Taking a walk across Pitch Lake

This post presented by PLANET EARTH Uncut. All Earth Day Weekend, April 21-22nd. On BBC America.

There are lots of places, all around the world, where oil and natural gas seep up out of the ground on their own, with no help from human beings. In fact, these places are probably how our ancestors first came to use fossil fuels.

But some seeps are more impressive than others. There are only a few places in the world where seeps become large enough to be called lakes. Rancho La Brea in California is probably the most famous. You'll remember it as the place with all the fossils. Mammoths, dire wolves, and saber-toothed cats all wandered into the tar pit, became stuck, and died—leaving pitch-stained bones for researchers to find thousands of years later.

And that well-known story is part of what makes Pitch Lake on the island of Trinidad so confounding. In the photo above, you'll notice people walking across the semi-solid surface of the asphalt lake.* This is not an anomaly. There's videos of tourists doing the same thing all over the Internet, and locals talk about kids playing soccer and cricket on the lake like it's an asphalt playground.

I want to do some more research into this, but it seems as though the consistency of Pitch Lake is, at least for part of the year, fundamentally different from the consistency of the Rancho La Brea Tar Pits. Instead of becoming stuck, people and animals can move across a semi-solid surface. Stand in one place for too long, and you'll start to slowly sink down. But even then you can step back out relatively easily, and as long as you keep moving there's no problem. Apparently, the only time Pitch Lake is dangerous is on very hot days.

Another fascinating thing that distinguishes Pitch Lake from its more famous cousin: Pitch Lake is actively being mined. Asphalt from the lake has been commercially extracted and shipped worldwide for 100 years. It's used to waterproof pipes and pave roads. In 2008, an Australian Broadcasting Corporation show reported that this mining is slowly lowering the level of Pitch Lake. At current extraction rates, it'll be gone in 400 years.

*If I'm understanding correctly, the water you see in the middle of the photo isn't a patch of open water, but a shallow rain pool that's formed on the surface of the asphalt. These pools are home to some of the hardiest microbes on Earth.

 

 

Image: IMG_3110, a Creative Commons Attribution (2.0) image from xenocrates's photostream.

• [awjt]

  I’m wondering how strongly “tarry” the place smells?

• [mamayama]

  Depending on the temperature, you can walk across some of the La Brea tar pits, too.  Which is why an athletic shoe got fossilized…an archeology volunteer tried to take a shortcut over a small pit that had worked fine in winter, but in summer, it sucked that sneaker right off!

• [Dv Revolutionary]

  Why is this lake solid and the La Brea tar pits not so solid?

  Pitch, tar, and asphalt are imprecise words – chemical generalizations if you will. They are made up of a mixture of many different long long hydrocarbon chains plus impurities. The impurities vary and the average hydrocarbon chain length can vary. Asphalt in one place may be made of mostly long-long-long chains and be very solid even in higher temperatures. The extremely long and twisted chains can’t quickly disentangle and slide past each other. Somewhere else pitch may only be composed of hydrocarbon chains on average just half the length and be relatively viscous at 70 degrees F and might be called tar pits.

  In Colorado we have a deposit of “oil” shale. After a lot of work getting the oil out of the shale what comes out is too thick to be crude oil and easily refined into gasoline, to viscus to use as asphalt. We have tar shale. Canada has tar sands.

  See the physical properties and melting points of alkanes to understand how the shorter hydrocarbon chains work and extrapolate out for a very mixed lot of longer chains. A thirty carbon molecule melts at 66º while a 60 carbon molecule melts at 100º.

  http://en.wikipedia.org/wiki/Alkane#Physical_properties

• [Quibbler]

  The area around the pitch lake in Trinidad is also called La brea, and you are more at risk from bandits than from sinking into the pitch. It also smells sulphury.

• [remi]

  I was in Trinidad a couple of years ago in the summer and among other places, I managed to visit the Pitch lake.  I had a guide who took me “onto” the lake and showed me around.  He insisted on me following exactly on his footsteps as he knew which parts where solid enough to step on and which parts would swallow your shoes! 

  I found the place fascinating.  I saw small petrified tree trunks in the middle of the lake.  In some places, there was bitumen slowly bubbling up through openings on the surface of the lake which gave the impression that we were walking on top of a huge boiling caldera.  I did manage to get my sandals stuck in pitch and it was not fun cleaning them afterwards.  My guide told me a bit about the history of the place and the factory close by which harvests the pitch and sends it overseas.

  Apparently when the Spanish arrived on the Island of Trinidad and claimed the place, they soon realized the value of the tar deposit as an unlimited source of sealant to waterproof their ships.  They also started shipping it overseas as did the later colonial powers that took control of Trinidad.  I was told that a majority of the roads in England (and in particular, streets of London) are asphalted with tar from the Pitch lake in Trinidad!

  Anyway, here are a couple of my photos from the trip (You can look at the rest of the gallery for other Trinidad photos):
  http://www.pbase.com/rmir/image/108268893
  http://www.pbase.com/rmir/image/108268898

• [RedShirt77]

  Can they clone the mammoths already? They need to do that so they can move onto the dire wolves.

  • [Antinous / Moderator]

    I want a pet Sabertooth Tiger.

• [Matthew Montano]

  I also can confirm that Trinidad’s Pitch Lake is exactly as described.

  The neighbourhood for miles around has strong clues of the proximity of this geographic anomaly. Outside of the normal land-slides, I remember evidence of pitch ‘oozing’ where you might expect to see someone’s grass covered lawn. 

  There is also a similar lake across the gulf in Venezuela.

  Good bucket list places to visit. I had forgotten how unique it was until I read this.