I think I’ve been over-rating myself as a geologist, at least as far as explaining this planet in terms of plate tectonics.

Oh, some of it’s all right. I know that rift valleys generally indicate that plates are pulling apart, mountains are most likely where plates have collided, and that linear features are most often faults. I haven’t seen any island arcs on this planet, but I expect there are some. But how do I explain what looks like an underwater jumble of mountains? The computer has the basics of plate tectonics, and I’m pretty sure plate tectonics are what controls the geology on this planet, but the basics don’t include underwater mountain ranges aside from midocean ridges.

Aegean bathymetryI was following the coast west when the mountain jumble to my right was replaced by a jumble of islands. I went high, as I usually do when I want to get a good look, and found that the coastline turns north, but the sea to its west was an unbelievable tangle of islands. Some looked volcanic, though not in a proper arc, and when I tried to sense the sea bottom I found it almost as rough as the land to the east. Ocean floor shouldn’t to that! It’s supposed to be too thin to support much in the way of mountains!

The area is still part of the tideless sea, and seems to be bordered by mountainous terrain to the north and west. The weather is still hot and clear, though the southward equinox is approaching and I suspect from the vegetation that this is a winter-rain area. Is it worth while trying to map all of these islands before going on to the land to the west?

I wish my old friend Nal was here. He used to study planetology, and I suspect he could explain this sea of islands.

Jarn’s Journal is the fictional journal of a human-like alien, Jarn, who was stranded in Africa 125,000 years ago. He has made contact with a group of our remote ancestors, roughly mapped Africa, and is now exploring the edges of the Mediterranean Sea, using his abilities to teleport and levitate.

Jarn, of course, would hardly have gone high enough to see the Aegean Sea as a whole, and the French names of island groups, seas and countries are out of period by about 125 millennia. But his ability of perception would have allowed him to tell that the sea bottom was as much a jumble of heights as the mountains of Anatolia. Unfortunately the best bathometric map of the area I could find was the one above, from Wikimedia.