Tracking 800,000 Years of Climate Change: Snippets from a Field Campaign in Tajikistan
by Aditi Krishna Dave
Exploring loess deposits
Loess (or wind-blown dust) deposits are natural archives that preserve responses to past climate and environmental change – thus, allowing for reconstruction of climate over the past hundreds of thousands of years, especially in arid and semi-arid areas. The piedmonts of the Alai-Pamir ranges in southern Tajikistan (Figure 1) are blanketed by thick loess deposits that act as crucial archives for understanding palaeoclimatic variability in continental Eurasia [1]. Furthermore, owing to its topography and location, which lies at the intersection of major climate subsystems, the deposits in this region provide unique insight into the dynamic interplay between geomorphic processes and climate change on dust transport, deposition and preservation [2, 3]. However, these loess records have remained largely unexplored.
In 2018, our research group at the Max Planck Institute for Chemistry (Mainz, Germany) undertook a 5-week campaign to continuously sample >100 m thick loess deposit, which preserves more than 800,000 years of climate change, at Karamaidan in southern Tajikistan. The field campaign was organised in cooperation with the Tajik National University and consisted of 17 scientists, one professional mountaineer and keen local villagers. Our research group aims to exploit the relatively continuous and high accumulation rates of loess at Karamaidan to generate a high resolution, quantitative multi-proxy record of long-term paleoclimatic variability, thus facilitating a better understanding of climate dynamics in Central Asia over Quaternary timescales.
Field Campaign: Camping, Digging, Logging and Sampling
In addition to expectations of producing good science, any field campaign has the cumbersome tasks of administration, organisation and logistics. Our expedition to the remote Karamaidan was no different, especially with no native Russian speaker, we had the additional linguistic challenge of having to organise everything in Russian! Our first week was spent finalising permits, stocking up on rations and bargaining for basic camp utensils and equipment at the bazaars and finding willing cooks and drivers. Finally, we were ready to deal with the logistics of transporting 17 scientists and their 1000+ kg of scientific equipment and personal luggage to the campsite – which involved diversions off the main roads due to recent landslides. Upon arrival in Karamaidan, we decided to set our camp at the bottom of the loess cliff, strategically located close to a local villager’s house with whom we negotiated access to fresh spring water and a bread oven, and plenty of orchard trees to save the tents from combusting in the Tajik summer heat (which typically exceeds 40 °C).
After we set up camp, our team divided into two groups – one focused on surveying and selecting overlapping stratigraphic sections for sampling; and the other to clear pathways through the densely vegetated slopes to provide access between the camp and targeted loess sampling sections. Our team then assembled the ropes for abseil at four partially overlapping sections along the cliff area. Simultaneously, four pairs of scientists cleaned back the four sections to prevent contamination from recent sediment movement, and to expose a clean surface for logging and sampling (Figure 2). The next few days were spent logging and describing the stratigraphic sections followed by in situ measurement of magnetic susceptibility using a portable Bartington meter. Magnetic susceptibility is a measure of the magnetisation ability of the loess material – which is generally indicative of warm and humid soil forming conditions or the cold and dry dust accumulation phases. In view of these results and the detailed description of the stratigraphic logs, we finally chose three partially overlapping sections yielding the highest accumulation rates for sampling. The next three weeks involved continuous and high-resolution sampling of bulk material for paleoenvironmental analyses and age control (Figure 2). Our field campaign finally ended after 5 tiring weeks, yielding more than 700 kg of samples and a team of 17 exhausted (but delighted, Figure 3) scientists, who are excitedly looking forward to the next year of laboratory analyses.
Being in the Field in Tajikistan
Fieldwork in this remote area of Tajikistan, albeit sweaty and dusty(!), has given me the unique opportunity to witness the enthralling landscape – where the dust-covered piedmonts give way to horizons marred by beautiful snow-covered peaks of the Pamirs – a magnificent sight indeed! Furthermore, the tiny scattered villages with their apricot orchards, the warm hospitality of the Tajikis and their love for Bollywood music (guess where I come from? ;) ) only accentuated the beauty of this landlocked country of Central Asia!
Aditi Krishna Dave
Doctoral student, Max Planck Institute for Chemistry, Mainz, Germany
If you have questions or comments concerning Aditi's post, please leave a comment below, or send her an email. You can also connect with her on ResearchGate and Facebook.
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References:
[1] Ding, Z. L., Ranov, V., Yang, S.L., Finaev, A.,Han, J.M., Wang, G.A., 2002. The loess record in southern Tajikistan and the correlation with Chinese loess. Earth and Planetary Science Letters 200, 387-400. https://doi.org/10.1016/S0012-821X(02)00637-4
[2] Fitzsimmons, K.E., Sprafke, T. Zielhofer, C., Guenter, C., Deom, J.-M., Sala, R., Iovita, R., 2018. Loess accumulation in the Tian Shan piedmont: Implications for palaeoenvironmental change in arid Central Asia. Quaternary International 469A, 30-43. https://doi.org/10.1016/j.quaint.2016.07.041
[3] Machalett, B., Oches, E. A., Frechen, M., Zöller, L., Hambach, U., Mavlyanova, N. G.,Marković, S. B., and Endlicher, W., 2008. Aeolian dust dynamics in central Asia during the Pleistocene: Driven by the long‐term migration, seasonality, and permanency of the Asiatic polar front. Geochemistry, Geophysics, Geosystems 9, Q08Q09. https://doi.org/10.1029/2007GC001938
Exploring loess deposits
Loess (or wind-blown dust) deposits are natural archives that preserve responses to past climate and environmental change – thus, allowing for reconstruction of climate over the past hundreds of thousands of years, especially in arid and semi-arid areas. The piedmonts of the Alai-Pamir ranges in southern Tajikistan (Figure 1) are blanketed by thick loess deposits that act as crucial archives for understanding palaeoclimatic variability in continental Eurasia [1]. Furthermore, owing to its topography and location, which lies at the intersection of major climate subsystems, the deposits in this region provide unique insight into the dynamic interplay between geomorphic processes and climate change on dust transport, deposition and preservation [2, 3]. However, these loess records have remained largely unexplored.
 |
| Figure 1: Location of Karamaidan, Tajikistan (inset). The exposed loess cliff at Karamaidan with the four overlapping sections |
In 2018, our research group at the Max Planck Institute for Chemistry (Mainz, Germany) undertook a 5-week campaign to continuously sample >100 m thick loess deposit, which preserves more than 800,000 years of climate change, at Karamaidan in southern Tajikistan. The field campaign was organised in cooperation with the Tajik National University and consisted of 17 scientists, one professional mountaineer and keen local villagers. Our research group aims to exploit the relatively continuous and high accumulation rates of loess at Karamaidan to generate a high resolution, quantitative multi-proxy record of long-term paleoclimatic variability, thus facilitating a better understanding of climate dynamics in Central Asia over Quaternary timescales.
Field Campaign: Camping, Digging, Logging and Sampling
In addition to expectations of producing good science, any field campaign has the cumbersome tasks of administration, organisation and logistics. Our expedition to the remote Karamaidan was no different, especially with no native Russian speaker, we had the additional linguistic challenge of having to organise everything in Russian! Our first week was spent finalising permits, stocking up on rations and bargaining for basic camp utensils and equipment at the bazaars and finding willing cooks and drivers. Finally, we were ready to deal with the logistics of transporting 17 scientists and their 1000+ kg of scientific equipment and personal luggage to the campsite – which involved diversions off the main roads due to recent landslides. Upon arrival in Karamaidan, we decided to set our camp at the bottom of the loess cliff, strategically located close to a local villager’s house with whom we negotiated access to fresh spring water and a bread oven, and plenty of orchard trees to save the tents from combusting in the Tajik summer heat (which typically exceeds 40 °C).
 |
| Figure 2: Action in the field: Team member’s abseiling down the loess section (left) and sampling bulk sediment material for palaeoenvironmental analyses (right) |
After we set up camp, our team divided into two groups – one focused on surveying and selecting overlapping stratigraphic sections for sampling; and the other to clear pathways through the densely vegetated slopes to provide access between the camp and targeted loess sampling sections. Our team then assembled the ropes for abseil at four partially overlapping sections along the cliff area. Simultaneously, four pairs of scientists cleaned back the four sections to prevent contamination from recent sediment movement, and to expose a clean surface for logging and sampling (Figure 2). The next few days were spent logging and describing the stratigraphic sections followed by in situ measurement of magnetic susceptibility using a portable Bartington meter. Magnetic susceptibility is a measure of the magnetisation ability of the loess material – which is generally indicative of warm and humid soil forming conditions or the cold and dry dust accumulation phases. In view of these results and the detailed description of the stratigraphic logs, we finally chose three partially overlapping sections yielding the highest accumulation rates for sampling. The next three weeks involved continuous and high-resolution sampling of bulk material for paleoenvironmental analyses and age control (Figure 2). Our field campaign finally ended after 5 tiring weeks, yielding more than 700 kg of samples and a team of 17 exhausted (but delighted, Figure 3) scientists, who are excitedly looking forward to the next year of laboratory analyses.
 |
| Figure 3: Team Tajikistan – Last day in the field! Picture credits: Maike Nowatski |
Being in the Field in Tajikistan
Fieldwork in this remote area of Tajikistan, albeit sweaty and dusty(!), has given me the unique opportunity to witness the enthralling landscape – where the dust-covered piedmonts give way to horizons marred by beautiful snow-covered peaks of the Pamirs – a magnificent sight indeed! Furthermore, the tiny scattered villages with their apricot orchards, the warm hospitality of the Tajikis and their love for Bollywood music (guess where I come from? ;) ) only accentuated the beauty of this landlocked country of Central Asia!
Aditi Krishna Dave
Doctoral student, Max Planck Institute for Chemistry, Mainz, Germany
If you have questions or comments concerning Aditi's post, please leave a comment below, or send her an email. You can also connect with her on ResearchGate and Facebook.
__________________________________________________________________
References:
[1] Ding, Z. L., Ranov, V., Yang, S.L., Finaev, A.,Han, J.M., Wang, G.A., 2002. The loess record in southern Tajikistan and the correlation with Chinese loess. Earth and Planetary Science Letters 200, 387-400. https://doi.org/10.1016/S0012-821X(02)00637-4
[2] Fitzsimmons, K.E., Sprafke, T. Zielhofer, C., Guenter, C., Deom, J.-M., Sala, R., Iovita, R., 2018. Loess accumulation in the Tian Shan piedmont: Implications for palaeoenvironmental change in arid Central Asia. Quaternary International 469A, 30-43. https://doi.org/10.1016/j.quaint.2016.07.041
[3] Machalett, B., Oches, E. A., Frechen, M., Zöller, L., Hambach, U., Mavlyanova, N. G.,Marković, S. B., and Endlicher, W., 2008. Aeolian dust dynamics in central Asia during the Pleistocene: Driven by the long‐term migration, seasonality, and permanency of the Asiatic polar front. Geochemistry, Geophysics, Geosystems 9, Q08Q09. https://doi.org/10.1029/2007GC001938
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