Abiogenesis News - UCL Scientists Show How LUCA Arose - No God(s) Required

Liquid brine veins, where RNA molecules can replicate, surround solid ice crystals in water ice, as seen with an electron microscope.

Credit: Philipp Holliger, MRC LMB

Graphic abstract

Attwater, J., Augustin, T.L., Curran, J.F. et al.(2025)

Chemists recreate how RNA might have reproduced for first time | UCL News - UCL – University College London

The day creationists dread — the final closure of their favourite god-shaped abiogenesis gap — moved a little closer last May, when scientists at University College London (UCL) announced that they had shown how the first RNA could have reproduced. In a selective environment with competition for resources, this would have led inevitably to ever-increasing efficiency in replication, kick-starting the whole evolutionary process and the emergence of self-organising systems (or “life”) from prebiotic precursors (or “non-life”). This is, of course, the very process that creationists insist is “impossible”, clinging to the idea that “life” is some magical essence that must be granted by a supernatural deity.

When this God-shaped gap is finally and conclusively closed — as all the others have been — creationists will need to scramble once again to reframe their beliefs and cling to whatever shrinking space remains for their god. Just as their old claim that evolution was “impossible” collapsed, to be replaced with notions of a short burst of warp-speed evolution “within kinds” after “The Flood” (and supposedly still happening today, but conveniently “guided” by God), so too will abiogenesis inevitably be rebranded as yet another process directed by divine intention — naturally, with the eventual production of (American) humans as the goal.

Refuting Creationism - The Real Universe is Nothing Like the One in the Bible

An optical image view of the Butterfly Nebula, NGC 6302, captured by the Hubble space telescope.

Credit: ESA/Webb, NASA & CSA, K. Noll, J. Kastner, M. Zamani (ESA/Webb)

This image, which combines infrared data from the James Webb Space Telescope with submillimetre observations from the Atacama Large Millimetre/submillimetre Array (ALMA), shows the doughnut-shaped torus and interconnected bubbles of dusty gas that surround the Butterfly Nebula’s central star. The torus is oriented vertically and nearly edge-on from our perspective, and it intersects with bubbles of gas enclosing the star. The bubbles appear bright red in this image, illuminated by the light from helium and neon gas. Outside the bubbles, jets traced by emission from ionised iron shoot off in opposite directions.

ESA/Webb, NASA & CSA, M. Matsuura, ALMA (ESO/NAOJ/NRAO), N. Hirano, M. Zamani (ESA/Webb) (CC BY 4.0).

An optical image view of the Butterfly Nebula, NGC 6302, captured by the Hubble space telescope.

Credit: ESA/Webb, NASA & CSA, K. Noll, J. Kastner, M. Zamani (ESA/Webb).

JWST observations of Butterfly Nebula reveal how cosmic dust is made in space - News - Cardiff University

There’s a double whammy for creationists in this new paper. Not only does it expose the Bible’s description of the Universe as laughably naïve, but it also shows how organic molecules — in the form of polycyclic aromatic hydrocarbons (PAHs) — that may have formed the basis of life on the prebiotic Earth, could have been created in deep space and later incorporated into our planet either at its formation or via impacts from space debris.

The paper, by a team of scientists led by Cardiff University, has just been published in Monthly Notices of the Royal Astronomical Society. Using data from the James Webb Space Telescope (JWST), the researchers reveal how stars generate space dust, organic material, and the fundamental building blocks from which rocky planets like Earth are formed. Their study focuses on the Butterfly Nebula (NGC 6302), a spectacular stellar remnant.

What Are PAHs?

Polycyclic aromatic hydrocarbons (PAHs) are complex organic molecules made of fused benzene rings — essentially arrangements of carbon and hydrogen in hexagonal patterns. On Earth, they are often associated with combustion (for example, in car exhaust fumes, cigarette smoke, or charred food). In space, however, they form naturally in the outflows of dying stars and in the dense molecular clouds that give rise to new stars and planetary systems.

PAHs are of great interest to astrobiologists because they are thought to be among the earliest organic compounds to have existed in the Universe. They can undergo chemical transformations to form more complex molecules, including amino acids and nucleotides, which are the essential components of life. Their presence in meteorites and interstellar dust suggests that the seeds of life were widespread long before Earth even formed.

Refuting Creationism - Oceanic Oxygenation Spured Rappid Evolution - 390 Million Years Before 'Creation Week'

An artist’s rendering of a prehistoric jawed fish from the Late Devonian called Dunkleosteus. These sorts of large, active vertebrates evolved shortly after the deep ocean became well-oxygenated.

© 2008 Nobu Tamura/CC-BY-SA.

How oxygen made the deep ocean home to animals, spurring rapid evolution | UW News

Another wave of reality breaks over the impervious rocks of creationist dogma, in the form of news that an international team of researchers led by the University of Washington has shown a correlation between the rapid radiation of marine vertebrates and the evolution of plants on land. As trees and other vascular plants spread, more atmospheric carbon became locked into their woody stems, reducing carbon dioxide levels. At the same time, increased photosynthesis raised atmospheric oxygen levels, which in turn oxygenated the oceans, making oxygen available in depths that had previously been anoxic.

Creationists will, of course, need to ignore the fact that this finding flatly contradicts their claims that evolution only occurs within “kinds” and that all diversification happened in a brief burst of warp-speed evolution following a genocidal global flood some 4,000 years ago. The timeline alone is utterly inconsistent with their favourite creationist fairy tale.

Scientists once believed this major oxygenation event had occurred about 500 million years ago, but the new research shows that episode was short-lived. A more significant oxygenation occurred around 390 million years ago. Initially, oxygenation would have taken place in shallow coastal regions where vertebrates first evolved. As oxygen penetrated deeper into the oceans, vertebrates followed into the newly opened niches, leading to a rapid proliferation of jawed vertebrate species — the ancestors from which terrestrial tetrapods later evolved.

The team reached their conclusions after measuring selenium isotopes in 97 sedimentary rock samples from five continents, dated between 252 and 541 million years ago. These rocks had been deposited near the edges of continental shelves, where shallow seas transition into the deep ocean. Selenium occurs naturally in several isotopic forms, and the ratios in which they were deposited depend on the level of oxygen dissolved in seawater. These isotopic signatures thus provide an indirect measure of oxygenation levels at the time the rocks were laid down.

Abiogenesis News - Fully Synthetic 'Life' Evolving in a Laboratory

Illustration showing the formation of new vesicles from the reorganization through self-reproduction of amphiphiles expelled into the bulk

S.K. Katla,C. Lin, & J. Pérez-Mercader (2025).

A step toward solving central mystery of life on Earth — Harvard Gazette

(A) Illustration showing the different stages of polymer vesicle growth leading to the action of expulsion of amphiphiles. (B) Illustration showing the formation of new vesicles from the reorganization through self-reproduction of amphiphiles expelled into the bulk.

S.K. Katla,C. Lin, & J. Pérez-Mercader (2025).

The frequent creationist assertion that abiogenesis is impossible without invoking supernatural intervention has taken another significant blow with the recent open‑access publication in Proceedings of the National Academy of Sciences (PNAS). The study, Self‑reproduction as an autonomous process of growth and reorganization in fully abiotic, artificial and synthetic cells, demonstrates, for the first time, the successful laboratory creation of simple, non‑biochemical self‑reproducing vesicle‑like systems exhibiting Darwinian evolution: each generation varies slightly in traits that influence their ability to replicate.

This breakthrough indicates that such self‑sustaining systems could plausibly arise through natural processes, and gradually—through Darwinian mechanisms—evolve into the first simple biological life forms, from which all life subsequently diversified. It also lends empirical support to the principle that when self‑replication with small variation occurs in a selective environment, evolution in the direction of increased fitness is inevitable.

Abiogenesis News - Organic Precursors to Life Detected In Deep Space.

Planet-forming disc around V883 Orionis. This star is currently in outburst. The dark ring midway through the disc is the point where the temperature and pressure dip low enough for water ice to form.
Orbits of the planet Neptune and dwarf planet Pluto in our Solar System are shown for scale.

Credit: ALMA (ESO/NAOJ/NRAO)/L. Cieza

This article is best read on a laptop, desktop, or tablet

This artist’s impression shows the planet-forming disc around the star V883 Orionis. In the outermost part of the disc volatile gases are frozen out as ice, which contains complex organic molecules. An outburst of energy from the star heats the inner disc to a temperature that evaporates the ice and releases the complex molecules, enabling astronomers to detect it. The inset image shows the chemical structure of complex organic molecules detected and presumed in the protoplanetary disc (from left to right): propionitrile (ethyl cyanide), glycolonitrile, alanine, glycine, ethylene glycol, acetonitrile (methyl cyanide).

© Credit: ESO/L. Calçada/T. Müller (MPIA/HdA) (CC BY 4.0)

The evolution of life may have its origins in outer space

If you listen to creationists, you might be persuaded to believe that the formation of inorganic chemicals—often deliberately conflated with 'life' to evoke an emotional reaction—is, for all practical purposes, impossible without the intervention of a supernatural intelligence. This is, of course, nothing more than the familiar creationist fallback: the god of the gaps argument, coupled with a false dichotomy, and dressed up with a spurious veneer of mathematical ‘proof’.

But this tactic suffered yet another fatal blow recently with the publication of a study led by Abubakar Fadul of the Max Planck Institute for Astronomy (MPIA), which reported the discovery of organic molecules in the protoplanetary disc surrounding the young star V883 Orionis. This finding provides compelling evidence that the formation of prebiotic molecules can begin even before planets form—suggesting that Earth may have developed with a complement of organic compounds already present in the accretion disc from which it emerged.

An alternative, but equally plausible, hypothesis is that these molecules could have been delivered by meteorites or other interplanetary bodies.

Abiogenesis News - Not Random Chance Or Divine Magic But Natural Selection

The sugar ribose is more quickly phosphorylated compared to other sugars with the same chemical formula but a different shape. This selective phosphorylation could explain how ribose became the sugar molecule in RNA.

Credit: Scripps Research

Where did RNA come from? | Scripps Research

One fallacy with which anyone who has tried to engage a creationist in debate will soon become familiar is the false dichotomy. This is where a creationist attempts to make a "god of the gaps" argument appear logical by presenting it as a binary choice between something so simplistic or absurd that no serious scientist would argue for it—and "God did it!" In doing so, they ignore the actual scientific explanations and exclude all other plausible natural mechanisms.

A classic example of this is the argument that abiogenesis—often deliberately misrepresented as the spontaneous assembly of a complex, living cell from inorganic materials—is far too improbable to have occurred by chance alone, and therefore must have required a supernatural intelligence. In their minds, the very existence of complex life is "proof" of their particular deity.

This line of reasoning overlooks the crucial role played by natural processes, such as chemistry and physics, and what amounts to an evolutionary process at the molecular level. In such a process, chemical pathways that are more efficient at producing copies of themselves are naturally favoured, leading over time to increased refinement and complexity. For instance, why was the five-carbon sugar ribose selected as the backbone sugar in RNA?

This is the question that two researchers at the Scripps Research Institute have tackled. They demonstrated that ribose is far more efficiently phosphorylated than its alternatives, forming the chemical basis of nucleotides—the building blocks of RNA (and later DNA). This efficiency gave ribose a natural advantage, allowing it to "win" the competition against other sugars.

Their findings show that the emergence of ribose was not the result of random chance, but the predictable outcome of the underlying chemistry and physics. The study has been published in the international edition of the journal of the German Chemical Society, Angewandte Chemie.

The work is also summarised in accessible terms in a Scripps Research press release.

Refuting Creationism - The 'Abiogenesis Gap' Just Got a Little Bit Smaller

Image generated with Adobe Stock by Josef Kuster / ETH Zürich)

How urea forms spontaneously | ETH Zürich

Graphical representation of urea formation in a droplet.

Figure: Luis Quintero / ETH Zürich.

Creationism's ever-shrinking, gap-shaped creator god has just lost a little more ground. New research suggests that the formation of basic organic molecules may have been far easier under early Earth conditions than previously thought. Remarkably, scientists have found that urea—a key organic compound—can form spontaneously from ammonia and carbon dioxide on the surface of water droplets. This process requires no catalysts, no high pressure or heat, and consumes minimal energy.

Although vitalism was refuted as early as 1828 — decades before Darwin — creationists still claim that life cannot arise from non-living matter. Yet they quickly retreat when asked how dead food becomes living tissue, or what exactly they mean by ‘life’: a substance, a process, or some kind of magical force. In reality, life is a set of chemical processes, and at its core, it’s about managing entropy—using energy to maintain order against the natural drift toward disorder.

The discovery was made by researchers at Eidgenössische Technische Hochschule (ETH) Zürich in collaboration with colleagues from Auburn University in Alabama, USA. Their findings have just been published in Science.

Refuting Creationism - That Ever-Shrinking Little Creationist God Just Got Even Smaller

Liquid brine veins, where RNA molecules can replicate, surround solid ice crystals in water ice, as seen with an electron microscope.

Credit: Philipp Holliger, MRC LMB

Chemists recreate how RNA might have reproduced for first time | UCL News - UCL – University College London

The problem with having a god who exists merely to fill gaps in human knowledge and understanding — as the god of creationism does — is that science has been steadily shrinking those gaps ever since the scientific method emerged and the Church lost its power to persecute scientists for discovering inconvenient truths. Today, only a few small gaps remain, scattered throughout the body of scientific knowledge —particularly in biology, which holds special interest for creationists.

Creationism persists because there are still people with such a poor understanding of science that they believe the authors of ancient religious texts — written during the Bronze Age, when humanity's knowledge gaps encompassed nearly everything in their small world — had access to some deeper, divine insight. Although what they wrote is often naively simplistic and demonstrably wrong in almost every respect, creationists insist that it somehow surpasses anything modern science has produced in terms of accuracy and reliability.

One of the few remaining gaps where creationists attempt to place their god — the abiogenesis gap — has just shrunk further. Predictably, this will be ignored, dismissed, or misrepresented by creationist frauds who exploit carefully maintained ignorance to preserve their cult followings and income streams.

This discovery by chemists at University College London and the Medical Research Council Laboratory of Molecular Biology reveals how a simple RNA molecule can self-replicate under conditions thought to have existed on prebiotic Earth. Many scientists believe this marks the origin of RNA-based life, which eventually gave rise to the more complex protein- and DNA-based life we see today. A self-replicating RNA molecule, competing for limited resources, will naturally evolve to become more efficient — leaving more copies of itself than rival variants. This is classic Darwinian evolution, operating in a context Darwin himself could scarcely have imagined, knowing nothing of RNA or DNA.

The new research is published open access in Nature Chemistry.

Abiogenesis News - Closing Creationism's Favourite God-Shaped Gap - Still No God(s) Found

Diagram of an early cell membrane.

AI Generated image (ChatGPT4o)

How membranes may have brought about the chemistry of life on Earth | Department of Biology

Another hefty spadeful of science has just been shovelled into one of creationism’s favourite god-shaped gaps: the ever-shrinking mystery of abiogenesis. This is the gap that, through the intellectually dishonest tactic of the false dichotomy, creationists claim as evidence for their chosen deity.

Not only is this approach scientifically bankrupt, it also conveniently spares them the bother of providing any evidence or a testable mechanism of their own. For a target audience conditioned to see science as an attempt to disprove their god, the logic goes: if science is wrong—or even just incomplete—then “God did it!” wins by default.

But that dreaded moment for creationists, when science finally closes the gap and, like every other gap in history, finds no need for gods or magic in the explanation, draws ever nearer. The latest discovery bringing us closer comes in the form of new research into the origin and function of membranes—an essential step on the path from chemistry to life.

This particular piece of gap-filling comes from a paper published in PLOS Biology, authored by a team led by Professor Thomas Richards, Professor of Evolutionary Genomics in the Department of Biology at the University of Oxford. The researchers demonstrate that early cell membranes could not only have formed through natural processes, but also had the crucial ability to control what passed through them.

In doing so, they explain what had been something of a mystery and a favourite claim of ID creationists - the chirality of 'living' molecules where all amino acids have the same chirality. Creationists claim this shows the hand of an intelligent designer. This work shows it has a natural explanation.

Abiogenesis News - Closing Another of Creationism's God-Shaped Gaps - Still No God Found

Formation of polyester protocells under early Earth-like conditions Polyester microdroplets, possible precursors to life, were formed from alpha-hydroxy acids (αHAs) in early Earth-like conditions even at low reaction volume, low reactant concentrations, and/or high NaCl or KCl concentrations.

Credit: Associate Professor Tony Z. Jia

How life’s building blocks took shape on early Earth: the limits of membraneless polyester protocell formation – ELSI｜EARTH-LIFE SCIENCE INSTITUTE

Creationism’ ever-shrinking little god that sits in the abiogenesis gap, just got smaller with the news that researchers led by PhD student Mahendran Sithamparam of the Space Science Center (ANGKASA), Institute of Climate Change, National University of Malaysia, working at the Earth-Life Science Institute (ELSI) in the Institute of Science, Tokyo, Japan, have shown how primitive protocells could have formed under a wide range of realistic probiotic Earth conditions. The research team included scientists from Taiwan and China.

The research showed that membraneless protocells could have formed by polymerization of alpha-hydroxy acids (αHAs) to form polyester microdroplets, not to be confused with the modern plastic polyester. These polymers were polymers of esters - simple organic compounds which are chemically similar to the monomers that make modern polyester fibres.

Refuting Creationism - First Steps to Abiogenesis

Diagram of the atmospheric evolution of Earth's ancient atmosphere estimated by this study

© Yoshida et al.

Research News - How Life Began on Earth: Modeling Earth's Ancient Atmosphere | Tohoku University Global Site

The fact that living organisms arose on Earth from inorganic sources rather than being made of nothing by magic, is an indisputable fact because there are living organisms on Earth and the chemicals they are composed of all exist on the planet in inorganic minerals and gases. 'Life' contains nothing that 'non-life' doesn't contain.

This much we know, but what we don't yet know and can probably never know with certainty, is precisely how and where that happen. In fact, we don't even know whether it did all start in the same place at the same time because the reason there are two different prokaryote cells - bacteria and archaea - could be because life arose on Earth not once but twice, by two different processes in two different places at two different times.

What we have though is lots of working hypotheses in the process of being validated.

What role would Earth's atmosphere have played in abiogenesis? Earth's early atmosphere was crucial in creating the right conditions for abiogenesis—the process by which life originated from non-living matter. While the exact composition of Earth’s primordial atmosphere is still debated, its unique conditions likely contributed in several essential ways:

1. Provision of Basic Building Blocks
   
   • Earth’s early atmosphere likely contained simple molecules like methane (CH₄), ammonia (NH₃), hydrogen (H₂), carbon dioxide (CO₂), nitrogen (N₂), and water vapor (H₂O). These molecules are rich in carbon, nitrogen, oxygen, and hydrogen—elements that are vital for organic compounds and, ultimately, for life.
   • When exposed to energy sources like ultraviolet (UV) radiation from the Sun or electrical discharges from lightning, these molecules could recombine into more complex organic molecules, such as amino acids and nucleotides, which are the building blocks of proteins and nucleic acids, respectively.
   
   
2. Facilitation of Prebiotic Chemistry
   
   • Experiments like the famous Miller-Urey experiment in 1953 showed that simple gases (methane, ammonia, hydrogen, and water vapor) in an atmosphere subjected to electrical sparks could produce amino acids. This suggests that Earth’s early atmosphere could have been instrumental in initiating chemical reactions that synthesized complex organic molecules.
   • Without a protective ozone layer, the early atmosphere allowed substantial UV radiation to penetrate the Earth’s surface, providing the energy necessary to drive these prebiotic reactions.
   
   
3. Supporting a Reducing Environment
   
   • The presence of reducing gases (such as methane and ammonia) would favor the formation of organic molecules because such conditions prevent the oxidation (and hence destruction) of organic compounds. Oxygen is highly reactive and can break down organic molecules, so the absence of free oxygen in the early atmosphere was likely a key factor that allowed these molecules to accumulate and react.
   • This reducing environment might have helped organic compounds to survive long enough to form stable, self-replicating systems.
   
   
4. Encouraging Geochemical Interactions
   
   • The interaction between the early atmosphere and the oceans, along with geothermal activity like volcanic eruptions and hydrothermal vents, provided a diverse range of chemical environments. In particular, hydrothermal vents may have supplied essential minerals and additional energy sources, further driving complex chemical reactions that are believed to be important in the formation of life.
   • The cycling of materials between the atmosphere and oceans would have contributed to creating localized "hotspots" for prebiotic reactions.
   
   
5. Protection and Concentration Mechanisms
   
   • The atmosphere also played a protective role by preventing the immediate dissipation of important compounds into space. It allowed the concentration of molecules and gases at Earth’s surface, increasing the chances of interactions among the essential precursors to life.
   • Early atmospheres may have helped regulate surface temperatures, preventing extreme fluctuations that would have been hostile to complex chemistry.
   
   
6. Encouraging Self-Organization and Membrane Formation
   
   • Interactions in the early atmosphere could have contributed to the formation of lipid molecules that could aggregate to form primitive cell-like structures or vesicles. These structures would eventually help in containing and protecting reactions necessary for early metabolic pathways.
   • These early "proto-cells" or vesicles would have been necessary to create a boundary for molecular interactions, which is a critical step toward the organization needed for cellular life.

In summary, Earth’s early atmosphere provided a chemically conducive, energetically rich environment that fostered the synthesis and concentration of organic molecules necessary for abiogenesis. This atmosphere also shielded these nascent molecules, allowing them to organize and evolve toward increasingly complex systems, eventually leading to the first living organisms.

One of which is the precise details of the atmosphere on the Early Earth, which is important because it would have had a major impact on the rest of the environment in which life arose. To gain a better understanding of that, a team from Tohoku University, Tokyo University and Hokkaido University, Japan, led by Tatsuya Yoshida have succeeded in modelling that atmosphere, as explained in a Tohoku University press release and published in the journal Astrobiology:

How Life Began on Earth: Modeling Earth's Ancient Atmosphere

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The key to unlocking the secrets of distant planets starts right here on Earth. Researchers at Tohoku University, the University of Tokyo, and Hokkaido University have developed a model considering various atmospheric chemical reactions to estimate how the atmosphere - and the first signs of life - evolved on Earth.

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Ancient Earth was nothing like our current home. It was a much more hostile place; rich in metallic iron with an atmosphere containing hydrogen and methane.

Shungo Koyama, co-author
Graduate School of Science
Tohoku University, Sendai, Japan.

These molecules contain an important clue to how life was initially formed. When exposed to solar ultraviolet (UV) radiation, they undergo a chemical reaction that produces organics (also known as the "building blocks of life"). Part of these organics were precursors to essential biomolecules, such as amino acids and nucleic acids. However, understanding the role of UV radiation is difficult. Firstly, this type of atmosphere is unstable and likely underwent rapid changes due to atmospheric chemical reactions. Secondly, when UV radiation efficiently breaks down water vapour in the atmosphere and forms oxidative molecules, the precise branching ratio and timescale has not been determined. In order to address these issues, a 1D photochemical model was created to make accurate predictions about what the atmosphere was like on Earth long ago.

The calculation reveals that most hydrogen was lost to space and that hydrocarbons like acetylene (produced from methane) shielded UV radiation. This inhibition of UV radiation significantly reduced the breakdown of water vapour and subsequent oxidation of methane, thus enhancing the production of organics. If the initial amount of methane was equivalent to that of the amount of carbon found on the present-day Earth's surface, organic layers several hundred metres thick could have formed.

There may have been an accumulation of organics that created what was like an enriched soup of important building blocks. That could have been the source from which living things first emerged on Earth.

Tatsuya Yoshida, lead author
Graduate School of Science
Tohoku University, Sendai, Japan.

The model suggests that the atmosphere on ancient Earth was strikingly similar to what we see on current day neighbouring planets: Venus and Mars. However, despite their proximity, Earth evolved into a completely different environment. Researchers are trying to understand what makes Earth so special. As such, this model allows us to deepen our understanding of whether atmospheric evolution and the origin of life on Earth are unique or share common patterns with other planetary systems.

These findings were published in the journal Astrobiology on October 22, 2024.

Publication Details:

Tatsuya Yoshida, Shungo Koyama, Yuki Nakamura, Naoki Terada and Kiyoshi Kuramoto
Self-Shielding Enhanced Organics Synthesis in an Early Reduced Earth's Atmosphere Astrobiology DOI: 10.1089/ast.2024.0048

Abstract
Earth is expected to have acquired a reduced proto-atmosphere enriched in H₂ and CH₄ through the accretion of building blocks that contain metallic Fe and/or the gravitational trapping of surrounding nebula gas. Such an early, wet, reduced atmosphere that covers a proto-ocean would then ultimately evolve toward oxidized chemical compositions through photochemical processes that involve reactions with H₂O-derived oxidant radicals and the selective escape of hydrogen to space. During this time, atmospheric CH₄ could be photochemically reprocessed to generate not only C-bearing oxides but also organics. However, the branching ratio between organic matter formation and oxidation remains unknown despite its significance on the abiotic chemical evolution of early Earth. Here, we show via numerical analyses that UV absorptions by gaseous hydrocarbons such as C₂H₂ and C₃H₄ significantly suppress H₂O photolysis and subsequent CH₄ oxidation during the photochemical evolution of a wet proto-atmosphere enriched in H₂ and CH₄. As a result, nearly half of the initial CH₄ converted to heavier organics along with the deposition of prebiotically essential molecules such as HCN and H₂CO on the surface of a primordial ocean for a geological timescale order of 10–100 Myr. Our results suggest that the accumulation of organics and prebiotically important molecules in the proto-ocean could produce a soup enriched in various organics, which might have eventually led to the emergence of living organisms.

Yoshida, Tatsuya; Koyama, Shungo; Nakamura, Yuki; Terada, Naoki; Kuramoto, Kiyoshi
Self-Shielding Enhanced Organics Synthesis in an Early Reduced Earth’s Atmosphere Journal of Astrobiology (2024) DOI: 10.1089/ast.2024.0048

© 2024 Mary Ann Liebert, Inc.
Reprinted under the terms of s60 of the Copyright, Designs and Patents Act 1988.

So, by the action if UV radiation from the sun on the inorganic molecules in Earth's early atmosphere for a period of some 10-100 million years, the oceans could have accumulated the basic building blocks for organic organisms to get started, and all th result of chemistry and physics with no magic gods involved at any point.

And, as usual with scientific discoveries, the truth is shown to have little resemblance to the origin myths the parochial Bronze Age pastoralists made up to fill the yawning chasm in their knowledge and understanding of the world around them, with their belief that Earth had only existed for a few thousand years, so were blissfully ignorant of the 99.9975% of its history that occurred before then.

Creationism Refuted - What a Mallorcan Cave Tells Us Of Events Before 'Creation Week'.

Bogdan Onac studies the phreatic overgrowths seen in this photo. They grow exactly at sea level and offer a more accurate reconstruction of past sea level history. He used these to determine the age of the submerged bridge.

Photo: M.À. Perelló

Close-up view of the submerged stone bridge from Genovesa Cave, Mallorca, Spain

Photo: R. Landreth

What a submerged ancient bridge discovered in a Spanish cave reveals about early human settlement

The Spanish Balearic Island of Mallorca (Majorca), a favourite holiday destination for Brits looking for sun, sea and sand, is composed largely of limestone which lends itself to cave formation and limestone caves lend themselves to stalactite formation.

They also provided shelters for early humans, so the evidence of human presence gives us a good picture of the timing of human migration into the area.

Like 99,9975% of Earth's history, the events recorded in these Mallorcan caves happened in the long pre-'Creation Week' history, long before creationists believe Earth was made out of nothing by magic.

Readers may recall my recent blog post concerning what is known of the changes in biodiversity as the Mediterranean dried up, then flooded again about 5.5 million years ago due to plate tectonic movements. These Mallorcan caves formed after those catastrophic events but still well before creationism's 'Creation Week'.

The stalactites in one cave in particular, the Genovesa Cave at the eastern end of the island hold a record of sea-level changes that correlate with known periods of glaciation and interglacial warmer periods. During periods of glaciation, water was locked up in polar ice and glaciers, so sea-levels fell.

What information do you have on the Genovesa Cave in Mallorca, Spain, and what it tells us of sea-level changes? Genovesa Cave, located on the eastern coast of Mallorca, Spain, is a notable site for studying past sea-level changes due to its unique speleothem formations (such as stalactites and stalagmites) and its position relative to current sea levels.

Key Information About Genovesa Cave

1. Geological Context:
   • Genovesa Cave is a partially submerged cave system found on the island of Mallorca, part of the Balearic Islands in the western Mediterranean Sea.
   • The cave has been naturally formed in limestone rock, a type of carbonate rock that is particularly responsive to changes in sea level.
   
   
2. Evidence of Past Sea-Level Changes:
   • Speleothem Growth Stages: The most significant evidence for past sea-level changes comes from speleothems, which are mineral deposits formed in caves by the precipitation of carbonate minerals from dripping water. When sea levels rise, the cave becomes submerged, and speleothem growth ceases due to a lack of contact with air. When sea levels fall, the cave is re-exposed to air, allowing speleothems to grow again.
   • Dating Techniques: Researchers use uranium-thorium (U-Th) dating methods to date these speleothems accurately. The growth and cessation periods can be correlated with known global sea-level fluctuations, such as those associated with glacial and interglacial cycles during the Quaternary period (the last 2.6 million years).
   
   
3. Sea-Level Highstands and Lowstands:
   
   
   • Studies of Genovesa Cave have identified speleothems that formed during several past interglacial periods when sea levels were higher than today. This provides evidence for higher sea levels during warm periods such as the Last Interglacial (about 125,000 years ago).
   • Conversely, periods when the cave was submerged or when speleothem growth was halted correspond to glacial periods when sea levels were much lower, sometimes up to 120 meters lower than the current level.

Implications for Understanding Sea-Level Changes

1. Local and Global Sea-Level Correlation:
   • The data obtained from Genovesa Cave speleothems align well with global records of sea-level changes, such as those derived from coral reefs and marine terraces. This reinforces the idea that the cave provides a reliable local record that reflects broader, global sea-level trends.
   
   
2. Understanding the Mediterranean Sea's Response:
   • The cave's findings contribute to our understanding of how the Mediterranean Sea responded to global climatic events. During periods of rapid deglaciation, for example, meltwater pulses could have caused rapid sea-level rises, which would be recorded in the cave's geological formations.
   
   
3. Insights into Future Sea-Level Rise:
   • Studying past sea levels helps scientists predict future changes, particularly in the context of global warming and potential ice sheet melting. The high-resolution records from Genovesa Cave can help refine models of future sea-level rise, especially in understanding how fast and how much sea levels could change.

In Summary

Genovesa Cave in Mallorca is a critical natural archive for studying past sea-level changes, providing both a local record of changes in the Mediterranean and contributing to the understanding of global sea-level fluctuations. The cave's speleothem formations, when dated, tell us about the timing and extent of past sea levels, helping us predict future changes.

Did the cave exist during the Messinian Salinity Crisis and the following Zanclean flood?

Genovesa Cave, like many other karstic cave systems on Mallorca, likely did not exist in its current form during the Messinian Salinity Crisis (MSC) and the subsequent Zanclean flood. However, understanding its formation requires a bit of geological context about these events and the development of the cave.

Geological Context of the Messinian Salinity Crisis and Zanclean Flood

1. Messinian Salinity Crisis (MSC) (5.96 to 5.33 million years ago):
   • The MSC was a period when the Mediterranean Sea was largely cut off from the Atlantic Ocean due to tectonic movements, leading to extreme evaporation and a significant drop in sea level. During this time, the Mediterranean became partially or fully desiccated, creating vast salt deposits and deep erosional features (like canyons and river systems) that extended below the current sea level.
   • Sea levels were drastically lower, estimated to have dropped by as much as 1,500 meters. The drop exposed large portions of the continental shelf and caused significant erosion of the landscape, including the areas around Mallorca.
   
   
2. Zanclean Flood (5.33 million years ago):
   • The Zanclean flood marked the end of the MSC, when the Strait of Gibraltar reopened, and Atlantic waters rapidly refilled the Mediterranean basin. This event is thought to have raised sea levels in the Mediterranean by up to 1,500 meters over a short period, flooding the previously exposed and desiccated areas.

Did Genovesa Cave Exist During These Events?

1. Formation of Genovesa Cave:
   • Genovesa Cave, like many karst caves, formed much later than the Messinian Salinity Crisis and the Zanclean flood. The formation of such caves typically occurs over long periods through the dissolution of limestone by slightly acidic groundwater. This process, known as karstification, is generally linked to periods when the sea level is relatively stable and when the water table is at an appropriate level to facilitate cave development.
   • Given that the MSC was a period of extreme environmental conditions (both in terms of erosion during the desiccation and rapid flooding during the Zanclean flood), the specific geological setting that would allow for the gradual formation of karstic caves like Genovesa likely did not exist until after these events.
   
   
2. Post-MSC Karst Development:
   • After the Mediterranean was refilled and the sea level stabilized following the Zanclean flood, conditions would have been more suitable for the formation of karst systems like Genovesa Cave. The Quaternary period, which began about 2.6 million years ago, saw multiple cycles of glacial and interglacial periods, during which fluctuations in sea levels, combined with periods of stability, promoted the development of karst caves in the limestone regions of Mallorca.
   
   
3. Timing of Cave Formation:
   • The specific timing of the formation of Genovesa Cave is not precisely known, but it is generally accepted that most of the karst caves in Mallorca formed during the Pleistocene epoch (2.6 million to 11,700 years ago) or even more recently. The cave's features and deposits suggest that it has undergone several phases of exposure and submersion due to sea-level changes throughout this period, well after the MSC and Zanclean flood.

Conclusion

Genovesa Cave, in its current form, did not exist during the Messinian Salinity Crisis or the subsequent Zanclean flood. The cave likely formed much later, during the Quaternary period, as conditions became suitable for karstification following the stabilization of Mediterranean sea levels after these dramatic geological events. The MSC and the Zanclean flood were important in shaping the broader landscape of the Mediterranean region, but the specific conditions necessary for the formation of caves like Genovesa developed much later.

What are phreatic overgrowths on Speleothems (POS)?

Phreatic overgrowths on speleothems (POS) are unique mineral deposits that form in coastal cave environments at the interface between freshwater and seawater. These overgrowths are specifically associated with periods when the cave is partially submerged in a mix of fresh and saline water, typically at or near sea level. They provide important clues about past sea-level positions and climate conditions.

Key Characteristics of Phreatic Overgrowths on Speleothems

1. Definition:
   • Phreatic overgrowths on speleothems are secondary carbonate deposits, typically composed of minerals like calcite or aragonite. They form on existing speleothems (such as stalactites, stalagmites, or flowstones) when the cave environment is inundated by a fluctuating water table that is influenced by sea level.
2. Formation Environment:
   • These overgrowths develop in the "phreatic zone" of caves— the zone that is below the water table and is saturated with water. In coastal caves, this zone is directly affected by sea-level changes. When sea level is stable or fluctuates within a certain range, the mixing zone between freshwater and saline water can lead to mineral precipitation on submerged speleothems.
3. Mechanism of Formation:
   • Phreatic overgrowths form due to a process known as "degassing" or "precipitation" when carbon dioxide (CO₂) dissolved in water escapes into the cave air. This loss of CO₂ from water that is saturated with calcium carbonate (CaCO₃) promotes the deposition of calcite or aragonite on existing cave formations.
   • In coastal caves, the mixing of fresh and saltwater enhances this process. Freshwater entering the cave mixes with seawater, creating conditions where minerals precipitate more readily due to changes in water chemistry, such as shifts in pH, temperature, and CO₂ concentration.
4. Morphology and Appearance:
   • Phreatic overgrowths typically form flat or gently sloping horizontal crusts, rims, or coatings on existing cave formations. Their horizontal nature reflects the stable water table level at which they formed.
   • These deposits can vary in thickness and are often found at multiple levels within the cave, corresponding to different sea levels over time.

Importance of Phreatic Overgrowths on Speleothems

1. Indicators of Past Sea Levels:
   • POS are valuable indicators of past sea levels because they form at specific elevations related to the water table, which in coastal environments is closely linked to sea level. By dating these formations using techniques such as uranium-thorium (U-Th) dating, scientists can reconstruct past sea-level positions and determine the timing and magnitude of sea-level changes over thousands to hundreds of thousands of years.
2. Understanding Paleoclimatic Conditions:
   • Beyond sea levels, POS can provide insights into broader paleoclimatic conditions. The chemical composition of these overgrowths (e.g., stable isotopes of oxygen and carbon) can offer information about past temperature, rainfall patterns, and even water source characteristics.
3. Calibrating Sea-Level Rise Models:
   • The precise dating of phreatic overgrowths helps in calibrating models of sea-level rise, particularly when cross-referenced with other geological and paleoclimatic data, such as coral reefs, marine terraces, and ice cores. This is particularly important for understanding the rate of sea-level rise in response to past climate events, such as glacial and interglacial periods.

Examples of POS Studies

• Mediterranean Caves (Mallorca, Spain): In Mallorca, POS have been extensively studied in caves like Genovesa Cave and others along the coast. These formations have been used to map out the history of Mediterranean sea-level changes over the last several hundred thousand years, including periods such as the Last Interglacial (about 125,000 years ago).
• Caribbean and Other Coastal Regions: Similar studies have been conducted in coastal caves in the Caribbean and other regions, where POS help reconstruct sea-level fluctuations and regional climate changes.

Summary

Phreatic overgrowths on speleothems are carbonate deposits formed in caves at the interface between freshwater and seawater, directly reflecting past sea levels. They serve as crucial archives for understanding past sea-level changes, climate conditions, and the complex interplay between global climate and regional environmental changes.

In the context of dating caves, what does the following mean?

'A ²³²Th/²³⁸U-²³⁴U/²³⁸U-²³⁰Th/²³⁸U (plotted as a Rosholt A type) isochron age of 5479 ± 120 years B.P.'

The phrase describes the result of a specific type of uranium-thorium dating method used to determine the age of materials, such as carbonate deposits in caves. Let's break down what each part of this phrase means:

Uranium-Thorium (U-Th) Dating Overview

Uranium-Thorium (U-Th) dating also known as Thorium-230 dating is a radiometric dating technique used to determine the age of calcium carbonate materials like speleothems (stalactites, stalagmites, and other cave formations). The method relies on the radioactive decay of uranium isotopes to thorium isotopes. Here's a breakdown of the isotopes involved:

• ²³⁸U (Uranium-238): The parent isotope, which decays over time into various intermediate daughter isotopes, including ²³⁴U (Uranium-234) and ²³⁰Th (Thorium-230).
• ²³²Th (Thorium-232): A stable, non-radioactive isotope of thorium that is not involved in the decay chain but can be present in the sample as a contaminant or from initial conditions.

Explanation of the Phrase

1. "²³²Th/²³⁸U-²³⁴U/²³⁸U-²³⁰Th/²³⁸U":
   • These ratios represent the proportions of different isotopes present in the sample.
     • ²³²Th/²³⁸U: Indicates the ratio of thorium-232 to uranium-238 in the sample.
     • ²³⁴U/²³⁸U: Indicates the ratio of uranium-234 (an intermediate decay product) to uranium-238.
     • ²³⁰Th/²³⁸U: Indicates the ratio of thorium-230 (the target daughter isotope) to uranium-238.
   
   
2. "Plotted as a Rosholt A type isochron":
   • An isochron is a graphical method used to determine the age of a sample by plotting the ratios of isotopes against each other. The slope of the line (the isochron) represents the time that has passed since the sample's formation.
   • "Rosholt A type" refers to a specific type of isochron plot developed by John Rosholt, which plots the ratios of these isotopes in a way that accounts for initial thorium contamination (²³²Th). This method provides a more accurate age by correcting for the presence of any initial, non-radiogenic thorium in the sample.
   
   
3. "Isochron age of 5479 ± 120 years B.P.":
   • This is the calculated age of the sample, determined by the U-Th dating method using the isochron plot.
   • 5479 years B.P.: This means "5479 years Before Present," where "Before Present" is typically defined as before the year 1950. The sample is estimated to have formed 5479 years ago.
   • ± 120 years: This represents the margin of error or uncertainty in the dating. The true age is likely within the range of 5479 years plus or minus 120 years (i.e., between 5359 and 5599 years ago).

Summary

The phrase refers to a method of dating a cave sample using uranium-thorium dating and an isochron plot (Rosholt A type) to determine that the sample is approximately 5479 years old, with an uncertainty of ±120 years. The use of multiple isotope ratios and the isochron method helps correct for initial contamination and provides a more accurate age estimate.

This allowed stalactites to grow as water containing dissolved minerals seeped through the cave roof and dripped down, evaporating as it did so, and leaving a record of rainfall. During interglacial period, sea-levels rose, submerging the caves and preventing the growth of stalactites, leaving a record of these sea-level rises.

But, apart from these records of climate and sea-level changes, the Genovesa Cave contains a more tangible record - that of human habitation on the island and so of colonisation of the Western Mediterranean and the Iberian peninsula in particular.

It is a submerged stone bridge, built when the sea-levels were lower at the height of the last ice age. The bridge was used to cross a now submerged small lake at a low point in the cave system and must have been deliberately constructed.

Scientists these days rarely, if ever, set out to refute creationist mythology but all do so incidentally, simply by doing what good science does and discovering the facts, and this discovery, by speleogeologists from the University of South Florida, does just that. It is the subject of a recent open access paper in Communications Earth & Environment and a recent news release from the University of South Florida:

What a submerged ancient bridge discovered in a Spanish cave reveals about early human settlement

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A new study led by the University of South Florida has shed light on the human colonization of the western Mediterranean, revealing that humans settled there much earlier than previously believed. This research, detailed in a recent issue of the journal, Communications Earth & Environment, challenges long-held assumptions and narrows the gap between the settlement timelines of islands throughout the Mediterranean region.

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Reconstructing early human colonization on Mediterranean islands is challenging due to limited archaeological evidence. By studying a 25-foot submerged bridge, an interdisciplinary research team – led by USF geology Professor Bogdan Onac – was able to provide compelling evidence of earlier human activity inside Genovesa Cave, located in the Spanish island of Mallorca.

The presence of this submerged bridge and other artifacts indicates a sophisticated level of activity, implying that early settlers recognized the cave's water resources and strategically built infrastructure to navigate it.

Professor Bogdan P. Onac, Lead author
Karst Research Group
School of Geosciences
University of South Florida, Tampa, FL, USA.

The cave, located near Mallorca’s coast, has passages now flooded due to rising sea levels, with distinct calcite encrustations forming during periods of high sea level. These formations, along with a light-colored band on the submerged bridge, serve as proxies for precisely tracking historical sea-level changes and dating the bridge's construction.

Mallorca, despite being the sixth largest island in the Mediterranean, was among the last to be colonized. Previous research suggested human presence as far back as 9,000 years, but inconsistencies and poor preservation of the radiocarbon dated material, such as nearby bones and pottery, led to doubts about these findings. Newer studies have used charcoal, ash and bones found on the island to create a timeline of human settlement about 4,400 years ago. This aligns the timeline of human presence with significant environmental events, such as the extinction of the goat-antelope genus Myotragus balearicus.

By analyzing overgrowths of minerals on the bridge and the elevation of a coloration band on the bridge, Onac and the team discovered the bridge was constructed nearly 6,000 years ago, more than two-thousand years older than the previous estimation – narrowing the timeline gap between eastern and western Mediterranean settlements.

This research underscores the importance of interdisciplinary collaboration in uncovering historical truths and advancing our understanding of human history.

Professor Bogdan P. Onac.

This study was supported by several National Science Foundation grants and involved extensive fieldwork, including underwater exploration and precise dating techniques. Onac will continue exploring cave systems, some of which have deposits that formed millions of years ago, so he can identify preindustrial sea levels and examine the impact of modern greenhouse warming on sea-level rise.

This research was done in collaboration with Harvard University, the University of New Mexico and the University of Balearic Islands.

Abstract
Reconstructing early human colonization of the Balearic Islands in the western Mediterranean is challenging due to limited archaeological evidence. Current understanding places human arrival ~4400 years ago. Here, U-series data from phreatic overgrowth on speleothems are combined with the discovery of a submerged bridge in Genovesa Cave that exhibits a distinctive coloration band near its top. The band is at the same depth as the phreatic overgrowth on speleothems (−1.1 meters), both of which indicate a sea-level stillstand between ~6000 and ~5400 years ago. Integrating the bridge depth with a high-resolution Holocene sea-level curve for Mallorca and the dated phreatic overgrowth on speleothems level constrains the construction of the bridge between ~6000 and ~5600 years ago. Subsequent sea-level rise flooded the archeological structure, ruling out later construction dates. This provides evidence for early human presence on the island dating at least 5600 and possibly beyond ~6000 years ago.

Introduction
Mallorca, the main island of the Balearic Archipelago, is the sixth largest in the Mediterranean Sea, yet it was among the last to be colonized¹. An in-depth discussion concerning the earliest colonization of various Mediterranean islands, including Mallorca, may be found in Cherry and Leppard1, Dawson², and Simmons³. Despite extensive research on this topic, there has been considerable disagreement about the timing of the earliest colonization of Mallorca. Radiocarbon dating of bone material excavated from Cova (Cave) de Moleta indicate human presence on the island as early as 7000 calibrated years before present (cal B.P.)⁴. Subsequent age determinations from findings in Cova de Canet, further extended the timeline, suggesting human occupation dating back to approximately 9000 cal B.P.⁵. A series of publications^{6,7,8,9,10,11} revealed inconsistencies regarding the exact stratigraphic position and context of the dated bone (sample KBN-640d12) in Cova de Moleta. Due to the overall poor preservation of the samples and the lack of clear and specific information on this particular radiocarbon-dated sample, Ramis and Alcover⁷ suggested that the bone fragment, initially identified as human, might actually belong to M. balearicus, an endemic bovid. Consequently, this sample was considered not relevant for determining the timing of the island’s colonization. Similarly, the radiocarbon dates from Cova de Canet were considered highly controversial because they originate from a charcoal layer that lacks clear evidence of human activity^7,8. Furthermore, in neither of these caves do the M. balearicus bones show butchery marks, making it difficult to establish a clear link to contemporary human presence2. Due to the aforementioned issues these early results were deemed unreliable^1,8,13.

Several studies have reevaluated most of the previously dated materials and supplemented them with new radiocarbon dates obtained from charcoal, ash, and bones^6,7,9,10. Based on these new results, there is now a consensus that the timeframe for earliest human settlement on the island is between 4600 and 4200 cal B.P.¹⁴.

Dawson2 presents a synthesis of the various lines of argument regarding arrival models in the Balearic islands that includes: (1) Early (~9000 cal B.P.), (2) Intermediate (~7600 cal B.P.), and (3) Late (~5000 cal B.P.) arrival phases. The last two models suggest the existence of stable settlements, yet only the third one has been deemed plausible in the local archeological literature^7,8,14.

While there has been a growing body of evidence revealing progressively earlier human settlements on many islands in the Mediterranean basin, the timeline for the initial human colonization in Mallorca has seen relatively minor adjustments over the past decades^8,15,16. The latest research suggests that this colonization occurred approximately 4400 cal B.P., coinciding with the human-mediated extinction of Myotragus balearicus¹⁴. This conclusion is based on two radiocarbon ages, which provide a relatively narrow time window of 350 years (p > 90%) between the last documented Myotragus bone (4581–4417 cal B.P.) and the first dated sheep bone (4417–4231 cal B.P.). However, it remains challenging to confirm whether the ages of these paleontological remains represent the latest or the earliest such occurrences on the island. Subsequent field work may shed light on this matter.

Our study site is a submerged archeological structure in the Genovesa Cave (also known as Cova de’n Bessó; 39°31’32” N, 3°19’2” E), situated in the eastern part of Mallorca (Fig. 1a, b). The cave hosts ceramic sherds and stone constructions. The latter includes a stone-paved path that connects the cave entrance to the first underground lake (Fig. 1d), a cyclopean stone wall running parallel to the path, and an 8.62 m long¹⁷ and 0.5 m high stone walkway (hereafter referred as to bridge) oriented NE–SW (Fig. 1c, e, Supplementary Fig. 1, Supplementary Table 1). This last structure was built across a lake by stacking large limestone breakdown blocks on top of each other, without the use of mortar or cement. The uppermost layer comprises flat boulders of considerable size (Supplementary Fig. 1b). The largest stone measures 1.63 m in length and 0.6 m in width. Relative to the preindustrial (pre-1900 CE) sea level, the bridge is submerged by 1.05 ± 0.1 m of water at its upper part (Figs. 1e, 2). However, at the time of its construction, it served as an access path to the only other dry chamber in the cave (Sala de les Rates-pinyades, i.e., Bats Room), where pottery, tentatively attributed to the Naviform period (ca. 3550–3000 cal B.P.) was discovered^18,19. The bridge structure was inferred to have been built around the same period²⁰.

Fig. 1: Cave and sample locations.

a Map showing Mallorca in the western Mediterranean (black square). b Location of Genovesa and Drac caves; CCG: Closos de Can Gaià archeological site. c Plan of Genovesa Cave showing the location of the phreatic overgrowth on speleothems samples (yellow circles) and the survey station (red dot). d Photograph of the stone-paved path leading to the bridge (person height = 167 cm). e Cross-section (x–x’) indicating the location of the submerged bridge relative to the cave entrance and the present sea level. Maps (a, b) are available under CC Public Domain License from https://pixabay.com/illustrations/map-europe-world-earth-continent-2672639/ and https://pixabay.com/illustrations/mallorca-map-land-country-europe-968363/, respectively.

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Fig. 2: Positional relationship between the bridge, preindustrial sea level, and analyzed samples.

The cross sections depict the spatial relationship between the submerged bridge and the U-series dated samples (phreatic overgrowth on speleothems: orange/yellow spindle; soda straw tips: red circle) from Genovesa and Drac caves. The vertical scale applies uniformly to all samples from both caves. All ages are reported as thousands of years (kyr) before present, where present is defined as 1950 CE.

Here, we integrate uranium-series (U-series) age data acquired from phreatic overgrowth on speleothems and stalactite tips in Genovesa and Drac caves, along with Late Holocene relative sea level (RSL) information available for Mallorca²¹. Additionally, we consider the presence of the bridge, the coloration mark on its upper part, and the depths at which these respective features occur. This combined evidence contributes valuable insights to the ongoing debate surrounding the timing of human colonization on Mallorca.

Because Creationists love to find fault with the geochronology in these records of pre-'Creation Week' events, I've included sections on geochronology here:

Results and discussion
Speleothems and sea level
Proxies for cave-based sea-level reconstructions include mineralogical (sediments, speleothems)^22,23, archeological (fish tanks, saltpans, submerged structures, etc.)²⁴, and biological (borings, worm tubes, etc.)²⁴ records. In the case of Genovesa Cave, a typical coastal karst feature situated <450 m from the shoreline, both mineralogical and archeological records are present. Many of its well-decorated passages, galleries, and chambers are now flooded due to rising sea levels²⁰. Because of the cave’s proximity to the coast and the high permeability of the Upper Miocene host rock²⁵, the hydraulic gradient is negligible (9 × 10^-5 m /m) for such short distances (see Methods), and thus the water table in the cave is, and was in the past, coincident with sea ^26,27. During times of high sea level stillstands, when the cave was partly flooded, distinct encrustations of calcite and aragonite accumulated over preexisting stalactites, forming the so-called phreatic overgrowths on speleothems²⁸ (POS). This is a particularly useful proxy for precisely and accurately reconstructing sea-level changes across various timescales^21,29. Furthermore, ordinary stalactites, which form in cave passages above the water table and later become submerged as sea-levels rise are also valuable in this process since they document the moment when the cave shifted from being air- to water-filled²².

A distinct light-colored band (~15 cm wide) is visible along the entire bridge at its upper part (Fig. 2, Supplementary Fig. 1a). This coloration mark bears a resemblance to a “bathtub ring” and its presence is likely related to a relatively short-lived stable water table that allowed the precipitation of a sub-millimeter calcite crust at the water/air interface. When the water level increased, the calcite did not disappear since the water below the water table remained somewhat saturated with respect to calcium carbonate. As discussed later, this feature along with the new POS ages and their elevation play a crucial role in determining when this bridge, now submerged, was constructed.

Geochronology
The U-series ages (n = 34; 28 for POS and 6 from stalactites) are given in Supplementary Table 2 and are all reported as years before present (BP), where present is 1950 CE. Ten of these ages are from POS samples GE-D8 (Genovesa Cave; Supplementary Fig. 2) and DR-D15 dated as part of a prior study²¹. The latter was collected in Drac Cave (39°32’9” N, 3°19’49” E), located 1.6 km to the north-east of Genovesa Cave (Fig. 1c, Supplementary Figs. S3–S4).

Regardless of the sampling depth, all the vadose stalactites on which the POS formed in both caves, produced ages older than 8200 years B.P. (Fig. 2, Supplementary Fig. 5). The phreatic overgrowth samples GE-D6, GE-D7, and DR-D23 (Supplementary Figs. S6–S8), precipitated at ~1.10 ± 0.1 m below the preindustrial sea level (mbpsl). A ²³²Th/²³⁸U-²³⁴U/²³⁸U-²³⁰Th/²³⁸U (plotted as a Rosholt A type) isochron age of 5479 ± 120 years B.P. (n = 3 of 4; hereafter, ± refers to 2 σ uncertainty) was measured for GE-D6 (Supplemental Table 2, Supplementary Fig. 9a). GE-D7, in the same room and at the same elevation as GE-D6, yielded a weighted average age of 5510 ± 549 years B.P. using the same correction (initial ²³⁰Th/²³²Th atomic ratio = 5.1 ± 0.4 ppm) generated by the GE-D6 isochron age. Onac et al.²¹. used a slightly higher initial for GE-D8 (8 ppm) that was located at a higher elevation than GE-D6 & -D7. For DR-D23, we obtained a ²³²Th/²³⁸U-²³⁴U/²³⁸U-²³⁰Th/²³⁸U (plotted as a Rosholt A type) isochron age of 5824 ± 140 years B.P. (n = 6) (Supplementary Table 2, Supplementary Fig. 9b). This isochron shows an exceptionally high initial ²³⁰Th/²³²Th atomic ratio = 527.5 ± 22.1 ppm, more than 10x higher than used for DR-D15 (44 ppm) from the same cave but at a different elevation²¹. The fluffy fibrous cotton-candy texture of the two sub-samples with high U component of DR-D23 may have something to do with the high initial ²³⁰Th/²³²Th. The isochron ages were necessary to produce accurate ages with smaller uncertainties.

Collectively, the POS data from Genovesa and the nearby Drac, reveal three distinct periods of relative sea-level stability (Fig. 2). One occurred at 0 ± 0.04 m from 2720 ± 11 to 296 ± 18 years B.P. The second period lasting from 3703 ± 14 to 3368 ± 8 years B.P., corresponds to a sea level of 0.25 mbpsl. Lastly, a third period at ~1.1 ± 0.1 mbpsl is documented between 5820 ± 140 and 5479 ± 120 years B.P. (Figs. 2, 3). By adding the uncertainty to the older age and subtracting the uncertainty from the younger age, the maximum time span of POS growth at 1.1 mbpsl ranges from 5964 – 5359 years B.P. During this interval, both the POS and the coloration mark formed. For the latter to develop, the bridge must have been submerged, at least to its upper surface, allowing calcite to precipitate during the sea-level stillstand. Therefore, this period is of particular interest because it may aid in providing the timeline of the bridge construction as detailed below.

Timing of bridge construction
The assembly date of the bridge in Genovesa Cave remains uncertain due to the absence of written records or a robust time-stratigraphic context. In order to constrain the building time of this archeological structure, we rely on a well-defined Late Holocene sea-level curve generated by Onac et al.²¹. for Mallorca (depicted by the solid blue line in Fig. 3) and the ages and depths at which POS grew and coloration mark formed. First, we assess previous assumptions regarding the timing of the submerged bridge construction using this curve. Then, we examine our new sea-level data in conjunction with the timing of the earliest human arrival model proposed by Bover et al.¹⁴.

The prehistoric pottery discovered in Sala de les Rates-pinyades of the Genovesa Cave has been linked to the Naviform period (3550–3000 cal B.P.). This attribution is based on typological similarities between the ceramics found in Genovesa and those documented at the Closos de Can Gaià, a Bronze Age site located ~10 km south of our cave (Fig. 1b). The archeological horizon in which comparable pottery was discovered at the latter site was dated to ~3600 cal B.P30. However, Costa and Guerrero31 argue that Closos de Can Gaià excavation required a reassessment of the chronological framework, due to issues with the radiocarbon dates. Despite this, adopting the previously reported radiocarbon age, Gràcia et al.²⁰ suggested that the construction of the bridge likely occurred toward the end of the Naviform period.

However, the RSL curve (Fig. 3) indicates that sea level was ~0.25 ± 0.1 m below the preindustrial baseline ~3500 years ago²¹, implying a total water depth of ~1.3 m in the cave lake. The vertical height of the bridge is 0.5 m, and thus it was submerged by 0.8 m of water at this time (Fig. 3). The construction of the bridge around 4400 years ago, the time suggested by Bover et al.¹⁴ to be the earliest evidence of human presence on the island, is also improbable. At that time, relative sea level in Mallorca was ~0.35 ± 0.1 m below preindustrial level, and the bridge would have been submerged by 0.7 m. Building a bridge below water level is a highly unlikely scenario, and thus it was likely built at an earlier time, when sea level was lower. The predicted relative sea-level curve for Mallorca (Fig. 3) indicates that the top of the bridge would have been close to water level no earlier than 5600 years ago and this provides an approximate lower bound on the age of the feature. The distinct coloration mark on the bridge also provides strong evidence of an age greater than the ages estimated by Gràcia et al.²⁰ and Bover et al.¹⁴. As discussed earlier and according to the POS-based relative sea-level record, this mark would not have developed if the top of the bridge was well below the water level, i.e., at times more recent than ~5500 years ago. However, an age older than 6000 years for the feature can be ruled out since sea level was even lower (Fig. 3), and the construction of a bridge at its current height would have been unnecessary.

Fig. 3: Proposed timing for bridge construction.

Comparison between the position of the submerged bridge, phreatic overgrowth on speleothems (POS), coloration mark, and the RSL prediction (blue curve)²¹ based on a Glacial Isostatic Adjustment model that uses the ICE-6G (VM 5) ice history with an upper mantle viscosity of 1.3 × 1020 Pa s. Solid symbols with age and depth uncertainties represent POS elevations. The brown rectangle depicts the bridge with its coloration band in the upper part. The insets show an underwater image of the bridge (Photo courtesy of R. Landreth) and a close-up view on the RSL position of samples GE-D6, GE-D7, and DR-D23 that grew at 1.1 mbpsl. The uncertainties for GE-D6, GE-D7, and DR-D23 are absolute 2 σ error bars based on three dimensional isochron ages or weighted average (GE-D7). The dotted blue line is a sea-level rise scenario that includes the brief stillstand inferred from the POS growth.

The phreatic overgrowths GE-D6, GE-D7, and DR-D23 from Genovesa and Drac caves formed at a relative sea level of 1.1 mbpsl, which is 5 cm below the upper part of the bridge. The two more precise isochron ages suggest sea-level remained relatively constant for a few hundreds of years between ~5964 and 5359 years B.P. The relative brevity of this time frame might explain why the morphology and size of the POS are somehow atypical and smaller compared to those POS that developed when the sea level was stable at 0 m for over 2000 years. Furthermore, this <600 year period of nearly constant sea level was sufficient to develop the coloration mark. Given that the occurrence of this feature correlates directly with the previously mentioned sea-level stillstand position, it suggests that the bridge was already in place. In fact, its construction could have commenced as early as ~6000 years ago when the water depth in the lake was ~0.25 m. However, it had to be completed before ~5600 years ago when the sea-level rose to the top surface of the bridge.

Onac, B.P., Polyak, V.J., Mitrovica, J.X. et al.
Submerged bridge constructed at least 5600 years ago indicates early human arrival in Mallorca, Spain. Commun Earth Environ 5, 457 (2024). https://doi.org/10.1038/s43247-024-01584-4

Copyright: © 2024 The authors.
Published by Springer Nature Ltd. Open access.
Reprinted under a Creative Commons Attribution 4.0 International license (CC BY 4.0)

Lots of stuff for creationists to lie about there. Firstly, there is the record of sea-level changes reflecting the advance and retreat of ice sheets over the past few tens of thousands of years.

Then there is the record of human habitation and construction of the bridge when creationist mythology says the world was subject to a genocidal flood in which all life was extinguished save a small handful of survivors that then repopulated the planet in just a few thousand years.

What a creationist now needs to do is explain why all the dating methods, which converge on these dates, are all wrong and should be converging on a much more recent date compatible with creation of Earth from nothing just 10,000 years ago and all human life originating from 8 related individuals just 4,000 years ago.

Sadly, because the authors of these myths knew nothing of the real history of the Western Mediterranean, the book they wrote, and which creationists think is a real history book, is entirely silent on the matter.