Bruce Levell

My research interest is in sedimentary basins.  I’m particularly interested in the extent to which the preserved portions of the geological record are representative  of the full sequence of geological events and depositional conditions. The sedimentary record is rarely, if ever, a continuous and compete archive of events that can be read as a time series, but neither is it always so riddled with gaps that it is uninterpretable. To what extent are its biases understandable or predictable?

• Major biases are provided by variations in preservation potential of  individual depositional events and  between depositional  sub-environments. A spectacular example of differential preservation is provided by thick, monotonous, Precambrian sandstone successions. Thsese are characteristic of the Neoproterozoic. These sandstones are homogeneous both in lithology and facies. It is generally agreed that non-vegetated landscapes encouraged the formation of sand-rich systems by virtue of more deflation by wind and less chemcial weathering in soils than at present. Even so, how did Precambrian depositional processes result in a record comprised of such highly fractionated sand /mud systems? The Jura Quartzite in the Neoproterozoic Dalradian Supergroup of Scotland is an extreme example : 5km thickness of clean sandstone. Our works shows that the key to the puzzle is differential preservation potential, with  substantial fine sediment bypass  leaving a very biased depositional record, consisting exclusively of the deepest erosional sub-environments-in this case tidal channels.
• The glacial sequences of the Port Askaig Formation, also in the Dalradian of  SW Scotland,  (probalby of Sturtian age), provide another field example of preservation controls, with relavance to our picture of “Snowball Earth”. To what extent do  the preserved sediments  provide an unbiased record of  the conditions on the surface of the planet? (Addtionally, these rocks also bear witness to the onset of the Jura Quartzite sedimentary basin).
• In broader research on the same topic I am interested in  the types and frequencies of those specific events that do get preserved,  eg storms, floods, channel switches. And the reasons why some of these events get preserved and others do not.
• Other areas of research interest include:
  • Using seismic to undertsand the flow of fluids out of sedimentary basins. This is sometimes expressed on seismic data as geometries or as changes in physical properties of the sediments that are detectable geophysically. S. How to recognise  and interpret these  clues on seismic data is not fully understood and hence they are not widely used predictively. They could be.
  • Using seismic to link the onshore and offshore geology of Northern Oman, specifcially the question of the relationship of the overthrust ophiolite nappe to the present day crust in the Gulf of Oman and the post-obduction sedimentary and tectonic history.
  • Using seismic and other data to reconstruct the sedimentary evolution of Neoproterozoiz sequences in Zambia. Bringing the techniques of the hydrocarbon exploration industry to  Minerals Exploration.

My background is in the Hydrocarbon Industry. I worked for Royal Dutch Shell for 35 years ending up as Chief Scientist Geology, VP of Exploration New Ventures, and VP Emerging Technologies which included leading research into scientific and business ideas for Shell’s new suite of investments in renewable energy.