Research

My research over the years has shifted from, initially, glaciological field studies performed at the Tarfala Research Station (generously funded by the Swedish Institute) and glaciological modelling studies (under the supervision of Prof. Hans Oerlemans), as part of my undergraduate studies in Physical Geography at Utrecht University, to geomorphological studies of glaciers and ice sheets in my subsequent career.

During my Masters' studies in Quaternary Geology at the University of Maine, I made the crucial step away from glaciology and into the realm of paleoglaciology with the help of my mentors Mike Prentice, Prof. George Denton and Prof. Johan Kleman. The following geographical areas have been targeted in chronological order:

1991-1996: Antarctica

MsC and PhD thesis studies concerned the question of mid-Pliocene glaciation in Antarctica using deposits of the Sirius Group (tillite). Those favouring ice sheet stability during global mid-Pliocene warmth, base their arguments on geomorphological analysis of ice-free Antarctic terrain and the stratigraphical position of outcrops of the Sirius Group tillites. Those pertaining that these deposits are consistent with a mid-Pliocene deglaciation of the East Antarctic Ice Sheet, base their arguments on the association of mid-Pliocene diatoms as well as vegetation and faunal remains in such deposits. This clash of viewpoints has sometimes resulted in heated debates. I was able to show that the occurrence of marine diatoms in the Sirius Group at Mount Fleming, at the head of Wright Valley (see photograph below), was incompatible with glacial deposition and could therefore not help constrain the age of the deposit (see publications 1992-1999). The research has been supported by a number of foundations, foremost by the Swedish Society for Anthropology and Geography Andrée Fund, and various funds at Stockholm University.

Left Panel: Photograph from a helicopter. In the lower right corner the tongue of UpperWright Glacier is just barely visible as the margin of the East Antarctic Ice Sheet in Wright Valley, Dry Valleys, Antarctica. The upper Sirius Group deposit on Mt Fleming is shown in yellow. Right Panel: The Sirius Group is a tillite (grey matrix visible in the wall of the pit) which has been heavily deflated as witnessed by the desert pavement at the surface including boulders with varnish and ventifaction. The deposit is draped on a sandstone bedrock bench but the dominant surface lithology of the tillite deflation surface is Ferrar Dolerite. See Stroeven et al. (1996), Stroeven (1997), Stroeven & Prentice (1997) and Stroeven & Kleman (1999).

 

1998-2004: Fennoscandia

After my PhD defence in October 1996, I secured a post-doctoral grant from the Wenner-Gren Foundations which allowed for a stay at the Centre for Glaciology, Aberystwyth University, with Prof. Julien Dowdeswell (1997). During this time I started to develop my long-term research avenue, together with Prof. Jonathan Harbor, on the paleoglaciology of ice sheets in the northern Hemisphere using cosmogenic nuclide studies and numerical modelling. Such studies have since been conducted in collaboration with additional scientists from Australia, Canada, China, Norway, U.S.A. and U.K., and leans strongly on the talent of several PhD students. 


Understanding the complexity of glacial landscapes in terms of patterns of preservation and erosion has importance for understanding sediment dispersal patterns as well as the representation of ice sheets in global climate models (height and volume of ice sheets are largely determined by their subglacial conditions). Our work has convincingly shown the longevity of landscape segments in the mountains and in the Swedish lowlands, surfaces that have been largely unmodified for at least the last 0.5 million years. This has been postulated from geomorphological evidence (Kleman & Stroeven, 1997; Hättestrand & Stroeven, 2002) and has been numerically tested using the production of several cosmogenic radionuclides in quartz crystals in bedrock outcrops as a measure of length of exposure, rate of erosion, and length of “glacial” burial. Because the systematic preservation of landscape elements underneath successive ice sheets is directly related to the long-term subglacial temperature field at these locations, this evidence constitutes an important boundary condition for numerical ice sheet models that study the 3-D evolution of the Fennoscandian Ice Sheet. Realistic reconstructions of the latter are of importance in the tuning of General Circulation “climate” models (GCMs) used to predict the direction and magnitude of future climate changes.

Bradley Goodfellow (PhD, 2008) was my first PhD student and he very successfully studied the long-term landscape evolution of "relict" surfaces in the northern Swedish mountains. His last publication, in Earth Surface Dynamics, summarizes his extensive findings supporting that blockfield-mantled surfaces, while demonstrably "relict" in relation to the last ice sheet coverage, are landscape elements that have formed during the Quaternary.

Upper Panel: Photograph from Lamuvaara, with Derek Fabel to the right.  Lower Panel:  
Photograph of the tor Naakakarhakka, with Ann-Marie Robertsson, Sheila Hicks, Clas 
Hättestrand, Lena Rubensdotter and Derek Fabel to the right. The isotopic ratios between
²⁶Al and ¹⁰Be for Lamuvaara of 5.12 ± 0.44 and for Naakakarhakka of 5.34 ± 0.35 indicate
 long periods of burial and insignificant subglacial erosion by the Fennoscandian Ice Sheet.

These field studies in northern Fennoscandia (Norway, Sweden, Finland) were conducted between 1998 and 2003 with generous support from The Swedish Research Council to Stroeven (1998, 1999-2001, 2002-2004) and from NSF to Harbor (1999-2001, 2002-2004). Twenty publications of which I am co-author have their origins from this research (2002-2014), and several are still in the making.

Related to this research, a programme led by Clas Hättestrand has investigated the paleoglaciology of the Kola Peninsula (e.g., Hättestrand et al., 2007). Our research campaigns complement each other and have led to a new deglaciation map for northern Fennoscandia, an excerpt of which was published this year in Nature Communications.

2006-2011: The Cordillera of North America

The Cordilleran Ice Sheet is one of the least understood ephemeral northern Hemisphere ice sheets. The ice sheet grew and contracted over steep topograpy; the coastal ranges of British Columbia (BC) and the Yukon Territory (YT) and the inland Rocky Mountains. Because of the influence of the steep topography on ice sheet behaviour, field evidence often only has local to regional significance. 


In the field component, we investigated the chronology of the northern margin of the Cordilleran Ice Sheet, that is the timing of maximum ice sheet extent and maximum ice sheet thickness, during the last glaciation and previous glaciations. In the modelling component, we studied the behaviour of the Cordilleran Ice Sheet during the last glacial cycle. The study was performed in collaboration with Dr. Derek Fabel, Prof. John Clague, and Dr. Irina Rogozhina.Two PhD students have been involved in the research. As part of his PhD under supervision of Dr. Krister Jansson, Dr. Martin Margold (PhD, 2012) investigated the deglaciation of the southern sector of the Cordilleran Ice Sheet using meltwater traces and cosmogenic nuclide dating. He found that meltwater traces yield a regionally and temporally consistent picture of ice sheet retreat, for which hitherto there was only local evidence. Julien Seguinot investigated the evolution of the Cordilleran Ice Sheet over a glacial cycle using using PISM, an open source, parallel, high-resolution ice sheet model. He found that once initiated early-on in the last glacial cycle, some ice centres persist throughout the last glacial cycle, whereas the Cordilleran Ice Sheet only persists during relatively short bursts of time in Marine Oxygen Isotope stages 4 and 2. 

Upland in the Anville Range where, between two high points, the Cordilleran Ice Sheet
deposited two end moraines (dashed lines) from ice tongues onlapping the intervening
mountain pass region.These dated moraines (Stroeven et al., 2010) help define the
highest ice surface level during the last glacial maximum in this region.

My field research in Canada was conducted between 2006 and 2008, with generous support from The Swedish Research Council to Stroeven (2006-2008). The modelling component, including the PhD position, was equally generously funded by the Swedish Research Council to Stroeven (2009-2011). Eight publications relate to research in this region (2010-2014), and several are still in the making.

2004-2014: Tibetan Plateau and Central Asia

The research developed in Tibet and Central Asia has been stimulated by Dr. Yingkui Li, been made possible by grants from the Swedish International Development Cooperation Agency (SIDA) through their cooperation with the Swedish Research Council in their "links" programme and through the Swedish Research Council to Stroeven, and support by the Dean of Science and the Department for the full funding of two PhD students (2006-2010; 2009-2013). We have performed fieldwork each year (up to four fieldworks/year) since 2004 in the following regions (responsible scientist(s) in brackets).

Kunlun Shan (2004, Li, Liu)

Dr. Yingkui Li, a former postdoctoral researcher with Harbor within the Fennoscandia project (Li et al., 2005, 2008), introduced us to long-term landscape evolution issues in Central Asia starting with a fieldwork in the Kunlun Shan (together with Gengnian Liu, Jon Harbor and Marc Caffee). Here we sampled river sands, fluvial terraces, and moraines to understand the complexity of landscape evolution in this region. Some results from this first field season have recently been published (Li et al., 2014). We also attempted to connect to an ongoing debate whether the Tibetan Plateau had been covered by an ice sheet the size of Greenland during the last glaciation. We found no evidence for this phenomenon, but decided that this question was perhaps better addressed in other regions of the Tibetan Plateau which motivated the writing of proposals to SIDA to start a new project in the Bayan Har Shan. 

Bayan Har Shan (2005-2007, Stroeven, Harbor, Heyman)

Support by Sida (2005-2007) allowed for the development of a new project on the north-eastern margin of the Tibetan Plateau in a region supposedly covered by a Tibetan Ice Sheet during the last glaciation, but for which Chinese scientists had presented evidence for the existence of a much smaller ice sheet during that time. Jakob Heyman (PhD, 2010) investigated this area for his PhD degree and found that former glaciation was highly restricted to the highest mountains. For this excellent piece of work he was awarded the Alfortska priset for the best thesis in Physical Geography in Sweden during 2010 and was awarded the Young Scientist Outstanding Poster Paper (YSOPP) Award of the European Geosciences Union two years in a row (2008, 2009). The work builds on three field seasons, two of which Jakob Heyman led.

Haizi Shan (2008-2011, Stroeven, Harbor, Fu)

Another grant by Sida (2008-2010) was instrumental in the organisation of fieldwork in support of another PhD study on the paleoglaciology of the Tibetan Plateau. The choice of fieldwork area, the Haizishan area, was motivated by the fact that this region is riddled by lakes and bare-bedrock outcrops- much as can be seen in other regions formerly glaciated by ice sheets, but which is rare on the Tibetan Plateau. Thanks to the support of the Dean of Science and the Department, we were able to recruit Ping Fu (PhD, 2013). She found that the paleoglaciology of this region immediately south of Jakob Heyman's was characterised by ice cap glaciations and with the timing of glaciation deviating from the former study. The latter is perhaps due to the influence of monsoon precipitation which does not affect the Bayan Har Shan araea. The work builds on four field seasons, three of which Ping Fu led. For her work, Ping Fu was awarded the Young Scientist Outstanding Poster Paper (YSOPP) Award of the European Geosciences Union 2013.

Eastern Tian Shan (2010, Li, Liu)

After many years of intensive research on the eastern Tibetan Plateau we realised that differences in timing of glaciation were probably due to large-scale shifts in climate patterns, affecting some regions differently than others. We therefore decided to "extend" the Tibetan dataset towards the high mountain regions of Central Asia, and the first ideas of the Central Asia Paleoglaciology Project (CAPP) were born. It was again Yingkui Li and Gengnian Liu who were instrumental in jump-starting this phase of the project by inviting Jon and myself to participate in a field season investigating the glacial history of the Urumqi River source region in the Tianger Range and the glacial history of the mountain slope on the other (southern) side of the water divide (Li et al., 2014). Due to differences in climate (drier) and hypsometry (more gentle), the southern slope preserves a much longer glacial record than the much-better investigated northern slope.

The CAPP logo designed by Casey Beel.

Western Tian Shan (2011-12, 2014, Stroeven, Harbor, Blomdin, Gribenski)

Thanks to an internationalisation grant from the Vice Chancellor of Stockholm University, my application, including prioritized partner universities in Russia, China and the USA, received enough support to organise a constituting meeting and kick-off of the CAPP project in Bishkek, Kyrgyzstan, and a visit to the Inylcheck Glacier region, summer 2011. Thanks to a regular grant from the Swedish Research Council to Stroeven (2012-2015), including resources for a PhD student, the project now includes two PhD students (Robin Blomdin, Natacha Gribenski) and more than a dozen partner universities and academy of sciences, all focussed on a documentation of and understanding of the spatial variability of glacial responses. Field seasons to the Eastern Tian Shan (2010), central Tian Shan in China (2012), and the Inylcheck area (2011, 2012; Lifton et al., 2014), Ak Shyrak area (2012, 2014), and the Ala Archa mountains close to Bishkek in Kyrgyzstan, have yielded an opportunity to field-check the glacial geomorphological map of the Tian Shan (Stroeven et al., 2013).The study of the Inylcheck area, spearheaded by Nat Lifton, details the chronology of the Inylcheck Glacier and adjacent glaciers in the Sary-Dzaz valley and constitutes the project's first "datapoints" in the western Tian Shan.

First Central Asia Workshop, CAIAG, Bishkek, 29/7-1/8 2011. From left to right Yixin 
Chen (Peking University), Arjen Stroeven (Stockholm University), Ryskul Usubaliev  
(CAIAG), Jakob Heyman (Purdue University), Mikhail Ivanov (Moscow State University), 
Yingkui Li (University of Tennessee), Tibi Codilean (GFZ Potsdam), Bolot Moldobekov 
(CAIAG, director), Ian Harbor (Peace Corps, Kyrgyzstan), Jon Harbor (Purdue University), 
and Dmitry Petrakov (Moscow State University). The workshop and subsequent field trip 
to the Inylcheck Glacier was sponsored by the Vice Chancellor of Stockholm University.

Same group as above during the fieldtrip, here at the Inylcheck settlement, including Nat
Lifton (Purdue University), third from the left, another Peace Corps volunteer, and three
 drivers.

Altai Mountains (2013-14, Blomdin, Gribenski)

The second area of interest to CAPP in central Asia is the Altai Mountains. Straddling the borders between, primarily, China, Russia and Mongolia, studying its glacial history involves fieldworks in all three countries. Over the past two years, each region has been targeted by at least two field campaigns, organised through Chinese (Zhang Wei), Russian (Dmitry Petrakov), and Mongolian (Michael Walther) colleagues, respectively. Blomdin and Gribenski have led the research in these field visits, and they have the further responsibility for the analysis of cosmogenic (Blomdin) and optically-stimulated luminescence (OSL; Gribenski) analyses, paper writing, and the production of their PhD theses.


We have currently written 14 articles, and published 4 glacial geomorphological maps, from the work conducted in Tibet-central Asia. We expect that by the end of the current project we will have c 20 articles and five published maps which will yield a consistent database of information (glacier extent and timing) which we, in future projects, will analyse in terms of climate change using medium-scale climate modelling tools.

Field reconnaissance trip in Mongolia. Upper panel. OK we are lost! Middle panel.
This country is full of pretty tors, what a pleasant surprise. Lower panel. The 2012
Mongolia field team. V. Oktyabri (Germany), A. Tuvshinjargal (National University
of Mongolia), J. Munkhbayar (driver), D. Оtgonbayar (National University of Mongolia,
Khovd campus), Jon Harbor (Purdue University), Robin Blomdin (Stockholm
University), Arjen Stroeven (Stockholm University), J. Jamyandorj (driver), Natacha
Gribenski (Stockholm University), Krister Jansson (Stockholm University), Aleksandr
Orkhonselenge (National University of Mongolia).