Escaping the latest heat wave along the Colorado Front Range, my wife and I will be visiting friends in Ketchikan, Alaska, over the next several days. There we will enjoy afternoon highs in the 60s (F) and overnight lows in the 50s; of course, rain showers are also in the forecast, as one might expect in Southeast Alaska.
As I discussed in Alaska's Collage of Terranes, most of the State is a mosaic of exotic terranes and volcanic island arcs, later molded by glaciers, earthquakes, volcanic eruptions, torrents of meltwater and fluctuating sea levels. Ketchikan sits in the Gravina Belt, composed of mid Jurassic to early Cenozoic volcanic rocks, sandwiched between the Alexander Terrane, to the west, and the Stikine Terrane, to the east. The Alexander Terrane is especially interesting; its Silurian and Devonian strata and their cargo of fossils indicate that it was torn away from Siberia as the Northern Pacific opened. The Stikine Terrane, on the other hand, formed as a volcanic island arc from the late Paleozoic Era into the early Mesozoic.
Today, Ketchikan, sitting on the Inside Passage, is a cruise ship port during the summer months. Having limited time for our journey, we will be flying from Denver (with a plane change in Seattle). More on our adventure in upcoming posts.
As I discussed in Alaska's Collage of Terranes, most of the State is a mosaic of exotic terranes and volcanic island arcs, later molded by glaciers, earthquakes, volcanic eruptions, torrents of meltwater and fluctuating sea levels. Ketchikan sits in the Gravina Belt, composed of mid Jurassic to early Cenozoic volcanic rocks, sandwiched between the Alexander Terrane, to the west, and the Stikine Terrane, to the east. The Alexander Terrane is especially interesting; its Silurian and Devonian strata and their cargo of fossils indicate that it was torn away from Siberia as the Northern Pacific opened. The Stikine Terrane, on the other hand, formed as a volcanic island arc from the late Paleozoic Era into the early Mesozoic.
Today, Ketchikan, sitting on the Inside Passage, is a cruise ship port during the summer months. Having limited time for our journey, we will be flying from Denver (with a plane change in Seattle). More on our adventure in upcoming posts.
