404 Media

2025-11-11 17:45:56

Remnants of Lost Continents Are Everywhere. Now, We Finally Know Why.

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Tiny remnants of long-lost continents that vanished many millions of years ago are sprinkled

around the world, including on remote island chains and seamounts, a mystery that has puzzled scientists for years.

Now, a team has discovered a mechanism that can explain how this continental detritus ends up resurfacing in unexpected places, according to a study published on Tuesday in Nature Geoscience.

When continents are subducted into Earth’s mantle, the layer beneath the planet’s crust, waves can form that scrape off rocky material and sweep it across hundreds of miles to new locations. This “mantle wave” mechanism fills in a gap in our understanding of how lost continents are metabolized through our ever-shifting planet.

“There are these seamount chains where volcanic activity has erupted in the middle of the ocean,” said Sascha Brune, a professor at the GFZ Helmholtz Centre for Geosciences and University of Potsdam, in a call with 404 Media. “Geochemists go there, they drill, they take samples, and they do their isotope analysis, which is a very fancy geochemical analysis that gives you small elements and isotopes which come up with something like a ‘taste.’”

“Many of these ocean islands have a taste that is surprisingly similar to the continents, where the isotope ratio is similar to what you would expect from continents and sediments,” he continued. “And there has always been the question: why is this the case? Where does it come from?”

These continental sprinkles are sometimes linked to mantle plumes, which are hot columns of gooey rock that erupt from the deep mantle. Plumes bring material from ancient landmasses, which have been stuck in the mantle for eons, back to the light of day again. Mantle plumes are the source of key hot spots like Hawai’i and Iceland, but there are plenty of locations with enriched continental material that are not associated with plumes—or any other known continental recycling mechanisms.

The idea of a mantle wave has emerged from a series of revelations made by Brune’s team, including a 2023 study that identified evidence of similar dynamics occurring within continents. By studying patterns in the distribution of diamonds across South Africa, the researchers showed that slow cyclical motions in the mantle dislodge chunks off the keel of landmasses as they plunge into the mantle. Their new study confirms that these waves can also explain how the elemental residue of the supercontinent Gondwana, which broke up over 100 million years ago, resurfaced in seamounts across the Indian Ocean and other locations.

In other words, the ashes of dead continents are scattered across extant landmasses following long journeys through the mantle. Though it’s not possible to link these small traces back to specific past continents or time periods, Brune hopes that researchers will be able to extract new insights about Earth’s roiling past from the clues embedded in the ground under our feet.

“What we are saying now is that there is another element, with this kind of pollution of continental material in the upper mantle,” Brune said. “It is not replacing what was said before; it is just complementing it in a way where we don't need plumes everywhere. There are some regions that we know are not plume-related, because the temperatures are not high enough and the isotopes don't look like plume-affected. And for those regions, this new mechanism can explain things that we haven't explained before.”

“We have seen that there's quite a lot of evidence that supports our hypothesis, so it would be interesting to go to other places and investigate this a bit more in detail,” he concluded.

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Enriched mantle generated through persistent convective erosion of continental roots - Nature Geoscience

Convective erosion and lateral transport of metasomatized continental keels may generate enriched mantle geochemical domains sampled by oceanic volcanism, according to a geodynamic modelling study.

^Nature

404 Media

2025-11-11 16:52:55

Visualize All 23 Years of BYTE Magazine in All Its Glory, All at Once

Fifty years ago—almost two decades before WIRED, seven years ahead of PCMag, just a few years after the first email ever passed through the internet and with the World Wide Web still 14 years away—there was BYTE. Now, you can see the tech magazine's entire run at once. Software engineer Hector Dearman recently released a visualizer to take in all of BYTE’s 287 issues as one giant zoomable map.

The physical BYTE magazine published monthly from September 1975 until July 1998, for $10 a month. Personal computer kits were a nascent market, with the first microcomputers having just launched a few years prior. BYTE was founded on the idea that the budding microcomputing community would be well-served by a publication that could help them through it.

“You need the hardware before you can progress through the first gate of a system. A virgin computer is useless so you add some software to fill it out. And the whole point of the exercise—in many but not all cases—is to come up with some interesting and exotic applications,” editor Carl Helmers wrote in the first issue’s introduction. “The technical content of BYTE is roughly divided into the trilogy of hardware, software and applications. Each component of the trilogy is like a facet of a brilliant gem—the home brew computer applied to personal uses.”

Dearman told me his first attempt at the site was in September of last year, but this version launched in August 2025. “Once I had a workable strategy it took a couple of weekends to put it all together,” he said.

Dearman told me he first became interested in BYTE after his dad Chris, also a software engineer, died in early 2022. Right out of university, Chris Dearman worked at a London computer company called Whitechapel Computer Works.

“There was very little on the internet about the computers he worked on (now mostly famous for being named after a computer in The Hitchhiker's Guide to the Galaxy),” Hector Dearman said. He came across an article titled “Realizing a Dream” by Dick Pountain in the February 1985 issue of BYTE in the Internet Archive’s scans that covered the Whitechapel Computer Works MG-I, named after the fictional computer called the “Milliard Gargantubrain” in Hitchhiker’s Guide.

“The article was amazing but I was captivated by the adverts,” Dearman said. “I kept coming back to them and the more I did the more I realized what an incredible core sample BYTE was—both of the personal computing revolution and of the changes in graphic design and printing over those decades. That compulsion eventually turned into this project.”

Pages from the February 1985 issue of BYTE

Dearman said he was inspired by the Image Quilts tool that makes collages of images, and Jef Raskin’s “zoomable user interfaces.” To create the BYTE visualizer, Dearman sourced scans from the Vintage Apple archive (the Internet Archive also has a massive searchable repository of BYTE magazine issues) and converted the archive’s PDFs to image tiles. He then put the image tiles into Seadragon—around 500,000 tiles at 1024x1024 pixels each. “I wrote some custom software for this. I tried locally on my computer for a while but ran out of patience pretty quickly. Luckily it's a very parallel problem, I ended up with something that could do every tile for a given layer of the Seadragon image pyramid in parallel,” Dearman told me. “According to my Google Cloud bill I used around 500 hours of CPU time that month. For the final run I think I used 200 instances for ~20 minutes to generate the tiles—the future is pretty cool sometimes.”

On the BYTE visualizer site’s about page, Dearman quotes pioneering computer scientist Alan Kay: "[...] pop culture holds a disdain for history. Pop culture is all about identity and feeling like you’re participating. It has nothing to do with cooperation, the past or the future—it’s living in the present. I think the same is true of most people who write code for money. They have no idea where [their culture came from]—and the Internet was done so well that most people think of it as a natural resource like the Pacific Ocean, rather than something that was man-made.”

Looking at the massive map of BYTE issues means looking at almost 23 years of computer history, at a time when the technology was exploding from hobby to household essential. When BYTE launched in 1975, it catered to a niche group of hackers, engineers, and people trying to tinker with expensive, chunky kits. By its final issue in 1998, it was publishing a Y2K survival guide and reviews of the hot new operating system Windows 98, and running ads for the world’s first 19 inch CRT computer monitor alongside an editorial about LCD monitors asking “Does Your Future Look Flat?”

“The relationship between Computing and its history is that of a willful amnesiac,” Dearman writes on the site. “We discard the past as fast as possible, convinced it cannot possibly contain anything of value. This is a mistake. The classic homilies are accurate: Failing to remember the past we are condemned to repeat it—as often as tragedy as farce.”
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Zoomable Interfaces

Asa Raskin, the son of the late Jef Raskin, recently gave a presentation at Google on the work his company, Humanized, is doing. It’s largely a continuation of the work of his father.

^{Jeff Atwood (Coding Horror)}