The cycling of water within Earth's interior regulates plate tectonics, volcanism, ocean volume, and climate stability, making it central to
The cycling of water within Earth's interior regulates plate tectonics, volcanism, ocean volume, and climate stability, making it central to the planet's long-term evolution and habitability and a key scientific question. While subducting slabs are known to transport water into the mantle, scientists have long assumed that most hydrous minerals dehydrate at high temperatures, releasing fluids as they descend.
Whether water can survive the extreme conditions of the deep lower mantle, however, has remained an open question.
Our names are Ben and Mandy, and we’re reaching out to the disabled geoscience and community and its allies today with an announcement as well as an opportunity that we hope will interest you.
We’re organizing a zine on the theme of disability in geoscience (DiG). We hope that the project will do a lot of good for our community by bringing people together through sharing experiences with access, inaccessibility, stigma, and support.
We’re looking to bring at least two (2) more staff members on to the zine project to help us organize and moderate it. Possible mod activities include answering and sending emails, monitoring our Discord server, drafting posts, making graphics, attending weekly editorial meetings, generating review criteria, managing reviewers, and formatting drafts of the zine.
Our current project timeline goes through July 2025, the idea being that publication coincides with Disability Pride month next year.
If you are interested in learning more about us and/or this volunteer position, please provide us with some basic information about you through filling out this Google Form.
If you are interested in supporting the DiG Zine in general, you may follow us on Tumblr, X/Twitter, and/or Instagram. We also have a Discord set up that you can join via this invite link. If you would like to join the DiG listserv, DM us your email address.
Thank you for reading! We hope to see you in the DiG Zine community,
The Maya had a dog-delivery supply chain before Amazon Prime.
In what is now Mexico, dogs were raised and fattened on meat and maize between 250 and 900 CE, most likely by wealthy households. This is when the dog-transporting service began. Then, up to 400 miles away, humans transported the dogs to important Maya centers. They were about the size of a Chihuahua-terrier mix. Why did they do this? For consumption or as a sacrifice. These were the reasons these dogs were plump, weighing as much as 10-20 lbs (4.5-9 kg). The findings overturn the assumption that Maya dogs were just local village animals. Instead, they were economically important livestock. Transporting dogs hundreds of miles only makes sense if they were valuable, & fattened animals are more valuable for feasting.
Archaeologists discovered this after finding dog bones, & isotope analysis revealed what they ate & where the dogs came from. Isotopes are tiny chemical "fingerprints" that get locked into bones & teeth while an animal is alive. The strontium isotopes show where they grew up, as different regions have different strontium ratios. The evidence points to lowland origins hundreds of miles away, not the highlands where the dogs ended up. The oxygen isotopes show the water they drank, which again matched warm, humid lowlands, not the mountainous, cooler highlands where the dogs were transported to. The carbon isotopes show what the dogs were fed, in this case, a lot of maize. The high nitrogen isotopes reveal they were also fed a lot of meat.
As a geologist, I use the words oxidation and reduction a lot. For example:
These rocks have gone through oxidation.
Or this rock contains reduction spots.
But what do I mean when I say these things? Primarily, this has to do with iron and its properties (but other elements can be oxidized or reduced too). Iron is super reactive with oxygen, like best friends who go everywhere together. However, what iron isn't aware of is that oxygen isn't a good friend.
Reduction is the opposite of oxidation. It is the gaining of electrons. So, if one element is being oxidized, another is being reduced.
Making sense so far? Here is what the reaction for rust (which is what happened to those red rocks above) looks like:
Copper also oxidizes. A great example is the Statue of Liberty.
So the next time you pass by red cliffs you can sound super smart to your friends and family by telling them that those cliffs have been oxidized.
Tune in tomorrow for a look at the father of mineralogy. Fossilize you later!
My experience of geochemical trip to the dried areas of Aral sea
So, after a second year of my geological studies I wanted to get some field experience. One of my professors offered me an internship in his company so I obviously immediately agreed to it.
I won't be talking much about how we got there, I'll just say it wasn't exactly easy.
This place is hostile to anyone. Constant wind and dust storms (also, dust here contains a lot of pesticides), temperature drops drastically after the sunsets and it's really hot out there at daytime (up to 43°C and it was a middle of September).
We were there for one month, living in tents. There's one thing in particular that made it really hard for me to live there — salt layer on the surface, which you can see in pictures 4 and 5. It was so hard and sharp, that it made sleeping comfortably in my sleeping bag almost impossible (low temperatures and strong wind also added up to it). I also once tried to taste it. It wasn't great. Salt there tasted really bitter and had an awful chemical aftertaste.
My job was simple and mostly physical— collect and label samples of soil with, and gather the underground air with a piece of rebar, hollow tube, sledgehammer and a syringe. We worked 8 hour shifts everyday with one 15 minute lunch break at the middle of the day. It was pretty exhausting. Every time we got back to our camp one of us had to cook a dinner for others, then we prepared air reservoirs for our chromatography machines, and laid samples in the sun for them to dry.
Overall it was interesting to get some experience in lithology, learn how chromatography works and test my own resilience.
Ancient Mars may have had a carbon cycle − a new study suggests the red planet may have once been warmer, wetter and more favorable for life
by Elisabeth M. Hausrath, Professor of Geoscience at the University of Nevada, Las Vegas
Mars, one of our closest planetary neighbors, has fascinated people for hundreds of years, partly because it is so similar to Earth. It is about the same size, contains similar rocks and minerals, and is not too much farther out from the Sun.
Because Mars and Earth share so many features, scientists have long wondered whether Mars could have once harbored life. Today, Mars is very cold and dry, with little atmosphere and no liquid water on the surface − traits that make it a hostile environment for life. But some observations suggest that ancient Mars may have been warmer, wetter and more favorable for life.
Even though scientists observing the surface of Mars conclude that it was once warmer than it is today, they haven’t been able to find much concrete evidence for what caused it to be warmer. But a study my colleagues and I published in April 2025 indicates the presence of carbonate minerals on the planet, which could help solve this puzzle.
Carbonate minerals contain carbon dioxide, which, when present in the atmosphere, warms a planet. These minerals suggest that carbon dioxide could have previously existed in the atmosphere in larger quantities and provide exciting new clues about ancient Mars’ environment.
As a geochemist and astrobiologist who has studied Mars for more than 15 years, I am fascinated by Mars’ past and the idea that it could have been habitable.
Ancient carbon cycle on past Mars
Observations of Mars from orbiting satellites and rovers show river channels and dry lakes that suggest the Martian surface once had liquid water. And these instruments have spotted minerals on its surface that scientists can analyze to get an idea of what Mars may have been like in the past.
If ancient Mars had liquid water, it would have needed a much warmer climate than it has today. Warmer planets usually have thick atmospheres that trap heat. So, perhaps the Martian atmosphere used to be thicker and composed of heat-trapping carbon dioxide. If Mars did once have a thicker carbon dioxide-containing atmosphere, scientists predict that they’d be able to see traces of that atmospheric carbon dioxide on the surface of Mars today.
Today, Mars is very cold, with a thin atmosphere and dry climate. But in the ancient past, it may have been warmer and wetter, with a thicker heat-trapping atmosphere. NASA/J. Bell - Cornell U./M. Wolff - SSI via AP, File
Gaseous carbon dioxide dissolves in water, a chemical process that can ultimately contribute to formation of solid minerals at and below the surface of a planet − essentially removing the carbon dioxide from the atmosphere. Lots of scientists have previously tried to find carbonate minerals on the surface of Mars, and part of the excitement about a warmer, wetter early Mars is that it could have been a suitable environment for ancient microbial life.
Finding carbonates on Mars
Previous searches for carbonates on Mars have turned up observations of carbonates in meteorites and at two craters on Mars: Gusev crater and Jezero crater. But there wasn’t enough to explain a warmer past climate on Mars.
For the past few years, the Mars Science Laboratory Curiosity rover has been traversing a region called Gale crater. Here, the rover’s chemistry and mineralogy instrument has discovered lots of the iron-rich carbonate mineral siderite.
The Curiosity rover has detected carbonates on Mars’ surface. NASA
As my colleagues and I detail in our new study about these results, this carbonate mineral could contain some of the missing atmospheric carbon dioxide needed for a warmer, wetter early Mars.
The rover also found iron oxyhydroxide minerals that suggest some of these rocks later dissolved when they encountered water, releasing a portion of their carbon dioxide back into the atmosphere. Although it is very thin, the modern Martian atmosphere is still composed mainly of carbon dioxide.
In other words, these new results provide evidence for an ancient carbon cycle on Mars. Carbon cycles are the processes that transfer carbon dioxide between different reservoirs − such as rocks on the surface and gas in the atmosphere.
Potential habitats for past microbial life on Mars
Scientists generally consider an environment habitable for microbial life if it contains liquid water; nutrients such as carbon, hydrogen, nitrogen, oxygen, phosphorus, sulfur and necessary trace elements; an energy source; and conditions that were not too harsh − not too acidic, too salty or too hot, for example.
Since observations from Gale crater and other locations on Mars show that Mars likely had habitable conditions, could Mars then have hosted life? And if it did, how would researchers be able to tell?
Although microorganisms are too small for the human eye to detect, they can leave evidence of themselves preserved in rocks, sediments and soils. Organic molecules from within these microorganisms are sometimes preserved in rocks and sediments. And some microbes can form minerals or have cells that can form certain shapes. This type of evidence for past life is called a biosignature.
Collecting Mars samples
If Mars has biosignatures on or near the surface, researchers want to know that they have the right tools to detect them.
So far, the rovers on Mars have found some organic molecules and chemical signatures that could have come from either abiotic − nonliving − sources or past life.
However, determining whether the planet used to host life isn’t easy. Analyses run in Earth’s laboratories could provide more clarity around where these signatures came from.
To that end, the Mars 2020 Perseverance rover has been collecting and sealing samples on Mars, with one cache placed on the surface of Mars and another cache remaining on the rover.
These caches include samples of rock, soil and atmosphere. Their contents can tell researchers about many aspects of the history of Mars, including past volcanic activity, meteorite impacts, streams and lakes, wind and dust storms, and potential past Martian life. If these samples are brought to Earth, scientists could examine them here for signs of ancient life on another planet.
petrichor
a distinctive scent, usually described as earthy, pleasant, or sweet, produced by rainfall on very dry ground.
Petrichor is an uncommon word used in mineral chemistry or geochemistry to describe the pleasant scent of rain falling on very dry ground. Petrichor is a compound of the Greek nouns pétrā “rock, stone” (as in petroleum “rock oil”) and īchṓr, the juice or liquid—not blood!—that flows in the veins of the Olympian gods. About 60 percent of ancient Greek words have no satisfactory etymology; īchṓr is one of them. Petrichor was coined by two Australian chemists, Isabel “Joy” Bear and Richard Grenfell Thomas, in 1964.
