My Research: Millie Watts

Hello MOOCers!

I am currently a second year PhD student at NOC working within the Geology and Geophysics research group on the Arctic Landslide Tsunami Project. This is a five year long consortium project involving 14 different research institutions across the UK. My role within it is to assess the occurrence of very large submarine landslides in the context of climate change. One of the main concerns of the work is that we already know some of the largest landslides on each have occurred during periods of rapid climate change, and it is essential that we understand the relationship between these two phenomena.

The first part of my work is looking at a set of new sediment cores collected on a cruise this summer from the Northern North Atlantic. Myself and Josh were lucky enough to spend a month aboard the RV Pelagia, during which time we collected over 80 new sediment cores from the region.

Josh and I on a recent study trip to Svalbard.

My main interest at the moment is looking at the Storegga Landslide, which occurred 8200 years ago on the Norwegian Margin. It is of interest as it happened during the coldest years of a climate event known as the 8.2 ka BP event, during which time the UK was approximately 5°C cooler on average than today. Part of my work is looking at cause and effect, which came first and could the cooling have contributed to the landslide, or vice-versa. The second part of my work is looking at older deposits from the same region and trying to date the previous large landslides that have occurred there. These deposits are clear in the sedimentary record, here is an example of what the Storegga landslide looks like after several thousand years of settling:

Why this research matters, is that when the Storegga landslide occurred, it generated a tsunami that affected large parts of the UK coastline. The amount of material moved during the event could cover all of Scotland in 100m of mud, in total 3500 km2. Previous landslides in the area have been even larger, yet we still do not have a reliable date for several of these.

Whilst we are unsure exactly what triggers these events, it is possible to use the mud that accumulates in between the landslides (hemipelagite) to build a chemical profile of the sea surface temperature, the salinity and the strength of the ocean currents. This allows us to put these events in context, and compare the changes that were taking place in the ocean then, to the changes that are happening now.

There are several other research projects that are looking at the potential triggering mechanisms, modelling the oceans and how they respond to this much sediment, the potential involvement of large lake outbursts (Lake Agassiz which covered large parts of North America at the time, suddenly drained into the North Atlantic at c. 8470 years ago), and the possible involvement of methane clathrates.

Sediment coring is one of the most important ways we can build up our records of past events, everything makes its way to the ocean at some point, and the bottom of the ocean is the perfect repository for records of changes to ice sheets, rivers, eroding mountains and oceanic circulation. Occasionally, the cores can be quite beautiful, such as the one below which went through an overturned block of laminated material:

@GeoMillie

3 Responses to "My Research: Millie Watts"

tim lazenby says:

January 7, 2015 at 8:52 pm

Hi Millie

Fascinating blog sounds like your really have some great data. I was wondering if i might pick your brains if you have time? I’m currently writing an essay and have chosen the possible comet impact theory as an exploitation for the demise of Clovis culture in N. America and the collapse of the laurentide ice sheet circa 12,900 cal BP. I’m focusing on the so called charred layer that has been proposed as evidence for this impact and was wondering if it has appeared in any of your cores at all?

Kind regards

Tim

Reply
Mark Jones says:

November 7, 2014 at 5:04 pm

Hi Millie, fascinating stuff, I envy you. I remember first hearing about the Storegga landslide a few years ago. A few things puzzle me. What is it about this location that makes it so vulnerable so that at least several episodes are visible in the sediment record? When roughly was the penultimate landslip – are we talking thousands, tens of thousands or even more years? And lastly, if the earthquake/methane hydrate release theory is correct would the necessary volume of methane be enough to conribute to any global warming? Good luck with your Phd.

Reply
1. Millie says:
  
  November 20, 2014 at 2:29 pm
  
  Hi Mark
  
  Good questions, unfortunately until our new cores are processed some of the answers are not clear! Whilst we know that the region is very prone to large landslides, the reason why is still unclear, there are several theories, the first relates to methane clathrates dissociating from sediment under excess pore pressure and destabilising the slope, this is under investigation by a team at NOC and one of the previous mentors on this course, Eric Attias. We are also looking at the earthquake theory, as the ice melted the land re-adjusted and the rebound can occur as large earthquakes which often trigger landslides. The region is at the mouth if the North Sea Fn, and area of exceptionally high sediment delivery, and this may also contribute to the slides.
  
  What we hope to find in the new core dataset is some indication of the climate changes happening at the time. There is a rough correlation between the end of the ice ages and the slides, but none of them beyond Storegga have been accurately dated. We have hopefully got a good record of the penultimate slide, the Tampen Slide, which is currently dated to 125 ka BP, and the previous 5 slides are believed to have occurred roughly once every 100 ka, though the dating on these slides is purely through geophysical interpretation of the units they have disturbed.
  
  This work will take some time, but we would hope to have some preliminary results within the next year. As to methane clathrates, potentially they could contribute substantially to global warming. Methane is approximately 21 times more powerful as a greenhouse gas than carbon dioxide, as such any large release would cause warming. What we don’t know at the moment, is whether this happens directly as a result of the slides.
  
  Interestingly, although Storegga is the largest slide in the Nordic seas, there are other vulnerable regions on the margin, including the Traenadjupet region, and the Voring Plateau, as this part of the margin hosts some of the most important and vulnerable global currents, we need to also understand how changes in the currents affect the sea floor. It is possible that these slides occur more regularly than we have previously thought, and that is part of the wider work being undertaken by the Landslide Tsunami Project.
  
  I hope that helps a little, these results will be very interesting when they come out!
  
  Reply

My Research: Millie Watts

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