For this week’s “Monday Geology Picture” here’s a picture of a spectacular sand-filled room in a house in the ghost town of Kolmanskop, Namibia. I visited this diamond mining ghost town back in 2014, and you can find more pictures from that visit here. If you ever visit Namibia I highly recommend a visit to Kolmanskop!
This past Saturday my husband and I went for a long walk along Noordhoek Beach with some friends. The beach is over 8 km long, and we walked about 2/3 of it… and back! As we walked, I enjoyed the beautiful, panoramic views of the mountains on one side and the sea on the other side. In addition, I periodically found myself enjoying the view at my feet (as geologists often do), admiring the patterns in the sand. I took a few pictures of the sand beneath my feet, and I thought I’d share one for this week’s “Monday Geology Picture” post. The picture above shows two generations of footprints, one fresh and made by my friends moments before and one older and halfway erased by the wind, both on top of some windswept sand patterns. I wonder how long ago the older generation of footprints was made. Were the footprints made a few hours before I snapped my picture? A few days? How long, in general, does it take for footprints to fade from a beach? I imagine that it must depend upon the wind, amongst other things.
Back in March and April 2015 my husband and I travelled to Australia for a couple of weeks for vacation. We went to visit some good friends who live in Sydney. We spent most of our time in Sydney and some of the surrounding areas, such as the Blue Mountains. We also spent a few days up in the Port Douglas area, including a couple of days on a boat out on the Great Barrier Reef.
While we were in Sydney, we were very impressed by all of the sandstone, which can be seen in outcrop at many places in Sydney, including along many of the beaches. We observed many interesting features in these sandstone outcrops, such as impressive cross-bedding structures, trace fossils, interesting erosional forms, and oxidation/coloring of various types and shades. We also observed that many buildings, walls, bridges, and other structures in Sydney are constructed out of sandstone blocks, which we assume were locally derived.
I’ve already shared some pictures of Sydney sandstone outcrops here, here, and here and of some sandstone building stones here. Today, I want to share some more pictures of Sydney sandstone and also briefly discuss its geology.
The sandstone that we observed around Sydney is known as the Syndey Sandstone or the Hawkesbury Sandstone. A nice scientific paper about the sandstone can be found here. The sandstone is Triassic in age and is interpreted to have been deposited in a fluvial environment by the ancient Hawkesbury River. Based on the scale and nature of features in the sandstone, such as cross-bedding and abandoned filled channels, this ancient river was likely a very large, sand-rich, braided river with deep main channels. Some of the abandoned channel fills are up to 18 m deep. The Hawkesbury Sandstone is extensively exposed in the Sydney area, outcropping over ~20,000 square kilometers in the Sydney Basin. The sandstone unit has a maximum thickness of ~290 m. The sandstone is a beautiful rock and has been used extensively as a building stone in Sydney, from the 1700s through to the present day.
Here’s a map showing the extent of the Hawkesbury Sandstone in the vicinity of Sydney:
Here are some more pictures of this remarkable sandstone that we encountered pretty much everywhere in Sydney. The pictures below were all taken during a walk along the ocean, near Bondi Beach.
That’s all for today… stay tuned for some more pictures from our recent Australian travels!
Apologies for the short hiatus in my blogging. I’ve been travelling and generally very busy with work these past two weeks. However, I have another “Geology Word of the Week” post coming up soon, so stay tuned!
Today I want to share another view of the abandoned diamond mining town of Kolmanskop. I’m currently in Namibia for business, and I flew over Kolmanksop earlier today and managed to snap a few aerial pictures of the town with my phone. I previously visited Kolmanskop on the ground, and I shared some pictures here and here. However, I like these aerial views of Kolmanskop. They show the small buildings surrounded by a sea of sand, with the real sea sparkling blue on the horizon.
For this week’s “Monday Geology Picture” I’m sharing another picture from Kolmanskop, an abandoned diamond mining town in Namibia. Many of the buildings at Kolmanskop have been partially filled with sand. You can see more of my pictures from Kolmanskop here. When you drive along the paved road near Kolmanskop, you pass a roadside warning sign that says “Sand”. I suppose that the sign is warning drivers about sand covering the road or perhaps sandstorms creating poor visibility for driving, but when I saw the sign I thought that it was quite funny because it really states the obvious. Of course there is sand in the Namib Desert, especially at Kolmanskop!
Does anyone else have pictures of fun geologically themed roadsigns?
Last month I spent some time in Namibia for work. During one of my days off, I was able to spend some time visiting Kolmanskop. Located in the Namib Desert a few miles outside of the seaside town of Lüderitz, Kolmanskop is a “Ghost Town” that is the remains of a former diamond mining town. Kolmanskop was founded shortly after diamonds were discovered in the region in 1908 and was abandoned to the elements in 1954, after the diamond supply was depleted. Over the last sixty years, Kolmanskop has been decaying in the desert, battered by the wind and swept over with sand. Today, many of the buildings are half-filled with sand. The discarded possessions of the town’s former inhabitants are either slowly disintegrating in the open air or are precariously protected by glass display cases. The town of Kolmanskop is managed as a tourist attraction by the diamond mining company Namdeb. Tourists can pay a fee to visit the town during certain hours. At their own risk, tourists can wander through the abandoned buildings.
Visiting Kolmanskop was a fascinating and surreal experience. As I explored the ghostly town, I felt keenly aware of the insignificance and ephemeral nature of my life. I wondered if, one day years from now, a young woman will wander through the decaying remains of my home… or perhaps come across a former possession of mine– maybe a book, with my name written on the front cover, dusty in the corner of an antique shop– and wonder, just for a moment, about the object’s former owner. Wandering through Kolmanskop, I found myself thinking about one of my favorite Carl Sagan quotations, from the book Pale Blue Dot:
Look again at that dot. That’s here. That’s home. That’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every “superstar,” every “supreme leader,” every saint and sinner in the history of our species lived there- on a mote of dust suspended in a sunbeam.
The Earth is a very small stage in a vast cosmic arena. Think of the endless cruelties visited by the inhabitants of one corner of this pixel on the scarcely distinguishable inhabitants of some other corner, how frequent their misunderstandings, how eager they are to kill one another, how fervent their hatreds. Think of the rivers of blood spilled by all those generals and emperors so that, in glory and triumph, they could become the momentary masters of a fraction of a dot.
Our posturings, our imagined self-importance, the delusion that we have some privileged position in the Universe, are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves.
The Earth is the only world known so far to harbor life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment the Earth is where we make our stand.
It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we’ve ever known.
With that quotation in mind, enjoy my pictures from Kolmanskop:
Here is Part II of the views that I observed during a flight from Amsterdam to Cape Town back in September 2012. Part I is here. I believe that all of these shots were taken over Algeria. There are some stunning desert views. Although I grew up in relatively lush New England, I have always liked deserts. I think I first became enchanted by deserts when I was an exchange student and lived in Jordan for 5 months when I was 15 years old. My school in Jordan took me on visits to places such as Wadi Rum and Petra, and I quickly fell in love with the sands, rocks, animals, people, and historical ruins of the deserts there. Visiting the Jordanian deserts certainly helped inspire me to study geology.
I’ve never been to Algeria, but the desert views I observed while flying over Algeria are certainly enchanting. The young, volcanic Hoggar Mountains look particularly enticing. I hope that I can one day visit the deserts of Algeria. Has anyone been there?
Enjoy the desert views below. And, as always, feel free to point out interesting locations and geological features.
I still have some more views to share from this flight, so stay tuned for Part III!
My post yesterday about the crab houses in the sand at Barr Al-Hikman turned out to be quite popular, so I thought I’d share some more pictures of crabs and crab houses and other crab life traces which I observed at Barr Al-Hikman. In addition to the Ocypode saratan “ghost” crab (thanks for the identification help, Tony Martin!), I observed at least two other species of crab at Barr Al-Hikman.
The first species is a dark red colored crab that I observed when walking out on some of the modern coral and carbonate deposits. These crabs were scuttling about everywhere, but if you came too close to them they would dart into small cracks and crevices in the carbonates and put up their big claw defensively.
The second species of crab which I observed is a very tiny, tan-colored crab. We actually pulled this poor little guy out of his home. On several of the beaches, we noticed small holes surrounded by small balls of sand. The field trip leaders informed us that these the little balls of sand are called “sand bubbles” and that they are produced by the tiny crabs that live in the little holes. The sand bubbles are made by the crabs when they emerge from their holes during low tide to search for bits of food that have been brought in by the recent high tide. After they search through a few grains of sand, the crabs roll the sand grains into a tiny ball so that they don’t search the same sand grains again. Smart behavior, if you ask me! Sand bubbles can leave some spectacular patterns and designs on the beaches, as show in this article.
We were curious to see one of the little crabs responsible for the sand bubbles, so we decided to dig one of the little crabs out of his (or her?) “safe” little home. We took a shovel and started turning over some sand. Before long, we found a little crab. After inspecting him for a minute or two, we returned him to the beach, where he quickly dug himself back into the sand. I feel bad that we disturbed the little guy and destroyed his home, but it was neat to see him!
I’m not normally that interested in biology. Generally, I find biology stuff such as vegetation annoying since it covers up the interesting rocks. However, I enjoyed meeting these two crabs: Mr. Red Crab and Mr. Little Crab. Can anyone identify these two crab species and tell me more about them?
Last month I participated in a three-day geology field trip to Barr Al-Hikman, a peninsula in Oman. On the peninsula there are numerous beautiful beaches and interesting geological features such as sabkhas and paleolagoons. We visited the peninsula to look at some recent carbonate deposits and also to investigate some modern beach features, such as the coral reefs located just off shore and the traces left on the beach by various modern critters. Yes, we went to the beach for three days. Being a geologist is fun sometimes! Seriously, though, looking at modern life traces gives geologists a better sense of how to identify trace fossils in the geologic record. If you want to learn more about traces and trace fossils, I recommend Tony Martin’s blog and forthcoming book Life Traces of the Georgia Coast. I’m certainly looking forward to the book!
I don’t normally study life traces or trace fossils, so looking at these traces in Oman was new and exciting for me. I don’t know much about the traces– other than what the field trip leaders told me– but I thought I’d share some pictures of some life traces I saw at Barr Al-Hikman. In this post I’m sharing some pictures of holes with piles of sand next to them. Apparently, these holes were dug by crabs. I’m not sure of the exact species. Does anyone know? I spotted a likely suspect a few meters from the holes.
I noticed that there has been a sand dune meme wandering around the science blogosphere over the past week or so.
Here is my contribution to the meme– some pictures of sand dunes in Death Valley, California. I visited these sand dunes near sunset after a long day of mapping with my undergraduate fieldwork program in Fall 2005. Our instructors had promised we could visit the dunes once we finished working, but by the time we finished we only had an hour or two of light left. So, we had to race out to the dunes, first by driving and then by walking or running as quickly as we could on the soft sand. We spent a few minutes tumbling and rolling down the dunes then made our way back to the vans as darkness fell.
Georneys 