Tektites: Black Rocks Of Catastrophe

Did the earlier human-like species Homo erectus see the storm of tektites? This reconstruction from the Museum of Archaeology, Herne, Germany. Credit: Wiki

800,000 years ago the sky over Asia was aflame with teardrops of molten earth, blasted heavenward by a gigantic meteorite impact. Members of Homo erectus, a precursor to modern humans, must have seen the firestorm and gone running for shelter.

What lit the terrified eyes of our distant ancestors were splatters of liquified rock catapulted high into the atmosphere immediately after the impact. This fiery rain cooled and solidified into wondrous and diverse forms as it fell back to Earth as the black rocks we know today as tektites.

Scientists still don’t know where the impact occurred, but it left a huge butterfly pattern of tektites spread across China, southeast Asia and southern Australia.

A variety of tektites ranging from an inch to 2.5 inches from southern China. Photo: Bob King

Tektites are not meteorites but rather Earth rocks that were liquified by the heat and pressure of impact and launched into the atmosphere, even as far as nearby outer space. They’re essentially local rock converted to glass.

Tektites resemble volcanic obsidian, that shiny black glass you find in mineral shops, but they’re a very different material. Composed mostly of silica, commonly found in nature as sand or quartz, the extreme heat they experienced, combined with passage through the rarefied upper atmosphere, have made tektites one of the driest materials found on Earth. Some tektites contain minute amounts of the original meteorite, but what really catches your eye are their shapes and textures.

Tektites, from the Greek for "molten", come in a wide variety of shapes depending on how far they were ejected and how they spun as they rained back to Earth. From left: an oval "hamburger patty", sphere, dumbbell, a hollow-centered ball and teardrop. The grooved surface textures, described below, are unique to tektites. Photo: Bob King

As the cooling but still plastic blobs fell back through the lower atmosphere, they were deformed by friction with the air into a variety of different shapes depending upon their spin. Spheres or balls formed from material spinning evenly in all directions. Blobs spinning or rotating in just two directions or axes stretched to produce oval-shaped tektites. Ovals were further stretched into dumbbells, and dumbbells snapped apart to create pairs of elongated teardrops. Click HERE for a great illustration of how tektite shapes form.

The backside of a beautiful flanged button tektite from Australia. It measures about 3/4" across. The shape of these buttons served as a model for heat shields on NASA space capsules like Mercury, Gemini and Apollo. Credit: Herbert Raab

Tektites ejected to great height at distances of 2,500 to 3,700 miles from ground zero had enough time to solidify. Falling back to Earth they melted again to produce exquisite little buttons surrounded by circular flanges. These rare forms are typically found in Australia far from the center of what’s known as the Australasian tektite strewfield.

Tektites developed fine cracks as they cooled upon reentry which were later enlarged into zillions of pits and grooves through interaction with water and soil in a process called chemical etching. They give these shiny rocks lots of character. Some tektites have smooth sides from material that flaked off after they cooled.

Flow lines in this tektite show us in a very graphic way that tektites were once soft and plastic. Photo: Bob King

While the Australasian tektites are the most recent and largest strewnfield, there are several other major tektite localities both with and without associated craters:

* North American strewnfield with tektites primarily found in the southeastern states and in Texas. Source: Chesapeake Bay Crater impact 34 million years ago
* European strewnfield famous for the green glass called moldavite, the most colorful of the tektites. Source: Ries Crater impact in Germany 15 million years ago
* Ivory Coast strewnfield originating from the Lake Bosumtwi Crater impact in Ghana 1 million years ago
* A new strewnfield recently discovered in Belize

Part of this tektite is thin enough to let light through and show color in the glass. Photo: Bob King

The most common tektites are those from China and southeast Asia. You’ll find several online sites offering them for sale. One of the best is The Tektite Source run by Norm and Cookie Lehrman. eBay has many dozens for sale every day.

A broken or chipped tektite will help you appreciate both their glassy quality and color. Some are translucent enough to show shades of brown and olive green. All of them have a certain enigmatic aspect. I like to pick one up, turn it in my hand and try to fathom the origin of this or that feature.

Closeup showing numerous pits and grooves. The radial lines were formed when the tektite hit the ground upon landing. Photo: Bob King

It used to be thought that tektites might have been blasted off the moon during a lunar impact or even volcanically, but their earthly composition, traces of meteoric materials and association with craters on Earth connect them to catastrophic events right here at home. To learn more about these cool rocks, I recommend a visit to Aubrey Whymark’s tektite site.

16 Responses

  1. Jacob Baker

    Trying to indoctroniate the kids with your liberal views I see. I pray to Jesus for you…. everyone with faith knows that the Earth is no more than 6000 years old as it says in the Bible. Quit trying to test my faith, I am stronger than you.

  2. Lanny

    … much better to learn from science than a bunch of plagiarized stories borrowed from so many old pagan beliefs (yes — including the Jesus myth). Science is ever changing — ever learning… All modern religions will eventually fade away in the same way of Roman and pagan gods of old.

    “Reality has a well know liberal bias.” — Steven Colbert

  3. thomas s

    hi Bob, as usual, extremely interesting article. too bad, however, that we had to get into the Great Debate between people who take the unfortunate, polarized views expressed in the preceding comments. pity!

    1. astrobob

      Hi Thomas,
      Yes, so it is. People are entitled to their opinions as long as everyone plays nice.

  4. Lynn

    Hi Bob
    I thought I was on the wrong blog when I read your first comment I was a bit shocked at that, everyone has their own opinions and we all have our beliefs and disbelief’s but I don’t think everyone wants to listen to them we get enough of that on other websites, I just hope comments like that don’t end up being a regular occurence as it just ends up in a silly debate, and that is not what your blog is about, so just keep up the good work Bob you do a great job and I’m sure there is a lot of other people out there who agrees with me. 🙂

    1. astrobob

      Hi Lynn,
      Thanks for your comments. I left them in to be fair and to see what others would think. If the discussion had turned into attack after attack (like we’ve seen on other sites) I would have cut if off.

  5. Mike

    Bob,

    Thanks for allowing different views to have a conversation on your blog. Even though I perscribe myself to a radical middle, believing in both an all powerful and personal God. I also have room for a process in which life can develop from star dust to human. I still get alittle frustrated by people’s comments like that. But if starring at the stars for hours and contemplating the breathe and distance of it all has taught me anything, it’s that we are all small, and living in the blink of the galactic eye. We have but this blue marble and we live here together. It would be a better place if we were able to just talk about our views, and have grace and compassion for those around us, ecspecially those that disagree with us, as it is said we are all in the same boat. Thanks again.

  6. Doug

    Astrobob,
    Asteroid 2012 lz1 is supposed to make a “close approach” tomorrow. If it is going to be 14 ld, why is it considered a close approach? Isn’t that considered far in astronomical terms.

    1. astrobob

      Doug,
      Close approaches have a range with some approaches closer than others. NASA defines Potentially Hazardous Asteroids (PHAs) as objects crossing Earth’s orbit within 4.65 million miles (or less) of the planet.

  7. brian burrer

    I travelled in Belize for a total of one month in 2011 and searched for tektites on most of those days. I can say after this experience that the new Central American Tektites are genuine and are separate from previously discovered events. Only the previously recovered Tikal tektites from Guatemala reported by Hildebrand are of the same origin. Age, chemistry and morphology all separate these tektites from Australasian, African and North American varieties.

    1. astrobob

      Hi Brian,
      I remember reading several articles about this new strewnfield including yours in Meteorite Times. Fascinating stuff.
      For those readers not familiar with this new location, here’s Brian’s article: http://bit.ly/NQj9BN

  8. Kimbuuma

    Hi I have a bunch of tektites for sale. Acquired them from a friend and was part of the Beyer Tektite collection believed to be the biggest collection in the world once.

  9. The Belize/Guatemalan tektites have virtually the same age as the Australasian, as measured by cosmogenic nuclides. What distinguishes them is variances in some chemical attributes. Given that there are only 4 documented tektite fields from 170 know impacts on the Earth (and only the Australasian’s crater has not been found) I suspect the Belize finds do not identify a fifth strewn field, but is an important extension to the already massive Australasian field. The crater may simply not be where everyone has been looking for the past 40 years.

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