I’m busy traveling at the moment, so Georneys will continue to be quiet for another couple of weeks. However, I thought that I’d quickly share a picture from my recent flight for this week’s “Monday Geology Picture” post. This picture shows the impressive topography of the Samail Ophiolite, which is located in northern Oman and the United Arab Emirates. An ophiolite is a section of oceanic crust and mantle that has been tectonically emplaced onto land.
Have you ever stayed in a hotel room and packed it to the brim with camping gear and scientific equipment and samples? Then chances are you’re a field geologist!
I took the above picture at a hotel in Muscat, Sultanate of Oman after 4 weeks of fieldwork in the Samail Ophiolite back in 2009. Our hotel room was packed full of camping gear, boxes of rocks and water samples, and various scientific instruments, such as pH meters. My favorite piece of scientific equipment was the light tan plastic box in the foreground on the right-hand side of the picture; that light tan box contained a storage container that was filled with liquid nitrogen in order to keep biological samples cold. We nick-named that storage container “R2 D2”, and we gave it a special place in one of the Land Cruisers. We even buckled it in with a seatbelt to keep it from tipping over!
Does anyone else have similar pictures of hotel rooms containing field gear?
I have the honor of hosting Accretionary Wedge #50 here at Georneys. The topic I chose for the September (Deadline: October 10th) Wedge is:
Share a fun moment from geology field camp or a geology field trip. You can share a story, a picture, a song, a slogan, a page from your field notebook– anything you like!
I have many fond memories from Dartmouth’s geology field camp (called “The Stretch”) in the Western USA and also from various geologic field trips I’ve taken over the years. However, for Accretionary Wedge #50 I’ve decided to share a moment from some fieldwork I did in the Sultanate of Oman for my PhD thesis research.
I participated in two ~1 month long fieldwork seasons in Oman: January 2009 and January 2010. For the first field season one of my PhD supervisors came along to help me with mapping and collecting samples. For the second field season neither of my two PhD supervisors were available to help me with my fieldwork, so I had to recruit another helper. I ended up bringing along my husband Jackie, who was my fiance at the time. Jackie was already working full-time as an industry geologist, but fortunately he had accumulated significant vacation time from several months that he spent at sea and in the field. So, Jackie cashed in 3 1/2 weeks worth of hard-earned vacation time… and then spent his vacation helping me do more geology work!
Jackie and I worked hard during the field season. We worked long days, eating a quick campfire breakfast of oatmeal with tea or coffee and then heading off to the day’s sampling location. We would map and sample until a couple of hours before dark and then head back to camp. Even though January is the middle of winter for Oman, the days were often sunny and hot. Temperatures in the 90s were not uncommon, and we had to be careful to keep our heads covered and stay hydrated. We usually drink plain water when hiking, but working in Oman is so hot that we frequently mixed Gatorade powder into our water bottles as the electrolytes seemed to help prevent dehydration. We usually arrived back at camp a little before sunset. Some nights we arrived at a new campsite and had to pitch our tent and set-up the rest of the camp. Other nights we returned to a campsite and just had to help make dinner. Most nights we joined up with a group of scientific colleagues who were working in similar field areas. A few nights we camped on our own and made a small makeshift meal, generally out of canned supplies that were perhaps supplemented by a few local ingredients from a nearby town. No fresh food stays fresh for very long in 90+ degree temperatures. We ate plenty of canned hummus and tahini, that’s for sure!
My PhD fieldwork in Oman mostly went smoothly, but there were some challenging days. During my first field season in 2009, we experienced a rare torrential downpour, and our hotel in Oman’s capital city of Muscat flooded. We had to dart around our rooms picking our bags and other gear and putting them on top of beds and sofas as the floors turned into rivers. I remember walking down the hotel stairs to inform the hotel management about the flood and feeling as if I were climbing down a waterfall. There was no need for me to inform the management– they were already rushing around with mops and buckets and trying to placate several disgruntled guests. During the 2009 field season we also had problems with goats invading one of our campsites. One of my scientific colleagues gave a half-rotted apple to one adorable goat that wandered into our camp, and within a few minutes all of the goat’s friends arrived– more than a dozen friends! The goats started eating through the cardboard boxes that contained our vegetables and fruit, eating the cardboard along with the food!
Jackie and I had a few challenging days during the 2010 field season, too. One morning we were packing up our tent when suddenly Jackie jumped away from the tent and screamed. I asked him what was wrong, and he replied, “There’s a spider under the tent fly.” I rolled my eyes and asked, “Is that all?” Then I looked under the tent fly and started screaming myself. Underneath the tent fly was an enormous camel spider. Now, I knew that camel spiders are relatively harmless: they aren’t poisonous, and accounts of them attacking people are mostly urban legends. In fact, they aren’t even spiders; they are solifugae. There is actually a variety of poisonous spiders, scorpions, and snakes in Oman, so camel spiders are really the least of your worries when camping in the Oman Mountains. However, camel spiders are very large and can run very fast, and for some reason this makes me– and I guess also Jackie– petrified of them. Eventually, we managed to gently coax the camel spider away from our tent with a stick. After carefully checking the rest of our tent for other critters, we packed up camp and started driving to our next sampling location.
Towards the end of the 2010 field season, we had a couple of very difficult days. One morning, I woke up and felt horribly ill. I think I must have caught some sort of flu. I don’t think it was food poisoning because I hadn’t had anything to eat or drink that was out of the ordinary, and no one else in our group fell ill from the food that we shared. Whatever I had, I was very, very sick. I immediately vomited up any food or water. All day, I could only keep a few sips of Sprite down. I left a certain public bathroom in a certain little Omani village in a terrible state. One day, I must go back and do something nice for the village– maybe donate a sparkling new public bathroom. By the end of the day of vomiting, I was becoming dangerously dehydrated. Jackie ended up driving me to a rural hospital, where a kind doctor treated me for free. The doctor did ask if perhaps I were pregnant with another child and experiencing morning sickness (note: Jackie and I have no children; I guess he thought Jackie and I were old enough to have a couple of kids), but once we assured him that I was not pregnant, he diagnosed me with flu, rehydrated me, and gave me some medicine to take back to camp. After a day or two I felt much better, just a little bit weak. However, I can’t say that I’d like to repeat the combination of having flu and camping in hot weather anytime in the near future! Poor Jackie ended up catching my “death flu”, as we called it, a few days later. However, I didn’t feel too sorry for him because he had “death flu” in the nice air conditioned hotel room with a proper bathroom in Muscat.
However, there were also plenty of wonderful field moments during the 2010 field season to make up for the challenging times. I wanted to share one moment in particular: a camel sunrise. As Jackie and I were driving out of camp early one morning along a dirt road, we stopped to observe four camels in the distance. As we stood by our Land Cruiser, the four camels slowly walked towards us and came over to say hello. We pet all of the camels, and a juvenile camel was particularly affectionate. After awhile, the camels continued on their way, stopping now and then to nibble on Acacia trees as they shuffled along. I have a vivid memory of the few minutes we spent watching the camels– the early morning light was beautiful, and for that moment all the world seemed to contain were the two of us, our Land Cruiser, the camels, and the mountains. In a busy, often crowded world, I’ve learned to treasure such moments. It was one of those moments that makes you remember why you became a geologist. It was one of those moments that makes you remember why you keep going into the field– floods, goats, camel spiders, “death flu”, and all.
For this week’s Monday Geology Picture, I thought I would share a picture of peridotite in thin section viewed under a microscope. This particular peridotite originates from the Samail Ophiolite, Sultanate of Oman, and is a weakly-deformed harzburgite that is ~40% serpentinized. You can see the fine network of serpentine veins throughout the sample. The brightly-colored patches are olivine and pyroxene minerals. I really enjoy looking at rocks in thin section– rocks can be so beautiful in thin section, particularly when viewed under cross-polarized light.
In other news, the defendable draft of my PhD thesis is due on Friday, so blogging (aside from posting cat pictures on Geokittehs) will continue to be light.
Today I am going to share some pictures of listwanite (also sometimes spelled listvenite, listvanite, or listwaenite), an unusual rock type that I bet even some of the well-educated geologists who read this blog have never seen or even read about. I don’t even think there’s a wikipedia entry about listwanite. Perhaps I’ll write one after my thesis defense next month.
Listwanite forms when ultramafic rocks (most commonly mantle peridotites) are completely carbonated. The pyroxene and olivine minerals found in peridotite commonly alter to form carbonate and serpentine minerals. However, peridotites are usually not completely carbonated. Rather, they typically contain carbonate veins (primarily magnesite; also calcite, dolomite, and other carbonates). Complete carbonation of peridotite means that every single atom of magnesium and calcium as well as some of the iron atoms has combined with CO2 to form secondary carbonate minerals such a magnesite and calcite. The silica atoms in listwanite are found in quartz. Thus, liswanites consist of quartz (a rusty red color) and carbonate and also sometimes talc and Cr-muscovite (a mineral known as mariposite/fuchsite). Geologists are still studying how listwanites form, but they likely form through the interaction of CO2-rich fluids with peridotites at higher than ambient temperatures up to ~200 degrees Celsius. Structural controls (faults and fractures) permit the percolation of the CO2-rich fluids through peridotite, so the formation of listwanites is generally structurally controlled.
Listwanites are important rocks to study for a number of reasons. First of all, listwanites contain large amounts of CO2 which originated from fluids and which is now stored in solid mineral form. Recently, geologists and other scientists have been investigating the potential of storing CO2 in solid minerals (which are more stable than CO2 stored as a liquid or gas) through carbonation of mafic and ultramafic rocks (see, for example, this Nature Geoscience Progress Article by Matter and Kelemen, 2009). Mafic and ultramafic rocks uptake significant CO2 through their natural alteration processes (that’s what I study for my PhD, so expect more on this in the next year or so as I submit my papers for publication). However, the natural carbonation rates of these rocks are too slow to significantly offset anthropogenic CO2 emissions. Therefore, scientists are currently investigating if it is possible to geoengineer CO2 uptake in mafic and ultramafic rocks so that this CO2 uptake happens more quickly. This could be done, perhaps, by fracturing and heating and injection of CO2-rich fluids. This is already being tested in mafic basalts through the CarbFix Project in Iceland.
However, scientists and engineers still have plenty of work to do in order to figure out the right conditions and protocols for CO2 sequestration in mafic and ultramafic rocks. In order to learn about what conditions lead to complete carbonation of ultramafic rocks, scientists such as Peter Kelemen and Gregory Dipple (and their many grad students and collaborators) are working to learn more about listwanites to see if mother nature can provide some clues.
In addition to the recent interest in listwanites for carbon sequestration efforts, listwanites are also important because they are often associated with economic mineral deposits, particularly gold deposits.
So, now that I’ve explained what listwanites are and why they are important, here are some pictures of listwanites which I observed during my trip to Oman back in January. Listwanites are pretty neat rocks, aren’t they?
For this week’s Monday Geology Picture post, I thought I would share some more pictures from my trip in January to Barr Al-Hikman, Oman. A few weeks ago, I posted about some crabs and their traces at Barr Al-Hikman. This week I am sharing some pictures of some large, beautiful, fossilized seashells which we observed along one of the beaches at Barr Al-Hikman. I believe that these seashell fossils formed fairly recently. I think that the seashell species (or perhaps a close relative) still exists today in Omani waters. Also, some of the fossilized shells contain un-fossilized shell fragments.
Can anyone identify the seashell species and give me any more information about these beautiful fossils?
Below are a few more pictures of the seashell fossils. Note that the fossils form as both molds and casts. Also note the pencil for scale.
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.
Over the past couple of weeks, I posted pictures of pillow basalts and sheeted dikes in the Samail Ophiolite, Oman. To round out the crustal ophiolite sequence, I thought I would post a couple of pictures of mantle peridotite in the Samail Ophiolite. As you can see in the below pictures, mantle peridotite in the Samail Ophiolite is generally highly-weathered and a dullish brown color. Harzburgite tends to be a darker red-brown color while dunite is a lighter tan (or “dun”, hence the name) color.
Last week I posted a picture of pillow basalts in the Samail Ophiolite, Oman. I recently visited Oman for a geology conference, and I was fortunate enough to see pillow basalts and many other wonderful geological sights in the Oman mountains and beyond. When I posted the picture of pillow basalts, geoblogger Ron Schott asked if I also had some pictures of sheeted dikes with chill margins. Good news, Ron. I do! Unfortunately, these aren’t the best pictures since they were taken in near-darkness with a flash. However, you can still see some of the dike features, including some classic chill margins.
For those of you who don’t know why ophiolites and sheeted dikes are really, really neat geologic features, I suggest reading an old post of mine titled O is for Ophiolite.
Here are the sheeted dike pictures:
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