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MATIENZO CAVES PROJECT
Reports. Papers and Presentations
Feedback reports
The following pdf files are provided as annual feedback reports for the Consejería de Educación, Cultura y Deporte and the Federación Cántabra Espeleología. The files start at 2012 when the FCE required a pdf file in addition to a paper printout. Larger surveys may be accessible through links in the pdf files. In previous years, printed reports included different page sizes for the larger surveys.
(Annual reports have also been produced for the (now defunct) BCRA publication Speleology (formerly Caves & Caving) since 1980.)
2012

low resolution : high resolution

2013 Castellano : English
2014 Castellano : English
2015 Castellano : English
2016 Castellano : English
2017 Castellano : English
2018 Castellano : English
2019 Castellano : English
2020 Castellano : English

Presentations & Papers This section was started in 2014. All known publications about Matienzo Caves Project sites are listed in the bibliography. Some documents relating to areas and sites beyond our historical and current permit areas can be found here.
2014 Los sistemas kársticos entre Arredondo y Matienzo presented at the 25th Scientific Conference of SEDECK (La Sociedad Española de Espeleología y Ciencias del Karst) in Ramales on September 29th by Phil Papard and Peter Smith.
PowerPoint presentation in Castellano (6Mb) and English (5Mb).
Matienzo 2013-2014 talk at Hidden Earth, Leek on September 29th by Diane Arthurs, Lloyd Cawthorne and Steve Martin. PowerPoint presentation authored by Phil Papard. Also included in the talk were video snippets from BigMat Calf Hole and Sima-Cueva del Risco.
PowerPoint presentation (25Mb).
Speleobiology in the Cantabrian Mountain karst massif of northern Spain presented at the 25th British Cave Research Association Cave Science Symposium on Saturday 25th October 2014 at the School of Geography, Earth and Environmental Sciences, University of Birmingham by Tom Thomson and Fergus McBurney. (This is part of the Matienzo Karst Entomology Project.)
Symposium programme notes.
PowerPoint presentation. (32Mb)
Millennial scale control of European climate by the North Atlantic Oscillation from 12,500 BP: The Asiul speleothem record. Andrew Smith presented this paper at the 25th British Cave Research Association Cave Science Symposium on Saturday 25th October 2014 at the School of Geography, Earth and Environmental Sciences, University of Birmingham.
An abstract is found on page 143 of Cave & Karst Science 41(3), 2014.

From Top to Bottom: a comprehensive study of the prehistoric pottery in Cave 3167 (Matienzo, Cantabria, Northern Spain). This paper by Peter Smith, Miriam Cubas, Juan Corrin, Jesús Tapia, Imanol De Pedro, Jesús Ruiz Cobo and Eva Mª Pereda Rosales was published in MUNIBE (Antropologia-Arkeologia), 2014, No. 65. The paper is available here.
Abstract
Although techniques for the characterisation of archaeological material enjoy a long tradition in Europe, they have been less influential in Spain, particularly in the Cantabrian region. This may be one reason why, in this region, the traditional approach to the study of prehistoric pottery has prevailed over the use of new methodologies, which require the application of technological (mineralogical, geochemical etc.) and functional analytical techniques (for example, gas chromatography) or the study of post-depositional alterations. However, an integral study of this kind of evidence is able not only to approach an understanding of ceramic assemblages but also to propose interpretative hypotheses contributing to the formulation and development of new research projects.
   In the present study, pottery is seen as a product within a sequence of operations transforming raw material into the final recipient. In this process, the final product may possess very different physical-chemical properties from the original material. In accordance with this approach, the technological, morphological and functional study of the pottery assemblage from Cueva 3167 in Seldesuto (Matienzo, Cantabria) applied different methods, from macroscopic description to techniques of mineralogical (petrography and X-ray diffraction) and functional characterisation (gas chromatography). The study succeeded in determining a series of characteristics of the storage urns, a pottery type widely documented in Cantabria from the third millennium cal BC. It covers such aspects as the raw materials used to make the urns, the way the fabric was prepared and the firing conditions and temperature, as well as the age determination of one of the urns and information about how the archaeological record formed.
   This site is located practically at the summit of the ridge between the valleys of Matienzo and Arredondo in eastern Cantabria, at 673m above sea level. It is a small cave where several groups of sherds were located in the first twelve metres of the passage, which is less than a metre high. The main concentration consisted of pottery fragments in situ, just as the recipient had been abandoned, upside down in the middle of the passage. The base of the vessel was not recovered, which may indicate that the urn had been placed in an inverted position because the base had already been lost.
   Macroscopic observation of the sherds determined that they belonged to a minimum of four recipients, differentiated by their technological, morphological and decorative traits. Thin section observation of the fabric revealed that it had been mostly tempered with grog between 0.5 and 1.5mm in size. X-ray Diffraction analysis showed the high proportion of illite in the clay fabric. The recipients were fired at a low temperature, possibly lower than 800ºC. The presence of idiomorphic quartz, epidotes and even gypsum in one of the samples suggests that the raw materials were related to Triassic deposits, the nearest of which are located several kilometres from the cave site. A thermoluminescence determination established a chronology of 2832-1820 BC for the main urn, which is coherent with the ages obtained for similar vessels in the same area.


2015 Drip water electrical conductivity as an indicator of cave ventilation at the event scale is a paper by Andi Smith et al documenting more research information from Cueva de Asiul (site 61).
Due to copyright, the paper (pdf) can be downloaded from the ScienceDirect site until August 8th 2015 and then may be available from the Matienzo website 2 years later.
Abstract
The use of speleothems to reconstruct past climatic and environmental change through chemical proxies is becoming increasingly common. Speleothem chemistry is controlled by hydrological and atmospheric processes which vary over seasonal time scales. However, as many reconstructions using speleothem carbonate are now endeavouring to acquire information about precipitation and temperature dynamics at a scale that can capture short term hydrological events, our understanding of within cave processes must match this resolution. Monitoring within Cueva de Asiul (N. Spain) has identified rapid (hourly resolution) changes in drip water electrical conductivity (EC), which is regulated by the pCO2 in the cave air. Drip water EC is therefore controlled by different modes of cave ventilation. In Cueva de Asiul a combination of density differences, and external pressure changes control ventilation patterns. Density driven changes in cave ventilation occur on a diurnal scale at this site irrespective of season, driven by fluctuations in external temperature across the cave internal temperature threshold. As external temperatures drop below those within the cave low pCO2 external air enters the void, facilitating the deposition of speleothem carbonate and causing a reduction in measured drip water EC. Additionally, decreases in external pressure related to storm activity act as a secondary ventilation mechanism. Reductions in external air pressure cause a drop in cave air pressure, enhancing karst air draw down, increasing the pCO2 of the cave and therefore the EC measured within drip waters. EC thereby serves as a first order indicator of cave ventilation, regardless of changes in speleothem drip rates and karst hydrological conditions. High resolution monitoring of cave drip water electrical conductivity reveals the highly sensitive nature of ventilation dynamics within cave environments, and highlights the importance of this for understanding trace element incorporation into speleothem carbonate at the event scale.
Matienzo 2015 PowerPoint presented by Steve Martin on 26th September at Hidden Earth 2015, authored by Phil Papard. Video snippets were also included from BigMat Calf Hole , Carcavueso molephoning and Not Too Bad Pot
Poster about the Matienzo Karst Entomology Project presented at Hidden Earth 2015 by Tom Tompson and Fergus McBurney.
A paper detailing the finds and conclusions of a 2010 archaeological study in Cueva de Barandas (Smith, Ruiz Cobo & Corrin)
Abstract
The archaeological site of Cueva de Las Barandas was discovered in 1982, when the pottery, metal and human remains were attributed to the Iron Age. No further studies were made of the site until 2010 when permission and funding was applied for and awarded from the Culture, Tourism and Sport Department of the Government of Cantabria. The archaeological remains were studied in situ and pottery and bone samples were taken for dating. The results indicate the cave was used in the first millennia before and after Christ.

Cave monitoring and the potential for palaeoclimate reconstruction from Cueva de Asiul, Cantabria (N. Spain)
A paper by Smith A.C., Wynn P.M., Barker P.A., Leng M.J., Noble S.R. and Stott A, published in the International Journal of Speleology, 45 (1), 1-9. Tampa, FL (USA) ISSN 0392-6672. The full paper can be read here.

Abstract
Palaeoclimate records from northern Iberia are becoming increasingly sought after as this region is one of the most southerly terrestrial locations in Europe to have its climate dictated principally by the North Atlantic. Terrestrial records therefore have the potential to offer insights into changing oceanic and atmospheric circulation in the wider North Atlantic region. Cave speleothems offer one of the most promising archives from northern Iberia due to their wide geographic distribution and potential for accurately dated climate reconstruction. Cueva de Asiul, situated in Cantabria (N. Iberia; 43°19'0.63''N, 3°35'28.32''W; 285 m.a.s.l) within the Matienzo karst depression is one such site that offers the potential for palaeoclimate reconstructions. Here we present three years of climate and cave monitoring from Cueva de Asiul, giving detailed insight into local meteorology, hydrology and cave ventilation dynamics. In doing so, this paper presents a background to high resolution, Holocene duration speleothem records which have been extracted from this cave. Annual average cave temperatures are +13.7°C, with a maximum range of 1°C, reflecting the seasonality of external air temperature (average external temperature +13.8°C). Cave ventilation is controlled by changes in external air temperature and variations in external air pressure during low pressure events. Local rainfall measurements show an average of 1400 mm/year with the majority of rainfall occurring during the winter, with periods of water excess between October and April. Speleothem drip rates are characterised by summer lows and a rapid transition to higher rates at the onset of the winter season. Stable isotope analysis (δ18O, δ2H) indicate that aquifer water is derived predominantly from the previous year's rainfall and the rainfall feeding the karst system is controlled by a strong amount effect. Speleothems from this site are potentially suited to preserving extended records of rainfall amount in northern Spain and therefore have the potential to inform more clearly about Holocene scale changes in the rainfall source region, the North Atlantic.


A blog by Laura Deeprose on the continuing work in Cueva de las Perlas, reconstructing palaeoclimate through the demise of the Neanderthals.
2016 Although not produced by people associated with the Matienzo Caves Project, the following two publications may have some relevance for cave development in the area:
- from Elsevier (Marine and Petroleum Geology) Characteristics, genesis and parameters controlling the development of a large stratabound HTD body at Matienzo (Ramales Platform, Basque - Cantabrian Basin, northern Spain)". The authors identify a large hydrothermal dolomite (HTD) body in Matienzo and discuss its characteristics - the "sandy limestone" often referred to by Matienzo cavers over the years.
- also from Elsevier (Sedimentary Geology) Hydrothermal dolomite - a product of poor definition and imagination". Perhaps the second should be read before the first!
North Atlantic forcing of moisture delivery to Europe throughout the Holocene   Another paper by Andi Smith about the paleoclimate work in Cueva Asiul (site 0061). This one is in nature.com/scientific reports (http://www.nature.com/srep/2016/160420/srep24745/full/srep24745.html) where it can be viewed online or downloaded as a pdf.

Abstract
Century-to-millennial scale fluctuations in precipitation and temperature are an established feature of European Holocene climates. Changes in moisture delivery are driven by complex interactions between ocean moisture sources and atmospheric circulation modes, making it difficult to resolve the drivers behind millennial scale variability in European precipitation. Here, we present two overlapping decadal resolution speleothem oxygen isotope (δ18O) records from a cave on the Atlantic coastline of northern Iberia, covering the period 12.10ka. Speleothem δ18O reveals nine quasi-cyclical events of relatively wet-to-dry climatic conditions during the Holocene. Dynamic Harmonic Regression modelling indicates that changes in precipitation occurred with a ~1500 year frequency during the late Holocene and at a shorter length during the early Holocene. The timing of these cycles coincides with changes in North Atlantic Ocean conditions, indicating a connectivity between ocean conditions and Holocene moisture delivery. Early Holocene climate is potentially dominated by freshwater outburst events, whilst ~1500 year cycles in the late Holocene are more likely driven by changes internal to the ocean system. This is the first continental record of its type that clearly demonstrates millennial scale connectivity between the pulse of the ocean and precipitation over Europe through the entirety of the Holocene.

    EuroSpeleo 2016 was held in August at Dalesbridge, Austwick and the Matienzo Caves Project had a week-long presence at this international event.
   Over eight days, Matienzo - 50 Years of Speleology books and other publications were sold along with Matienzo Caves clothing - all from a stand which displayed maps, surveys, photos and some of the IT applications used within the Matienzo Caves Project.
   Matienzo Caves Project (117Mb download) was a talk and PowerPoint presentation by Juan Corrin about the 56 years of expeditions - 138 of them - and the top 10 caves.
   Laura Deeprose presented a talk on her ongoing paleoclimate work in Cueva de las Perlas - "Caves, climate change and Neanderthals: ongoing palaeoclimate research in Matienzo"
   Andi Smith displayed a poster entitled: "12,000 years of rainfall history revealed by stalagmite deposits from Cueva de Asiul".
   An A3 landscape survey of Cueva de las Injanas received a Merit Award in the Survey Salon for innovative use of QR codes to link with photos and videos.

A volume produced by the Cantabrian Government, edited by Gustavo Sanz Palomera, contains summary articles about archaeological work allowed by permits from the Consejería de Educación, Cultura y Deporte. Entitled Actuaciones Arqueológicas en Cantabria, 2004 - 2011, it contains 10 articles with Matienzo connections:

- Smith Peter. Recogida de sedimento de la cueva Cofresnedo (Matienzo, Ruesga) para el análisis de ADN. pp 63 - 64.
- Ruiz Cobo Jesús. El yacimiento de la sima El Torco de Cubija (Matienzo, Cantabria). pp 142 - 146.
- Smith Peter y Cubas Morera Miriam. Excavación y análisis de la cerámica prehistórica en la Cueva 3167 de Seldesuto (Matienzo, Ruesga). pp 147 - 154.
- Smith Peter, Ruiz Cobo Jesús y Corrin Juan. Estudio y datación absoluta de los restos ósesos y cerámicas de la cueva sepulcra de Las Barandas (Matienzo, Ruesga). pp 166 - 170.
- Hierro Gárate José Ángel y Gutiérrez Cuenca Enrique. Proyecto Mauranus 2010. Toma de muestras de materiales arqueológicos. pp 212 - 223.
- Hierro Gárate José Ángel y Gutiérrez Cuenca Enrique. Proyecto Mauranus 2011. Intervención arqueológica en al cueva Riocueva (Entrambasaguas). pp 224 - 231.
- Smith Peter, Etxeberría Francisco, Martínez de Pancorbo y Cardoso Sergio. Recogida de los restos de neonatos de la cueva 2741 de Matienzo (Ruesga, Cantabria). pp 291 - 295.
- Ruiz Cobo Jesús. La prospección arqueológica del medio Asón: municipios de Ampuero, Rasines y flanco occidental de Ruesga. pp 316 - 320.
- Ruiz Cobo Jesús. La prospección arqueológica del Bajo Asón. pp 327 - 330.
- Smith A, Wynn Peter M y Baker P, 2016. Registros de alta resolución del cambio climático, conservados en espeleotemas en Matienzo (Cantabria), en el norte de la Península Ibérica. pp 375 - 379.

Descent 253, December / January 2016-17 contained three articles relating to the Matienzo Caves Project:
- A short piece (on page 7) outlined the speleological activities of Alasdair Neill (1960 - 2016)
- An article by Tony Radmall and Paul Fretwell about Paul Dold (1973-2016), his life and caving
- An article by Tom Thomson outlining the past and future work of the Matienzo Karst Entomology Project


The "cave of the femurs", site 3153 or El Cubío del Escalón in the Vega valley was first found in 2009. The definitive publication about the archaeological work in the cave has now (December 2016) been published in MUNIBE Antropologia-Arkeologia no. 67.
La cueva sepulcral calcolítica del Cubío del Escalón (Matienzo, Cantabria) y el modelo de las pequeñas cuevas sepulcrales en Cantabria by Peter Smith, Jesús Ruiz Cobo, Anabel Sanz, Lourdes Herrasti, Ignacio Castanedo Tapia and Juan Corrin. The full article can be downloaded.

Abstract
   Cubío del Escalón is the name of a small cave in the polje of Matienzo, Cantabria, north Spain. A small number of human remains were discovered there by the caving expedition in 2009 and four years later permission was obtained to carry out an archaeological excavation to recover these remains and others as the site was clearly being disturbed by badgers. The excavation recovered remains from a number of squares marked out in the final part of the central passage and in small spaces to the side. Sectors in Squares C and D had to be lowered to allow access to the spaces F and G, where many of the best preserved bones were recovered. These were generally in loose sediment containing stones, plant matter and animal excrement. However, a few bones were found in compact cemented sediment against the passage walls, where they had not been disturbed by the badgers. The anthropological study determined that these remains belonged to a minimum of six individuals, five adults and a child. Despite the poor state of conservation of most of the bones, it was possible to identify signs of osteoarthritis on a femur and rib. Other cuts and fractures are attributed to the post-depositional damage suffered by the remains. A small assemblage of pieces of flint, pottery and faunal remains is not particularly diagnostic and cannot be explained as grave goods with any certainty. A radiocarbon determination of a fibula yielded a date of 3645 ± 35 BP.
   This site can be included within a certain model of burial cave frequently used in later prehistory in Cantabria. Archaeological surveying in the Saja, Miera and Asón valleys in the region has studied 121 burial sites attributed to the Chalcolithic and Bronze Age. It has established that the mean width of the entrances of these caves is 3.5m and over 50% of them have entrances of under 2.5m width. In most cases, the inhumations took place in small passages. In this way, they differ from the sites used for non-funerary purposes, which often have entrances over 5m in width. It is possible that small caves were used because they would be easier to seal off, and in fact some of these entrances were covered by large boulders at the time of their discovery. El Escalón is thus comparable with other similar small burial caves excavated in the Camargo area, also in Cantabria, although these contained a greater wealth of grave goods, including arrowheads and ground stone axes. However, at the same time, within a diversity of funerary practices, large caves were also in use, with the burials often situated in small chambers to the side of the main passage. In any case, it is clear that the known total number of inhumations would represent a very small percentage of the population at that time.

2017 A very quiet year for publications and talks. There was no talk at Hidden Earth in September but Juan Corrin delivered a short (18 minute) lecture (with PowerPoint) as part of A Golden Age of Cave Exploration and Science, celebrating 50 years of pioneering British cave exploration and science, 1st - 4th December at the Royal Geographical Society, London.
A YouTube channel, "A Golden Age of Cave Exploration and Science" holds videos of all of the talks presented. 
The Matienzo Caves talk is found in the list of Sunday Lectures. ( https://www.youtube.com/watch?v=85KRcxjZwiY )
All the talks can be found here:https://www.youtube.com/channel/UCkKeWp08_lX6c7yk4l1JaxQ
Anyone else who wants to give this talk (or just to view it) can download the files (including a script) here.
2018

Descent 260, February / March 2018 has a short article on page 9, Farewell 'Squirrel' Wood.


2020 The current uses of QGIS in the Matienzo Caves Project were summarised by Juan Corrin in an illustrated article in the CREG Journal 109, March 2020, pages 6 - 10.
Juan also contributed to a lead article by Mike Bedford in Practical Wireless magazine (Vol 96 No 9 September 2020) that detailed the use of various underground communication and location devices including Ron Taylor's sub-phones and Bob Machin's molefone. The successful use of the sub-phone in first locating another entrance to Llanío and then aiding the link between the cave and the 4 Valleys System was highlighted.

Due to the Covid-19 situation, Tom Thomson delivered a talk about the Matienzo Karst Entomology Project (MKEP) on Zoom to a large, international audience. This was part of the 2020 BCRA Science Symposium on 12th November. (The seminar information below also appeared in Cave & Karst Science 48:1, April 2021)

Abstract

Speleobiology in Northern Spain: The Work of the Matienzo Karst Entomology Project.
Tom Thomson1,2,4,5 Amata Hinkle 3,5 Fergus McBurney 2
1 Department of Entomology, Natural History Museum, Cromwell Road, London, SW75BD.
2 The Invertebrate Conservation Trust, The Lindens, 86 Lincoln Road, Peterborough PE1 2SN
3 Wealden Cave & Mine Society.
4 Wessex Cave Club.
5 British Cave Research Association.

Correspondence to Tom Thomson: (t.thomson@nhm.ac.uk)

The Matienzo Karst Entomology Project (MKEP) is an independent research initiative that has worked within the international caving and academic communities to study the fauna of the caves in the Matienzo depression and the surrounding Cantabrian karst of Northern Spain. Prior to MKEP, virtually no formal scientific work had been carried out to study this specific karst massif to identify or collect species data. The first phase of the project began in 2014 with the support of the British Cave Research Association (BCRA) with the aim to build an initial overview of the ecological and geographic significance of the area. This has since progressed to several targeted field seasons investigating specific cave sites and species communities via both short and long term trapping of fauna underground. Gathering of environmental data, recording behavioural observations and habitats traits have also greatly added to the ecology context of the species discovered and their place in the trophic structure. Sub-projects to study specific species started in 2018, and now include in-depth observations of individual taxa via electron microscopy, defining micro habitats within key cave sites, and classification of cohabitation ranges by cave topography, illumination variance, and environmental factors such as of airflow, temperature, and humidity.

Acknowledgments:
MKEP has been a large collaboration and the authors would like to thank the following for research collation and identification of taxa: Pete Smithers and Jane Ackerman of Plymouth University, Max Barclay of the Natural History Museum (BMNH); for the funding, material, and support from the British Entomology & Natural History Society (BENHS), British Cave Research Association (BCRA), and Oxford University Department of Zoology. In addition, MKEP would like to thank the members of Matienzo Caves Project for their support.


Matienzo Caves Project 2010 - 2019, an A4, 518-page volume was published at the end of the year. Edited by Juan Corrin and translated into Spanish by Carolina Smith de la Fuente, the back cover blurb summarises:

Cavers have been exploring and documenting caves around Matienzo, in Cantabria, since the 1960s. There are now over 5000 sites of speleological interest ranging from small, draughting holes to the 67km-long Four Valleys System. This dual language book covers the last 10 years of exploration, 2010 - 2019, and is fully illustrated with maps, cave surveys and photos. More than 30 authors and 80 photographers have contributed, providing in-depth accounts of the explorations and scientific investigations, including palaeo-climate research, cave life, cave diving and archaeology updates, personal reminiscences and a full account of the expeditions' work over the decade.

Espeleólogos han explorado y documentado cavidades alrededor de Matienzo, en Cantabria, desde la década de 1960. En la actualidad hay más de 5000 cavidades de interés espeleológico que van desde pequeños agujeros sopladores hasta el Sistema de los Cuatro Valles de 67 km de desarrollo. Este libro bilingüe recoge los últimos 10 años de exploración, 2010-2019, y está ilustrado con mapas, topografías y fotos. Han participado en él más de 30 autores y 80 fotógrafos, proporcionando descripciones detalladas de las exploraciones e investigaciones científicas, desde estudios paleoclimáticos, la vida en las cuevas, espeleobuceo a arqueología, recuerdos personales y una crónica completa del trabajo de las expediciones a lo largo de la década.


Further details can be found here.
2021 Over a couple of years, Dr Peter Wynn, Andy Quin and Scott Ambler have collected samples for a study of nitrogen levels in water, mud and stal in Cueva-Cubío del Llanío (site 3234).
The concluding science paper was published by Peter Wynn et al in Chemical Geology (Elsevier) in April 2021, Titled "Contemporary systematics of vadose zone nitrate capture by speleothem carbonate", the paper concludes that nitrate trapped in stal forms a good historical and on-going record of levels of nitrate above and below ground. The potential for measuring changing nitrate pollution in karst areas is obvious. A link to the paper should be available until May 22nd 2021.

Contemporary systematics of vadose zone nitrate capture by speleothem carbonate

P.M. Wynna, S. Amblera, I. Grefea, D.X. Sotob, B.W.J. Surridgea, R.I. Gabitovc, P.A. Barkera, J. Anward, A. Quina, M.G. Pereirab, H.K. Grantb

a Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
b UK Centre for Ecology and Hydrology, Lancaster LA1 4AP, UK
c Department of Geosciences, Mississippi State University, Mississippi State, MS 39762, United States
d Department of Chemistry, Lancaster University, Lancaster LA1 4YB, UK

Abstract
   The movement of nitrate through the vadose zone has major implications for environmental and human health. This issue is particularly prevalent in karst terrain where agricultural activity, thin soils and dual permeability compound the problem of high nitrate loading to the overlying ecosystem. However, a paucity of records which document vadose zone nitrate concentrations prior to the 21st century render legacy nitrate dynamics, source attribution and baseline conditions to be poorly parameterised. Speleothems growing within karst cave settings may provide an opportunity to obtain records of vadose zone nitrate contamination which extend throughout the anthropogenic era.
   Here, we use dual isotope analysis of δ15NNO3 and δ18ONO3 in a contemporary study at Cueva-cubío del Llanío, N. Spain, designed to examine the transformation of nitrate between surface to cave environment, taking account of biogeochemical transformation, karst hydrology and partitioning as controls on the delivery of nitrate to the speleothem record. Concentrations of nitrate within speleothem calcite are low (measured range of 0.05 mM to 0.37 mM) due to partitioning (DNO3) across the dripwater-calcite interface. Values of δ15NNO3 extracted from cave waters in Cueva-cubío del Llanío (range +2.0 to +7.0‰) are shown to be excellent indicators of nitrate source and demonstrate no fractionation during incorporation into speleothem carbonate (range of δ15NNO3 in speleothem carbonate +1.6‰ to +6.4‰). Values of δ18ONO3 contained within cave waters (range -2.5‰ to +6.0‰) and speleothem carbonate (range +12.3‰ to +32.3‰) reflect a mixed signal of source, biogeochemical processing and hydrological pathway, providing critical insight into the behaviour of the karst aquifer.
    Contemporary systematics at Cueva-cubío del Llanío therefore confirm speleothem carbonate contains an excellent record of vadose zone nitrate. Analysis of nitrate contained within speleothem carbonate from other regions confirms the ubiquitous nature of partitioning across the water-carbonate interface and the use of speleothem nitrate isotopes for recording surface ecosystem processes and vadose zone behaviour. Application of these principles to dated speleothem records should provide critical timeseries of nitrate loading, enabling understanding and remediation against the presence of vadose zone legacy nitrate.

Conclusion
The potential for speleothem carbonate to accurately record signals of vadose zone nitrate which extend prior to the era of groundwater monitoring is dependent upon understanding the impact of biogeochemical cycling, karst hydrological dynamics and partitioning, upon signal integrity. Within cave waters, measurements of δ15NNO3 demonstrate source characteristics of input nitrogen to be well preserved throughout the soil and epikarst biogeochemical cycle. Values of δ18ONO3 within dripwaters provide a deeper insight into biogeochemical processing and hydrological dynamics, highlighting the importance of atmospheric nitrate deposition entering directly through the karst without prior biogeochemical modification. Both biogeochemical cycling and hydrological dynamics work in concert to determine the characteristics of dripwater nitrate entering into the cave system. Across the dripwater-contemporary carbonate interface, partitioning controls the concentration of nitrate incorporated into the speleothem record in a quantifiable manner and the speleothem isotopic record seems unaffected by fractionation between phases. δ15NNO3 within speleothem carbonate is thus deemed an excellent indicator of source, whilst δ18ONO3 within carbonate provides a sensitive indicator of karst hydrological dynamics and biogeochemical processing. On the basis of nitrate isotope systematics established within contemporary speleothem calcite, application to age-constrained records which extend throughout the anthropogenic era promise an exciting development in the ability to trace vadose zone pollution dynamics. Of specific interest is the ability to establish a baseline pollution status to contextualise current levels of nitrate inputs, to determine nitrate retention (legacy) dynamics through the direct comparison of input records and speleothem concentration profiles, and the opportunity to trace inputs to source using stable isotopes. Parameterisation of vadose zone nitrate dynamics in this way is also important for the refinement of karst hydrological models which are currently in a limited state of development for the prediction of nitrate groundwater quality within karst.
Speleobiology in Northern Spain: The Work of the Matienzo Karst Entomology Project.
The Abstract and Acknowledgements for this seminar, delivered November 2020 (see above), appeared in Caves & Karst Science, 48:1, April 2021.
Latest update 14th May 2021