Terrestrial Palaeoclimates

Group leader: Dr. Kathryn E. Fitzsimmons

L-R: Johannes Albert (PhD), Aditi Dave (PhD), Charlotte Prud’homme (Postdoc), Kathryn Fitzsimmons (Group leader)
L-R: Johannes Albert (PhD), Aditi Dave (PhD), Charlotte Prud’homme (Postdoc), Kathryn Fitzsimmons (Group leader)
The uppermost 80m of piedmont loess at the Remizovka site in Kazakhstan (K. Fitzsimmons for scale). Source: R. Iovita
The uppermost 80m of piedmont loess at the Remizovka site in Kazakhstan (K. Fitzsimmons for scale). Source: R. Iovita

Central Asia lies at the core of the largest and most populous continent on Earth - Eurasia - however we know little about its role in global climate dynamics past and present. This is largely because we have yet to recognise the full potential of Eurasia’s most widespread, yet most valuable, archive for past environmental change: wind-blown dust (loess). Long sequences of primary loess and buried soils blanketing Eurasia reflect responses to past climatic change over at least the last million years. Broadly speaking, loess accumulation intensifies during phases of mountain glacier advance, and decreases and is overprinted by soil formation under relatively milder climates. Central Asia and its extensive loess deposits, in particular, are notably sensitive to the interplay between the powerful climatic drivers of the north Atlantic westerlies, the polar front and the Asian monsoon. The Tibetan Plateau to the south drives the modern monsoon due to its orographic influence on precipitation regimes. Ongoing mountain uplift has likewise affected the climate of the central Asian basins to the north through time, driving aridification and continentality. In spite of its key position in the northern hemisphere climate circulation systems, however, the climatic history – and trajectory – of arid central Asia remains largely unknown.

Location of Central Asia and the main climate subsystems acting on the region. Source: NASA Shuttle Radar Topography Mission (SRTM)
Location of Central Asia and the main climate subsystems acting on the region. Source: NASA Shuttle Radar Topography Mission (SRTM)

In order to improve our understanding of climate dynamics in the terrestrial zone, we need well resolved, unambiguous palaeoenvironmental records embedded within robust chronological frameworks. While progress has been made in developing analytical techniques for reconstructing palaeoclimates in loess, and in generating new chronologies for these deposits, these are strongly geographically biased towards the north Atlantic and Asian monsoonal regions. This imbalance hinders our ability to understand the missing continental link in global climate dynamics. Furthermore, despite these developments, quantifiable reconstruction of past temperature and precipitation regimes, and their timing, eludes us still.

The Research Group for Terrestrial Palaeoclimates aims to:

  1. Develop powerful new terrestrial proxy methods for the timing and variability of past climate change, in long sedimentary archives deep in the continental zone, far from marine and ice core records;
  2. Extract quantitative palaeoclimate information from these proxy data;
  3. Generate the missing link in our understanding of northern hemisphere climate dynamics, by the reconstruction and modelling of past climatic change through time preserved in the long loess records of the Eurasian continental core.
Relative climatic change through the last million years, reflected in the magnetic susceptibility of loess sediments, can be correlated between loess profiles in Serbia (in orange, Marković et al., 2015; the Stari Slankamen profile is pictured to the left) across to China (in red; Sun et al., 2006). These records can then be correlated with global climatic changes derived from oxygen isotope proxy records (Lisiecki and Raymo, 2005; in blue). Comparable data from Central Asia are so far lacking. Source: S. Marković (photo). Figure prepared by K. Fitzsimmons
Relative climatic change through the last million years, reflected in the magnetic susceptibility of loess sediments, can be correlated between loess profiles in Serbia (in orange, Marković et al., 2015; the Stari Slankamen profile is pictured to the left) across to China (in red; Sun et al., 2006). These records can then be correlated with global climatic changes derived from oxygen isotope proxy records (Lisiecki and Raymo, 2005; in blue). Comparable data from Central Asia are so far lacking. Source: S. Marković (photo). Figure prepared by K. Fitzsimmons

To achieve these aims, we will primarily explore the following approaches:

  • Organic and inorganic geochemistry;
  • Palaeoecology;
  • Sedimentology and stratigraphy;
  • Environmental magnetism;
  • Luminescence dating and palaeomagnetism.

Our Research Group will provide an integrated synthesis of terrestrial palaeoclimatic change in the continental core of central Eurasia. On land, few major continuous palaeoenvironmental archives exist, and of these, loess deposits are not only the most geographically widespread, but also the least well developed in terms of exploiting potential proxy information. Through the development of new proxy methods, we aim to substantially expand on the palaeoenvironmental toolkit applicable to loess. Our Research Group will provide significant insights into the role played by temperate central Asia within the global climate framework past and present, and will underpin trajectories for future change in this region at risk of desertification. The new methods developed by my Group will provide a foundation on which future interdisciplinary research in comparable settings can build.