Deep in the heart of the Borneo rainforest lies one of South-east Asia most important natural sites: the of Sarawak, Malaysia. Despite being home to one of the most diverse tropical rainforests on the planet, arguably the world heritage area most astonishing feature lies underground.

The caves of the Gunung Mulu National Park

Under the limestone ridge of Gunung Api lies the extensive Clearwater cave system. At over 260 km in length and with passages often exceeding 30 m in diameter, it is believed to be the world largest cave system by volume, and is a haven for local wildlife.

The nearby Deer Cave is home to an estimated three million wrinkle-lipped bats, which fly out of the cave each evening to feed, creating a stunning visual display. Cave swiftlets also fly many kilometres into the Clearwater cave system to make their nests, which are prized as a local delicacy and used to make bird nest soup. Lying in wait to try and catch them as they fly past are cave racer snakes, whilst an astonishing array of cockroaches, millipedes, crabs, crickets and spiders are sustained by the piles of guano (bat poo) that line the cave floor. The ecosystem featured in a series.

History of the caves

Caves are fantastic repositories of geological and archaeological data, preserving information that would otherwise be lost to surface erosion and degradation. They and the deposits they contain hold clues to past landscape change, allowing us to reconstruct how the Earth’s surface has changed over millennia.

The caves were first explored as part of a Royal Geographical Society expedition in 1978. Working in collaboration with the Sarawak Forestry Corporation and the national park, the has been exploring, surveying and undertaking research in the caves ever since. This includes caving expeditions led by Andrew Eavis, a veteran of the 1978 expedition.

Dating of stalagmites and cave sediments indicates the Mulu caves are up to three million years old. Other analysis of cave stalagmites has yielded a climate record spanning hundreds of thousands of years, whilst volcanic ash provides evidence of a massive volcanic eruption in the Philippines 189 000 years ago. More recent archaeological finds also provide evidence of human activity and burials in some of the caves.

Recent research within this incredible cave system led to a surprising discovery about the formation of the caves within it.

Unusual dissolution

One of the unusual aspects of the Mulu caves is the way the cave passages have been sculpted.  Most caves in the region are formed by the dissolution (dissolving or break down) of limestone by acidic water, primarily from rivers flowing through the cave. The action of flowing water on the limestone rock creates small asymmetrical scoops etched into the passage walls, called scallops. These are preserved on the passage walls even after the formative river has abandoned the passage, as the water finds new, lower routes through the rock. The scallops are of interest to scientists as they can be used to deduce past water flow, providing a record of how water flowed through the caves over time.

In the Clearwater cave system, typical scallops are present in the lower levels of the cave system, close to the present river. However, in the older, higher levels of the cave system, which have long since been abandoned by the river, they are strangely noticeable by their absence, having been dissolved away and replaced by unusual corroded and pitted rock architecture.

The passage walls are frequently eroded into small dissolution pots and coated with a weathered crust: analysis has shown these are composed of calcium phosphate minerals, which is highly unusual in caves. Corroded stalagmites are common, dissolved away like rotten teeth to reveal their internal growth rings. These features suggest some form of atmospheric dissolution of the passage walls and stalagmites has taken place in the time since the passage was abandoned by the underground river.

Comparison with other caves suggests these features are generally restricted to tropical cave systems. One of the key aims of recent Mulu expeditions has been to understand how these features form and why. A team of researchers led by BGS geologist Dr Andrew Farrant, cave microbiologist Prof Hazel Barton (University of Alabama), her PhD student J Max Koether and BGS isotope geochemist Dr Andi Smith set out to investigate what may be happening.

Caving and exploration

Undertaking cave research can be hard work. Sampling trips into a cave system over 250 km long takes time and, in some cases, involved making camp underground. It is hard, sweaty, sometimes muddy work, occasionally requiring ropes to climb up pitches or descend vertical drops. But the rewards are enormous: the caves are spectacular, with stunning formations, huge chambers and amazing biota.

The Clearwater streamway is probably one of the finest cave passages in the world. Not only is there the prospect of new scientific discoveries, but also the chance to explore new cave passages where no human has ever trodden. On one trip, the team crawled through a flat-out squeeze to emerge into an undiscovered chamber over 200 m long, 70 m wide and 50 m high (big enough to hold two Airbus A380 jets) and adorned with 20 m-high stalagmites.

Research

Complex ecosystems are a distinctive feature of tropical caves, driven by the daily input of guano from bats and swiftlets. Bats create large piles of pungent excrement beneath their roosts, whilst the swiftlets’ guano is dispersed more widely, sometimes kilometres into the caves. The teams’ initial hypothesis was that the guano was somehow implicated in creating the unusual dissolution forms and smooth walls seen in the caves. Initial analysis of the guano piles in the caves indicated that they are strongly acidic, comparable to stomach acid or lemon juice, with a pH as low as 1.9. This could account for dissolution beneath the guano pile, but not the pervasive dissolution features seen throughout the caves.

Further work on the microbiology of the guano showed that microbial breakdown of urea (from bats) and uric acid (from birds) generates significant quantities of ammonia and carbon dioxide, which are released into the cave air. Measurable plumes of ammonia can be detected in some caves; could this be responsible for the unusual features?

Attention turned to the weathered ‘paste’ seen on many passage walls. This turned out to be teeming with microbial life, in some places containing a higher microbial cell count than cultured yogurt. Analysis of condensation water droplets on the cave walls revealed extraordinarily high levels of nitrate (up to 7000 mg/l; for comparison, the UK drinking water standard is 150 mg/l), whilst drips feeding the stalagmites had little or no nitrate.

These observations suggest that ammonia released into the cave air by the microbial decay of bat and bird guano adsorbs onto water droplets on the passage walls and stalagmites. Here, microbes use the ammonia as a food source, producing nitrates, nitric oxide, nitrogen dioxide and nitric acid as byproducts. This acid dissolves the passage walls and stalagmites, removing the original dissolutional scallops and replacing them with a suite of biogenic dissolution features. It is estimated that, in some places, several metres of dissolution have occurred in just a few tens of thousands of years: geologically speaking, this is a very short time period.

Further work is ongoing to learn more about the microbial processes that occur within the guano and on the cave walls. The discovery of this novel mechanism of cave development has significant implications, such as how we interpret past environments from caves, the preservation of cave art, and the impact of this acidic environment on ropes and other caving equipment.

The great thing about the Mulu Caves Project expeditions is they have enabled us not just to explore new caves, but to do some amazing science too. One thing is clear from our work in the caves; the surface and underground environments are inextricably linked. There is much we still have to discover and one wonders what other secrets are waiting to be discovered beneath Gunung Api…

Publication

Our research has been recently published in the journal Geomorphology.

Farrant, A R, Koether, J M, Barton, H A, Lauritzen, S E, Pennos, C, Smith, A C, White, J, McLeod, A, and Eavis, A J. 2025. . Geomorphology, Vol. 483, 109822. DOI: https://doi.org/10.1016/j.geomorph.2025.109822

Thanks                 

Thanks go to Andrew Eavis and members of the Mulu Caves Project, the Sarawak Forestry Corporation and the Gunung Mulu National Park management and staff, without whom this work would not have been possible. Part of the research was funded by a NEIF steering committee grant to Andi Smith.

About the author

Chalk: a shared geology

The Upper Cretaceous-aged (commonly known as ‘the Chalk’) is perhaps Europe most iconic geological unit. Besides forming the famous white cliffs, the Chalk:

• is a major aquifer, supplying millions of people with drinking water and sustaining rare ecological habitats
• is important for energy as it hosts oil and gas reservoirs in the North Sea, provides the foundation for offshore wind farms and hosts numerous shallow geothermal-energy schemes
• has the potential act as storage for hydrogen and CO2
• is a raw material for cement
• hosts many major civil engineering and infrastructure schemes across northern Europe including, in the UK alone, the recently approved Lower Thames Crossing, HS2, the Channel Tunnel and the new ‘super sewer’, the Thames Tideway Tunnel in London

Yet the Chalk is also one of the most misunderstood geological units. It is a common misconception that it is a uniform rock unit with very little structure or faulting. In reality, it has significant variations in physical properties and is often faulted.

Recent geological mapping in the Chilterns and Yorkshire Wolds, undertaken by BGS in collaboration with the Environment Agency and water companies, has shown how geological discontinuities in the Chalk affect groundwater flow. These discontinuities facilitate the development of dissolutional conduits and rapid flow pathways, creating a very heterogenous aquifer. This heterogeneity generates major challenges for the water industry, civil engineers and planners.

As an aquifer, the Chalk is under pressure, both in terms of water quality and resource. The demand for water, especially in more populated areas of southeast England is increasing, but there is also a need to protect rare chalk stream habitats and maintain river flows. Climate change, drought and contaminants such as nitrate exacerbate the problem. Addressing these issues require a greater geological understanding of the aquifer and how groundwater flows it.

These challenges aren’t just restricted to the UK: France has similar problems in the extensive chalk outcrops across the north of the country, as do the Netherlands, Denmark and Belgium.

Current research

A good understanding of the Chalk Group is needed to better predict groundwater flow and engineering ground conditions. This requires good quality geological maps and 3D models fit for the 21st century, using all the available information including field data, geophysical borehole logs, geophysical surveys and biostratigraphical data. In the UK, geological maps used to show the Chalk Group with just three subdivisions; we now divide the chalk into nine individual mappable formations, reflecting their differing engineering and hydrogeological properties. These more detailed maps are able to show much more geological structure, and are more relavent to engineers and hydrogeologists.

Recent groundwater modelling in BGS work has focused on building the national scale British Groundwater Model, simulating groundwater flooding, and projecting the impact of climate change on chalk streams and public water supplies. Other geological surveys are also modelling groundwater, for example, to investigate the impacts of nitrate and other contaminants on the chalk aquifer.

Likewise, more detailed understanding of the Chalk Group has helped civil engineers better predict ground conditions on major infrastructure projects. For example, BGS maps and models help identify zones of weak faulted ground that might be an issue for tunnelling or road cuttings. Similarly, BGS helped characterise flint content in the Chalk in the Thames Estuary to help design cutting heads for the Lower Thames Crossing tunnel-boring machines. Lessons learned from major projects in the UK can be equally applied in northern France and vice versa.

Common problems: common solutions

A key remit of geological surveys and research institutions is to work to find solutions to geological problems. BGS has teamed up with other northern European geological surveys and research institutes to discuss common interests in the Upper Cretaceous Chalk. Twenty-eight participants from 13 different research institutions and geological surveys, including geologists, hydrogeologists, biostratigraphers and engineering geologists, gathered for the inaugural in the town of Étretat on the French coast. Étretat hosts spectacular chalk cliffs and rock arches made famous by the painter Claude Monet. These amazing outcrops admirably demonstrate how variations in the Chalk influence the local hydrogeology and cliff stability.

Outcomes

Exactly how does the Chalk vary across northern Europe? Many productive discussions were had during the workshop and several common themes were identified. Key to understanding the variability of the chalk is the application of a unified Chalk Group stratigraphy, so variations and changes in rock properties across the Anglo–Paris basin can be better understood and predicted.

Another area of common interest is the development of karst features in the chalk such as sinkholes, dissolution pipes, caves and dissolutional conduits. These are important not only from a hydrogeological perspective, but also as an engineering hazard. The French geological survey, BRGM, has been leading the way here, undertaking numerous tracer tests and identifying sinkholes across Normandy. A similar approach is being taken by BGS, learning from the French.

A third area of interest is incorporating lithological variability and karst into groundwater models. At present, many groundwater models treat the Chalk as a single porous medium, often modelled as just one or two layers. This ignores much of the complexity within the group. Much discussion was had on how to best approach modelling groundwater in the Chalk at a range of scales.

Next steps

This first meeting generated a huge amount of interest and enthusiasm. The next steps are to translate this into concrete actions. Essential to this is identifying potential funding sources for common projects, such as stratigraphical correlations across the Anglo–Paris basin. A special issue on Chalk Group stratigraphy in a relevant journal is another possibility.

Another workshop is being planned for 2026, either in Maastricht or in south-east England.

Thanks

Thanks to Ophélie Faÿ (University of Mons) and Eric Lasseur (BRGM) for organising the event.

About the author

Dr Andrew Farrant is a geologist and karst geomorphologist based at the BGS. He is the Regional Geologist for Southeast England and has extensive experience mapping the Chalk across southern and eastern England.

As part of our NERC ‘Exploring the frontiers’ grant, Dr Peter Wynn of Lancaster University and I have been out undertaking fieldwork in the Matienzo valley in northern Spain. The Matienzo valley is a fantastic karstic depression; it over two million years old and contains hundreds of kilometres of natural cave systems. Beyond its fantastic history of use as a repository for scientific data, the region is also heavily used by recreational cavers and cave explorers.

Our current work is focused on a small cave system called Llanio, just outside the main Matienzo karst depression. The work aims to develop a novel method for extracting cave speleothem (stalagmite) formation temperatures.

Cave temperatures

Caves have stable annual temperatures, only fluctuating within one degree over the annual cycle. This stable temperature reflects the average external annual temperature very accurately. For this reason, the development of a palaeothermometer from speleothem carbonate has been something of a ‘holy grail’ for palaeoclimate scientists over the last 50 or more years.

The entrance to Llanio involves a flat-out crawl for several metres before some more small passages lead into the larger sections of the cave, where our water and speleothem sampling takes place. This spring, the crawl was made even worse than normal as the entrance had numerous large spiders in residence and the remains of some unidentifiable animal that we had to crawl over on both the way in and way out of the cave!

Inside the caves

Once we entered the cave, we had an excellent and productive research trip. We were able to collect numerous water samples and extract the phosphate from them using an in-cave chemical extraction method. The data from these samples will be compared to what we would expect at the known cave temperature. We also collected some already-broken calcite, which we will dissolve later back in the BGS Stable Isotope Facility.

Further work

All these samples will be collated with samples that have been sent to us from collaborators from around the world, to see if we can use our new method to develop a reliable cave palaeothermometer in the BGS laboratories.

About the author

Dr Andrew Smith

Located on the border of Derbyshire and Nottinghamshire, is an enclosed limestone gorge surrounded by woodland, meadows and a lake. It has many caves and fissures containing prehistoric fossils and artefacts and is an area of interest to many scientific communities. The Victorians first discovered ancient artefacts in the cave sediments in the 19th century and, since then, scholars have been excavating the caves to answer pressing palaeontological and archaeological questions, and recreating fascinating stories of life during the last ice age, between 50 000 and 11 700 years before present (BP). 

The Cresswell Crags Museum

The objects excavated from the caves at Creswell Crags and from the wider Creswell Heritage Area are stored in the Creswell Crags Museum, which holds a collection of nearly 40 000 objects, approximately 80 per cent of which are bones. The palaeontological collection is composed of subfossils that date back to the late Pleistocene (125 000 BP) and include the remains of a large range of mammal, bird, amphibian, fish and mollusc species.  

In addition to being used for exhibition display, the fossils from Creswell Crags Museum collections are used for research purposes. BGS is currently collaborating on one such research project, the NERC-funded ‘Nature of the beast’, with Prof Danielle Schreve at Royal Holloway, University of London. The project is investigating past and present diets of European wolves. 

Why are we studying wolves and their diet? 

Wolves are one of the northern hemisphere top predators, keeping populations of their prey in check and positively influencing overall biodiversity through their activities. However, the wolf (Canis lupis) is an endangered species in Europe and concerns exist as to the viability of European wolf populations as environmental and climate conditions change. The overarching aim of the ‘Nature of the beast’ project is to assess the effect of forcing factors such as changes in climate, environment, the prey community and carnivore competition on the feeding behaviours of wolves. 

One of the best ways to investigate the adaptability of any animal, including wolves, is through the study of their dietary behaviour. Diet is closely linked to climate and environment, which determine the available prey species and which predators are competing for resources on those same landscapes. This project employs a multi-proxy approach that combines dental microwear texture analysis, isotope analysis, cranio-dental morphology and analysis of scat to reconstruct wolf diets from the late Pleistocene and throughout the Holocene (the current warm period). 

Dental microwear texture analysis

Dental microwear textural analysis (DMTA) is a way of investigating features on the biting surface of teeth. DMTA uses three-dimensional technology to image the tooth surface, which can be measured with specialised software in an unbiased way that is independent of human observer errors. Once measured, tooth surface features can show the extent to which carnivores are consuming meat or processing carcasses more fully, in other words, assessing the flesh-to-bone ratio of their diets.  

One way to think about how we analyse dental microwear is to consider animals that populate the extremes of the carnivore dietary behaviour continuum today. For example, the spotted hyena consumes a lot of bone as part of its natural behaviour; on the other hand, the cheetah primarily consumes flesh and prefer fresh kills.

Wolves fall on this spectrum somewhere between hyenas and cheetahs, and are known to flex their diet according to their surroundings. Observations from modern wolves have shown that they do consume some bone and prefer greasy, less dense, marrow-rich bones. Dental microwear studies of modern and ancient wolves confirm this dietary behaviour.

However, when unable to access their preferred prey species (likely due to limited prey availability in their surroundings) wolves scavenge more intensively, resulting in dental textures that indicate elevated amounts of bone in their diet. Scavenging is part of the flexible dietary behaviour of wolves, which is reflected in their dental microwear and can inform our understanding of past environmental conditions, such as the size and availability of prey species.  

Initial project results  

A key goal of this research is to understand how wolves have adapted to changing circumstances in the past, so that current and future conservation policy can be appropriately tailored. Preliminary results have shown that, when temperatures were colder, the dental microwear of wolves indicates high flesh consumption. Inversely, when temperatures were warmer, wolves increased scavenging behaviour (consuming more bone). 

Creswell Crags Museum collections hold fossil bones of wolves dating back 40 000 years. Some of these fossils were discovered due to a rock fall near the Dog Hole cave in 1978, along with bones of a diverse range of other animals including lynx, cow, horse and wild boar. They have since been used to provide evidence of a complex sequence of prehistoric animal occupation within the area. 

Three individual wolves have been analysed for dental microwear and represent one glacial and one interglacial period. The results from Creswell Crags will be combined with data collected from other museum fossils across the UK, including the collection housed at BGS, and spanning the entirety of the late Pleistocene to the Holocene.  

About the authors

Dr Diksha Bista

Dr Angela Lamb

Dr Amanda Burtt (Royal Holloway, University of London) 

(Creswell Crags Museum and Heritage Centre) 

Prof Danielle Schreve (Royal Holloway, University of London)

Karst results from the dissolution of rocks and is usually associated with cave systems and landscapes characterised by rocks sculpted by dissolution, large surface depressions, disappearing rivers and major springs. However, karst processes occur in all soluble rocks, resulting in high vulnerability to pollution. The BGS karst reports provide an overview of the evidence of karst in different regions of England with Cretaceous chalk or Jurassic or Permian limestone geology, where karst is less well known.

The next BGS karst report is now available, covering the . This is not an area that has been considered karstic in the past and there are no known karst caves that can be explored. It is certainly very different from the karst of the Carboniferous-aged limestones of the nearby Mendips, where classic karst features such as Cheddar Gorge and Wookey Hole cave are found.

Karst in the Wessex Chalk area

However, there is a surprising amount of evidence for karst in the rocks of Wessex, with many streams that disappear into the chalk via karstic solution features as well as large springs where water from karst networks is discharged. The karst networks are made up of solutional conduits (voids) that are too small for humans to explore but which nonetheless enable rapid flow of water in the subsurface. This has important implications for pollutant movement and the protection of groundwater resources and ecosystems.

Tracer tests in the area have shown that water can travel at velocities of almost 5 km/day over distances of several kilometres. This is very fast for groundwater and similar to the sorts of flow velocities that are seen in classic karst.

The new report provides an overview of the geomorphological and hydrogeological evidence for karst in this area with maps showing the distributions of karst features.

Other BGS karst reports

51ÁÔÆæ has , including a report on karst in the Jurassic of northern England, where there is substantial cave development and large karst river sinks. Tracer tests have revealed very rapid flow over long distances.

Another report, on karst in the Jurassic limestones of central England, documents many karst stream sinks, with tracer tests demonstrating rapid flow over long, complex flowpaths that cross river catchments.

The karst reports on the chalk of the Chilterns and the North Downs also show strong evidence for karst, for example with many stream sinks associated with the Cretaceous/Palaeogene margin. Stream sinks in this setting are also detailed in the report on the South Downs chalk area, where coastal surveys provide further insights into karstic caves and conduits. 

Overall these reports are building a picture of the importance of karst in aquifers that were previously not considered karstic due to their low levels of cave development. They provide a resource for hydrogeologists and others interested in the nature of these unusual karst aquifers that provide vital water resources and sustain rivers and wetlands.

More information

Find more information on .

Contact

Email Andy Farrant (arf@bgs.ac.uk)

New research has thrown fresh light on what scientists understand about the role of karst in the aquifer, which provides public water supplies to millions of people, agriculture and industry, and sustains vital habitats. A study led by BGS, published in the Geological Society of London Special Publication SP517, The Chalk Aquifers of Europe, has compiled evidence showing that karst and rapid groundwater flow are much more widespread in the Chalk than previously thought.

The study will be of particular interest for regulators and water companies, both globally and in the UK, when planning future approaches to groundwater source protection and catchment management. Existing research shows that globally, around 20 to 25 per cent of people rely on karst groundwater for supply.

What is karst?

‘Karst’ is a geomorphological term that is applied to a type of landscape where erosion caused by dissolution, in other words the dissolving of bedrock, has resulted in fissures, sinkholes, sinking streams, ridges, caves, springs and other characteristic features. It is typically associated with soluble rock types such as limestone, marble and gypsum.

The Chalk is an unusual karst aquifer with limited cave development, but extensive networks of smaller solutional conduits and fissures that enable rapid groundwater flow. Small-scale karst features such as dolines, stream sinks, dissolution pipes and springs, are common.

This research is the culmination of many years work and is a step forward in our understanding of the Chalk aquifer. Our research presents evidence of the extent of karst in the Chalk throughout England, including almost 100 tracer connections demonstrating rapid groundwater flow.

We found high densities of stream sinks, and karstic conduits, springs, dolines and dissolution pipes are common.

We demonstrate that rapid groundwater flow and karst occur much more frequently than previously thought, which provides an important step forwards in our conceptual understanding of the Chalk and of global karst aquifers more generally.

Our work examines the implications of karst in the Chalk for groundwater protection and demonstrates how the evidence for karst should be central to future strategies for groundwater protection and management.

Louise Maurice, BGS Senior Hydrogeologist and lead author of the study.

Studying karst

Improved understanding of Chalk karst will expand understanding of similar karst aquifers with limited cave development that are globally widespread and provide vital public water resources to millions of people.

Such insights into the unique nature of Chalk karst may also help to advance understanding of classical karst aquifers, where major caves are often the main focus of research and fissures or smaller conduits are less understood.

The full study is titled . The work is funded by the NERC knowledge Exchange fellowship scheme.

Other work in the Geological Society of London special publication also highlights the importance of karst in the Chalk, including a further BGS-led study, .

As an MRes student at Lancaster University, my dissertation is looking at the phosphorus cycle within caves, especially using the oxygen isotope signature of phosphate (PO₄) to understand phosphorus cycling and its use as a palaeotemperature proxy.

Water in caves

Water that enters caves has travelled from the ocean, evaporated and precipitated as rain, moved through rivers and soils before percolating into the cave environment. Along the way, this water picks up dissolved nutrients including carbon (C), phosphorus (P) and nitrogen (N). These offer a wealth of scientific information. Under certain conditions, cave drip waters form calcite features such as stalagmites, much like those found in Poole Cavern in Buxton, Derbyshire. Similar to tree rings and ice cores, stalagmites incorporate a wealth of environmental information as they grow, building a ‘nutrient record’ layer by layer over time.

Why study phosphate?

Phosphate (PO₄) is a key component for microbiological function, including the formation of DNA. A metabolic process exists in many bacteria (pyrophosphatase hydrolysis) that swaps out oxygen within the PO₄ molecule with oxygen from cave drip waters. This process is controlled by the temperature at which the reaction occurs. This means that we can potentially back-calculate the formation temperature using the PO₄ oxygen isotope signature.

PO₄ is naturally found in some stalagmites and, because these stalagmites take many years to grow, they could hold a record of temperature locked up in their PO₄ that is tens of thousands of years old. However, this is all currently theory: we are still unsure exactly where the oxygen within PO₄ is exchanged or how and, whilst we believe this should take place near to or within the cave, this novel approach needs testing. These are the questions on which my research will focus.

The research method

Water is being collected from stalagmite drip sites and dosed with PO₄ within Poole’s Cavern. It is hoped that natural bacteria in the water will metabolise this PO₄, ‘locking in’ the oxygen isotope signature as a factor of temperature. The water will then be dripped onto glass plates to precipitate calcite (mimicking natural cave stalagmite formation), analysed for stable isotope composition at BGS and compared to cave temperature. By conducting the experiment at different temperatures, it is thought that an equation can be formulated that maps temperature versus PO₄ oxygen. If successful, a trend could be tracked through each layer that makes up the stalagmite, producing a temperature record though time without direct measurement.

Personally, I hope this experience will add significantly to the field of palaeoclimate research in caves and put me in better stead for a PhD studentship within the cave science field. 

About the author

Alistair Morgan is a masters by research (MRes) student at Lancaster University. His research is focused on understanding how phosphorous enters cave systems and if, as it is incorporated into stalagmites, it could be used to unravel past temperatures.