The Magic of the Barrow

In the past few nights, shockwaves of magic suddenly appeared from the Barrow, followed by a burst of howling. I believe someone has constructed a magic circle in the area. Please investigate this for me.
Here, take Katrina's Scroll with you. If you see any strange patterns or markings, copy them and bring the sketches back to me.
I will give you a reward if you finish this task.
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== Gossip ==
The magic seems to be coming from the Barrow. If you find any strange patterns or markings, please draw them for me.
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== On Completion ==
This is the rune mark that works. I will consult some of my ancient books to find out what it means.
Thank you for your assistance. Here, this reward is for you.
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== Notes ==
Click on the middle pillar in the stone circle.
Coordinates: (32.2, 18.9)