The Nuvvuagittuq Greenstone Belt (NGB) – a complex geological sequence in northeastern Canada – harbors surviving fragments of Earth’s oldest crust, dating back to ~4.16 billion years old, according to a new study. The preservation of Hadean rocks on Earth’s surface could provide valuable insights into the planet’s earliest times. Much about Earth’s earliest geologic history remains poorly understood due to the rarity of Hadean-age (>4.03 billion-year-old) rocks and minerals. These ancient materials are typically altered or destroyed as the planet’s crust is recycled through ongoing tectonic processes. One candidate for surviving Hadean-age crustal rock is the NGB, which contains rock argued to be as old as 4.3 billion years. However, this claim is controversial; some argue that the isotopic data underpinning these estimates may instead reflect later geological mixing processes rather than the true age of the formation. If shown to be Hadean in origin, the NGB would represent the oldest preserved rock sequence on Earth. It would offer critical insights into early Earth geology, including the potential setting for the emergence of life.

 

To constrain the age of the NGB, Christian Sole and colleagues focused on a specific type of ancient rocks – metagabbroic intrusions – within the belt. According to the authors, these intrusions intersect older basaltic rocks, and this feature allowed the authors to use combined uranium-lead (U-Pb) dating with both short- and long-lived neodymium (Sm-Nd) isotopic analyses to determine a lower age limit on the more ancient formations (the older basaltic rocks). Sole et al. report that the Sm-Nd data yielded consistent isochron ages around 4.16 billion years, regardless of sample location or mineral composition. The fact that both isotopic systems yield the same age in rocks linked by clear evidence of magmatic differentiation strongly supports their Hadean-age crystallization. This, in turn, supports the idea that fragments of mafic crust from the Hadean Eon have survived in the NGB.

Using an innovative “digital fossil-mining” approach, researchers have uncovered hundreds of previously hidden fossil squid beaks, revealing a record that squids originated and became ecologically dominant roughly 100 million years ago – well before the end-Cretaceous extinction. Squids are the most diverse and globally distributed group of marine cephalopods in the modern ocean, where they play a vital role in ocean ecosystems as both predators and prey. Their evolutionary success is widely considered to be related to the loss of a rigid external shell, which was a key trait of their cephalopod ancestors. However, their evolutionary origins remain obscure due to the rarity of fossils from soft-bodied organisms. The fossil record of squids begins only around 45 million years ago, with most specimens consisting of just fossilized statoliths – tiny calcium carbonite structures involved in balance. The lack of early fossils has led to speculation that squids diversified after the end-Cretaceous mass extinction 66 million years ago. While molecular analyses of living species have offered estimates of squid divergence times, the absence of earlier fossils has made these estimates highly uncertain.

 

Here, Shin Ikegami and colleagues address these gaps using a novel approach – “digital fossil-mining” – which uses high-resolution grinding tomography and advanced image processing to digitally scan entire rocks as stacked cross-sectional images to reveal hidden fossils as detailed 3D models. Ikegami et al. applied this technique to Cretaceous-age carbonate rocks from Japan, uncovering 263 fossilized squid beaks, with specimens spanning 40 species across 23 genera and five families. The findings show that squids originated roughly 100 million years ago, near the boundary between the Early and Late Cretaceous, and rapidly diversified thereafter. According to the authors, the previously hidden fossil record greatly extends the known origins of both major squid groups – Oegopsida by ~15 million years and Myopsida by ~55 million years. Early Oegopsids displayed distinct anatomical traits that disappeared in later species, suggesting swift morphological evolution, while Myopsids already resembled modern forms. What’s more, the study suggests that Late Cretaceous squids were more abundant and often larger than coexisting ammonites and bony fishes, an ecological dominance that predates the radiation of bony fishes and marine mammals by over 30 million years, making them among the first intelligent, fast swimmers to shape modern ocean ecosystems.

 

For reporters interested in research integrity issues co-author Yasuhiro Iba notes, “accessibility and reproducibility in fossil-based studies have been strongly restricted by the fixation on studying physical specimens. In contrast, we performed all processes from fossil hunting to analysis in cyberspace and digitally released all specimens to the public. I believe that this breakthrough is critical to ensuring research integrity and will facilitate groundbreaking discoveries worldwide.”

In a Review, Brian Yanites and colleagues argue the need for a unified, interdisciplinary approach to studying cascading land surface hazards. Earth’s surface is continually shaped by a range of natural processes, from slow erosion to sudden disasters like earthquakes and floods. Notably, one hazardous event can trigger a series of subsequent, interrelated disasters, or ”cascading hazards,” that unfold over timescales ranging from seconds to centuries. However, despite their growing impact on human populations, a comprehensive mechanistic framework from which to understand, predict, and manage these interconnected threats remains lacking. Here, Yanites et al. review current research on how Earth systems and the resulting land surface processes can interact in complex, sequential ways that intensify hazard risk. Unlike compound hazards, where multiple events occur independently but simultaneously, cascading hazards involve a direct causal link – one event alters the physical state of the landscape in a way that increases the likelihood of subsequent hazards. For example, earthquakes can destabilize hillslopes, raising landslide risk for years, while wildfires can transform vegetation and soil properties, amplifying the potential for debris flows during post-fire storms. According to the authors, the dynamic nature of these hazards challenges current risk assessment tools. To address this critical gap, Yanites et al. present a collaborative, cross-disciplinary framework that leverages recent technological advances and brings together atmospheric scientists, geologists, geomorphologists, engineers, and others to refine theory, models, and hazard monitoring. The authors argue that the development of a cascading hazards index could offer a promising tool by serving as an integrative, location-specific metric that synthesizes process-based models, observational data, and knowledge of hazard evolution to help communities assess these chains of evolving, interlinked hazards.