For many, the ruins look like scattered bricks layered on top each other with little importance, but to an anthropology major, the ruins remind me of the past, of what could have been. They demonstrate the greatness of the Spartan military and their empire. Since I came for geology though, I also look for the story and history of the rocks and how they landed at the second highest point on the island.

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Figure. 1
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Figure. 2

At first glance, the ruins look like many other Spartan ruins, but what made Ancient Thera special to me were the large blocks of black andesite and red scoria built into the walls compared to the white limestone, which most of the city is made of . Only the ruins of ancient Thera had these massive stones embedded in their walls which brings us to the question: Why? How did these blocks get here and why were they so important to the Spartans?

Andesite (Fig. 3 ) is a type of volcanic rock and which can be found almost anywhere on the island making it easy for the Spartans to obtain the rocks and use them to build their city. Andesite is formed from lava flows which contain an intermediate amount of silica (SiO2) content of 53 to 60 percent and erupts around 800 to 1000 degrees. These two aspects combined create a medium resistance to flow, or viscosity (think honey). This type of lava would have built up over time as Santorini passed in and out of its dormant and active periods. During the Minoan eruption, the vent would have exploded from the power of the eruption leaving andesitic blocks sproaditcally across the island. The Spartans would have then utilized them to build their structures [2].

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Figure.3 *Note the black rock in the middle is an andesite block built into the structure with other limestone rocks.

The other ‘rock that doesn’t belong’ in the walls of Ancient Thera is red scoria. Cinder cones are volcanoes that have one explosive event and create this red scoria. The magma breaks because high amounts of gas in it expand so quickly that the magma cannot withstand the pressure and then fragments into scoria pieces [2]. The high amount of gas causes scoria to have many vesicles (holes), thus red scoria is very bubbly. It originates from mafic magma which has a SiOcontent of 45 to 53 percent and erupts from 1000 to 1200 degrees celsius at any time. Both silica and temperature create a low viscosity for mafic magma (a low resistance to flow…think oil). Scoria is naturally black because it’s basalt but through oxidation (iron reacting with the air) it turns into a reddish orange color (Fig. 4).

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Figure. 4 *The reddish/orange block of scoria in the center of the picture is compared to 14.5 cm ruler to indicate the size of the rocks used. Note also the rough surface is formed from the vesicles created during fragmentation.

On Santorini, the red scoria dates back to roughly 650 to 550  thousand years ago and though the exact location is unknown, the scoria would have come from early Akrotiri on the southwestern tip of Thera (Fig.5). For the Spartans to build a city with blocks of scoria, they would have needed to travel a minimum of four miles just to collect the rocks and then another four miles to haul them back to Ancient Thera (Fig. 5). The determination of the Spartans was incredible because not only is the trek long but it is also steep, let me remind you that the hike to Ancient Thera is almost 400 meters straight up. Most Americans don’t even have the motivation to cook their own dinner but would rather just get take out at McDonalds. Just imagining the strength and will power it took to build such an amazing city is exhausting to think about but it does illustrate how advanced the Spartans were when they were in their prime.

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Figure. 5 *A map showing where the red scoria (red star) can be found in correlation to where Ancient Thera (purple flag) is. Note also where the Minoan Caldera; where the andesite would have originated from.

Ancient Thera maintains a special appeal because of the volcanic rock that is embedded in the walls of the houses, baths, and city structures. Collected from all over the island, the rocks utilized bring a sense of uniqueness and also create a story behind the construction of their homes. For me, when I see the structures I read a story of how the city was built, what the Spartan society was like and how they went along with their daily lives. Though the exact reason as to why they collected red scoria and black andesite is unknown, it brought a certain pop that is not found at many locations. Regardless of if you study anthropology or geology, Ancient Thera is worth the an hour of burning calves. `


”Santorini Archaeological Sites : Ancient Thira.” Archaeology / Ancient Thira. SANTORINI WEB PORTALS, 2015. Web. 4 June 2015. <https://www.santorini.com/archaeology/ ancient_thira.htm>.[1]

Friedrich, Walter L. Santorini . Denmark : Aarhus University Press, 2009. Print.[2]

6 thoughts on “A Little Bit of Color in Ancient Thera

  1. Rachel – Great job on this post. Some Americans may be offended by the McDonald’s comment, but I get your point. 🙂 Great use of scale in your photos. I’m very proud! I wonder if we will ever find out why the andesite and scoria are there. Did you go to the Spartan museum?

  2. Hi Rachel,

    I really enjoyed reading your post and gaining some insight into a fascinating aspect of ancient Spartan culture. What is working best for you are your first and final paragraphs because they show so much of who you, as the writer, are. Your strong points are when I, as a reader, get to see clearly what you’re experiencing so far away. Your impressions and thoughts are worth putting into writing like this, because you’re the authority here.

    Your scientific analysis is interesting and well presented, but what those sections that focus purely on the scientific study are lacking is your unique perspective. In your third paragraph you write about lava flows creating Andesite which the Spartans used to build their city, which is a really interesting thing to learn. I think it could add more of your personality to the blog if you included more of what you actually see and study. You say that Andesite is a common rock on the island, and it could be worth noting whether you saw evidence of this around you: were you constantly stepping on it, was there enough for you to build a summer home, was there enough for me to build a summer home too? One point that stands out is the little blurb on Americans Professor Skinner noted. I’m not pointing it out because of the possibility for offense, just that it doesn’t quite fit in with the rest of the paragraph. I do actually think a comparison of ancient construction practices to something modern is a good idea to explore because it makes your imagery relatable to a modern audience, but you may want to make a comparison that really drives the point home that these people were near superhuman in their home-making.

    Your perspective is obviously educated and that comes across easily in the text, so I’d enjoy seeing more of it. You start and end strong because you start and end with your impressions of an incredible place. I also enjoyed your last sentence and it’s clear from your enthusiasm that this place really is something worth reading about. I’m looking forward to seeing your future posts.

    Justin Kanzler

    1. Thank you for your insight and I will try to be more personal in the body paragraphs. In regard to where andesite blocks can be found, most of the blocks are easy accessible on most of the beaches and can be found on the side of roads. You could build a summer home but I’m not sure how stable it would be since all the blocks are differently shaped and sized, would definitely need to cut the rock to make better shapes for building. I see how removing the McDonalds quote would be more beneficial also, and instead including information about how people from the US have construction workers build their homes and how some families have designers come in to decorate it instead of decorating it themselves. You definitely handed me some information I will incorporate into my next post, thank you again!

  3. Rachel, loved your post! Your use of words helped me imagine the Spartans carrying these huge rocks. I liked how you explained everything thoroughly. If I didn’t know anything about geology, your post definitely would have given me insight. Also, I liked how you gave examples of the viscosities. Overall, good read. And yes, the hike is worth it. 🙂

  4. Hello Rachel.

    I really enjoyed learning about your day at the Spartan ruins of Thera. You provide a personal, yet factual account that combines both geological and anthropological perspectives. Your post does well in introducing the main idea of the Spartans’ intentional use of rock other than limestone and transitions smoothly to providing the historical and geological backgrounds of such rocks. Throughout the post, you demonstrate a consistent and casual voice that makes for a nice reading and allows me (an outside reader) to clearly receive the wonder of the Andesite and Red Scoria appearing in Thera. Your visual (Fig. 5) also does well with assisting readers in grasping just how tough and cool it is that the Spartans utilized such stones.

    Overall, your post read as well informed and provided much geological information in a simple yet thorough manner. It was interesting to learn (and see) how far the Spartans would have had to transport the Andesite and Red Scoria and how these rocks came to form. However, I must agree with Justin, in concerns to the Mcdonalds’ comment. I feel that omitting the sentence would better suit the flow and voice of your piece.

    I found myself learning so many intriguing and historical information from your post and I look forward to reading more of your work. (Also, it was super cool to use actual photos of the ruins).

    Jose Martinez

    1. I’m glad you enjoyed reading my post and learning a little bit about geology. I tried to keep it casual so that way non-geologist could understand what I was trying to point out. I myself get exhausted reading papers that don’t have personal characteristics of the reader in them which is why I tried to put my personalality into the post. For my next post, I definetly plan on choosing better examples for demonstrating the strength and motivation of the people. Thank you for your insight, Rachel Niesen.

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