Dr Andrew Carr

Senior Lecturer in Physical GeographyDr Andrew Carr

Bennett Building F43

Tel: +44 (0)116 252 3851

Email: asc18@le.ac.uk

ORCID ID: orcid.org/0000-0001-5794-6428

Research

My research focus is primarily on arid environments and palaeoenvironmental change in the tropics and low latitudes. This work is underpinned by the use of stable isotope environmental proxy methods and the development of depositional chronologies using optically stimulated luminescence (OSL) dating methods.  My main interests are:

Palaeoenvironmental change in southern Africa

A significant proportion of my work has focused on Pleistocene environmental changes in desert and coastal environments of southern Africa. This area lies within an important transitional zone between the sub-tropical and temperate latitudes, and as a result it has been very sensitive to past global climatic changes. This work has taken various forms and has included the development of chronologies for relict aeolian (wind-blown) landforms, the analysis of fossil pollen from wetland and lake sediments and the application of stable isotope and biomarker proxy techniques. Currently, I am a member of an international team of researchers that makes up the European HYRAX research project. This project seeks to develop detailed records of past environmental change in this region using a remarkable source of evidence – the ancient latrines of the Rock Hyrax.

Stable isotopes and organic matter (biomarker) palaeoenvironmental proxies

This work focuses on the analysis of organic matter composition (biomarkers) and the use of stable isotope analyses as palaeoenvironmental proxies. Initiated by a project “Novel Biomolecular insights into dryland ecosystem dynamics”, which was funded by the Leverhulme Trust (2010-2012,) this work has focused on analysing the composition and fate of organic matter in arid and semi-arid environments. A key goal has been to consider the nature and preservation of terrestrial organic matter across southern Africa, and the implications (particularly in terms of relationships with climatic parameters) for the interpretation of Quaternary biomarker/stable isotope records from sedimentary archives and hyrax middens. This work has involved lipid biomarker analysis, compound-specific stable isotope analyses and py-GC/MS techniques for the elucidation of macromolecular organic matter composition, including:

  • The analysis of organic matter sources (primarily plant leaf waxes and cuticles)
  • Characterisation of the macromolecular composition of organic matter in arid dryland soils with a view to understanding the mechanisms and rates of (selective?) OM degradation in arid environments
  • The fate and preservation of organic matter in long-term (Quaternary) sedimentary archives, and associated implications for palaeoenvironmental reconstructions.

Additionally, recent work has begun to focus on the analysis of organic matter from regions of extreme aridity, and to consider the results in the context of instrumentation being developed to detect organic material on future Mars missions. You can read more about this work here.

Drivers of long-term landscape change

One approach to reconstructing the nature of past environmental changes is to consider evidence with the landscape and sedimentary record. Linking in with my interest in luminescence dating, some of this work has sought to use records of past landscape change to infer past climatic shifts. A large proportion of my work in this area has, however, focused more specifically on the responses of landscapes to environmental change, particularly the coastal regions of southern Africa. Here we have sought to understand how coastal landscapes responded to long-term cycles (glacial-interglacial) of sea-level change driven by the waxing and waning of the ice-sheets during the middle and late Pleistocene. From these periods it's also been shown that during the last interglacial relative sea level was markedly higher than the present, which has important implications for understanding global ice volumes during periods of relative climatic warmth.

Geochronology

The chronological framework underpinning much of my research has been based on the application optically stimulated luminescence (OSL) dating techniques. This technique provides depositional (burial) age estimates for quartz and feldspar minerals and is typically used to construct chronologies of sediment deposition and landscape change, particularly phases of past aeolian (dune) sedimentation. In 2012 I was involved in the set up the new luminescence dating facility at the Department of Geography at Leicester. This includes bespoke preparation facilities, a new Risoe DA20 OSL/TL system with an accompanying single grain reader and a Risoe low-level beta counter. Research projects currently include the reconstruction of aeolian sediment accumulation in the Mojave Desert and the provision of age constraints for tectonic activity in the Tien Shan Mountains (in collaboration with Oxford University). I have also used the single grain technique to consider the potential effects of bioturbation (post-depositional disturbance) on the reliability of OSL age estimates.

Publications

Example publications (full details of all publications can be found here)

Southern African Palaeoenvironmental Change

Chase, B.M., Chevalier, M., Boom, A., Carr, A.S. 2017. The dynamic relationship between temperate and tropical circulation systems across South Africa since the Last Glacial Maximum. Quaternary Science Reviews 174, 54-62.

Collins, J.A., Carr, A.S., Schefuß, E., Boom, A., Sealy, J. 2017. Investigation of organic matter and biomarkers from Diepkloof Rockshelter: insights into Middle Stone Age site usage and palaeoclimate. Journal of Archaeological Science 85, 51-65

Roberts, D.L, Neumann, F.H., Cawthra, H.C., Carr, A.S., Scott, L., Durugbo, E.U., Humphries, M.S., Cowling, R.M., Bamford, M., Musekiwa, C., MacHutchon, C.M. 2017. Palaeoenvironmental fluctuations during a terminal Oligocene-early Miocene transgression at the southwestern tip of Africa. Global and Planetary Change 150, 1-23

Carr, A.S., Chase, B.M., Boom, A., Medina-Sanchez, J. 2016. Stable isotope analysis of rock hyrax faecal pellets, hyraceum and associated vegetation in southern Africa: implications for dietary ecology and palaeoenvironmental reconstructions. Journal of Arid Environments 134. 33-48

Carr, A.S., Chase. BM. Mackay, A. 2016. Mid to Late Quaternary Landscape and Environmental Dynamics in the Middle Stone Age of Southern South Africa. In: Jones, S., Stewart, B.A., (Eds.), Africa from MIS 6-2: Population Dynamics and Paleoenvironments, pp. 23-47. Springer.

Quick, L.J., Carr, A.S., Meadows, M.E., Boom, A., Bateman, M.D., Roberts, D.L., Reimer, P.J., Chase, B.M. 2015. A late Pleistocene–Holocene multi-proxy record of palaeoenvironmental change from Still Bay, southern Cape Coast, South Africa. Journal of Quaternary Science 30, 870-885.

Chase, B.M., Boom, A., Carr, A.S., Carré, M., Chevalier, M., Meadows, M.E., Pedro, J.B., Stager, J.C., Reimer, P.J 2015. Evolving southwest African response to abrupt deglacial North Atlantic climate change events. Quaternary Science Reviews 121, 132-136

Carr, A.S., Boom, A., Chase, B.M., Meadows, M.E., Grimes, H.L. 2015. Holocene sea level and environmental change on the west coast of South Africa: evidence from plant biomarkers, stable isotopes and pollen. Journal of Paleolimnology 53 (4), 415-432

Chase, B.M., Lim, S., Chevalier M., Boom, A., Carr, A.S., Meadows, M.E., Reimer, P.J. 2015. Influence of tropical easterlies in southern Africa's winter rainfall zone during the Holocene. Quaternary Science Reviews 107, 138-148

Chase, B.M., Boom, A., Carr, A.S., Meadows, M.E., Reimer, P.J. 2013. Holocene climate change in southernmost South Africa: rock hyrax middens record shifts in the southern westerlies. Quaternary Science Reviews 82, 199–205

Truc, L., Chevalier, M., Favier, C., Cheddadi, R., Meadows, M.E., Scott, L., Carr, A.S., Smith, G.F., Chase, B.M. 2013. Quantification of climate change for the last 20,000 years from Wonderkrater, South Africa: implications for the long-term dynamics of the Inter-tropical Convergence Zone. Palaeogeography Palaeoclimatology Palaeoecology 386, 575-587

Stable isotopes and organic matter (biomarker) palaeoenvironmental proxies

Herrmann, N., Boom, A., Carr, A.S., Chase, B.M., West, A.G., Zabel, M., Schefuß, E. 2017. Hydrogen isotopic fractionation of leaf wax n-alkanes in soils from southern African ecosystems. Organic Geochemistry 109, 1-3

Herrmann, N., Boom, A., Carr, A.S., Chase, B.M., Granger, R., Hahn, A., Zabel, M., Schefuß, E. 2016. Sources, transport and deposition of terrestrial organic material: A case study from southwestern Africa. Quaternary Science Reviews 149, 215-229

Malherbe, C., Ingley, R., Hutchinson, I., Edwards, H., Carr, A.S., Harris, L., Boom, A. 2015. Biogeological analysis of desert varnish using portable Raman Spectrometers. Astrobiology, 15 (6) 442-452

Boom, A., Carr, A.S., Chase, B.M., Grimes, H.L., Meadows, M.E. 2014. Leaf wax n-alkanes and δ13C values of CAM plants from arid southwest Africa. Organic Geochemistry 67, 99-102.

Carr, A.S., Boom, A., Grimes. H.L., Chase, B.M., Meadows, M.E., Harris, A. 2014. Leaf wax n-alkane distributions in arid zone South African flora: Environmental controls, chemotaxonomy and palaeoecological implications. Organic Geochemistry, 67, 72-84.

Carr, A.S., Boom, A., Chase, B.M., Meadows, M.E., Roberts, Z.E. Britton, M.N., Cumming, A.M.J. 2013. Biome-scale characterisation and differentiation of semi-arid and arid zone soil organic matter compositions using pyrolysis-GC/MS analysis. Geoderma 200-201, 189 – 201.

Carr, A.S., Boom, A., Chase, B.M., Roberts, D.L., Roberts, Z.E. 2010. Molecular fingerprinting of wetland organic matter using pyrolysis-GC/MS: an example from the southern Cape coastline of South Africa. Journal of Paleolimnology 44 (4), 947-961.

Drivers of Quaternary coastal landscape change

Cawthra, H.C., Bateman, M.D., Carr, A.S., Compton, J.S., Holmes, P.J. 2014. Understanding Late Quaternary change at the land–ocean interface: a synthesis of the evolution of the Wilderness coastline, South Africa. Quaternary Science Reviews 99, 210-223

Bateman, M.D., Carr. A.S., Holmes, P.J., Dunajko, A., McLaren, S.J., Marker, M.E., Roberts, D.L, Murray-Wallace, C.V., Bryant, R.G. 2011. The evolution of barrier dune systems: A case study of the Middle-Late Pleistocene Wilderness barrier dunes, South Africa. Quaternary Science Reviews 30, 63-81

Carr, A.S., Bateman, M.D., Roberts, D.L., Murray-Wallace, C.V., Jacobs, Z., Holmes, P.J. 2010 The last interglacial sea-level highstand on the southern Cape coastline of South Africa. Quaternary Research 73, 351-362

Geochronology

Abdrakhmatov K., Walker, R., Campbell, G., Carr, A.S., Elliot, A., Hillemann, C., Hollingsworth, J., Landgraf, A., Mackenzie, D., Mukambayev, A., Magali, R., Sloan, A. 2016. Multi-segment rupture in the July 11th 1889 Chilik earthquake (Mw 8.0-8.3), Kazakh Tien Shan, identified from remote-sensing, field survey, and palaeoseismic trenching. Journal of Geophysical Research - Solid Earth 121, 4615-4640. Also a research spotlight, featured in EOS.

Carr, A.S., Armitage, S.J., Berrio-J-C., Bilbao, B.A., Boom, A. 2016. An optical luminescence chronology for late Pleistocene aeolian activity in the Colombian and Venezuelan Llanos. Quaternary Research 85, 299-312

Bateman, M.D., Carr, A.S., Murray-Wallace, C.V., Holmes, P.J., Roberts, D.L. 2008. A dating inter-comparison study on Late Stone Age Midden deposits, South Africa. Geoarchaeology, 23, 715-741.

Telfer, M.W., Bateman, M.D., Carr, A.S., Chase, B.M. 2008. Testing the applicability of a large Standardized Growth Curve (SGC) data set: Kalahari dunes, South African coastal dunes and Florida dune cordons. Quaternary Geochronology 3, 137-142

Supervision

Current PhD students

Alex Hay: "A process history of an aeolian transport corridor in the Mojave Desert" with Mark Powell (Leicester) and Ian Livingstone (Northampton).

Natalia Gonzalez Michaels: "Holocene palaeoecological change in the Sabana de Bogotá, Colombia" with Dr Arnoud Boom (Leicester).

Berivan Esen: "Organic matter in extreme environments: arid zone soils, rock varnishes and Mars analogues" NERC CENTA, with Dr Arnoud Boom and Dr Ian Hutchinson (Leicester).

Ollie Hardy: "Development of Raman Laser Spectroscopy for Mars: an inter-disciplinary approach" UK Space Agency Aurora funding with Dr Arnoud Boom and Dr Ian Hutchinson (Leicester).

Research areas for PhD supervision

  • Stable isotopes
  • Plant biomarkers
  • Palaeoecology
  • Palynology
  • Pyrolysis-GC/MS
  • Organic matter
  • Desert ecosystems
  • Luminescence (OSL) dating
  • Long-term evolution of landscapes
  • Aeolian landscape history
  • Coastal landscape history

Enquiries: If you are interested in studying for a PhD in one of these research areas, please make informal enquiries via pgrgeog@le.ac.uk.

You can also find out more information about Geography PhDs including more research areas, how to apply, funding and entry requirements.

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School of Geography, Geology and the Environment
Bennett Building
University Road
University of Leicester
Leicester
LE1 7RH

T: 0116 252 3933
E:
geography@le.ac.uk

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