One year ago, I was on Heard Island. Over the course of the expedition I took more than 6000 photos. Although I took three images with the Gigapan (Big Ben, the Azorella Peninsula, and—my favorite—Windy City), I also took photos for stitching together manually using my own camera.
I have been slow in stitching these pictures together, but with the one-year anniversary of their production coming around, I decided it was time to finish one or two of them. This is the first, and I hope I’ll find time to finish more. Putting it together, I was amazed that this is still a relatively wide-angle compared to what I had available: 70 mm on a 70–200 mm lens. The detail came out well, as is evident at full-size. The glaciers, moraines, and hills are all more than a kilometer distant over the “nullarbor”, a broad, flat, volcanic-sand plain.
Toward the left half of the image are some penguins for scale. They look like king penguins, putting their height around 1 meter. I count at least 31 penguins in the entire image.
I think I spot some of the relatively rare basement limestones cropping out at the very left edge of the image, and their appearance is consistent with a dip of 25–35° to the south. A closer view (200 mm focal length) shows them more clearly.
Heard Island is home to a spectacular outcrop. It’s the coolest outcrop I’ve ever seen, besting the Bishop Tuff tablelands, the potholes along the St. Croix River at Taylor’s Falls, Zion Canyon, The Badlands, and various outcrops in Yellowstone and Grand Teton. Admittedly this outcrop doesn’t intrinsically have the scale of many of the others just mentioned—it’s a roughly car-sized block—but the power that went into creating it and the effect it created is truly amazing.
On its face (see above), it looks quite pedestrian: a block of lithified glacial till with clasts of vesicular basalt reaching up to grapefruit size. However, it’s important to consider it from a different perspective.
When viewed from the side, a pile of sand in on the leeward (left, east) side of the block is evident. Additionally, the basaltic clasts of the rock face seem to be protecting the softer, tan-colored glacial matrix from the sand-blasting.
Here’s a close-up from an oblique angle:
In the oblique view, the volcanic clasts making up the face of the outcrop are seen sheltering the matrix directly to the leeward from mechanical erosion. To tie all of these views together, I took a short video (embedded below).
This outcrop is located on the edge of a volcanic sand plain roughly 1.5×1.5 km. Strong westerly winds are present most of the time (9 m/s is average, measured at a site nearby). In fact, the audio which accompanies the video is mostly wind noise, though there’s a little unintelligible chatter with my field partner, Carlos. Winds when the recording was made were “moderate” (for Heard Island) and from the west, exactly the kind of winds that shaped this outcrop. At the time of the recording, the winds weren’t strong enough to kick up much sand, nor were ice pellets falling from the sky, but on a gustier, stormier day, the face of this outcrop will take a beating.
In my travels and geo-adventures, I’ve seen differential weathering and ventifacts (outcrops shaped by wind), but never so strikingly combined as at this outcrop on Heard Island. That’s why I can confidently say it’s the coolest outcrop I’ve seen on Heard Island or anywhere else in the world.
 Thost, D., Allison, I. “The climate of Heard Island” in Heard Island: Southern Ocean Sentinel, ed by K. Green and E. Woehler. Surrey Beatty & Sons, Chipping Norton 2005, p. 52-68.
A few days have gone by, and they have been busy! We’ve been fortunate in that when the weather has been poor, the radio propagation has been good. A fair bit of windy, drizzly weather has been present this week, and we have managed to make more than 50,000 contacts with stations all around the world.
Unfortunately, the weather has meant I haven’t had the opportunity to take more gigapans. I am prepared for wet weather, and this morning I went a few hundred meters across the lake which had formed in front of camp (ankle deep) to Wharf Point, the point inside Atlas Cove. There on the cobbles lining the beach I did a stationary count of the birds in the hummocks nearby, on the water, and along the beach. It took about 10 minutes, and I managed to get the list recorded in a weatherproof notebook for upload later. Getting out of the tent and away from things for a while was a welcome change.
One thing which has been abundantly clear on this expedition is that if you want to do something that depends on the weather, be prepared to do it. The weather can shift very rapidly (especially if it’s permissive weather), so “I’ll just wait until later” often won’t cut it. If you see Big Ben and want a photograph of it, get your camera and shoot. There may not be another chance. This evening I didn’t immediately take a picture when there was a clear, starry sky. I at least saw the starry sky, but did not get the photograph. With only a bit more than a week to go, I hope I can still get that picture.
In the afternoon a few days ago, the weather cleared enough to get a view of Mawson Peak atop Big Ben. I quickly grabbed the camera, put on the telephoto lens, and got a few pictures of the summit. Indeed, there was a small plume indicating (at minimum) hydrothermal activity or venting, but possibly a small active lava flow.
Heard Island’s mood changes with the weather, and the effect that has on the landscape can be quite striking. The picture at the top of this post and the one immediately below are taken in pretty similar places looking in similar directions. What a difference the weather makes!
Finally, the king penguins make tracks as they walk around on the wet sandy ground.
This summer, I took a field trip up to Split Rock State Park in northern Minnesota, along the north shore of Lake Superior. While I wrote a little bit about the trip, there is still a bit more to be said and shown.
Part of what makes Split Rock interesting, besides a picturesque lighthouse which I didn’t take many pictures of, is the large blocks of anorthosite. Anorthosite is a rock formed primarily of the mineral anorthite, which is a calcium-rich feldspar, and the mineral zircon—used in U/Pb dating—can be found in anorthosite as well. Its appearance is generally light grey or whitish, and has relatively coarse grains (mm to cm).
Anorthosite is an intrusive igneous rock formed through the crystallization and accumulation of anorthite within a magma body. It is abundant on the Moon, and lunar anorthosites are believed to have accumulated on top of a magma ocean early in lunar history. A relatively dense magma will act as a heavy liquid, and cause the less dense anorthite to float, separating the original magma from the crystallized anorthite. These types of crystallization processes, where the magma becomes separated from crystals it produces, are called fractional crystallization, and can cause the resulting magma to be enriched in some elements or components (such as SiO2). Even with massive basalt flows, fractional crystallization can cause an occasional rhyolite flow as well, but I’ll leave discussion of the rhyolites of the North Shore for another day.
Pictured above is the view from Corundum Point, a large block of anorthosite at Split Rock State Park. Below is a close-up view of some of the anorthosite, as well as a benchmark which has been placed in the anorthosite block [Thanks to Jessica Ball (@tuff_cookie) for giving me the idea of photographing the benchmark]. Despite being far from the ocean, Minnesota is home to National Ocean Survey benchmarks.
The name Corundum Point suggests the presence of corundum—a mineral used in abrasives—and it comes from a mining operation on the site in the early 1900s. However, the point is actually anorthosite, which was much less useful for abrasives. Between the incorrect mineral identification and a fire which burned down the crushing house, the operation was eventually shuttered.
 Mark D. Schmitz, Samuel A Bowring, Trevor R Ireland, “Evaluation of Duluth Complex anorthositic series (AS3) zircon as a U-Pb geochronological standard: new high-precision isotope dilution thermal ionization mass spectrometry results” Geochimica et Cosmochimica Acta (2003), 67, p. 3665–3672. DOI: 10.1016/S0016-7037(03)00200-X
Update Upon further study, it appears that the naming convention of Split Rock State Park is to call this point Corundum Point. However, Google Maps displays this point as Split Rock Point, with Corundum Point a few hundred meters to the northeast. Regardless of the arbitrary common name, the benchmarks are on the point to the southwest.
Second, the Joides Resolution blog (the Joides Resolution is an ocean sediment coring vessel) has a series of posts (1, 2, 3) on geologic thin sections. Not surprisingly, the thin sections pictured are from rocks such as gabbros or sheeted dikes, which are expected in oceanic crust and in ophiolites (oceanic crust exposed on land). There’s a great exposure of the Coast Range Ophiolite just west of Patterson, CA, in Del Puerto Canyon, which is described in a recent blog post by Garry Hayes.