What lies beneath the Acropolis?

Growing up as the oddball of the family, I found comfort in reading.. reading and learning about history. The things of the past and how they differentiate from how things are today. On the very first day we spent in Athens, we walked up the three thousand year old pathway to the Acropolis, the very same pathway that the Athenians of Classical Greece took. At first glance I saw this piece of history, from the marble columns to the Porch of Maidens and I was amazed that people of the past without the technology that we have today built these things with such precise and critical thinking.

The Acropolis was stated to have originally been a military base, on top of a high, flat, piece of rock that that is high enough where you could see any and all attacks. The name comes from the Greek word “Akro” which means high and “Polis” which is city,   I slowly started to notice that looking down off of one of the edge, that there were two noticeably different rock layers. I later learned that the Acropolis was strategically placed on a layer of limestone and other metamorphic rock. Limestone is a sedimentary rock consisting mostly of calcium carbonate (CaCO3). Limestone is only the top layer of the base of the Acropolis. The second layer called the “Athenian Schist” is actually not even a true schist in the correct geological terms.

Instead, the rocks of the Athenian schist are very lightly metamorphosed sedimentary rocks. Metamorphic rocks are formed when pressure and high amounts of heat are added. That added heat and pressure cause the atoms in rocks to rearrange and create and new rock without melting.

Limestone, on the other hand, forms in shallow and calm marine water. Knowing this tells us that the area where the limestone is had to have been surrounded by the ocean for the limestone to form. . This leads me to question, why is there only limestone in this particular place in Athens? The rest of the modern city is built in a low lying valley.

Acropolis Seperation

Figure 1: This picture shows where the construction meets with the limestone underneath.

While sitting in the garden of our hostel in Athens, just down the road from this massive 3,000 year old ruin, I learned that the limestone under the acropolis wasn’t originally there in the beginning. The limestone itself was brought up by faulting. Faulting is the process in which tension and pressure between plates is so powerful that blocks of rock fracture or break. The particular fault that moved the limestone is called a thrust fault. Thrust faults are the result of compression between two plates, which or where the land is being pressed together.

2016-05-28 23.33.00

Figure 2: Here you can see the clear separation of the limestone, the schist, and the constructed base of the acropolis.

The limestone under the Acropolis is older than the sandstone at the base of the hill (the “Schist”). It moved to its present position from an original position some distance away. It moved there along a break in the rock a “thrust fault.”

You can the Acropolis towering over the land from any location in Plaka. The Acropolis was placed on top of this complex layer of rocks. Sedimentary Limestone and the Athenian Schist. The limestone was moved from a distance away and shifted on top of the Athenian schist by thrust faulting. Thinking back at pictures taken of the acropolis, I no longer just see odd looking rocks. I see in my head a series of events from each rock movement to the next.

 

References

  1.  Regueiro, M., Stamatakis M., Laskaridis K., The Geology of the Acropolis (Athens, Greece) European Geologist, November 2014
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5 thoughts on “What lies beneath the Acropolis?”

  1. Elacha – This blog would benefit from a little deeper explanation of the thrust faulting that brought the limestone to this location. Use an analogy for the readers who don’t understand faulting? When did it happen? Are there other platforms like this around the Athen’s valley? Figure 2 would benefit greatly from putting labels on the photo pointing at what you are referring to. Some grammatical errors in the conclusion (please fix these). I’m glad you chose to write about this so you have a better understanding of faulting! Looking forward to your next idea.

  2. Hello Elacha,

    Your post is well written and held on to my attention. Your title relates directly to your discussion and your voice is developed in a way that creates for a smooth reading experience. This being said, your post loses traction as attention to your language falls away. From the middle of the post onward there are typos and redundant sentences.

    Your first two paragraphs read as the strongest because they are to the point and introduce you and your topic. They also create a discussion of your topic in a way that allows those outside the discipline of geology and history to learn from your post. That is until you mention the “schist”. Define schist and how it works (in terms of your post) as you do with the terms “Faulting” and “Thrust Faulting”. This would clarify your ideas, develop them fully, and allow a larger outside audience to follow along with your discussion.

    Overall, your writing does well in creating an atmosphere, an idea of yourself, and discussing topics related to the course and your time in Greece. For future posts be sure to revise your work. This post would benefit from expanding on ideas of natural processes as well as personal attention to detail. As Dr. Skinner suggests, a more developed explanation of natural processes involved in construction of Acropolis would help those unfamiliar with geology in understanding how cool this ancient city’s design is. Before submitting your posts try reading them aloud or in different chunks to ensure you’ve developed ideas and that there are little to no typos.

    Happy Writing,

    Jose Martinez

  3. Thank you Jose Martinez for the constructive responses to my blog. I will definitely try to apply them to my next blog.

  4. Hi Elacha!
    Really cool blog topic! I liked reading about the geological aspect of Athens since we were just there last week. I think you’re a really good writer and I could hear your personality through this blog. Like Lisa said, I think having dates of the thrust faulting would be beneficial, just so the reader can gauge when these geological events happen.
    I’m excited for your next topic! Thank you for the good read!

  5. Hey Elacha,

    This is a good introductory topic that is tied right into your introduction to Greece which is cool to read about. The Acropolis is easily recognizable no matter who your audience and that is an advantage when portraying geologic concepts to non-geologists. Annotated figures are also a great tool for scientific writing and your figures are clean and concise.
    I’m also interested in the Athenian Schist. Sometimes rocks are packaged into Formations, for example the Moenkopi Formation in Flagstaff has sandstones, siltstones, claystones, and even limestones. I’d be interested to see if there is an actual Athenian Schist somewhere in Athens that is part of the same package as the low grade metamorphic sedimentary rocks at the base of the Acropolis?

    Alex

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