Peter Molnar and the Crafoord Medal

This post comes from Carl Hoiland who is a Ph.D. Candidate at Stanford University working on tectonics of the Cordillera, but is currently an NSF GRFP GROW visiting researcher at Stockholm University (a mouthful, I realize) where he is collaborating on a project to better understand the geology of the Arctic.

Crafoord Days at the Royal Swedish Academy of Sciences

Peter Molnar, awardee of the 2013 Crafoord Prize in Geosciences
Image from the Royal Swedish Academy of Sciences
There is no Nobel Prize offered for geoscience. Alfred Nobel himself intended that honor exclusively for physics, chemistry, medicine, peace, and literature.  And though there exist a number of respectable awards for geoscientists from a variety of societies and institutions, it is obvious that with regard to prestige, financial benefit, and global admiration there is no true substitute to the Nobel.  A few awards do, however, come close in their attempt to praise the accomplishments of uniquely influential figures within our science. Perhaps the most prestigious of these – which, like the Nobels, is awarded by the Royal Swedish Academy of Sciences and includes a sizeable financial award of more than $600,000 – is the Crafoord Prize, given for geoscience every fourth year. See more information here.

 

Crafoord Medal.
Image from the Royal Swedish Academy of Sciences





Yesterday, here in Stockholm, with H.M. King Carl XVI Gustaf and H.M. Queen Silvia of Sweden, the Crafoord Prize was awarded to Geologist/Geophysicist Peter Molnar.  And because I happened to be here already as a visiting researcher at Stockholm University, I had the opportunity to join in the festivities of the Crafoord Days celebration, which in addition to the award ceremony included a scientific symposium and a public lecture with Q&A from the laureate.
 
 
 
 
 
 

 


Royal Swedish Academy of Science, Lilla Frescativägen 4A, 114 18 Stockholm where the first two days of the Crafoord Days were celebrated, photo by Lars Falck, ©RSAS.

 

It is fitting that the award be given in Stockholm, one of the few densely populated cities in the world where natural rock outcrops are nearly as ubiquitous as pavement. And where more than a billion years of erosion and exhumation has exposed the deep roots of an ancient orogen. Everyone who lives here seems to grow more intimately aware of their proximity and ultimate dependence on the Earth.

 

Stockholm city playground (for both kids and geologists!). Note the many cross cutting relationships in these Svecofennian outcrops that were scoured out by ice sheets. Stockholm is a fitting place to confer one of the highest honors in geology.

 

A few years back, as I was preparing to join Chris Spencer and others on a geologic excursion across the Indian Himalaya (see T.G. blog posts: Ladakhand possibly High in the Himalaya) I remember being especially fascinated by a 1990 review article I read by Peter Molnar and Phillip England published in the journal Nature.  It came to me at a time when I was still just barely beginning to discover the extent to which geology could both capture the imagination while intriguing the intellect. So, even if the idea was already nearly two decades old to the community, to me it was refreshingly new, a novel perspective on the Earth around me. I was captivated.
In their paper that has now been cited one-thousand times since in the literature, Molnar and England (1990) walk the reader through a thought experiment in which climate change is shown as being capable of driving the uplift of mountains worldwide, creating some of the highest mountain peaks in Earth’s history (e.g. the Himalayas). This was exactly opposite the previous notion that orogenic uplift as a result of tectonic shortening is what leads to changes in the climate system. Naturally, then, they frame the question of which drives which as one of “chicken or egg”. 

 

Figure 2b of Molnar & England (1990): If a gentle highland of mean elevation h (left) were deeply incised by rivers that eroded valleys nearly to sea level (right), the mean elevation should drop slightly to about 5h/6, the remaining rock and Moho would rise by an amount equal to h, and the highest peaks would be much higher than before, In this way, a climatically induced increase in erosion rate can cause exhumation of rocks, and hence the appearance of uplift, with no increase (in fact, with a decrease) in mean elevation.”
Photo by Jani Radebaugh (here),Ganges River Gorge, Indian Himalayas, exemplifying steep river incision resulting from intense Monsoon precipitation. Such a scenario results in uplift of the peaks despite a decrease in mean elevation (as per Molnar & England, 1990).

 

I, as a proto-geologist, was still grappling with the previous view and yet now was struck by a new paradigm altogether. First was that the long march of plate tectonics could drive the climate system towards extremes like the ice ages or the Indian Monsoon; and, second, even more earth-moving a notion, was that the seemingly-intangible climate system itself could actually drive the uplift of millions of tons of solid rock high into the skies!
Molnar’s work goes far beyond the paper I just described and spans topics from the driving forces behind plate tectonics, to the formation of mountain belts, to lithospheric delamination and orogenic collapse, to frictional heating of the crust, to earthquake mechanics and risks in the southern Himalayas, etc.
The following is a clip of Martin Whitehouse of the Swedish Museum of Natural History discussing Peter’s work.

The Crafoord Days celebration calls for a symposium to be held in the specific sub-discipline of the recipient, which this year was for Tectonics of the Himalaya. I was enthused to be able to hear talks presented from some of the people whose papers I had always admired. Here was the line-up: Mike Searle, Oxford; Dan McKenzie, Cambridge; JoAnn Stock, CalTech; Leigh Royden, MIT; Jean-Pierre Burg, ETH-Zurich; Peizhen Zhang, China EQ Admin.; and Clare Warren, Open University.
Abstracts from their talks can be found here.
What I appreciated most about the symposium is how much room for healthy disagreement there was between the speakers, and with no disrespect for this year’s laureate, Peter Molnar. He seemed aware as any that the verdict is still out on many of the proposed models for the Himalayas, but that despite our own preferences and opinions there is always a need for collaboration, discussion, and lively debate amongst a community of researchers all chipping away at the same problems.

 

The society chose to award Peter Molnar the Crafoord Prize “for his ground-breaking contribution to the understanding of global tectonics, in particular the deformation of continents and the structure and evolution of mountain ranges, as well as the impact of tectonic processes on ocean-atmosphere circulation and climate“. What they failed to mention is the impact his work has had on inspiring a new generation of young scientists to join in the effort of trying to tease out Earth’s secrets and how our planet has evolved and is evolving through time.

 

 

 

A few selected Molnar contributions:

 

Molnar P., Tapponnier P., 1975, Cenozoic tectonics of Asia: Effects ofa continental collision: Science, v. 189, p. 419–426doi:10.1126/science.189.4201.419.Houseman, G.A., McKenzie, D. & Molnar, P., 1981, Convectiveinstability of a thickened boundary layer and its relevance for the thermalevolution of continental convergent belts. J. Geophys. Res. 86, 6115- 32.Molnar P., England P., 1990a, Late Cenozoic uplift of mountainranges and global climate change: Chicken or egg?: Nature, v. 346, p. 29–34Molnar P., England P., 1990b, Temperatures, heat flux, andfrictional stress near major thrust faults: Journal of Geophysical Research, v.95, p. 4833–4856 doi:10.1029/JB095iB04p04833.

 

Molnar P., Stock J.M., 2009, Slowing of India’s convergence withEurasia since 20 Ma and its implications for Tibetan mantle dynamics:Tectonics, v. 28, TC3001, doi:10.1029/2008TC002271.


 


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