Skip navigation

You are in:  Home » Quaternary Discussion Group

Quaternary Discussion Group (QDG): archive

Return to the list of forthcoming seminars.

# Wednesday 21st February 2024, 5.30pm - Saija Saarni, University of Turku
Building doors are card operated, so latecomers may not be able to access the venue.
Microplastics from geologists' perspective
Venue: Small Lecture Theatre, Department of Geography, Downing Site

Abstract not available

# Wednesday 7th February 2024, 5.30pm - Eric Wolff, Department of Earth Sciences, and the WACSWAIN team
Building doors are card operated, so latecomers may not be able to access the venue.
The West Antarctic Ice Sheet and sea level in the last interglacial
Venue: Harker 2, Department of Earth Sciences, Downing Street

There is intense interest in the future stability of the West Antarctic Ice Sheet (WAIS). Models range widely in their predictions and in the physics they include. We can constrain possible outcomes by observing what happened to ice sheets at previous times when the polar regions were warmer than present. The last interglacial (LIG) is a particularly important time because both Greenland and Antarctic temperature were higher than present and so was sea level.

Within the WACSWAIN (WArm Climate Stability of the West Antarctic ice sheet in the last INterglacial) project, in 2019 we retrieved a 651 metre ice core to the bed of Skytrain Ice Rise. This ice rise is adjacent to the Ronne Ice Shelf and the WAIS, and therefore sensitive to their extent. The ice core has been processed and analysed continuously for a range of analytes, and we can show that ice from the LIG is present.

I will start by describing the project, fieldwork and analyses. Eventually, I will show what happened to the ice around Skytrain Ice Rise in the LIG, and discuss how this fits with other evidence about LIG sea level.

# Wednesday 29th November 2023, 5.30pm - Abi Stone, University of Manchester
Building doors are card operated, so latecomers may not be able to access the venue.
Pantastic archaeology in the northern Namib Sand Sea
Venue: Harker 1, Department of Earth Sciences, Downing Street

Abstract not available

# Wednesday 15th November 2023, 5.30pm - Gina Moseley, University of Innsbruck
Building doors are card operated, so latecomers may not be able to access the venue.
The Greenland Speleothem Record of Past Hydroclimate and Vegetation Changes
Venue: Harker 1, Department of Earth Sciences, Downing Street

Abstract not available

# Wednesday 18th October 2023, 5.30pm - Aidan Starr, Department of Geography
Building doors are card operated, so latecomers may not be able to access the venue.
The Pleistocene Evolution of the Antarctic Circumpolar Current: An Interglacial Perspective
Venue: Harker 1, Department of Earth Sciences, Downing Street

The Antarctic Circumpolar Current (ACC) is today the world’s largest ocean current, dominating the transfer of heat, salt, and tracers around the Southern Ocean. The ACC also helps to draw carbon-rich deep waters to the surface, prying open the window between the ocean interior and the atmosphere. In this talk, I will present a new 1.9 Million Year record of deep flow speeds at the northern edge of the ACC. Using this record as a proxy for the vigour/latitudinal position of the Subantarctic Front jet, I show that the ACC responds sensitively to climate forcing through the Pleistocene. In particular, I will focus on anomalously intense reorganisations of the ACC which occur during “super-interglacial” intervals, punctuating the glacial-interglacial pattern and providing potential clues into how Southern Ocean circulation might respond to ongoing and future warming.

# Wednesday 4th October 2023, 5.30pm - Kevin J. Edwards, SPRI, McDonald Institute & University of Aberdeen
Building doors are card operated, so latecomers may not be able to access the venue.
Vacuuming the Atlantic, Paepalology and getting things ‘wrong, wrong, wrong!’ – pollen tales from the archives
Venue: Harker 1, Department of Earth Sciences, Downing Street

Abstract not available

# Wednesday 14th June 2023, 5.30pm - Matthew Adeleye, Department of Geography
Building doors are card operated, so latecomers may not be able to access the venue.
Understanding Aboriginal-constructed landscapes in SE Australia, the impact of colonisation, and implications for land management under changing climate
Venue: Large Lecture Theatre, Department of Geography, Downing Site

Abstract not available

# Wednesday 17th May 2023, 5.30pm - Andrea Manica, Department of Zoology
Building doors are card operated, so latecomers may not be able to access the venue.
Squaring the circle: a coherent reconstruction of past species responses from multiple lines of evidence
Venue: Large Lecture Theatre, Department of Geography, Downing Site

Abstract not available

# Wednesday 3rd May 2023, 5.30pm - Poppy Harding, University of Hertfordshire
Building doors are card operated, so latecomers may not be able to access the venue.
Holocene palaeoclimate reconstruction from a varved lake in East Anglia
Venue: Large Lecture Theatre, Department of Geography, Downing Site

Abstract not available

# Wednesday 15th March 2023, 5.30pm - Mark Sier, CENIEH
Building doors are card operated, so latecomers may not be able to access the venue.
The Hominin Sites Paleolakes Drilling Project (HSPDP): applications and challenges of paleomagnetism in human evolutionary studies
Venue: Large Lecture Theatre, Department of Geography, Downing Site

Abstract not available

# Wednesday 8th March 2023, 5.30pm - Lauren Davies, Department of Geography
Building doors are card operated, so latecomers may not be able to access the venue.
Constraining ash dispersal from historical eruptions
Venue: Large Lecture Theatre, Department of Geography, Downing Site

Abstract not available

# Wednesday 22nd February 2023, 5.30pm - Chris Day, University of Oxford
Building doors are card operated, so latecomers may not be able to access the venue.
North-West Saharan Holocene rainfall driven by interhemispheric temperature differences (with climatic and archaeological considerations)
Venue: Large Lecture Theatre, Department of Geography, Downing Site

There is abundant evidence of wetter conditions in the Sahara during the early- to mid-Holocene, but a paucity of high-resolution spatial and temporal rainfall reconstructions, which has impeded the robust understanding of climate and archaeology. North of 28oN there is a particular lack of rainfall records, which limits testing of the processes controlling climate change in the sub-tropics. I will be sharing the results (from students in my group) of stalagmite records from inland, north-west Sahara – south of the Atlas Mountains – which demonstrate peak increased rainfall between 8.7-4.3 kyr BP. The location, timing, and oxygen isotopes of this stalagmite growth, when compared to other records, demonstrate that subtropical rainfall continues after the decline of the West African Monsoon. We propose that this rainfall is driven by an increased North-South interhemispheric temperature anomaly, shifting the ITCZ northwards and increasing tropical-plume rainfall in the South of Atlas region. This rainfall supported a significant increase in the region’s population during the Neolithic. Improved habitability and increased recharge to rivers flowing south through the Sahara will have facilitated connections, during a key period in the development of land use and animal production.

# Wednesday 15th February 2023, 5.30pm - Willem van der Bilt, University of Bergen
Building doors are card operated, so latecomers may not be able to access the venue.
Stable Southern Hemisphere westerly winds throughout the Holocene until intensification in the last two millennia
Venue: Large Lecture Theatre, Department of Geography, Downing Site

Abstract not available

# Wednesday 30th November 2022, 5.30pm - Dr Marco Aquino Lopez, Department of Geography
Building doors are card operated, so latecomers may not be able to access the venue.
Embracing uncertainty: developing methods that take advantage of it
Venue: Large Lecture Theatre, Department of Geography, Downing Site

Abstract not available

# Wednesday 16th November 2022, 5.30pm - Dr. Thomas Bauska, British Antarctic Survey
Building doors are card operated, so latecomers may not be able to access the venue.
When did humans first alter atmospheric CO2? Constraining the Holocene CO2 conundrum with new ice core data
Venue: Large Lecture Theatre, Department of Geography, Downing Site

Abstract not available

# Wednesday 2nd November 2022, 5.30pm - Prof Markus Jochum, University of Copenhagen
Building doors are card operated, so latecomers may not be able to access the venue.
Dansgaard-Oeschger events and their impact on atmospheric carbon dioxide
Venue: Large Lecture Theatre, Department of Geography, Downing Site

Abstract not available

# Wednesday 19th October 2022, 5.30pm - Dr Amy McGuire, University of Leeds
Building doors are card operated, so latecomers may not be able to access the venue.
How high and how fast? Improving future predictions of long-term sea-level rise through studying the Last Interglacial
Venue: Large Lecture Theatre, Department of Geography, Downing Site

Abstract not available

# Wednesday 15th June 2022, 5.30pm - Dr. Daniel Veres, Romanian Academy, Cluj
Building doors are card operated, so latecomers may not be able to access the venue
Unravelling the legacy of 7000 years of metal pollution in south-eastern Europe
Venue: Large Lecture Theatre, Department of Geography, Downing Site
# Wednesday 8th June 2022, 5.30pm - Martin Werner, Palaeoclimate Dynamics, Alfred-Wegener-Institut
Building doors are card operated, so latecomers may be unable to access the venue
Examining glacial-interglacial climate changes by water isotope modelling efforts
Venue: Large Lecture Theatre, Department of Geography, Downing Site

Stable water isotopologues are among the key proxy data to study glacial-interglacial climate changes. A wealth of isotope data sets from numerous paleoclimate archives exists and allows us to examine Quaternary climate variations on a wide range of time scales. Climate models enhanced by stable water isotope diagnostics are successfully to interpret the various records in a quantitative manner. In this talk, I will give a brief introduction on the current state of water isotope modelling efforts in paleoclimate research. I will present recent research studies from Antarctica, the Southern Ocean, and other regions to discuss recent progress and remaining uncertainties of glacial-interglacial temperature reconstructions and further key Quaternary climate changes.

# Wednesday 25th May 2022, 5.30pm - Céline Vidal, Dept of Geography, University of Cambridge
Middle Pleistocene Tephrochronology in the Ethiopian Rift: implications for the paleoanthropological and paleoclimatic records
Venue: Large Lecture Theatre, Department of Geography, Downing Site

Abstract not available

# Thursday 5th March 2020, 5.30pm - Nick Scroxton (University College Dublin)
Integrating northern and southern hemisphere stalagmites: what they can tell us about tropical climate dynamics and civilization collapse at the 4.2 kyr event
Venue: Harker 2, Department of Earth Sciences, Downing Street

Abstract not available

# Thursday 6th February 2020, 5.30pm - Christoph Nehrbass-Ahles (University of Cambridge/BAS)
Abrupt CO2 release to the atmosphere under glacial and early interglacial climate conditions
Venue: Clare College (Latimer Room)

Abstract not available

# Thursday 23rd January 2020, 5.30pm - Russell Drysdale (University of Melbourne)
This is part I of a two part seminar dedicated to synchronising climate archives. Second talk is being given by Raimund Muscheler (Lund University): "Synchronising climate records via the cosmic ray signal in environmental archives"
Talk 1 of 2: Speleothem records of abrupt warming events during the last glacial period
Venue: Riley Auditorium, Clare College Memorial Court, Queens Road

Abstract not available

# Thursday 9th January 2020, 5.30pm - Raimund Muscheler (University of Lund)
This is part 2 of a two part seminar dedicated to synchronising climate archives
Talk 2 of 2: Synchronising climate records via the cosmic ray signal in environmental archives
Venue: Riley Auditorium, Clare College Memorial Court, Queens Road

Abstract not available

# Thursday 28th November 2019, 5.30pm - Nick McCave, University of Cambridge
Evading problems of IRD in palaeocurrent estimation: Glacial to Recent changes in flows around Greenland
Venue: Clare College (Latimer Room)

Abstract not available

# Thursday 21st November 2019, 5.30pm - Thomas Laepple, Alfred Wegener Institute
Beyond mean climate change:  Using paleoclimate archives to better constrain climate variability.
Venue: Clare College (Latimer Room)

In order to adapt to the changing climate, not only changes in the mean state but also the magnitude and change of climate variability have to be known.
Whereas synoptic to interannual variations in the climate system are well documented and current climate models are generally able to simulate them realistically, much less is known about the amplitude and the mechanisms of climate variability on longer time-scales. Estimating that variability is the basis for the detection and attribution of the anthropogenic component, determines the range of plausible future climate changes and also provides information about the time-scales of the earth system components.

Paleoclimate archives such as ice-core and marine sediment records can provide the needed information about climate variability but are sparse, inherently noisy and and at times provide contradictory evidence. This hampered quantitative reconstructions of climate variability and systematic testing of the variability simulated from climate models.

In the last years, several advances have been made to better extract climate variability estimates from climate archives.
These include a better characterisation of the non-climate effects and the proxy response based on replicate, multi-proxy and core-top compilations,
proxy system models bridging the gap between climate and proxy variations as well as novel statistical techniques tailored to separate climate from noise components.
Based on these advances we were able to considerably improve our understanding of the present climate variability as well as to estimate how climate variability responds to a changing climate.
I will discuss recent advances in the toolbox of teasing out climate variability from marine and ice-core based proxy records and also point out future directions how to enhance the use of the paleoclimate record for quantitatively constraining present and future climate variability.

# Thursday 14th November 2019, 5.30pm - Paula Reimer, Queens University Belfast
The IntCal20 radiocarbon calibration curve - composition and consequences
Venue: Riley Auditorium, Clare College Memorial Court, Queens Road

Abstract not available

# Thursday 31st October 2019, 5.30pm - Joe McConnell, Desert Research Institute, current "Shackleton visiting fellow" at Clare Hall
Aerosols and Ancient History in Arctic and Alpine Ice
Venue: Clare College (Latimer Room)

Aerosol records developed from polar ice cores are powerful tools for reconstructing the timing and extent of natural and anthropogenic changes in Earth’s environment during past centuries to millennia. Recent analytical advances enable rapid development of accurately dated aerosol records of sea spray, windblown dust, biomass burning, volcanism, and industrial activities. Here we used high-depth-resolution measurements in an array of 13 ice cores to develop a 3000-year, sub-annually resolved record of Arctic lead pollution extending from the Iron Age to present, including European Antiquity, the Middle Ages, and the Modern Period. After describing the methods used to develop these unique pollution records, we discuss inherent uncertainties in these and all ice-core aerosol records, and interpret our records in terms of their historical implications. We also present the first Alpine ice record of lead and antimony pollution during Antiquity.

# Thursday 24th October 2019, 5.30pm - Cameron Petrie, University of Cambridge
Does climate change really cause collapse? Insights from the Land, Water and Settlement and TwoRains projects
Venue: Riley Auditorium, Clare College Memorial Court, Queens Road

Abstract not available

# Thursday 22nd November 2018, 5.30pm - Prof. Francois Primeau (University of California Irvine, USA)
Global Estimates of Marine Nitrogen Fixation based on a Non-Redfield Inverse Model
Venue: Latimer Room, Clare College

Abstract not available

# Thursday 1st November 2018, 5.30pm - Dr Mario Krapp (Department of Zoology)
A comprehensive climate history of the last 800,000 years and its application to ecological modelling
Venue: Cripps Meeting Room 3, Magdalene College

Understanding ecosystems and their evolution through the climate of the Pleistocene ice ages requires detailed palaeo-climate reconstructions.
Global climate models (GCM) are frequently used to explore the many diverse aspect of past climates. However, due to their high computational demand a continuous and spatially detailed exploration of the past remains elusive. In this talk, I will present a GCM emulator, which is based on climate snapshot simulations of the last 120ka, that allows us to reconstruct the climate of the last 800,000 years (and
beyond) in a quasi-continuous way. I will show how the predictive skill of the GCM emulator can be tested against existing Pleistocene climate proxies and I will present a few highlights of how such an emulator can be used for ecological modelling, for example, the dispersal of anatomically modern humans out of Africa.

# Thursday 18th October 2018, 5.30pm - Prof. Ulf Buentgen (Department of Geography)
Re-thinking the boundaries of dendrochronology
Venue: Cripps Auditorium, Magdalene College

Abstract not available

# Thursday 26th April 2018, 5.30pm - Denis-Didier Rousseau - Laboratoire de Meteorologie Dynamique & CERES-ERTI
Record of abrupt changes of last climate cycle in European glacial dust deposits
Venue: Bawden Room, West Court, Jesus College

This presentation is an overview to the project ACTES, supported by the French ANR, and previous projects I conducted on European loess sequences. The main aim was to study the record of abrupt climate changes, corresponding to the Dansgaard-Oeschger and Heinrich events, in European terrestrial records, especially loess sequences. Loess is an eolian material that can be considered in a first order as “paleodust”. This study was designed as a data-model comparison to investigate how these sequences recorded the DO events in a periglacial environment, how the dust was emitted and deposition occurred, and from which source zones.

Europe has been strongly impacted by the millennial climate changes related to variations in the sea-ice extent and therefore also affected the moisture sources of precipitation on the Greenland ice sheet. These variations in the extent of the sea ice during the last climatic cycle (LCC, about 130-15 kyr) impacted the westerlies and the position of the polar jet stream, and consequently storm track trajectories. Furthermore, the presence of ice sheets and ice caps over Great Britain, Scandinavia and the Alps enhanced the zonal circulation, as recorded by the European paleodust deposits located along the 50°N parallel.

Loess sequences are well developed all over Europe, but especially in the so-called loess belt between 48° and 52°N. Such intensive deposition of paleodust over Europe has been favored by the reduced arboreal cover (even practically absent in NW Europe during both GS and GIs, by sea-level lowering, exposing large areas of the continental shelves to eolian erosion, and by strong increases in fluvial transport and sedimentation by periglacial braided rivers. Extensive investigations of European loess series along a longitudinal transect at 50°N reveal that the millennial-scale climate variations observed in the North-Atlantic marine and Greenland ice-core records are well preserved in loess sequences. Among them, the Nussloch loess site yields an important record of the LCC although its paleosol-loess unit couplet succession is not unique, but observed with a variable thickness and a diverse nature of the paleosols in sequences ranging from Western Europe eastward to Ukraine over more than 1800 km.
Recent numerical simulations of the past global dust cycle for the first time included glaciogenic dust sources and, compared to earlier attempts, resulted in an improved performance when confronted to data available for the Last Glacial Maximum. Still, even the improved modeling failed to capture spatial and temporal dynamics of past dust deposition. We achieve recently a step increase in understanding sub-continental scale climate change by identifying dust sources and constraining dust residence time in the atmosphere. Using dust deposition over Europe during the last glacial cycle, geochemical fingerprinting, and numerical dust emission simulations we identify the main aerosol sources for different depositional areas. Dust was transported at low elevation and over regional distances only. The glaciogenic sources considered so far in climate modeling, like frontal moraines and outwash plains of the European ice-sheets, were of considerably less relevance for the global dust budget than proposed earlier. The main contributors were regions between 48°and 52°N, with variable hot spots depending on climate conditions. Loess units are interpreted to correspond to coarse paleodust transported at rather low elevations, in the active layer of the atmosphere (about 300 to maximum 3000 m) at regional to local scales, while finer paleodust deposited at high latitudes seems transported at much higher elevations.

A recent study raised the problem in correctly estimating the sedimentation (SR) and mass accumulation (MAR) rates of the sequences for comparison with model estimates, which cannot be estimated by just taking into account the whole thickness of the considered deposits as classically performed. To solve this issue, Greenland ice and northwestern European eolian deposits are compared in order to establish a link between GI and the soil development in European mid-latitudes, as recorded in loess sequences. For the different types of observed paleosols, the precise correlation with the Greenland records is applied to propose estimates of the maximum time lapses needed to achieve the different degrees of maturation and development. To identify these time lapses more precisely, two independent ice-core records are compared: d180 and dust concentration, indicating variations of temperature and atmospheric dustiness respectively in the Greenland area. This method slightly differs from the definition of a GI event duration applied in other studies where the sharp end of the d18O decrease gives the end of a GI. The same methodology is applied to both records (i.e., the GI last from the beginning of the abrupt d18O increase or dust concentration decrease until when d18O or dust reach again their initial value) determined both visually and algorithmically, and compare them to GI published estimates.

# Thursday 8th March 2018, 5.30pm - Barbara Maher, Lancaster University
Recent developments and debates in East Asian monsoon palaeoclimatology
Venue: Latimer Room (Old Court), Clare College, Trinity Lane

Quaternary rainfall reconstructions for the monsoon-dominated region of East Asia remain both of critical importance for testing general circulation model estimates of past and future rainfall for this populous region, and intensely debated. The oxygen isotope variations of the well-dated Chinese speleothem records have been very widely perceived as proxies of summer monsoon intensity and summer rainfall totals. Mass balance calculations demonstrate that extremely large changes in rainfall are required in order to generate the magnitude of oxygen isotope variations seen both within the Holocene and over glacial and interglacial timescales throughout the Quaternary. Rainfall proxy records derived from the famous loess/palaeosol sequences of the Chinese Loess Plateau do not accord with the cave records (and are rarely if ever discussed by the cave science community). Here, the key areas of debate will be explored. The possible dominance of Pacific- rather than North Atlantic-sourced influences on the East Asia monsoon will also be discussed.

A Quaternary Discussion Group seminar

# Thursday 22nd February 2018, 5.30pm - Andrey Ganopolski, Potsdam Institute for Climate Impact Research
Normal time and place
Modeling and understanding of Quaternary climate cycles
Venue: Latimer Room (Old Court), Clare College, Trinity Lane

In spite of significant progress achieved in recent decades in understanding of Quaternary climate dynamics, there are still a number of important questions remained to be answered. Among them is the cause of Mid-Pleistocene transition (MPT). To address this questions we used the Earth system model of intermediate complexity CLIMBER-2 which incorporates all major components of the Earth system – atmosphere, ocean, land surface, northern hemisphere ice sheets, terrestrial biota and soil carbon, aeolian dust and marine biogeochemistry. We performed a set of simulations covering the entire Quaternary using as the only forcing variations in Earth orbital parameters and gradually evolving in time land-ocean distribution and terrestrial sediment cover. We found that a gradual removal of terrestrial sediment from the Northern Hemisphere continent by glacial processes is sufficient to explain transition from 40-ka to 100-ka worlds around the MPT. Gradual change in volcanic outgassing or weathering rate during Quaternary is required to explain early Pleistocene climate dynamics. Our results strongly suggest that Quaternary glacial cycles are externally forced and almost deterministic.

Quaternary Discussion Group seminar

# Thursday 8th February 2018, 5.30pm - Alex Piotrowski (Dept of Earth Science)
Reconstructing deep ocean circulation pathway and strength using sediment dispersion
Venue: Latimer Room (Old Court), Clare College, Trinity Lane

Ocean circulation is thought to play a key role in the Earth’s climate system because surface ocean currents transport heat from the equator to the poles and deep ocean water sequesters carbon dioxide from the atmosphere. Geochemical proxies measured on the biogenic components of marine sediments have been widely-utilized to reconstruct past ocean changes. However, because these proxies are controlled by biology and chemistry in addition to physical circulation it is difficult to use them to quantitatively reconstruct physical oceanographic parameters such as deep water advection speed. I will present new data of coupled sediment grainsize and source measurements, from highly resolved grain-size separates across the clay and silt fraction, allowing reconstruction of the dispersion of fine detrital sediment by ocean currents. We have initially worked in the North Atlantic because it hosts a strong deep current that transports sediment from geological sources with distinct and well-constrained geochemistry (i.e. Iceland and the Canadian Shield). Our core-top data shows that grainsize separation in the 0-63 m range allows “unmixing” of North Atlantic marine sediment samples into at least three different sources; the finest grain-sizes are derived from Scandinavia and Iceland and have been transported great distances by deep current flow, while the coarser fractions are locally derived. Time slice reconstruction during the last deglaciation place new constraints on glacial-interglacial changes in sediment sources, input, and ocean circulation pathways.

Quaternary Discussion Group seminar

# Thursday 1st February 2018, 5.00pm - Samuel Jaccard, University of Bern
Please note different time/venue
On the role of the Southern Ocean in modulating (past) climate variability
Venue: Harker 1, Department of Earth Sciences, Downing Street

Quaternary Discussion Group seminar

# Thursday 25th January 2018, 5.30pm - Phil Hughes, University of Manchester
Please note different venue
Reconstructing the extent, timing and palaeoclimatic significance of Quaternary glaciations in the Mediterranean region
Venue: Castlereagh Room, Fisher Building, St Johns College, Cambridge

Glaciation has affected many Mediterranean mountains on multiple occasions through the Quaternary. In the Pleistocene, glaciers were extensive and the altitudinal pattern of glaciation closely matches the modern distribution of precipitation, with some of the lowest glaciers forming in the western Balkans and northwestern Iberia. Conversely, the highest glaciers formed in areas that are currently the hottest and driest of the Mediterranean, such as in Morocco and central Turkey. In the western Balkans, ice caps covered large areas of Croatia, Montenegro and Albania. Further south in Greece, ice caps, plateau ice fields and valley glaciers were widespread throughout the Pindus Mountains. The largest glaciers of the Balkans formed during the Middle Pleistocene, although substantial cirque and valley glaciers were also present during the Late Pleistocene. In the western Mediterranean, ice caps and plateau ice fields formed over many of the mountains of Iberia and even in Morocco. Understanding the extent and timings of glaciations in this region is important for understanding landscape evolution and the effects of global climate change on the Mediterranean region. In recent years the timing of glaciations during the late Pleistocene has been revolutionised using cosmogenic exposure dating, revealing asynchronous glacier behaviour across the Mediterranean through the last cold stage. There is also evidence that small glaciers survived into the Holocene. Today, only a few small niche glaciers survive. These modern glaciers are much smaller than 150 years ago at the end of the Little Ice Age when Mediterranean glaciers were much more common.

# Thursday 30th November 2017, 5.30pm - Paola Moffa Sanchez, Cardiff University
Quaternary Discussion Group seminar
North Atlantic variability and its link to European climate and history over the last 3000 years
Venue: Latimer Room (Old Court), Clare College, Trinity Lane

The subpolar North Atlantic is a key location for the Earth’s climate system. In the Labrador Sea, intense winter air–sea heat exchange drives the formation of deep waters and the surface circulation of warm waters around the subpolar gyre. This process therefore has the ability to formation of Labrador Sea Water. Yet, crucially, its longer-term history and links with European climate remain limited. We present new decadally-resolved marine proxy
reconstructions which suggest weakened Labrador Sea Water formation and gyre strength with similar timing to the centennial cold periods recorded in terrestrial climate archives and historical records over the last 3000 years. These new data support that subpolar North Atlantic
circulation changes, likely forced by increased southward flow of Arctic waters, contributed to modulating the climate of Europe with important societal impacts as revealed in European history.

# Thursday 16th November 2017, 5.30pm - Angela Gallego-Sala, University of Exeter
Climatic controls on peatland carbon accumulation during the last millennium
Venue: Latimer Room (Old Court), Clare College, Trinity Lane

Peatland ecosystems are a small but persistent sink of carbon and currently store more than 600 Pg C globally. Peatlands preserve a stratigraphic record of net carbon accumulation, the net outcome of plant respiration and respiration. The rates of both these processes will increase with warming and an important question is which of these will dominate the overall response of the global peatland carbon sink to future climatic changes. In this seminar, I will present the results of a global study of changes in peatland carbon accumulation rates over the last millennium. This study explores the relationship between carbon accumulation rates over the last millennium and modern climate space. The results indicate that there is a positive relationship between carbon accumulation and photosynthetically active radiation for mid- to high-latitude peatlands in both hemispheres, i.e. carbon accumulation is lowest at high latitudes where PAR0 is lowest. However, this relationship reverses for sites at lower latitudes, suggesting that carbon accumulation is reduced under the warmest climate regimes. This is important because it highlights that there are limits to the predicted negative feedback of the peatland carbon sink to warming. I will additionally present modelled future projections under RCP2.6 and RCP8.5 scenarios to explain that the overall peatland negative feedback does not necessarily persist in time.

# Thursday 2nd November 2017, 5.30pm - Francis Wenban-Smith, University of Southampton
MIS 7, The "Ebbsfleet Interglacial": sub-stage structure and recognition in the UK record
Venue: Latimer Room (Old Court), Clare College, Trinity Lane

More than 20 UK Quaternary sites are reliably related to MIS 7 of the global marine isotope stage framework. This interglacial has a distinctive O18:O16 profile of an early warm peak (MIS 7e) followed by a well-defined cooler episode (MIS 7d), which is followed in turn by a double warm peak (MIS 7c and MIS 7a) divided by a minor cool episode (MIS 7b). Foremost among UK MIS 7 sites is the Ebbsfleet Valley, a
minor tributary on the south side of the Thames estuary. Here, approximately half a dozen separate localities have provided evidence of sequences from MIS 7, ranging from localities first investigated in the 1930s to currently-unpublished localities investigated as part of the HS1 archaeological programme. When the disparate palaeo-environmental, litho-stratigraphic and dating evidence from
these Ebbsfleet localities is considered as a whole, a picture emerges in which all three warm MIS 7 peaks can be recognised and distinguished from each other, and their distinctive palaeo-environmental and biostratigraphic characteristics can thus provide the framework within which other UK sites should be integrated.

# Thursday 19th October 2017, 5.30pm - Michael Sigl, Paul Scherrer Institut & Oeschger Centre for Climate Change Research, University of Bern
Volcanic eruptions, climate and humans: How lessons from the past can help us to prepare for the future
Venue: Latimer Room (Old Court), Clare College, Trinity Lane

Large volcanic eruptions are a major driver of natural climate variability responsible for numerous cooling extremes and throughout human history have often been followed by severe famines and pandemics. Spanning from the last glacial maximum into the future, I present case studies of how volcanic eruptions can impact our climate with implications for human societies in past, present and future. From pre-anthropogenic ozone depletion to “failures” of the critical Nile summer flood causing famines in Ancient Egypt, I track the influence of volcanic eruptions on climate and human societies and demonstrate that the significance of volcanic eruptions goes beyond a short-lived reduction of surface temperatures (e.g., “Year without a Summer”).

# Thursday 18th May 2017, 4.00pm - Shaun Marcott, University of Wisconsin-Madison
The timing of cirque glaciation in western North America revisited: No Neoglacial in the U.S. Cordillera?
Venue: Castlereagh Room, Fisher Building, St John's College

Glaciers are intrinsically linked to climate, and given the sensitivity of small alpine glaciers to climate change, accurate and precise chronologies of their fluctuations are important in elucidating both the temporal and spatial structure of climate variability. Despite nearly a century of research, the timing of latest Pleistocene and Holocene alpine glaciation in much of western North America remains poorly constrained. I will present ~125 10Be ages from ~20 cirque moraines in 10 mountain ranges across western North America that were previously interpreted as mid- to late Holocene in age. Our new 10Be glacial chronology indicates that these moraines were deposited during the latest Pleistocene to earliest Holocene, requiring a refined interpretation of Holocene glacial activity in western North America and the associated climate forcing. Although alpine glaciers may have continued to fluctuate during the Holocene, they never advanced beyond their Little Ice Age maximum limit. Instead, cirque glacier activity in western North America has followed in near step with late Pleistocene high and mid latitude climate with alpine glaciers retreating to high altitude cirques early during the last deglaciation.

# Thursday 4th May 2017, 5.30pm - Chris Stokes, Durham University
How ice sheets collapse: a lesson from the Laurentide Ice Sheet
Venue: Cripps Auditorium, Cripps Court, Magdalene College

The contribution of the Greenland and West Antarctic ice sheets to sea level has increased in recent decades, largely due to the thinning and retreat of rapidly-flowing outlet glaciers and ice streams. This ‘dynamic’ loss is a serious concern, with some modelling studies suggesting that the collapse of a major ice sheet could be imminent or potentially underway in West Antarctica, but others predicting a more limited response. A major problem is that observations used to initialize and calibrate models typically span only a few decades and, at the ice-sheet scale, it is unclear how the entire drainage network of ice streams evolves over longer timescales. This represents one of the largest sources of uncertainty when predicting the contributions of ice sheets to sea-level rise. A key question is whether ice streams might increase and sustain rates of mass loss over centuries or millennia, beyond those expected for a given ocean–climate forcing. In this paper, we utilise a unique Quaternary record of 117 ice streams that operated at various times during deglaciation of the Laurentide Ice Sheet from about 22,000 to 7,000 years ago). We show that as they activated and deactivated in different locations, their overall number decreased, they occupied a progressively smaller percentage of the ice sheet perimeter and their total discharge decreased. The underlying geology and topography clearly influenced ice stream activity, but— at the ice-sheet scale—their drainage network adjusted and was strongly linked to changes in ice sheet volume. It is unclear whether these findings can be directly translated to modern ice sheets. However, contrary to the view that sees ice streams as unstable entities that can accelerate ice-sheet deglaciation, we conclude that ice streams exerted progressively less influence on ice sheet mass balance during the retreat of the Laurentide Ice Sheet.

# Thursday 9th March 2017, 5.30pm - Thomas Chalk, National Oceanography Centre, Southampton
Causes of ice-age intensification across the Mid-Pleistocene Transition, insights from a new boron isotope CO2 record
Venue: Latimer Room (Old Court), Clare College, Trinity Lane

During the Mid-Pleistocene Transition (MPT; 1200–800 thousand years ago, kyrs) Earth’s orbitally paced ice-age cycles intensified, lengthened from ~40 to ~100 kyrs, and became distinctly asymmetrical. Testing hypotheses that implicate changing atmospheric CO2 levels as a driver of the MPT has proven difficult with available observations. Here we use orbitally resolved, boron-isotope CO2 data to demonstrate that the glacial-to-interglacial CO2 difference increased from ~43 to ~75 µatm across the MPT, mainly due to lower CO2 levels during glacials. Through carbon-cycle modelling, we attribute this decline primarily to the initiation of substantive dust-borne iron fertilization of the Southern Ocean during peak glacial stages. We also observe a two-fold steepening of the relationship between sea level and CO2-related climate forcing that is suggestive of a change in the dynamics that govern ice-sheet stability, such as that expected from the removal of subglacial regolith. We argue that neither ice-sheet dynamics nor CO2 change in isolation can explain the MPT. Instead, we infer that the MPT initiated by a change in ice-sheet dynamics, and that longer and deeper post-MPT ice ages were sustained by carbon-cycle feedbacks related to dust fertilization of the Southern Ocean as a consequence of larger ice sheets.

This talk is part of the Quaternary Discussion Group (QDG).

# Thursday 23rd February 2017, 5.30pm - Francis Wenban-Smith, Archaeology, University of Southampton
MIS 7, the "Ebbsfleet Interglacial": sub-stage structure and recognition in the UK record
Venue: Latimer Room (Old Court), Clare College, Trinity Lane

More than 20 UK Quaternary sites are reliably related to MIS 7 of the global marine isotope stage framework. This interglacial has a distinctive O18:O16 profile of an early warm peak (MIS 7e) followed by a well-defined cooler episode (MIS 7d), which is followed in turn by a double warm peak (MIS 7c and MIS 7a) divided by a minor cool episode (MIS 7b). Foremost among UK MIS 7 sites is the Ebbsfleet Valley, a minor tributary on the south side of the Thames estuary. Here, approximately half a dozen separate localities have provided evidence of sequences from MIS 7, ranging from localities first investigated in the 1930s to currently-unpublished localities investigated as part of the HS1 archaeological programme. When the disparate palaeo-environmental, litho-stratigraphic and dating evidence from these Ebbsfleet localities is considered as a whole, a picture emerges in which all three warm MIS 7 peaks can be recognised and distinguished from each other, and their distinctive palaeo-environmental and biostratigraphic characteristics can thus provide the framework within which other UK sites should be integrated.

# Thursday 9th February 2017, 5.30pm - Paul Valdes, School of Geographical Sciences, University of Bristol
Modelling the Last Glacial-Interglacial Cycle: How sensitive are past climates?
Venue: Latimer Room (Old Court), Clare College, Trinity Lane

Understanding the mechanisms involved in Late Quaternary glacial cycles is one of the ultimate challenges for palaeoclimate science. The driving cause of the variability is related to changes in the Earth’s orbit but there are numerous feedbacks between the atmosphere, ocean, ice sheets and carbon cycle. Earth System Modelling can play an important role in quantifying some of these feedbacks and helping us to determine the major components of change. Through a combined modelling and data approach, palaeoclimate studies improve our understanding of key processes and hence contribute to improved confidence in future predictions. However, palaeoclimate studies have also attempted to directly estimate past climate sensitivity to CO2, a key parameter for future climate change. A key assumption of such work is that climate sensitivity is unchanging, so that knowing climate sensitivity in the past is relevant for climate sensitivity in the future. The talk will describe a series of modelling simulations that help us understand the feedback processes important during the last glacial-interglacial cycle, and show that the model relatively well represents the changes observed in the proxy climate data. We further use the model to investigate climate sensitivity. The simulations show that the sensitivity varies throughout the last 120,000 years, indicating that there are serious limitations on direct estimates of future climate sensitivity from palaeo-data.

This talk is part of the Quaternary Discussion Group (QDG)

# Thursday 26th January 2017, 5.30pm - Christine Lane, Department of Geography, University of Cambridge
Late Quaternary tephrostratigraphies from East African lakes
Venue: Latimer Room (Old Court), Clare College, Trinity Lane

This talk is part of the Quaternary Discussion Group (QDG)

Understanding the spatial and temporal variability of climate forcing and palaeoenvironmental response across a continent as climatically diverse as Africa relies upon comparison of data from widespread palaeoenvironmental archives. Accurate, precise and independent chronologies for such records are essential; however this remains a challenge in many environments and often prevents the valid comparison of detailed palaeo-proxy records. Many studies have now shown that volcanic ash (tephra) can be detected in terrestrial and marine sediments thousands of kilometres from their source, often as microscopic or “cryptic” layers. As well as offering opportunities for both direct (e.g. by 40Ar/39Ar methods) and indirect (e.g. by associated 14C dates) dating of the sediment sequence, tephra layers can provide stratigraphic tie-lines between archives, facilitating precise correlations at single moments in time. Furthermore, where two or more tephra layers are co-located in multiple records, rates of change can be compared within a period of equivalent duration, even in the absence of absolute age estimates.
Investigations into the presence of visible and non-visible (crypto-) tephra layers within lacustrine palaeoenvironmental records of the last ~150 ka BP from across East Africa are revealing the potential for this approach to (i) correlate palaeoclimate archives from across and beyond tropical Africa within a regional tephrostratigraphic framework; (ii) provide age constraints for individual core chronologies, in particular beyond the limits of radiocarbon dating; and (iii) increase our knowledge of the history of Late Quaternary explosive volcanism in East Africa.

# Thursday 24th November 2016, 5.30pm - Mick Frogley and Alex Chepstow-Lusty, University of Sussex
From Cambridge to Cuzco and back again: 4000 years of environmental history from the heart of the Inca Empire
Venue: Latimer Room (Old Court), Clare College, Trinity Lane

A sediment core brought back to Cambridge in 1993 from the small infilled lake of Marcacocha located at 3300 m above sea level in Andean Peru has provided a 4000-year record that, even today, continues to shed new light on environmental changes and how humans managed their environment. Surrounded by pre-Inca and Inca terraces and ruins, Marcacocha is located next to a major trade route that connects the Inca settlement of Ollantaytambo with the rainforest. By combining the study of conventional proxies such as pollen, dung fungal spores, plant macrofossils and sediment geochemistry with those that are less orthodox (such as oribatid mites), we have shown that the record spans the early development of agriculture and pastoralism, the rise and fall of the Inca Empire (c. AD 1400–1533) and into the historic period. Besides providing a detailed palaeoenvironmental record, there are indications that, particularly from 1000 years ago, major efforts in agroforestry and landscape stabilisation were being practiced. Indeed, these historic strategies may yet prove important in helping to alleviate the impacts of Peru’s increasingly acute water shortage issues, as Andean glaciers disappear and ancient aquifers are stressed by unregulated abstraction. This talk presents a welcome opportunity to bring the results of the project back to Cambridge after more than two decades.

# Thursday 10th November 2016, 5.30pm - Lucy Farr, University of Cambridge
Archaeological insights into the 8.2 ka event
Venue: Latimer Room (Old Court), Clare College, Trinity Lane

Greenland ice cores show a sharp decrease in oxygen isotope ratios and ice accumulation rates at 8.2 ka BP which persisted for c. 150 years (Dansgard et al., 1993; Grootes et al., 1993; Alley et al., 1997). Marine, ice and terrestrial proxy records from the Atlantic high and mid-latitudes, appear to consistently record a sharp change to colder, drier and possibly windier climatic conditions at this time (Pross et al., 2009).

The 8.2 ka event is a significant marker in palaeoclimatic studies, being identifiable in so many northern hemispheric records and recently posited as an official boundary marker dividing the Early and Mid-Holocene periods (Walker et al. 2012). Officially dividing the Holocene at the 8.2 ka event may be useful for archaeologists. Many archaeological records in Europe and south-west Asia show very clear technological, cultural and subsistence changes dating to the Early to Mid-Holocene transition, approximately 8000 years ago (e.g. Horn et al., 2015) but resolution issues frequently prohibit the identification of human responses in direct relation to the 8.2ka event. Recent advances in radiocarbon dating are now enabling archaeologists to better evaluate the role of the 8.2 ka event in cultural evolution occurring at this time (e.g. Flohr et al., 2016).

# Thursday 27th October 2016, 5.30pm - Jenny Collier, Imperial College London
The separation of Britain from mainland Europe in the late Quaternary
Venue: Latimer Room (Old Court), Clare College, Trinity Lane

It has been previously suggested that the separation of Britain from mainland Europe in the late Quaternary was a consequence of a catastrophic flood caused by a spillover of a proglacial lake that occupied the present-day southern North Sea basin during the Elsterian glaciation. Such an event would have significant palaeogeographic, biological and archaeological implications, but it remains controversial. Ten years ago we discovered a drainage system carved into the floor of the English Channel that is consistent with the catastrophic flood model. In this talk I will present a new compilation of seabed bathymetry and sub-bottom profiler data that we have used to analyse key landform features both within the downstream region and at the proposed breach point at the Straits of Dover. Our observations support the hypothesis that the landforms were initially carved by high-water volume flows via a unique catastrophic drainage of a pro-glacial lake in the southern North Sea at the Dover Strait rather than by fluvial erosion throughout the Pleistocene. The system also shows evidence for modification by a second flood that may have been a consequence of spillover of younger ice-marginal lake systems to the east, either in the North Sea basin or mainland Europe.

# Thursday 13th October 2016, 5.30pm - Kate Hendry, University of Bristol
Silicon cycling and opal production in the Atlantic: lessons from the last deglaciation
Venue: Latimer Room (Old Court), Clare College, Trinity Lane

Major shifts in ocean circulation are thought to be responsible for abrupt shifts in temperature and atmospheric CO2 as the Earth warmed up after the last ice age, linked to changes in latitudinal heat transport and deep ocean carbon storage. There is also widespread evidence for shifts in biological production during these times of deglacial CO2 rise, including enhanced growth of silica-producing algae (diatoms) in regions such as the equatorial Atlantic. In this talk, I’ll show how we can use marine sediment geochemical archives to demonstrate that the supply of dissolved silicon – a key nutrient for diatoms – was enhanced in the NE Atlantic during the abrupt climate events of the deglaciation. However, despite an enriched supply of this critical nutrient at depth, diatoms could only proliferate during abrupt climate shifts in regions of the NE Atlantic where the deep supply of dissolved silicon could reach the surface. These regions were influenced by enhanced regional wind-driven upwelling and weakened stratification due to circulation changes during phases of weakened Atlantic meridional overturning. Globally near-synchronous pulses of diatom production and enhanced subsurface concentrations of dissolved silicon suggest that widespread deglacial surface-driven breakdown of stratification, linked to changes in atmospheric circulation, had major consequences for biological productivity and carbon cycling across the North Atlantic.

# Thursday 12th May 2016, 5.30pm - Benjamin Stocker. Department of Life Sciences, Imperial College London
Large CO2 emissions from pre-industrial land use change – Does the carbon budget add up?
Venue: Thirkill Room, Clare College

CO2 emissions from preindustrial land use change (LUC) are subject to large uncertainties with model-based estimates ranging from 60 to 360 GtC (Olofsson and
Hickler, 2008; Pongratz et al., 2009; Kaplan et al., 2011; Stocker et al., 2011). Thus, early anthropogenic impacts rose to significance between 7-3 kyr BP depending on reconstruction and may have altered the natural carbon © cycle and climate states to a degree that would lend support for the definition of a correspondingly
early onset of the Anthropocene. However, the reconstructed parallel evolution of atmospheric CO2 and its 13C-signature indicate only 36+/-37 Gt loss of terrestrial C during the last 5 millennia (Elsig et al., 2009). It has been argued that this is the result of compensating effects of large LUC emissions and C sequestration in northern peatlands, which is estimated to be on the same order as upper-end estimates of
preindustrial LUC (Ruddiman and Ellis, 2009).

Here, we combine updated observation-based and model-based reconstructions of peat C buildup (∆Cpeat) and model-based LUC emission estimates for a range of
recently published reconstructions (Kaplan et al., 2009; Klein Goldewijk and Verburg, 2013) and accounting for changing land management regimes over time and space.
Using the independent constraint on the total terrestrial C budget from ice core measurements of CO2 and d13C (∆Ctot), we assess the compatibility of different LUC
scenarios with ∆Ctot and ∆Cpeat.

This reveals that large LUC emissions required to explain the observed CO2 rise between 7 and 5 kyr BP cannot be reconciled with ∆Ctot and ∆Cpeat unless a large additional terrestrial sink is invoked. Furthermore, this analysis points to the importance of other, non-anthropogenic impacts for explaining the ~150 Gt terrestrial C source between 5 and 2 kyr BP, where scenarios suggest emissions of only 20-50 GtC. More highly resolved ice core (Bauska et al., 2015) and peat C balance data (Charman et al., 2013) covering the last millennium further reveals that only extreme assumptions on the extent of post-Columbian reforestation in the Americas can close the C budget between 1500 and 1650 CE and that upper-end scenarios of preindustrial LUC are incompatible with the C budget between 1760 and 1920 CE.

# Thursday 5th May 2016, 5.30pm - Mike Walker, School of Archaeology, History & Anthropology, Trinity Saint David, University of Wales, Lampeter, and Department of Geography and Earth Sciences, Aberystwyth University
A formal subdivision of the Holocene Series/Epoch
Venue: Thirkill Room, Clare College

This presentation considers the prospects for a formal subdivision of the Holocene Series/Epoch. Although previous attempts to subdivide the Holocene have proved inconclusive, recent developments in Quaternary stratigraphy, including the definition of the Pleistocene–Holocene boundary and subdivisions of the Pleistocene Series/Epoch, mean that it may be timely to revisit this matter. The Quaternary literature reveals a widespread, but variable, informal usage of a tripartite division of the Holocene (‘Early’, ‘Middle’ or ‘Mid’, and ‘Late’), and it is suggested that this de facto subdivision should now be formalized to ensure consistency in stratigraphic terminology. The proposal is for three stages and subseries/subepochs of the Holocene: the Greenlandian, Northgrippian and Meghalayan, each of which is underpinned by a Global Standard Stratotype Section and Point (GSSP). It is suggested that the Early–Middle Holocene boundary should be defined by the global cooling event at 8.2 ka BP, and the Middle–Late Holocene boundary by the widespread low-latitude aridity phase at 4.2 ka BP, Should the proposal find support from the Quaternary community, a submission for ratification will be made to the International Union of Geological Sciences (IUGS), via the Subcommission on Quaternary Stratigraphy (SQS) and the International Commission on Stratigraphy (ICS).

# Thursday 21st April 2016, 5.30pm - Maryline Vautravers (University of Cambridge)
1 million years of Pacific Ocean paleoceanography viewed from IODP Exp350 sites 1436C and 1437B foraminifers' records recovered near the IZU subduction Arc
Venue: Thirkill Room, Clare College

In 2014 I sailed for 2 months on IODP EXP350 on board JOIDES Resolution, South of Japan near the Izu-Arc formed by the subduction of the West Pacific plate under the Phillippine plate. The area investigated near 30° N is affected by the Kuroshio Current. The age models for 2 Sites; U1436C and U1437B are based on stable isotopes stratigraphy N. dutertrei. The quantitative micropaleontological (planktonic foraminifer) content for 460 samples includes the indices of calcium carbonate preservation, individual shell weight, percent planktonic foraminifer fragments, planktonic foraminifer concentrations, various faunal proxies, and benthic/planktonic ratio. Altogether evidencing qualitative surface temperatures changes traced by faunal polar/subpolar versus subtropical assemblages recording the changing influences in the Kuroshio/Oyashio currents over the last 1 My. The remarkable locations of the sites at intermediate water depth in the Pacific Ocean; but separated by the hydrographic divide created by the Izu rise provide a rare insight opportunity into the operation of intermediate circulations and the influence of Quaternary Northern Hemisphere glaciations on the operation of the intermediate water mass as can be traced by changes in carbonates preservation recorded by foraminifers. The study points to the so-called Pacific carbonate cycles pattern recorded in the NW Pacific at intermediate depth to be the result of climatological and/or geochemical changes originating in the North Atlantic affecting the NADW production during interglacials and the NAGW during glacials. In term of paleoceanographic/climatic evolution it also points at MIS17 as a remarkable interglacial within the Pacific Ocean realm.

# Thursday 10th March 2016, 5.30pm - James Scourse (Bangor University)
North Atlantic annually resolved temperatures for the last millennium: the Arctica islandica record.
Venue: Latimer Room, Clare College

Abstract not available

# Thursday 25th February 2016, 5.30pm - Michael Weber (Institute of Geology and Mineralogy, University of Cologne)
Ice sheet, atmosphere, and ocean dynamics in the Atlantic sector of Antarctica – past reconstruction and future course.
Venue: Latimer Room, Clare College

Abstract not available

# Thursday 11th February 2016, 5.30pm - Eric Galbraith (ICREA, Barcelona, Spain),
Orbital wobbles, ice sheets, CO2, and the deep sea: a model-informed perspective on the ocean’s role in Quaternary climate.
Venue: Cripps Meeting Room 5, Cripps Court Building, Chesterton Road, Magdalene College

Abstract not available

# Thursday 3rd December 2015, 5.30pm - Sebastian Breitenbacher (Earth Sciences Department, University of Cambridge)
Climate and Society: Examples of the climate impact on civilizations
Venue: Latimer Room, Clare College

Abstract not available

# Thursday 19th November 2015, 5.30pm - Mark Bateman (Department of Geography, University of Sheffield)
Using the Land-Ocean Transition to understand coastal landscapes
Venue: Latimer Room, Clare College

Abstract not available

# Thursday 5th November 2015, 5.30pm - Christopher Evans (Division of Archaeology, University of Cambridge)
Landscape Retreat and 'Jumping': Late Prehistoric Fenland Environmental Adaption/Response
Venue: Latimer Room, Clare College

Abstract not available

# Thursday 15th October 2015, 5.30pm - Anais Orsi, Laboratoire des Sciences du Climat et de l'Environnement, Gif-sur-Yvette (France)
The last 1000 years in East Antarctica: insights from a new temperature proxy.
Venue: Cripps Meeting Room 4, Cripps Court Building, Chesterton Road, Magdalene College

Abstract not available

# Thursday 28th May 2015, 5.30pm - Prof Dr. Dominik Fleitmann (University of Reading)
Stalagmites as excellent recorders of major volcanic eruptions
Venue: Cripps Meeting Room 3, Cripps Court Building, Chesterton Road, Magdalene College

Abstract not available

# Thursday 14th May 2015, 5.30pm - Dr. Sambuddha Misra (Godwin Laboratory for Palaeoclimate Research, Earth Sciences Department, University of Cambridge)
Boron isotopes as pH proxy: a critical evaluation
Venue: Cripps Meeting Room 3, Cripps Court Building, Chesterton Road, Magdalene College

Abstract not available

# Thursday 5th March 2015, 5.30pm - Prof Chris D. Clark, Department of Geography, University of Sheffield (UK)
Retreat of the last British-Irish Ice Sheet; landforms, sediments, dates and the BRITICE-CHRONO project
Venue: Thirkill Room, Clare College

Abstract not available

# Thursday 19th February 2015, 5.30pm - Prof Mary E. Edwards, Department of Geography and Environment, University of Southampton (UK)
New DNA approaches to understanding Late-Quaternary and recent biodiversity changes – potential and problems
Venue: Thirkill Room, Clare College

Major advances in the ability to sequence many DNA samples has led to a proliferation of Quaternary molecular studies. The Ecochange project developed a methodology that allows DNA of vascular plants and mammals to be extracted from Quaternary sediments and used as proxy data for the components of terrestrial ecosystems. It uses an approach called “metabarcoding”: for plants, this is based on short (10-200 BP) sequences of chloroplast or nuclear DNA. Taxonomic resolution is potentially better than that of pollen and matches that of macrofossils. Furthermore, DNA detects the presence of taxa at when biomass levels are relatively low. I will illustrate the current status of DNA-based palaeoecological reconstructions with a range of modern (calibration) and fossil studies from Siberian yedoma, northern lake sediments (from Svalbard and Scotland) and modern tundra landscapes. Key findings are that modern soil DNA matches the taxa present in modern vegetation with few false positives and roughly reflects biomass, that DNA in lakes does not seem to reflect pollen when there is no vegetative biomass in the catchment, that forb taxa were a surprisingly large component of glacial-age vegetation across unglaciated Eurasia, and that the Holocene DNA record from Svalbard shows rapid early colonization and resilience of the flora in the face of climatic deterioration. New and stricter protocols for sequencing and bioinformatics filtering are improving the ability to determine false positives in the data, which were likely a problem in the first, pioneering studies.

# Thursday 29th January 2015, 5.30pm - Dr. Heather Ford (Lamont Doherty Earth Observatory, Columbia University)
El Niño and El Padre: a deep equatorial Pacific thermocline during the Pliocene warm period
Venue: Cripps Meeting Room 4, Cripps Court Building, Chesterton Road, Magdalene College

Abstract not available

# Thursday 15th January 2015, 5.30pm - Prof Eric J. Steig, Department of Earth and Space Sciences, University of Washington (US)
The role of the ocean and the atmosphere in the expression of D-O and AIM events in Antarctica: new evidence from the WAIS Divide Ice Core
Venue: Cripps Meeting Room 4, Cripps Court Building, Chesterton Road, Magdalene College

Abstract not available

# Thursday 4th December 2014, 5.30pm - Dr Peter Abbott (University of Swansea)
Cryptotephrochronology in the North Atlantic Region: Linking North Atlantic Marine Sediments to the Greenland ice-cores
Venue: Thirkill Room, Clare College

Tephrochronology is a powerful technique that can be utilised for the correlation and synchronisation of disparate palaeoclimatic records from different depositional
environments. Thus, this technique has considerable potential for addressing key questions relating to rapid climatic events that characterised the last glacial period. In particular, our search for microscopic tephra layers or cryptotephras within the Greenland ice-cores and marine cores from the North Atlantic Ocean has the potential to test the phase relationships between the atmospheric and oceanic responses to these high-magnitude and abrupt climatic events.
Tephrochronological investigations are currently being undertaken on a network of marine cores from a range of locations and depositional settings within the North Atlantic as part of the ERC-funded project Tephra constraints on Rapid Climate Events (TRACE). Tephra horizons have been identified in the marine records through the successful use of cryptotephra extraction techniques more commonly applied to the study of terrestrial sequences. The two main challenges associated with cryptotephra work in the glacial North Atlantic are i) determining the dominant transportation processes and ii) assessing the influence of secondary reworking processes and the integrity of the isochrons. The potential influence of these processes is investigated by assessing shard size, geochemical (major and trace element) heterogeneity and co-variance of IRD input for some cores. We are also applying the innovative techniques of micromorphology and X-ray tomography to the study of these processes.
Early comparison of the tephrochronological record of cores within the network highlight a number of potential marine to ice linkages and the potential for these to allow an assessment of the relative timing of climatic changes between the ocean and atmosphere will be discussed.

# Friday 14th November 2014, 5.30pm - Dr Lauren Gregoire (School of Earth and Environment, University of Leeds)
The North American deglaciation: linking rapid climate change, ice sheet retreat and sea level rises
Venue: Latimer Room, Clare College

The last deglaciation (approx. 21-7ka) was punctuated by several abrupt climatic and sea level changes in which ice sheets are thought to have played an important role.
This talk describes the role of the N. American ice sheet in two of the most important event of rapid sea level change:
(i) the MWP-1a, a ~ 14-18 m global sea level rise in less than 350 years which coincided with the rapid N. Hemisphere Bolling warming;
(ii) the ‘8.2 kyr event’, a century long cooling event attributed to the sudden release of N. American glacial lakes.
By combining, climate, ice sheet and sea level modelling with a variety of palaeo-environment data I evaluate (i) the mechanisms that lead to accelerated ice melt and (ii) the impacts of these on the climate. I will present recent efforts to constrain the contribution of the N. American ice sheet to MWP1a from the Bolling warming and a mass balance mechanism named the saddle collapse. Finally, I will introduce the recent plans of the Palaeo Model Intercomparison Project for simulating the climate of the last deglaciation.

# Thursday 6th November 2014, 5.30pm - Prof Dr Hubertus Fischer (Oeschger Centre for Climate Change Research, University of Bern)
Changes in the Global Carbon Cycle over the last 800,000 years - an ice core perspective
Venue: Thirkill Room, Clare College

Abstract not available

# Wednesday 22nd October 2014, 4.00pm - Prof Bill Ruddiman (Department of Environmental Sciences, University of Virginia, US)
Top-down and bottom-up evidence for the early anthropogenic hypothesis
Venue: Tilley Lecture Theatre, Department of Earth Sciences, Downing Street

Abstract not available

# Monday 7th July 2014, 5.00pm - Professor Richard Alley, Evan Pugh Professor of Geoscience, Penn State University, USA
People should be aware that 7th July is Tour de France day, but we hope things will have become accessible by 5.00 pm.
Fracking the fjords: Earthquakes and glacial erosion, with some additional thoughts about stability of the West Antarctic Ice Sheet
Venue: Tilley Lecture Theatre, Department of Earth Sciences

Abstract not available

# Wednesday 27th November 2013, 5.00pm - Dr. Patrick Grunert (U. of Graz, Austria)
CHANGE OF DATE: now on Wednesday Nov. 27th
Benthic foraminiferal assemblages as proxies of paleoceanographic changes across Pleistocene glacial terminations in the NE Atlantic
Venue: Thirkill Room, Clare College

The study of fossil foraminifera goes back to the early 19th century, making them one of the best studied microfossil groups. More recently, our increasing understanding of their distribution and ecological requirements in the present-day oceans has made the quantitative evaluation of foraminiferal assemblages a powerful means of actualistic paleoenvironmental reconstruction.
In this paper I present examples for the application of benthic foraminiferal assemblages from IODP Site U1385 (“Shackleton Site”) as proxies of paleoceanographic Change in the Pleistocene NE Atlantic. A brief introduction to the present-day distribution of benthic foraminifera in the area and the relation to the oceanographic setting is followed by an evaluation of differences between the present-day situation and major glacial/interglacial transitions. The presentation is wrapped up by a discussion of the implications of observed turnovers in the benthic foraminiferal fauna for changes of sea-water properties at the water/sediment interface during these rapid climatic transitions.

# Thursday 7th November 2013, 5.00pm - Prof. Eric Wolff (Dept. of Earth Sciences, Cambridge)
Interglacials of the last 800,000 years
Venue: Thirkill Room, Clare College

Abstract not available

# Thursday 24th October 2013, 4.00pm - Prof. Howard J. Spero (University of California)
Note unusual time
The paleoceanography frontier: proxies, new technologies and novel questions
Venue: Latimer Room, Clare College

Please note different time and venue: Latimer Room, 4pm

In recent years, new geochemical proxies and emerging technologies have been combined to explore novel paleoclimatic questions that were only dreamed about a decade ago. In this presentation I will discuss how the application of new technologies such as laser ablation ICP-MS (e.g. Mg/Ca, Ba/Ca), SIMS (e.g. d18O, d13C) and nanoSIMS can be used to address old and new paleoceanographic problems. I will present data from laboratory experiments with living planktonic foraminifera that have allowed us to calibrate these proxies and reduce the spatial resolution of geochemical analyses to the micron and sub-micron level. These data confirm many of the fundamental geochemical relationships used by researchers to reconstruct ocean temperatures and water geochemistry from the fossil record. When individual foraminifera from a fossil assemblage are analyzed using LA-ICP-MS (Mg/Ca, Ba/Ca) and coupled to d18O measurements from standard isotope ratios mass spectrometry (IRMS), we may be able to extract novel information from the fossil record that was not previously possible. I will present data collected at the interface of these two geochemical technologies that has allowed us to calculate the oxygen isotopic composition of Laurentide Ice Sheet meltwater during the last deglaciation.

# Thursday 17th October 2013, 5.00pm - Dr. Maryline Vautravers (Cambridge)
Canceled
Taking a closer look at the last glacial sediments
Venue: Thirkill Room, Clare College

Abstract not available

# Thursday 14th March 2013, 5.15pm - Dr. Katy Pol (British Antarctic Survey)
Evidence for enhanced Antarctic climate variability during the last interglacial period
Venue: Thirkill Room, Clare College

Abstract not available

# Thursday 21st February 2013, 5.00pm - Prof. James Rose (Dept. of Geography, Royal Holloway U. of London)
The Bytham river story - key evidence for understanding pre-glacial environmental change and early human occupance in Britain
Venue: Thirkill Room, Clare College

A special double session on the Bytham river!

# Thursday 21st February 2013, 5.00pm - Prof. Philip Gibbard (Dept. of Geography, U. of Cambridge)
Testing the Bytham river hypothesis
Venue: Thirkill Room, Clare College

A special double session on the Bytham river!

# Thursday 7th February 2013, 5.00pm - Prof. Liping Zhou (Peking University, China)
Late Quaternary loess records from northern China and central Asia: implications for variations in monsoon and westerly circulation
Venue: Thirkill Room, Clare College

Abstract not available

# Thursday 24th January 2013, 5.00pm - Prof. Graeme Barker (McDonald Institute of Archaeological Research, U. of Cambridge)
Modern human adaptations to Pleistocene rainforest: the archaeology of the Niah Caves, Sarawak, Borneo
Venue: Thirkill Room, Clare College

Abstract not available

# Thursday 10th January 2013, 5.00pm - Dr. David Thornalley (Woods Hole Oceanographic Institution, USA)
The release of d14 C and d18 O-depleted water from the Arctic Ocean upon glacial termination
Venue: Thirkill Room, Clare College

Abstract not available

# Friday 30th November 2012, 5.00pm - Dr Anna-Lena Grauel (Dept. of Earth Sciences, Cambridge)
New estimates of tropical ice age temperature
Venue: Thirkill Room, Clare College

Abstract not available

# Friday 23rd November 2012, 5.00pm - Dr Emilie Capron (BAS)
Please note change of speaker
Using nitrogen isotopes to constrain the age of the air extracted from antarctic ice cores
Venue: Thirkill Room, Clare College

Abstract not available

# Friday 9th November 2012, 5.00pm - Dr Aline Govin (MARUM, Bremen)
Precipitation changes in the Amazon Basin during the last 240 ka
Venue: Thirkill Room, Clare College

Abstract not available

# Friday 26th October 2012, 5.00pm - Dr David Wilson (Dept. of Earth Sciences, Cambridge)
Decoupled ocean circulation and carbon cycling during glaciations: Implications for the dynamics of glacial cycles
Venue: Thirkill Room, Clare College

Abstract not available

# Friday 18th May 2012, 5.00pm - Dr Natalia Vazquez-Riveiros (Earth Sciences, University of Cambridge)
Carbon isotopes and glacial-interglacial CO2: the curious case of Marine Isotope Stage 12
Venue: Thirkill Room, Clare College

Abstract not available

# Friday 11th May 2012, 5.00pm - Prof. Martin Jones (Archaeology, University of Cambridge)
The Moravian Gate project: new insights into the human food quest in Stage 3 Central Europe
Venue: Thirkill Room, Clare College

Abstract not available

# Friday 4th May 2012, 5.00pm - Dr Luke Skinner (Earth Sciences, University of Cambridge
A bipolar seesaw in Atlantic deep-water ventilation: Wally was right
Venue: Thirkill Room, Clare College

Due to the absence of key individuals this week, there has been a change to the topic of the seminar scheduled.

# Friday 27th April 2012, 5.00pm - Prof. Hema Achyuthan (Anna University, Chennai)
Quaternary palaeoclimate changes from the margins of the Indian Thar Desert
Venue: Thirkill Room, Clare College

Abstract not available

# Friday 24th February 2012, 5.00pm - Prof. Veli-Pekka Salonen (Dept. of Geosciences and Geography, University of Helsinki, and Visiting fellow at Clare Hall)
Lessons from the High Arctic: new results from late Quaternary studies in Nordaustlandet, Svalbard
Venue: Thirkill Room, Clare College

Abstract not available

# Friday 20th January 2012, 5.00pm - Kate Darling (University of Edinburgh)
Genetic diversity, global phylogeography and seasonality of the planktonic foraminifera G. bulloides: implication for palaeoproxies
Venue: Thirkill Room, Clare College

Abstract not available

# Friday 2nd December 2011, 5.00pm - Dr Aleksey Sadekov (Department of Earth Sciences, Cambridge)
Role of the Tropical Pacific in Millennial-Scale Climate Events
Venue: Seminar Room 3, Cripps Court, Magdalene College

IMPORTANT: In order to avoid conflict with the new CCfCS seminar series held on on Thursdays, we have had to reschedule these QDGs to Fridays and host them in MAGDALENE COLLEGE. The seminars will take place in CRIPPS COURT in Meeting Room 3. Cripps Court is opposite Magdalene College on Chesterton Road (http://conference.magd.cam.ac.uk/find-us). The room will be signposted to help you find us.

As usual, wine and discussion will follow the seminars.

# Friday 18th November 2011, 5.00pm - Outi Hyttinen (Department of Geosciences and Geography, University of Helsinki, FInland)
Traces of the Baltic Ice Lake drainage in the northern Baltic Sea and southern Finland
Venue: Seminar Room 3, Cripps Court, Magdalene College

IMPORTANT: In order to avoid conflict with the new CCfCS seminar series held on on Thursdays, we have had to reschedule these QDGs to Fridays and host them in MAGDALENE COLLEGE. The seminars will take place in CRIPPS COURT in Meeting Room 3. Cripps Court is opposite Magdalene College on Chesterton Road (http://conference.magd.cam.ac.uk/find-us). The room will be signposted to help you find us.

As usual, wine and discussion will follow the seminars.

# Friday 4th November 2011, 5.00pm - Professor Harry Elderfield (Department of Earth Sciences, Cambridge)
Evolution of ocean temperature and ice volume from the Mid Pleistocene Climate Transition
Venue: Thirkill Room, Clare College

Abstract not available

# Wednesday 26th October 2011, 5.00pm - Dr Ian Bailey (School of Ocean & Earth Science, National Oceanography Centre Southampton)
New insights on old questions concerning Quaternary northern hemisphere glaciation
Venue: Thirkill Room, Clare College

Abstract not available

# Tuesday 31st May 2011, 5.00pm - Dr Axel TImmermann (SOEST, University of Hawai'i, USA); Dr Jess Adkins (CALTECH, USA)
A special set of QDG talks
Venue: Latimer Room, Clare College

5:00 pm – Dr Axel TImmermann (SOEST, University of Hawai’i, USA): ‘Understanding orbitally-driven climate change in the Southern Hemisphere’

5:45 pm – Discussion, wine and finger food

6:00 – Dr Jess Adkins (CALTECH, USA):
‘The deep ocean’s role in glacial-interglacial cycles’.

6:45 – Discussion, and more wine!

All are welcome; you may not get another chance to hear how the Southern Hemisphere and the deep ocean both control global glacial-interglacial climate change, in one sitting!

# Thursday 19th May 2011, 5.00pm - Martin Ziegler, Cardiff University
Orbital forcing of Late Pleistocene climate variability - From the global monsoon to glacial terminations
Venue: Thirkill Room, Clare College

Abstract not available

# Thursday 28th April 2011, 5.00pm - Dr Samuel Toucanne (IFREMER, France)
Pleistocene Fleuve Manche palaeoriver discharges : Response to glacial oscillations and climate changes
Venue: Latimer Room, Clare College

Abstract not available

# Friday 18th February 2011, 5.00pm - Dr Phillip Hughes, The University of Manchester
Quaternary glaciation in the Mediterranean mountains: new results from North Africa and the Balkans
Venue: Thirkill Room, Clare College

Abstract not available

# Friday 11th June 2010, 5.00pm - Richard West (Professor emeritus, Cambridge University, Clare College)
The History of Quaternary Research at Cambridge University
Venue: Thirkill Room, Clare College

Abstract not available

# Friday 13th February 2009, 5.15pm - Steven Pawley (Royal Holloway, University of London)
Canceled
Glacial Chronologies Spanning the Past 450 ka Around the Margins of the Southern North Sea and implications for the age of the Strait of Dover
Venue: Lloyd Room, Christ's College

Abstract not available

# Friday 30th January 2009, 5.15pm - Peter Koehler (Alfred Wegener Institute, Germany)
The carbon cycle during the Pleistocene
Venue: Lloyd Room, Christ's College

Abstract not available

# Friday 23rd January 2009, 5.15pm - Anne Osborne (Bristol University)
A humid corridor across the Sahara for the migration "Out of Africa" of early modern humans 120,000 years ago.
Venue: Lloyd Room, Christ's College

Abstract not available