Chiswell Islands

There are islands trailing off in the distance as you go out to sea. This group of islands is called the Chiswells and was formed in the same manner of the two islands ahead of you towards the one and two o'clock positions. (Rugged and Hive islands). Think back to the sedimentary formation, it was scraped off of a subducting North Pacific Oceanic Tectonic plate. About a mile inland of the area of subduction the North Pacific plate begins to melt and then subsequently pushes up molten fingers of magma called batholiths. These batholiths intrude into the sedimentary rock, the "country rock" of the area. Because they are intrusive igneous rocks they cool slowly forming large crystals in the process. The resultant rock is granodiorite. At one time all of these islands you see (excluding Fox Island) were covered in sedimentary rock. However, the softer sedimentary rock was easily eroded by storms and glacial travel. The batholiths of harder igneous rock were left standing.

Getting There

Latitude: 59.64138
Longitude: -149.621
Driving Directions