Deciphering Clastic Cave Deposits

Convenors: Ira Sasowsky (University of Akron, USA)

Description: Clastic sediments in caves can originate from fluvial, lacustrine, glacial, periglacial, incasion, aeolian, corrosional, and biologic (including anthropogenic) processes. These deposits are more problematic to decipher and date than speleothems. Yet they hold critical information about early phases of speleogenesis, climate, and regional paleohydrology that may be unavailable from other archives. Application of techniques such as paleomagnetism and cosmogenic isotope measurement has allowed determination of conditions going back beyond 6 Ma. The main challenges faced are the discontinuity of many deposits, and the uncertainty of regional fidelity. This session welcomes presentations on all aspects of the deposition, description, and interpretation of clastic deposits in karst settings, with an emphasis on their utility as recorders of environmental conditions. Novel archives and approaches, and especially linkages to the speleothem record, are of special interest. 

Karst Records of Climate Variability on Orbital Timescales

Convenors: Ana Moreno (Pyrenean Institute of Ecology, Spain) & Valdir Novello (University of São Paulo, Brazil)

Keynote: Heather Stoll (ETH Zurich, Switzerland)

Description: Terrestrial paleoarchives have revealed pronounced environmental changes throughout the Quaternary due to climate oscillations modulated by orbital variability. Karst records, in particular speleothems, represent important paleoclimate archives that record the timing of these orbital-scale climate oscillations and shed light on the mechanisms that drive them. The high quality of U-Th ages in terms of accuracy and precision has allowed the investigation of leads, lags and synchronicity during global climate events as documented in speleothems and other archives over the last  ~640,000 years. In addition, recent improvements in U-Pb dating provide the opportunity to go deeper into the past. We invite studies that present insights into timing, phases, amplitude and mechanisms of past climate variability over orbital timescales using different proxies and archives from karst systems (speleothem, sediments, tufa, and travertine). 

Millennial-Scale Records

Convenors: Haiwei Zhang (Jiaotong University Xi'an, China) & Nicolás M. Stríkis (University of São Paulo, Brazil)

Description: Millennial-scale climate shifts (e.g., Dansgaard-Oeschger cycles) are one of the most notorious features of glacial climate, affecting the temperature and the hydrological regime of tropical and subtropical areas during the glacial cycles of the Pleistocene. Centennial-scale climate shifts in the Holocene (e.g., 8.2 ka BP and 4.2 ka BP events) have also been identified in many regions, and some authors suggest that these events significantly affected human civilizations. Benefiting from U-Th dating and a worldwide distribution, speleothems have yielded climate records from different key climate areas during the late Pleistocene, providing highly-precise timing and high-resolution structures of abrupt climate changes. This session invites contributions presenting new records of millennial- or centennial-scale climate shifts, including but not limited to those featuring temperature, precipitation, sea level, and monsoon intensity, from speleothem, tufa, and travertine archives. We welcome studies investigating the timing, phases, amplitude and mechanisms of these climatic changes across the Pleistocene and Holocene.

From Decadal to Seasonal Resolution: Speleothem Records on Human Timescales 

Convenors: Gayatri Kathayat (Jiaotong University Xi'an, China) & Ian Orland (University of Wisconsin, USA)

Keynote: Ashish Sinha (California State University Dominguez Hills, USA)

Description:  The temporal resolution of speleothem paleoenvironmental proxy records has increased in tandem with steady improvements in the spatial resolution and precision of geochemical analytical techniques. As a result, speleothems are now an important source of records of environmental change on human timescales. Such records are critical for three broad themes of scientific study: 1) understanding the timing and atmospheric dynamics of past climate change, 2) calibrating the rate and magnitude of future climate change, and 3) studying the effects of past environmental change on human history. We invite abstracts that leverage decadal-or-better temporal resolution of speleothem geochemistry in order to address any of these three topics. Contributions that integrate multiple climate proxies, or include model, archaeological, historical or instrumental data are particularly welcomed.

Geochemical Modelling and Laboratory Experiments

Convenors: Denis Scholz (University of Mainz, Germany) & Adam Hartland (University of Waikato, New Zealand)

Description: The increasing number of high-resolution speleothem proxy records and detailed cave monitoring programs highlight the complexity of the processes affecting speleothem proxy signals. In particular, processes occurring in the soil and karst above the cave as well as inside the cave during precipitation of speleothem CaCO3, have for a long time been considered as generating “noise” superimposing the climate signal contained in the δ 18O values of the rainfall and drip water. In the recent decade, however, major progress has been achieved in quantitative modeling of the processes affecting speleothem proxy signals both in the karst and the cave. These models are not only useful to improve the understanding of a particular cave system, but also to test the general potential and limitations of speleothems for reconstruction of specific climate phenomena. In some cases, they may even allow us to relate karst and in-cave processes to surface climate and eventually utilize them for palaeoclimate reconstruction. All models require isotope fractionation factors and element distribution coefficients specifically determined for speleothems, which do not necessarily grow under conditions of stable isotope equilibrium. For this session, we welcome contributions on: quantitative descriptions of processes occurring in the soil and karst above the cave as well as during precipitation of CaCO3, and; laboratory experiments aiming to determine isotope fractionation factors and element distribution coefficients.

Data-Model Integration for a better understanding of Past Climatic and Environmental Dynamics

Convenors: Laia Comas-Bru (University of Reading, UK) & Kira Rehfeld (University of Heidelberg, Germany)

Keynote: David McGee (MIT, USA)

Description: Paleoclimate proxies and climate models constitute two contrasting and yet complementary sources of information on past climates. Both approaches independently generate insights into the dynamics of the climate system. However, more information can be extracted about the drivers of climate variability and change when the two approaches are combined. Climate proxy data can be used to constrain and evaluate model simulations, while climate models can be used to explore the mechanisms that have driven past climatic changes. Palaeoclimate data–model comparisons can also be used to assess model performance, to constrain projections of future climate change, or to study the drivers of climate variability and change. Here we invite abstracts that integrate speleothem records and isotope enabled climate models and/or karst models; data-model comparisons (including isotope enabled models or local calibration studies); studies that use speleothem records to evaluate climate models or studies that use climate model outputs to understand the physical controls of speleothem variability (δ18O, δ13C or trace elements). We also encourage submissions on proxy system models and their tuning.

Cave Monitoring

Convenors: Pauline Treble (ANSTO, Australia) & Carol Tadros (ANSTO, Australia) 

Description: An understanding of the processes that control the speleothem geochemical record is essential for the development of climate and other environmental proxies. This is particularly important for locations where processes may be site specific. Cave monitoring is one approach that enables direct measurement of the environmental parameters controlling stable isotope, radiogenic and trace elements in cave waters and farmed calcites. This approach has previously revealed the impacts of cave microclimate and karst hydrology on the speleothem record. More recently, cave monitoring studies have also contributed to our understanding of nanoparticles and colloids in karst systems, the role of aerosols and soils, and the impacts of vegetation and fire on the speleothem record. Long-term studies have the potential for monitoring the hydrogeochemical response to climate change, as well as providing datasets for data-model comparisons that enable the development of speleothem forward models that are of benefit to the broader paleoclimate community. We invite contributions to this session that provide new initiatives and updates on long-term studies, novel findings, and other applications of cave monitoring data.

Methods and Technical Developments in Speleothem Science

Convenors: Nele Meckler (University of Bergen, Norway) & Franziska Lechleitner (University of Oxford, UK)

Keynote: Hagit Affek (Hebrew University of Jerusalem, Israel)

Description:  Speleothems have been used as climate and environmental archives over many decades, but their full potential as multi-proxy, quantitative archives has not yet been explored. As the field expands, however, an exciting array of new approaches is becoming available, such as biomarker or DNA studies, ultra-high resolution methods, and novel isotope systems. In addition, continuing improvements in U-Th and U-Pb dating are allowing increasingly precise and accurate age control. With these techniques, new insights can be gained, including the re-assessment of more traditional methods, steps towards quantification of speleothem palaeoclimate records, and the reconstruction of previously elusive environmental processes with more confidence. This session welcomes all contributions that extend our toolbox for deciphering climate and environmental changes from speleothems, by developing and/or testing novel methods, improving existing methods, or re-assessing more traditional approaches. 

Ice Caves

Convenors: Marc Luetscher (Swiss Institute for Speleology and Karst Studies, Switzerland) & Maria Leunda (Pyrenean Institute of Ecology, Spain)

Description: Perennial ice caves are visual indicators of sporadic permafrost and, thus, represent valuable end members for studying present and past heat exchanges in karst systems. Understanding the dynamics of these caves is fundamental for the interpretation of the paleoenvironmental record of cave ice, which may extend over several millennia. Proxy-records from cave ice have been revealed to be complementary to other karst records, enabling detailed investigations in relation to past climate and environments before a complete waning of this unique archive. In addition, evidence for the former presence of cave ice deposits may also represent a precious indicator of past permafrost distribution. This session welcomes any contribution dealing with the presence of modern and past cave ice deposits and their contribution to environmental reconstructions.

Cave Records of Human History

Convenors: Dirk Hoffmann (University of Goettingen, Germany)

Keynote: Robyn Pickering (University of Cape Town, South Africa)

Description: Caves played a significant role in human (pre)history and today many caves are home to important archaeological sites. We find evidence for past human presence in cave environments, mainly in the entrance areas, but sometimes also in deeper parts of the caves, where remains of human activities are often captured in sediments that accumulated inside or outside caves. Excavations at such cave sites yielded, for example, human bones, tools or portable art and provided important insights into human evolution and prehistory. Prehistoric cave paintings or engravings inside caves are further examples for evidence of early human behaviour. 

Speleothems can serve as constraints to interpret archaeologically relevant materials. For example, age constraints for archaeological excavations or artefacts can be obtained by dating associated speleothem formations. Furthermore, speleothem records of environmental variability can provide important information about boundary conditions for human activities. This session invites presentations on cave records in an archaeological context. The focus of the session is on speleothem research, but we also welcome presentations in related fields like rock shelters, dolines or travertine / tufa formations.

Open Session

Convenors: Jeff Munroe (Middlebury College, USA) and Andrea Columbu (University of Bologna, Italy)

Description: Surface and underground features in karst regions are rich records of past climatic and environmental changes.  This session will showcase the diverse array of studies focused on these records. A partial list of relevant topics includes sea level fluctuations, river incision and base-level oscillations, hydrology and floods, palynology, microbiology, paleontology, petrography and mineralogy, speleogenesis, and the evolution of karst landscapes. There is essentially no restriction on the methods, the archive, or the type of study, as long as it diverges from “classical” paleoclimate time-series based on clastic, speleothem, or cave ice proxies.  Multi-disciplinary approaches and novel techniques are strongly welcomed.  



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