July 20, 2011

Geology Word of the Week: H is for Halokinesis

Posted by Evelyn Mervine

Piles of salt ready to be collected at Salar de Uyuni, Bolivia. Photo courtesy of Tannis McCartney. Click photo to enlarge.

def. Halokinesis:
1. The movement of salt and salt bodies. The study of halokinesis includes subsurface flow of salt as well as the emplacement, structure, and tectonic influence of salt bodies. Another term used to refer to the study of salt bodies and their structures is “salt tectonics.”
2. The magical (and non-existent) ability to move salt with your mind.

This week, as usual, I have been asking for suggestions for the Geology Word of the Week on Twitter and Facebook. I find Twitter and Facebook to be great resources– I receive so many great word suggestions. After I select a geology word for the week, I also use Twitter and Facebook to find out more information about the geology word and to find some pictures related to the word. For those of you wondering how useful social networking sites such as Twitter might be for geologists, MJ Vinas of AGU wrote a great post on The Plainspoken Scientist blog titled Why should scientists use Twitter? Of course, Twitter is no substitute for mainstream scientific publications or scientific conferences, but personally I find Twitter a great place to go for geology news and for asking geology-related questions.

If you haven’t noticed already, I work my way through the alphabet for the Geology Word of the Week. For example, for my first geologist’s alphabet, I made my way from A is for Alluvium to Z is for Zanclean. This week I am at the letter H, so I asked for suggestions of geology words beginning with the letter H. As usual, I had many wonderful suggestions of geology words. However, I was particularly struck by Brian Roman‘s suggestion on Twitter of the word “halokinesis” as I had never heard of this word before, and it sounded– to me– like some psychic pseudoscience nonsense. Here is the twitter exchange I had with Brian this morning:

Well, I was intrigued. So, I did a little bit of research on the word “halokinesis,” both the scientific definition and the pseudoscientific definition.

Scientifically, halokinesis is the movement (-kinesis) of salt and salt bodies. Salt often forms on Earth’s surface as a result of evaporation.  Salt is highly soluble, so surface salt deposits are generally ephemeral and short-lived, disappearing with the rain. Significant salt deposits only develop in very dry places. For example, salt deposits form in the hot, dry– and aptly named– Death Valley, California. The world’s largest salt flat is located at Salar de Uyuni, Bolivia.

Salt flat from a distance. Death Valley, California, Fall 2005.

Venturing out onto the salt flat. Death Valley, California, Fall 2005.

While salt deposits are somewhat ephemeral and ever-changing on Earth’s surface, salt deposits become somewhat more stable when they are buried. Salt is often found in subsurface sedimentary sequences. However, even when buried salt deposits can move. Furthermore, subsurface salt deposits can move in quite strange ways. Normal sediments contain a large amount of pore space, so as they are buried and transformed into sedimentary rocks, they tend to compress and increase in density. Salt deposits, on the other hand, do not contain much pore space, so their density does not increase significantly as they are buried. Because salt deposits tend to be less-dense than the surrounding sedimentary rocks, these salt deposits tend to deform and migrate, moving in a fluid-like manner– almost like magma or the plastic aesthenosphere– and forming structures such as diapirs and domes.  Because oil is often found above subsurface salt deposits, there is much interest in better understanding how salt deposits form and migrate in the subsurface.

Seismic image showing salt diapirs on the Brazil margin. Image courtesy of Peter Clift.

Seismic image showing salt bodies in the Gulf of Lions, France. Image courtesy of Peter Clift.

For more discussion on salt and halokinesis, I highly recommend reading the post Salt and Sediment: A Brief History of Ideas over at the Hindered Settling blog.

Both surface and subsurface salt deposits are often mined for salt and other evaporite minerals.  However, the mining of salt deposits must be done carefully as salt dissolves easily in water, and therefore the presence of water can destabilize salt deposits. Most salt mining is relatively straightforward, but the potential danger was highlighted in a disaster at the Jefferson Salt Mine, which operated underneath Lake Peigneur in Louisiana. As I mentioned above, oil is often found above subsurface salt deposits. On November 20th, 1980, Texaco was drilling into Lake Peigneur to search for oil above the salt deposit. Due to an error, the 14″ drill bit accidentally breached the subsurface salt mine, and water began leaking down into the mine. As the salt deposit and surrounding sediment dissolved and were washed away, the original drill hole was enlarged. An enormous whirlpool developed in the lake as water poured down into the salt mine. When most of the lake water had drained into the hole, a canal that normally drained to the Gulf of Mexico actually reversed direction and continued providing water to the whirlpool for several days.

Here’s a video with images and more information about the Jefferson Salt Mine disaster:

Pseudoscientifically,”halokinesis” is the ability to move salt with your mind— with magical psychic abilities, I guess. First and foremost, let me say that all telekinesis (also called “psychokinesis”)– the ability of a person to move or manipulate objects with their mind– is complete nonsense. There is no scientific evidence at all that people can manipulate objects with their mind. But don’t take my word for it. Listen to my friend James Randi explain how simple magic tricks can look like telekinesis:

I don’t know about you, but I think that a simple magic trick to explain the motion of a salt shaker on a table makes much more sense that calling upon some strange supernatural magic or exception to fundamental physics.

According to PsiWikia (I cannot believe such a wikia actually exists!),

Halokinesis is the psi ability to manipulate salt. One with this power could dehydrate another person (or occasionally rocks). Theoretically one with this power could control water of the ocean (salt water) as well. With the salt thoroughly dissolved, it could be extracted or used to help control the water.

Wow- that’s quite the telekinetic power! Can you imagine becoming angry with someone and then dehydrating them? Ouch. And how wonderful would it be to use such powers to desalinate ocean water? That would certainly help with freshwater shortages all over the world. I’m a little confused, though, about the movement of salt to “dehydrate” rocks– aren’t salty rocks, which are generally evaporites, generally already dehydrated? Come to think of it, how can you dehydrate a person by moving salt? Do you add salt to the person?

I must say that I am extremely skeptical of halokinesis. As Randi is fond of saying, “Everyone who believes in telekinesis, raise my hand.” Or, in this case, “Everyone who believes in halokinesis, dehydrate me.” Go on. I dare you.

I think that’s enough pseudoscience. Back to some real science.

Here are a few more salty pictures from Death Valley and Salar de Uyuni:

Salt flat reflection. Death Valley, California, Fall 2005.

Striking a post on the salt flat. Death Valley, California, Fall 2005.

Shoes become cumbersome on a salt flat. Death Valley, California, Fall 2005.

Salar de Uyuni Salt Flat, Bolivia. Photo courtesy of Tannis McCartney. Click photo to enlarge.

Another view of Salar de Uyuni, Bolivia. Photo courtesy of Tannis McCartney. Click photo to enlarge.

A block of salt at Salar de Uyuni, Bolivia. Photo courtesy of Tannis McCartney. Click photo to enlarge.

When I asked for pictures of salty things, my friend Peter Clift sent me on a Google Earth quest to investigate the Great Kavir salt diapir, which is located at 34° 40.007’N 52° 13.732’E in Iran. You should go check out that location on Google Earth– the diapir as well as nearby the nearby Namak Lake salt flat are quite impressive.

Google Earth image showing the Great Kavir salt diapir and the Namak Lake salt flat in Iran. Click image to enlarge.

An aerial photo of the Great Kavir salt diapir, an eroded salt diapir that has reached the surface. The sediment is all twisted and deformed around the salt column, which breaches the surface in the middle of the photo. The central part is around 5 km across. Image courtesy of Peter Clift.


***Thanks to Brian Romans for recommending this week’s word. Thanks to Peter Clift for the seismic images and for introducing me to the Great Kavir salt diapir in Iran. Thanks to Abdelrhman Selim and Brian Romans for recommending the Hindered Settling post. Thanks to Anne Jefferson for information and a video about the Lake Peigneur salt mining disaster. Finally, thanks to Tannis McCartney for pictures of the Salar de Uyuni salt flat.***