Both external and internal speakers are invited to the School of Geography, Geology and the Environment to present the latest results of their research. All seminars will be accessible on Microsoft Teams until further notice. Everyone is invited, so please join us!
Thawing permafrost, peat fires, and loss of ecological legacies in Canada’s north
14 October 2020, 4.00pm
Dr. Merritt Turetsky, Director, INSTAAR, Ecology and Evolutionary Biology Department, University of Colorado Boulder
Join us for a description of climatic and environmental change occurring across the circumpolar region. Both wildfire and permafrost thaw affect vegetation and old carbon stored in deeper peat layers, and release greenhouse gases to the atmosphere on short- and longer- time frames. This seminar will discuss recent trends, outline what is known about landscape changes and feedbacks to the climate system, and propose new frameworks required to incorporate these dynamics in Earth system and climate models for more accurate predictions of our climate future.
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A deep-time perspective on macroecology
15 October 2020, 1.00pm
Dr Erin Saupe, Department of Earth sciences, University of Oxford
Dr Saupe's talk will integrate paleontological and neontological data to disentangle some of the long-term ecological and evolutionary responses of species to environmental change. More specifically, Erin will discuss some of her recent empirical and simulation research that examines (1) the causal mechanisms responsible for the latitudinal diversity gradient; (2) the role of palaeogeography in regulating extinction magnitudes; and (3) the degree to which competition structures species’ geographic ranges. These studies provide a bottom-up perspective on the generation and maintenance of biodiversity under climate change, and they enhance our understanding of the interaction of species’ intrinsic macroecological characteristics with a dynamic extrinsic climate.
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Queer Constellations & the Myth of Neighbourhood Liberation
21 October 2020, 4.00pm
Dr Jack Gieseking, University of Kentucky
The path to lesbian, gay, bisexual, transgender, and queer (LGBTQ) liberation has been narrated through a claim to long-term territory in the form of urban neighbourhoods and bars. Lesbians and queers fail to attain or retain these spaces over generations—as is often the case due to lesser political and economic power—so what then is the lesbian-queer production of urban space in their own words?
Drawing on interviews, archival research, and data visualizations with and about lesbians and queers in New York City from 1983 to 2009, my participants queered the fixed, neighbourhood models of LGBTQ space in producing what I call constellations. Like stars in the sky, contemporary urban lesbians and queers often create and rely on fragmented, fleeting experiences in lesbian-queer places, evoking patterns based on generational, racialized, and classed identities. Lesbians and queers are connected by overlapping, embodied paths and stories that bind them over generations and across many identities, like drawing lines between the stars that come and go in the sky. This queer feminist contribution to critical urban theory extends current models of queering and producing urban space.
Sustainability in the Mine Life Cycle
22 October 2020, 1.00pm
Dr Rob Bowell, SRK Consulting, Cardiff
Details to follow...
Global peatland carbon: challenges and opportunities
28 October 2020, 4.00pm
Dr Angela Gallego-Sala, University of Exeter
Peatlands store large amounts of carbon, with recent estimates doubling (Nicholls and Peteet, 2019) previous estimates (Yu et al., 2011). Not only is there uncertainty on the carbon inventories, but more importantly, in how carbon exchange between peatlands and the atmosphere will change in the future. Previous work has suggested increases in the carbon sink for high latitude peatlands and possible decreases in the tropics with warming (Gallego-Sala et al., 2018). This has been corroborated by expert survey results, although experts also suggest that gains at high latitudes may be offset by regional carbon losses from permafrost thaw, peat fires, and drought (Loisel, Gallego-Sala et al., in prep.).
On-going work will test the hypothesis that peatlands will expand into the Arctic and increase carbon accumulation rates and therefore help mitigate some of the carbon releases expected at high latitudes (ICAAP, a NERC funded project). In the tropics, carbon accumulation rates may decrease in the future (Gallego-Sala et al., 2018), and experts suggest that carbon losses are already underway and are likely to increase as a result of warmer temperatures, drought, land-use and fire (Loisel, Gallego-Sala et al., accepted). This expert survey has also highlighted the importance of not only restoration but managing and preserving current stores as a key factor in decreasing emissions from tropical peatlands in the future.
If we want to use peatlands as a possible nature based climate solution, then we need to increase our understanding of global peatland functioning and carbon cycling at high and low latitudes to better safeguard these important ecosystems and use their full potential to store carbon in the future.
Alexandrov G.A. et al. 2019. The limits to northern peatland carbon stocks. Biogeosciences
Gallego-Sala, A. V., Charman, D.J., et al. 2018. Latitudinal limits to the predicted increase of the peatland carbon sink with warming. Nature Climate Change 8, 907–913.
Nichols J., Peteet D. 2019. Rapid expansion of northern peatlands and doubled estimate of carbon storage, Nature Geoscience, doi:10.1038/s41561-019-0454-z Loisel, J., Gallego-Sala, A. et al. 2020 (under revision) Future vulnerability of the global peatland carbon sink. Nature Climate Change.
Yu, Z. C. 2011. Holocene carbon flux histories of the world's peatlands: Global carbon-cycle implications. The Holocene 21, 761-774.
Understanding the maximum-likely eruption hazards at Tongariro Volcano, New Zealand
29 October 2020, 1.00pm
Dr Mirja Heinrich, University of Auckland NZ
The Tongariro Volcanic Complex (TVC) on the North Island of New Zealand is a subduction related, active andesitic volcano composed of 12 overlapping vents located along a 13 km long graben axis within a tectonic rift. Over a brief (200 year) period ~11 ka BP, the largest explosive eruption episodes known from this volcano occurred. The activity was characterized by stable Plinian and collapsing sub-Plinian eruption columns from one or more vents. We hypothesize that tectonic movement, particularly extension along the graben led to influx of fresh mafic magma that mixed with and reactivated reservoirs to cause this “flare-up” of highly explosive volcanism.
Eruptions during multi-vent episodes progressed from north to south consistent with a northward-widening graben. Detailed textural and geochemical analyses on pyroclasts reveal that the special variations in structure and tectonics influenced the eruption style. The most stable Plinian eruptions occurred at northern vents, under highest extensional stresses and possibly widest most stable conduits. By contrast, collapsing, unstable eruption columns occurred at southern vents, where mainly degassed and crystalline magma erupted at lower ejection rates through narrower, unstable and shifting conduits. Highly variable and mingled textures within individual juvenile lapilli evidence diverse conditions developed across the conduit during the eruption.
From this study a series of systematic hazard scenarios ermerged that help understand the possible events during a future Plinianeruption episode at Tongariro Volcano.
Out of Time: The Queer Politics of Postcoloniality
4 November 2020, 4.00pm
Dr Rahul Rao, SOAS University of London
Between 2009 and 2014, an anti-homosexuality law circulating in the Ugandan parliament came to be the focus of a global conversation about queer rights. The law attracted attention for the draconian nature of its provisions and for the involvement of US evangelical Christian activists who were said to have lobbied for its passage.
Focusing on the Ugandan case, this seminar seeks to understand the encounters and entanglements across geopolitical divides that produce and contest contemporary queerphobias. It investigates the impact and memory of the colonial encounter on the politics of sexuality, the politics of religiosity of different Christian denominations, and the political economy of contemporary homophobic moral panics. In addition, Out of Time places the Ugandan experience in conversation with contemporaneous developments in India and Britain—three locations that are yoked together by the experience of British imperialism and its afterlives.
Intervening in a queer theoretical literature on temporality, Rahul Rao argues that time and space matter differently in the queer politics of postcolonial countries. By employing an intersectional analysis and drawing on a range of sources, Rao offers an original interpretation of why queerness mutates to become a metonym for categories such as nationality, religiosity, race, class, and caste. The book argues that these mutations reveal the deep grammars forged in the violence that founds and reproduces the social institutions in which queer difference struggles to make space for itself.
Distinct formation history for deep-mantle domains reflected in geochemical differences
5 November 2020, 1.00pm
Dr Luc Doucet, Curtin University, Perth Australia
The Earth’s mantle is currently divided into the African and Pacific domains, separated by the circum-Pacific subduction girdle and each domain features a large low shear-wave velocity provinces (LLSVPs) in the lower mantle. However, it remains controversial as to whether the LLSVPs have been stationary through time or dynamic, changing in response to changes in global subduction geometry.
Here we compile radiogenic isotope data on plume-induced basalts from ocean islands and oceanic plateaus above the two LLSVPs which show distinct Pb, Nd and Sr isotopic compositions for the two mantle domains. The African domain shows enrichment by subducted continental material during the assembly and breakup of the supercontinent Pangaea, whereas no such feature is found in the Pacific domain. This deep-mantle geochemical dichotomy reflects the different evolutionary histories of the two domains during the Rodinia and Pangaea supercontinent cycles and thus supports a dynamic relationship between plate tectonics and deep mantle structures.
A line in the Sand: Sea level as a territorial apparatus in a vertically relative world
11 November 2020, 4.00pm
Dr Kate Sammler, Helmholtz Institute for Functional Marine Biodiversity at the University of Oldenburg
Sea level rise has destructive material impacts on coastal communities and low-lying nations. While it is largely perceived and experienced via these impacts, the level of the sea is less often thought about as a political surface. The boundary where land and sea intersect is determined by the ocean’s height, manifesting materially as a realm of coastal features and produced politically as baselines. Defined through international treaties, baselines are the low-water line upon which national boundaries are traced. Yet, this line between adjoining mediums of land and sea is much more physically blurred and dynamic than represented politically and legally.
The difficulties of delimiting a coastline, a phenomenon referred to as the Coastline Paradox, means the measurement of a coastline is dependent on the ruler used, an entanglement of instrument and measurement. As rising sea levels encroach on physical coastlines, they are also impacting legal baselines, shifting national terrestrial and maritime borders inland posing existential dilemmas to island and low-lying nations.
This talk considers baselines as a political technology, the calculative apparatus that enacts cuts to refashion lively ocean worlds into divisible spaces and objects. It examines how the concept of sea level was constructed scientifically and enrolled in the legal demarcation of territorial borders based on a land/sea binary that is in direct opposition to many coastal peoples and First Nations, while also being eroded by rising sea levels in a climatically changing world.
12 November 2020, 1.00pm
Professor Nick Graham, Lancaster University
Details to follow...
Unmaking a Chocolate City: Spatial Aesthetics of Race and the Gentrifying Urban Landscape
18 November 2020, 4.00pm
Dr Brandi Thompson Summers, University of California, Berkeley
Dr Thompson Summers' talk focuses on the production of racial aesthetics through the management of black excess in a rapidly-gentrifying neighborhood of Washington, D.C. Tracing the city’s shift from a “Chocolate City” to becoming a “post-chocolate” cosmopolitan metropolis, I consider the continuing significance of blackness in Washington D.C. and discuss how blackness is integral to our understanding of the city. In other words, I use blackness as a logic to understand and theorize contemporary urban processes, especially processes and practices of gentrification. Theoretically, I offer black aesthetic emplacement as a way to understand how blackness is aestheticized and deployed to fortify public order, organize urban landscapes, and foster capital. Where physical imaginations of the street are enforced as linear, blackness renders the street a site of paranoia, crime, danger, and excitement.
Finally, I end with a discussion of black aesthetic emplacement in relation to continuing global protests against structural racism and police brutality in the midst of the COVID-19 pandemic.
‘Renewable´ resource potentials of the Upper Rhine Graben: Structural geology, geothermal systems, and lithium potentials
19 November 2020, 1.00pm
Dr Jens Grimmer, Department of Geothermal Energy and Reservoir Technology, Karlsruhe Institute of Technology (KIT)
The NNE-trending essentially non-volcanic Upper Rhine Graben (URG) of the European Cenozoic Rift System (ECRIS) developed from c. 47 Ma onwards in response to changing lithospheric stresses in the northwestern foreland of the Alps. Late Eocene to early Miocene normal faulting induced a total extension of 5–8 km of the 1–2 km thick Mesozoic sedimentary Franconian platform and underlying Variscan basement rocks. Distribution of an up to 3.5 km thick sedimentary graben fill and cumulative displacements near Eastern and Western Main Border Fault (EMBF, WMBF) systems suggest that subsidence of the graben floor and shoulder uplift created strong cross-sectional asymmetries with larger W-down displacements along the EMBF system.
Middle to late Miocene uplift and partial erosion of the graben fill was accompanied by volcanic activities that created the Vogelsberg and Kaiserstuhl volcanic edifices and a major unconformity along the entire URG covered by Pliocene fluvial-lacustrine sediments. Structural complexity arises from sinistral reactivation of earlier segmented NNE-striking normal faults and associated relay ramps locally causing compressional structural features within the recent regional transtensional stress field. Recent deformation is characterized by polymodal faulting though NW-striking normal faults and NNE-striking sinistral strike-slip faults prevail and partition transtensional strain in uppermost crustal levels. Thermal gradients > 50 K km-1 have been documented from several boreholes in the URG. These positive thermal anomalies are commonly regarded to result from structurally controlled convection of hydraulically active faults. Thermal energy of deep brines has been converted into electrical energy in binary geothermal power plants in France and Germany for more than ten years. Beside established geothermal usage these brines display relatively high concentrations of lithium. Lithium circulating through the geothermal power plants is considered to be extracted in order to contribute to satisfy the steadily increasing need of lithium products in central Europe.
Drüppel K, Stober I, Grimmer JC, Mertz-Kraus R (2020) Experimental alteration of granitic rocks: implications for the evolution of geothermal brines in the Upper Rhine Graben, Germany. Geothermics, v. 88, 101903, doi:10.1016/j.geothermics.2020.101903
Meixner J, Grimmer JC, Becker A, Schill E, Kohl T (2018) Comparison of different digital elevation models and satellite imagery for lineament analysis: Implications for identification and spatial arrangement of fault zones in crystalline basement rocks of the southern Black Forest (Germany). Special Issue, Journal of Structural Geology, v. 108, p. 256-268, doi: 10.1016/j.jsg.2017.11.006
Grimmer JC, Ritter J, Eisbacher GH, Fielitz W (2017) The late Variscan control on the location and asymmetry of the Upper Rhine Graben. International Journal of Earth Sciences, v. 106, no. 3, p. 827-853, doi:10.1007/s00531-016-1336-x
Meixner J, Schill E, Grimmer JC, Gaucher E, Kohl T, Klingler J (2016) Structural control of geothermal reservoirs in extensional tectonic settings: an example from the Upper Rhine Graben. Journal of Structural Geology, v. 82, p. 1-15, doi:10.1016/j.jsg.2015.11.003
25 November 2020, 4.00pm
Professor Dr Arzu Çöltekin, University of Applied Sciences and Arts Northwestern Switzerland
Details to follow...
What triggered the Cambrian Explosion?
26 November 2020, 1.00pm
Professor Rachel Wood, University of Edinburgh
The origin and rise to dominance of animals - the Cambrian Explosion - from about 575 to 520 Million years ago was a revolutionary event on Earth. But why, and how, this happened at this time remains unresolved. Here I will explore two possible triggers for this event - a rise of oxygen in the atmosphere and in the oceans, and changes in the chemistry of sea water. I will explore these using examples from insight gained from fieldwork in Siberia and Namibia. We have made great strides over the last decade in understanding how changes in the earth system itself may have enabled the rise of complex life, but there is still much we have left to understand about this extraordinary event.
Moving beyond 'stuck' and 'still' immobility: Towards a new typology of rural stayers.
2 December 2020, 4.00pm
Professor Aileen Stockdale, Queens University, Belfast
3 December 2020, 1.00pm
Dr Luke Parry, University of Oxford
9 December 2020
Dr Ana Gutierrez, University of St Andrews
Details to follow...
10 December 2020
Dr Matthew J. Comeau, Münster University
Details to follow...
16 December 2020, 4.00pm
Ophélie Véron, Department of Geography, University of Sheffield
Details to follow...