It is amazing how tiny plants start growing on a surface which seems to be a bare rock without any soil cover:

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Why is the road still closed? Because we humans are helpless against mother nature. Kilauea and especially Pu’u O’o vent are very active and would certainly destroy the road very soon. I spent several days on this huge lava field and also saw flowing lava. The landscape is full of fantastic lava forms which I hope to soon demonstrate in another post.

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In some patches garnet and other heavy minerals are so abundant that the sand has a deep purple color.

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Be careful when you venture near “smokes” like that because they can be hazardous. It is not recommended to expose your lungs, eyes, etc. to it. People have lost their lives because of acidic laze clouds.

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It is sometimes assumed that wind stretches these filaments out of a basaltic lava flow but I find it too hard to believe. Lava flow is too compact and thick for that. There must be more intense force involved that puts a real strain on the molten material. However, similarly stretched strands often form as lava tongues break out and stretch the already partly solidified outer crust of the flow. You can see such strand in the last picture but the majority of Pele’s hair is most likely associated with fire fountaining.

The term “Pele’s hair” comes from Hawai’i just as many other volcanological terms. Pele is a local volcano goddess there. For some reason her hair is usually imagined to be black and/or red by artists. There is an obvious inconsistency because these are not the colors of Pele’s hair. At least not the color of the material we call that way. Her hair is therefore not composed of lava flows and should be golden brown. Perhaps we should think again how to really draw her.

Pele’s hair is not associated with Hawaii only. Similar lava threads form in other places too, for example in Nicaragua (Masaya) and Ethiopia (Erta’ Ale)¹.

References

1. Francis, P. & Oppenheimer, C. (2003). Volcanoes, 2nd Edition. Oxford University Press.

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This is how they look. It often pays to turn the other sides of the clinkery chunks of aa lava because some nice xenoliths are not immediately visible.

I spent maybe 20 minutes looking for the xenoliths and found a nice collection of rocks containing xenoliths of peridotite and dunite for a picture. I scattered most of the pieces after taking the picture for you to find them again.

Only a very small part of this dunite xenolith was initially visible. After spliting the rock with a hammer, this beautiful example of the mantle embedded in vesicular basaltic lava was revealed. The sample is 8 cm in width.

There is a possibility that these xenoliths are not xenoliths in the strict sense of the word. They might be genetically related to the lava which embeds them. If this is the case, they should be called inclusions instead of xenoliths.

The lava flow is quite wide and long. There is little chance that the location I visited is the best place to find xenoliths there. But here are the coordinates if you are interested to follow my footsteps: 19° 46′ 40″ N 155° 54′ 53″ W. Altitude 620 meters.

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The air above the Mauna Kea summit is usually very dry which means lots of cloudless nights. Tropical temperature inversion is well below the summit (it fluctuates between 1200…2400 meters, if present) which protects it from particulate matter from volcanoes and industrial sources and moisture from the ocean. Temperature inversion means that air temperature increases as we go higher. This is unusual situation. As we know, it usually gets colder as we move higher. If there are inversion layer in the atmosphere, it blocks clouds and pollutants from going up because they are cooler and can not penetrate hotter atmosphere above. It is a common phenomenon in many places and when that happens above industrial cities, it means bad air quality for its inhabitants. In Hawai’i, such conditions are very common and associated with prevailing trade winds that blow from northeasterly direction. The inversion is present about 50…70% of the days. Apparently, the inversion was not present on the day I visited the summit because you can see lots of clouds on the pictures below.

Mauna Kea is home to many telescopes operated by scientists from more than 10 countries. Here are some of these telescopes:

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There are a number of similarly shaped rocks in the world. Most of them are shaped by wind-blown sand grains and are therefore ventifacts. There are some nice examples of ventifacts in Death Valley nearby (read my post about them: Ventifacts and dreikanters). However, this rock is probably shaped by salt erosion, not wind¹. Crystallization of salt crystals can be an effective way to disintegrate rocks.

I read from several sources that the sign erraneously claims that Mushroom Rock is a ventifact (shaped by wind). There is no such sign anymore and not even a place to stop a car. Maybe because the rock was vandalized some years ago. It has been repaired and I did not notice anything wrong while I was there. So it must be a job nicely done.

References

1. Miller, M. & Wright, L. A. (2012). Geology of Death Valley: Landforms, Crustal Extension, Geologic History, Road Guides, 2nd edition. Kendall Hunt Publishing.

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Siim having fun

Initially when I started writing this blog I had very limited stockpile of images to show and stories to tell. I did not have much to choose and sometimes faced the problem perhaps familiar to many bloggers — I wanted to write something but did not have a good idea or even more importantly lacked appropriate pictures. This blog is very much based on images. Text seems to be of secondary importance to me and serves to describe the pictures. It varies, of course. Some posts are more text-based but I can not imagine myself blogging without pictures.

Hence, I grab my camera whenever I go to some geologically interesting place and now I have thousands of pictures waiting to be edited, described, blogged, uploaded to photo banks, etc. So I am having another type of problem that is actually the reverse of what I was struggling with at the beginning. It is an issue for me because I would really like to make these pictures pay for my travel expenses, at least partly. So far it seems hopeless but I don’t want to give up yet. Otherwise, blogging, photographing, and geotraveling is not financially sustainable way of living. Right now I can do it because my regular job at university allows much flexibility.

But it seems that I am more interested in just one part of the equation. I just want to go out there and see the rocks. I bet many geologists feel the same. They are not particularly interested in writing reports and journal papers but love to see real geology. Unfortunately, we all know it is not sustainable. Somebody has to do the hard work as well.

I just returned from California and Hawaii where I took lots of photos that are waiting for my attention but I already discover myself preparing for another trip. There are so many places I would love to go. It’s like an itch that needs to be scratched. I already started to prepare a list of places I would like to see in Utah and Arizona. This is insane. I have no way to go there any time soon. I don’t have time for that and it would be a financial ruin. Plus it would clearly demonstrate that I fail big time in my pursuit to make my photos earn something. They won’t earn a dime while they are sitting on my computer’s hard drive. Another place I would like to go to is Cyprus. I was there only a year ago but since that time my photographic skills and equipment have improved considerably. I took photos with an iPhone which are almost useless now. There are lots of beautiful places in Cyprus to visit again with a good camera that takes pictures with acceptable quality. Yesterday I saw that right now I could grab some last minute plane tickets cheaply…

But no, it is not time for that now. Perhaps later and maybe even within this year. I guess I just need to find a healthy balance between fun and work. I must lock myself somewhere with only my computer (and preferrably without Internet) and work from morning till night. Then I can catch up with unfinished tasks and can go out sooner. Ok, I don’t believe I am going to be that radical but I need to move towards being more effective. That’s for sure.

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It had to be a part of some limestone formation. Most likely in northern Estonia where such rocks from the Ordovician Period are exposed. It has a rather distinct appearance and seems to be partly composed of clastic fragments but I am not familiar enough with Estonian bedrock to locate its exact source. I believe it comes from the coast because it is a pebble. Something had to break it from the limestone bed and then polish it to a nicely rounded shape. I guess it was done by sea waves.

What happened after that is harder to explain but it is obvious that something had to crush it. The pebble is now composed of four distinct parts. However, these fragments were not separated from each other which needs some sort of explanation. They are only slightly displaced. Most likely the pebble was surrounded by other rocks which held the fragments in place. What was the crushing force is impossible to tell. It was hardly an earthquake because these occur in Estonia very rarely and are weak. Maybe some bigger rock fell onto it? Maybe the event was associated with glacial activity during the last glacial epoch?

Anyway, the four main fragments of the pebble stayed next to each other and were cemented together again as a single rock and were later liberated from the surrounding material. So the pebble was crushed and then the pieces were glued together again and the same pebble, although seriously wounded, formed again.

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Conversely, sediments that formed in place are called autochthonous or authigenic. It does not mean that the material these sediments or rocks are made of can not be from an external source (it usually is) but the resulting rock or its particles did not exist in this form as part of a pre-existing rocks. For example, quartz grains in sandstone were already in existence inside granite before this rock weathered and liberated these grains which were then transported to another place and deposited as sand. These quartz grains are allochthonous. However, sodium ions that were part of the same granite were liberated as well but they combined with chlorine ions to become rock salt. This is entirely different material that was not present in granite. Hence, rock salt is said to be an autochthonous chemical sediment.

The bulk of sediments are allochthonous. They are usually referred to as detrital or clastic sediments. Common allochthonous sediments are sand, silt, clay, and gravel. On the other hand, the vast majority of the Earth’s upper crust is autochthonous because the upper part of the crust tends to be relatively young and is usually composed of sedimentary rocks which generally have not moved since they were deposited. Things are different deeper in the crust. Metamorphic rocks beneath the thin veneer of sedimentary rocks are usually formed as a result of regional metamorphism which may include several mountain building episodes which tend to move large blocks of the crust out of its original position. However, these rocks are usually so old, often poorly exposed, and may have suffered multiple episodes of metamorphic overprinting which makes it very difficult to understand the bigger picture. It is a better idea to go and see some younger mountain range up-close if you want to see allochthonous parts of the crust.

Are “autochthonous” and “authigenic” (or “allochthonous” and “allogenic”) entirely synonymous? Actually not. There is a slight difference. Authigenic refers to constituents (sand grains and other sediments) rather than whole formations. Therefore, it is more correct to talk about allochthonous crustal blocks and authigenic sediments¹. However, in real life most people are not so pedantic (or correct) and seem to use especially the term “allochthonous” in both situations.

References

1. Jackson, J. A. (1997). Glossary of Geology, 4th Edition. American Geological Institute.

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It is obvious that Racetrack Playa is sometimes covered with water not only because its surface is muddy but also because there are rocks on the playa surface which apparently are moving along the surface, leaving behind clear tracks. This can happen only when the surface is saturated with water. As much as I know, there is no certainty about the mechanism that moves the rocks. It is generally believed that it must be a very strong gust of wind that initiates the movement on the wet and slippery surface (there is much less push needed to keep the rocks moving, initiating the movement is the hardest part). I support the view that rocks are moving primarily because of wind although I have to admit that it is very hard to imagine wind that is so strong. Some rocks are really big and heavy. It has to be one hell of an environment there when these things are happening. It is no wonder that no one has ever witnessed the process.

Racetrack Playa is in Death Valley National Park but it is somewhat harder to access than many other tourist attractions there. It is an isolated and remote valley 27 miles away from Ubehebe Craters where the paved road ends. However, don’t let it scare you. It is quite possible to go there even with a small car. I have read that this rough road is notorious for puncturing tires of small cars but it can really happen anywhere. It happened to me in Death Valley as well but not on a gravel road. It was paved road near Stovepipe Wells. When that happened I thought that I have a nasty and possibly time-consuming problem at hand because the temporary tire is really only a temporary solution in such conditions and it was Sunday. In Europe, people are not moving their lazy ass in Sunday but America seems to be somewhat different, help was actually nearby in the valley. There is a man working at the Chevron of Furnace Creek who quickly repaired the tire for $20. Thanks, you saved me lots of valuable time!

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These mountains stand so high from the center of the Earth because they are located almost at the equator. Earth is slightly flattened sphere which means that areas at the equator are farther from the center than are polar areas. Hence, equatorial mountains have an unfair advantage over the summits at higher latitudes.

Measuring the height of a mountain from the center of the Earth is understandably very theoretical and perhaps even useless approach. I have never heard that anyone seriously thinks that Chimborazo is the highest mountain on Earth. But the list of possible ways to measure the might and height of a mountain does not end here. Another way to do it is to measure the height from the base of the mountain to its summit. Such an approach could be attractive to geologists because in some cases it gives really much better representation of the real height of a mountain.

It does not make much sense to measure the height of oceanic islands from the mean sea level. Sea level is no permanent marker anyway. It fluctuates in geological time and island volcanoes really do not care about the sea level. They start growing usually from the abyssal plain which is some 5000 meters below the sea level. It doesn’t do much justice to kilometers high and very voluminous oceanic island if we say that it is just a mere 100 meter high rock in the sea.

Oceanic islands are indeed the highest or perhaps I should say tallest mountains in the world. Highest and most voluminous oceanic island is Hawaii which is composed of several volcanoes, highest of them are Mauna Kea and Mauna Loa. Mauna Loa is the most voluminous but Mauna Kea reaches few tens of meters higher. Here is the summit of Mauna Kea which stands 4205 meters above sea level but its height from its base is more than 10 kilometers!

The summit of Mauna Kea is a cinder cone. Its appearance and the angle of slopes may be somewhat misleading because the bulk of the massive island is composed of basaltic lava, not pyroclasts. And its slopes are way more gentle because basalt flows easily and composes mountain with a very large base. I climbed the summit which was quite easy because you actually have to climb less than 100 meters. Mauna Kea has one of the best conditions for land-based astronomical observatories. There are lots of telescopes very close to the summit and obviously there is a road leading to them which means that one can almost drive to the summit.

Be careful, though, more that 4000 meters above sea level means that air is thin which can cause problems to some people. Driving straight from sea level to the top might not be such a good idea. Your body needs some time to adjust. It is a good idea to make a short pause at the visitor’s center on the road at much lower altitude. There is a nice gift shop with lots of scientific toys for kids. I used it to to purchase something for my children.

By the way, visitor centers of American national or other such parks surprised me positively. Gift shops are full of toys that have at least some connection with science, there are books about local geology and biology, and nice exhibitions about the surrounding nature. We in Europe are used to think arrogantly that most Americans are science illiterate but our similar shops are full of cheap jewelry, useless sex-related toys, and coffee cups. It seems that we have something to learn in this area as well.

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Ventifacts are common in desert environments where there is enough rocks and sand and little vegetation to keep the sand in place. Strong winds are also needed to lift and carry sand grains. During my recent visit to California I visited a small hill or ridge in Death Valley which is covered with thousands of nice examples of ventifacts. Not surprisingly, this ridge is known as Ventifact Ridge. It was indeed very windy that day and there were lots of rocks and enough sand to blast them.

Well faceted ventifacts are called dreikanters (if there are three wind-blown faces) or sometimes zweikanters or einkanters (two and one faces, respectively). This is obviously German language which provides the prefixes ein-, zwei, and drei. Ventifacts can be sometimes used to determine the dominant direction of wind. The direction of parallel grooves needs to be measured for that.

Ventifact Ridge does not seem to be among the important natural tourist attractions of Death Valley. It is just an ordinary hill and there are no signs pointing to it. Perhaps because the terms “ventifact” and “dreikanter” are virtually unheard of to the general public. However, geologically this is really interesting place which I recommend to visit if you have a plan to go to Death Valley.

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