Wednesday, May 14, 2025

Study uncovers mystery of how mini sand dunes form

University of Southampton

Prof Jo Neild studying mini dune — image:
Professor Jo Neild standing behind a patch of mini dunes in Namibia conducting research using terrestrial laser scanning equipment.
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Credit: Credit Matthew Baddock

A new study led by the University of Southampton and research institutes in France has uncovered the mystery of how mini sand dunes form on beaches and in deserts.

While the formation of large desert dunes is well understood, scientists haven’t been able to use the same theory to explain how smaller-scale dunes - the kind you might walk through on a beach holiday, emerge.

The findings, published today [12 May 2025] in the journal PNAS, not only reveal how these so-called ‘proto dunes’ occur on Earth, but could hold clues to how they form on Mars and other planets.

“These are the kind of smaller scale sand bedforms that people would see forming before their eyes on the beach before the wind stops or the waves wash them away,” says Professor Jo Nield from the University of Southampton who led the study.

“The theory of how the large, wavy dunes you might picture in the Sahara Desert form assumes you have near limitless amounts of soft, dry sand which is picked up and deposited by the wind. But this doesn’t account for how these small dunes take shape on moist surfaces like a beach or in hard gravelly areas.”

Proto dunes have been difficult to study in detail because they are small (up to a few centimetres in height), move and grow rapidly (from nothing to six centimetres within half an hour) and can disappear as quickly as they emerge.

The international research team, with team members from Southampton, Paris, Oxford, Loughborough, Illinois and Denver, were able to capture how these small dunes form for the first time using high-resolution laser scanning in the Namibian desert.

They found that sand moving on harder, more consolidated surfaces bounces higher and is transported more by the wind. Once it lands on a softer, rippled surface, the sand accumulates.

Prof Nield said: “On these surfaces, the sand doesn’t just roll across the land, it jumps up to a meter or so and so there is a gradual transition when grains will feel the change from a consolidated to rippled surface.

“Once bumps start to form, this influences wind patterns, adding further sand and helping the dune to grow, as happens in larger dunes.”

This new theory, coupled with the high-resolution data captured, has been developed by coauthors in Paris to create a computer model of the dynamics at play. Excitingly, the model can accurately reproduce what researchers have observed in their field studies in arid conditions such as Namibia but also in moist conditions in Colorado and Norfolk.

The model also allows the team to tweak different parameters, such as the amount of sand and wind, to understand different scenarios.

Prof Philippe Claudin, a co-author on the paper from the French National Centre for Scientific Research (CNRS), said: “The model can replicate almost perfectly what we see in our field data. Interestingly we see similar patterns in arid areas with gravel and coastal areas where there’s moisture.

“Using the model, we can see that if there are really strong winds, the dunes will get bigger and bigger, whereas if there is not much sand coming in, the proto-dune will erode and disappear.”

These proto-dunes aren’t unique to Earth. The research team are now looking at how mini dunes form on Mars.

“We are really excited to see how what we’ve learned on Earth could be applied to Mars and to understand similarities and differences between proto-dunes on the two planets,” says Prof Nield.

The paper Modeling the dynamics of aeolian meter-scale bedforms induced by bed heterogeneities is published PNAS and is available online.

The research was funded by the Natural Environment Research Council (NERC) and the National Science Foundation (NSF).

Ends

Contact

Steve Williams, Media Manager, University of Southampton, press@soton.ac.uk or 023 8059 3212.

Notes for editors

The paper Modeling the dynamics of aeolian meter-scale bedforms induced by bed heterogeneities will be published PNAS, An advanced copy is available upon request.
For Interviews with Prof Jo Neild, please contact Steve Williams, Media Manager, University of Southampton press@soton.ac.uk or 023 8059 3212.
Images available here: https://safesend.soton.ac.uk/pickup?claimID=WUjcYiQA9fpYajek&claimPasscode=xVXuQDwM7ckkRVJJ

Additional information

The University of Southampton drives original thinking, turns knowledge into action and impact, and creates solutions to the world’s challenges. We are among the top 100 institutions globally (QS World University Rankings 2025). Our academics are leaders in their fields, forging links with high-profile international businesses and organisations, and inspiring a 22,000-strong community of exceptional students, from over 135 countries worldwide. Through our high-quality education, the University helps students on a journey of discovery to realise their potential and join our global network of over 200,000 alumni. www.southampton.ac.uk

www.southampton.ac.uk/news/contact-press-team.page

Researchers conducting field research on mini dunes in Namibia.

Mini dunes in Namibian desert.

Terrestrial laser scanning equipment in Namibian desert.

Credit

University of Southampton

Journal

Proceedings of the National Academy of Sciences

DOI

10.1073/pnas.2426143122

Method of Research

Computational simulation/modeling

Subject of Research

Not applicable

Article Title

Modeling the dynamics of aeolian meter-scale bedforms induced by bed heterogeneities

Article Publication Date

12-May-2025

Study reveals vast Aztec trade networks behind ancient obsidian artifacts

Tulane University

New archaeological research by Tulane University and the Proyecto Templo Mayor in Mexico reveals how obsidian – a volcanic glass used for tools and ceremonial objects and one of the most important raw materials in pre-Columbian times – moved across ancient Mesoamerica and shaped life in its capital, Tenochtitlan. The study sheds new light on the economic networks, rituals and political influence of the Mexica (Aztec) Empire.

Published this week in Proceedings of the National Academy of Sciences, the study analyzed 788 obsidian artifacts excavated from the Templo Mayor of Tenochtitlan, the main temple and core of the Mexica Empire located in what is now Mexico City. The research represents the largest compositional study of obsidian ever conducted at the site.

Archaeologists found that while the Mexica primarily used green obsidian from the Sierra de Pachuca source, they also acquired obsidian from at least seven other locations, including regions beyond their political borders, such as Ucareo, in the Purépecha territory in West Mexico. The findings suggest a sophisticated economy that relied not only on conquest but on active long-distance trade, even with rival polities.

“Although the Mexicas preferred green obsidian, the high diversity of obsidian types, mainly in the form of non-ritual artifacts, suggests that obsidian tools from multiple sources reached the capital of the Empire through market instead of direct acquisition in the outcrop,” said lead author Diego Matadamas-Gomora, a PhD candidate in Tulane’s Department of Anthropology. “By studying where this material came from, we can explore the movement of goods across Mesoamerica.”

The analysis showed that nearly 90% of the obsidian artifacts in the sample were made with Sierra de Pachuca obsidian – prized for its green hue and symbolic connection to the mythical city of Tollan. Almost all the ceremonial artifacts found inside buried offerings at the Templo Mayor were made with this type of obsidian, including miniature weapons, jewelry and inlays for sculptures.

A smaller but significant portion of the obsidian came from places like Otumba, Tulancingo, Ucareo and El Paraíso, some of which lay outside the control of the Mexica Empire. These materials were more commonly used for tool production and found in the construction fill, indicating that these obsidian types were available to the general population through local markets rather than being tightly controlled by the state.

The study also tracked how obsidian use shifted over time, from the city’s earliest phases around 1375 CE through its fall in 1520 CE.

During the empire’s early phases, more diversity in obsidian sources appeared in both ritual and everyday objects. After the Mexica consolidated power around 1430 CE, obsidian for ritual purposes became almost exclusively sourced from Sierra de Pachuca, suggesting growing religious standardization and centralized control.

“This kind of compositional analysis allows us to trace how imperial expansion, political alliances and trade networks evolved over time,” Matadamas-Gomora said.

The research was made possible through a partnership between Tulane and Mexico’s Proyecto Templo Mayor of the National Institute of Anthropology and History (INAH), with artifacts analyzed using portable X-ray fluorescence (pXRF), a non-destructive method that identifies the geochemical fingerprint of each artifact.

“This work not only highlights the Mexica Empire’s reach and complexity but also demonstrates how the archaeological sciences can be leveraged to study ancient objects and what they can tell us about past cultural practices,” said study co-author Jason Nesbitt, an associate professor in Tulane’s Anthropology Department.

This publication was partially funded by Tulane’s Supporting Impactful Publications (SIP) Program. It is co-authored by Tulane researchers Nesbitt, Julia Sjödahl and Tatsuya Murakami, and INAH researchers Leonardo López Luján, Rodolfo Aguilar Tapia and Alejandro Pastrana.

Journal

Proceedings of the National Academy of Sciences

DOI

10.1073/pnas.2500095122

Article Title

Compositional analysis of obsidian artifacts from the Templo Mayor of Tenochtitlan, capital of the Mexica (Aztec) Empire

Article Publication Date

12-May-2025

Name diversity sheds light on ancient societies

The Hebrew University of Jerusalem

Seals and Inscriptions from Ancient Judah and Israel — image:
A collection of inscriptions, seals, and seal impressions (bullae) bearing names and dated to the Biblical Kingdoms of Judah and Israel of the Iron Age.
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Credit: Credits: Seals and seal impressions (bullae) Square seal from Bet Shemesh – courtesy of Benjamin Sass. Photo: Benjamin Sass. Reproduction of the lion seal (from Megido) – RTI photo: Michael Magen. King Hezekiah bulla (winged figure stamped on clay) – courtesy of the Hebrew University of Jerusalem. Photo: Ouria Tadmor. Nathan-Melech bullae (oval-shaped seal stamp) – courtesy of the City of David archive. Photo: Eliyahu Yanai. Black stone seal – courtesy of the City of David archive. Photo: Eliyahu Yanai. Inscribed inscriptions Arad 49 inscription (bottom of bowl) – courtesy of the Archaeological Institute, Tel Aviv University. Photo: Michael Cordonsky. Arad 3 inscription (red-brown clay inscription) – courtesy of the Archaeological Institute, Tel Aviv University. Photo: Michael Cordonsky. Samaria 18 inscription (Black and White rectangular shape) – courtesy of the Semitic Museum, Harvard University. Photo: Harvard’s expedition to Samaria. Graphic Design: Barak Sober

A new study has uncovered hidden social patterns in ancient Hebrew kingdoms by analyzing personal names from archaeological findings. Applying diversity statistics typically used in ecological studies, the researchers found that the Kingdom of Israel had a far more diverse onomastic (naming) landscape than Judah—indicating a more open, cosmopolitan society. Over time, name diversity in Judah declined, likely reflecting increasing religious centralization and sociopolitical control. This interdisciplinary approach opens new possibilities for studying ancient cultures using statistical methods usually reserved for the natural sciences.

Link to pictures: https://drive.google.com/drive/folders/1bsU41E51W8OF6fe4_3kIMnVOh-LkYKQP

Personal names etched into clay and stone over 2,500 years ago are revealing new truths about ancient societies in the Southern Levant. In a novel interdisciplinary study, published in PNAS, researchers from the Hebrew University of Jerusalem, Tel Aviv University and University of Haifa, applied advanced diversity statistics—borrowed from ecology—to ancient onomastic (name) data, uncovering striking differences between the biblical kingdoms of Israel and Judah during the Iron Age II period (950–586 BCE).

The study, led by Ariel Vishne and Dr. Barak Sober from the Hebrew University’s Department of Statistics & Data Science and the Center for Digital Humanities, finds that the Kingdom of Israel displayed significantly greater diversity in personal names than the Kingdom of Judah. This suggests that Israelite society was more open, cosmopolitan, and exposed to cultural exchange, while Judah increasingly narrowed its naming conventions over time—likely due to growing religious centralization and sociopolitical consolidation.

“Names are more than just labels; they are cultural artifacts,” said Dr. Barak Sober. “By analyzing naming diversity the way ecologists measure species diversity, we can detect patterns of identity, openness, and change that might otherwise be invisible in the archaeological record.”

Dr. Mitka R. Golub, of the Institute of Archaeology at the Hebrew University, who compiled the comprehensive onomastic database used in the study, added, "The preserved personal names are windows into the past, revealing not just linguistic trends but also religious practices and social hierarchies of these ancient societies."

Drawing from over 1,000 personal names preserved on archaeological artifacts—such as seals, ostraca, and inscribed storage jars—the researchers applied sophisticated statistical methods originally developed to measure biodiversity in natural ecosystems. This allowed them to quantify not just how many different names were used, but how evenly they were distributed across the population.

Their findings show that:
• Israelite names were more diverse, even though fewer Israelite inscriptions survive, indicating a broader variety of cultural or linguistic influences.
• Judah’s name diversity declined over time, comparing the end of the 8th century BCE to the later 7th-early 6th centuries BCE, suggesting shifts in social and religious structures during the kingdom's final century.
• Geographic patterns also emerged: While Israel’s capital Samaria showed lower diversity than its peripheral regions—suggesting a more geographically dispersed elite population throughout the kingdom—Judah displayed the opposite, with Jerusalem exhibiting higher name diversity than the rest of the kingdom, indicating a more concentrated elite in the capital, possibly due to refugee inflows following Assyrian campaigns.

Professor Israel Finkelstein, a leading archaeologist from Haifa University and one of the authors, commented, "These findings align with archaeological evidence suggesting that the Kingdom of Israel was more cosmopolitan than Judah, with its strategic location along key trade routes fostering diverse cultural influences."

The research establishes name diversity as a powerful indicator of broader social dynamics. "Our findings suggest that societies with higher name diversity tend to be more cosmopolitan and open to external influences," explained Eli Piasetzky, a physics Professor from Tel Aviv University, also involved in the study. "Conversely, lower name diversity often corresponds to more traditional societies with stronger cultural conformity."

To validate this principle and to test the reliability of their findings, the team applied their methodology to modern naming datasets from countries including Israel, France, the United States, Australia, and United Kingdom. The analysis revealed fascinating patterns: female names typically show greater diversity than male names in the same population; name diversity has generally increased since the 1960s across all countries studied; and societies with more traditional characteristics tend to have lower name diversity. Furthermore, these experiments showed that the statistical analysis performed is robust to the small sample sizes, a feat of many historical investigations.

“This is the first time that onomastic data has been studied using ecological diversity statistics,” said Vishne, the study’s lead author. “It allows us to view ancient societies through a more nuanced statistical lens and raises exciting possibilities for studying cultural change across time and place.”

The researchers emphasize that the surviving names mostly represent elite males, given the limitations of the archaeological record. Still, they argue that comparing elites across kingdoms can yield valuable insights into broader societal dynamics, especially in the absence of large-scale written sources from the period.

This study not only sheds new light on the Hebrew kingdoms during the First Temple period but also opens doors for applying statistical tools to other historical and archaeological corpora—proving that even in the ancient world, there’s a lot in a name.

Caption

A collection of seals and seal impressions (bullae) bearing names and dated to the Biblical Kingdoms of Judah and Israel of the Iron Age.