The New Year welcomed us with the best weather we could have asked for! Naturally, we decided to spend the first day of 2013 outside. After sleeping in and grabbing a late brunch, a group of us decided that we would make the hike out to Castle Rock, a rock spire that juts up from a ridge atop Hut Point Peninsula, here on Ross Island.
The rock stands 1360 ft. tall, and it was discovered by the British National Antarctic Expedition under Captain Robert F. Scott, who named it Castle Rock because of its resemblance to a castle.
The hike to Castle Rock is approximately 2.9 mi. from the trailhead, which is about 0.8 mi. from our dorms, and with the tenth of a mile scramble to the top of the rock the hike adds up to 3.8 mi. (one-way). It is a fairly easy hike if the weather is good, but it does require that you dedicate some time to getting there and back. The last time that Bev and I hiked out to Castle Rock was on a windy and cold evening in late September, back in the days when the sun still set. We got to see stars then, but the temperature was in the -10º to -20ºF range and it was a bit windy, so we made it a fairly short hike.
By contrast, our New Year’s day hike was more enjoyable: it was sunny and warm (~37ºF), hardly any wind, and almost no clouds in the sky. Once we got there, we decided to hang out for a while, because why not? We were there for most of the afternoon and evening, spending about 6 hours enjoying the never-ending sun. I suppose that’s one nice thing about having a sun that never sets. Though we did get some thin clouds precipitating just around us later in the evening, as I will soon show you. That was about the time we decided to make the trek home.
Here are some pictures. Enjoy!
Quick geology lesson: Castle Rock
Geologically speaking, Castle Rock is what we call an old volcanic neck, or volcanic plug. Actually, geologically speaking it is quite young, as it formed only about 1.12 million years ago. These types of features form when lava or tuff (a combination of hot gasses, water, and volcanic rocks, ash, and debris) solidifies inside the “neck” (or the throat) of an active volcano. Because they sit inside the volcano where they can’t spread out, they tend to remain at higher temperatures longer than lava or tuff that is ejected from a volcano, resulting in the formation of a very solid, glassy, and more resistant plug within the neck of the volcano. We call this more resistant plug material a “welded” tuff. Over the last thousands of years erosion has carved out and removed all of the weaker “non-welded” tuff, leaving behind the plug that we now call Castle Rock. The specific type of rock that we find at this location is called a palagonite hyaloclastite. The first term (palagonite) means that the rock formed as a result of the interaction between volcanic glass (lava) and water. The second term (hyaloclastite) means that the eruption that produced this lava took place either underwater (submarine) or under a glacier (subglacial).
Still following? Great! Now back to the pictures:
Quick atmospheric optics lesson: Solar Coronas (Optical Phenomenon)
There are a few atmospheric phenomenons that tend to be quite common around polar regions, or regions where the temperatures get quite low, including in countries like Canada, Russia, the Nordic countries, and even areas like the upper mid-West and New England. The most commonly recognized ones are sun dogs and sun halos (these two phrases are commonly interchanged, though they are quite distinct things). The one I want to talk about, because I have pictures to show you, is called a solar corona. This optical phenomenon requires light and the presence of moisture in the atmosphere, so it is not necessarily only associated with the sun; the moon can create a lunar corona. The presence of moisture, in the form of tiny cloud droplets or tiny ice crystals, in the air causes light to diffract, or bend and scatter, when it interacts with the light. There are two parts to a solar corona: a central and very bright aureole, and one or more surrounding colored rings (basically circular rainbows). The color in the rings is the result of the scattered light, and it shows up best around the sun when the droplets or ice crystals are very tiny and low in density (when there isn’t much moisture, like when there is a very thin veil of mist in the air). During our time at Castle Rock, this happened towards the end of the day when very thin clouds started forming around us.
Whew! You made it through yet another science-y blabber? Great job! Enjoy some more pictures!
And lastly, a few other views of Castle Rock:
USGS Geographic Names Information System (GNIS): Antarctica Detail (Castle Rock)
J. J. Anderson, 1965. Bedrock Geology of Antarctica: A Summary of Exploration, 1831-1962. Geology & Paleontology of the Antarctic, Vol. 6.
P.R. Kyle, and S.B.Treves, 1974. Geology of Hut Point Peninsula, Ross Island. Antarctic Journal.
Atmospheric Optics by Les Cowley: Corona.
Metereological Optics by Dr. James Calvert: The Corona.