Dr Jaco Baas
Reader in Ocean Sciences

Contact info
Position: Reader
Room: 305 Craig Mair
Phone: 01248 382894
E-mail: j.baas@bangor.ac.uk
Web: Google Scholar, ResearchGate
I am Reader in Fine Particle Dynamics in the School of Ocean Sciences, and specialise in the erosion, transport, and deposition of fine, cohesive sediment. I graduated from the University of Utrecht (the Netherlands) with a combined BSc/MSc in Sedimentary Geology in 1988. At the same university, I completed my PhD in Bedform Dynamics in 1993. Subsequently, I was Postdoctoral Research Fellow at Geomar Research Centre in Kiel, Germany (studying Late-Pleistocene climate signals in slope sediments from the North-Atlantic continental margin), at the University of Rouen, France (on resuspension processes in the Seine estuary and gravel mining in the English Channel), and at the University of Bergen, Norway (investigating grain orientations in turbidite deposits).
In 1998, I moved to the School of Earth and Environment at the University of Leeds, where I started as a Marie Curie Research Fellow and then became a Senior Research Fellow. My research in Leeds included the physical properties of particulate density currents and their deposits and the dynamics of turbulence-modulated flows carrying cohesive clay particles. I took up my present post in Bangor in January 2007.
I am a process sedimentologist with more than 25 years of experience in sediment transport in fluvial, shallow marine, and deep-marine environments. My main fundamental and applied research interests include physical and biological cohesion in fine-grained sediment, the dynamics of sedimentary bedforms, and sediment gravity flows in the deep ocean, but my expertise also stretches to hydraulic engineering, palaeoclimatology, and mathematical modelling. I combine experimental research with field work to answer timely research questions, taking a blue-skies approach as well as collaborating with industry.
Research Area
- Published
When is a clay-laden current turbulent, transitional or laminar? A new stability diagram based on flow dynamics and clay concentration.
Baas, J. H., Best, J. L., Peakall, J. & Wang, M., 1 Jan 2005.Research output: Contribution to conference › Paper
- Published
Wave ripples in mixtures of cohesive clay and cohesionless sand: Preliminary results
Baas, J. H., Westlake, A., Eggenhuisen, J., Amoudry, L., Cartigny, M., Coultish, N., McLelland, S., Mouazé, D., Murphy, B., Parsons, D., Rosewell, K., Ruessink, G., Schrijvershof, R., Wu, X. & Ye, L., 1 Jul 2014.Research output: Contribution to conference › Paper
- Published
Wave ripple development on mixed clay–sand substrates: Effects of clay winnowing and armoring
Wu, X., Baas, J. H., Parsons, D. R., Eggenhuisen, J., Amoudry, L., Cartigny, M., McLelland, S., Mouazé, D. & Ruessink, G., Nov 2018, In: Journal of Geophysical Research: Earth Surface. 123, 11, p. 2784-2801 35 p.Research output: Contribution to journal › Article › peer-review
- Published
Visualizing the flow fields of sediment-laden density currents.
Peakall, J., Best, J. L., Baas, J. H. & Al-Musallami, Z., 1 Jan 2000.Research output: Contribution to conference › Paper
- Accepted/In press
Using mixed-clay sediment gravity flow rheology as an indicator for flow velocity and run-out distance
Baker, M., Baas, J., Malarkey, J. & Silva Jacinto, R., 10 Jul 2024, (Accepted/In press) Particulate Gravity Currents in the Environment. American Geophysical UnionResearch output: Chapter in Book/Report/Conference proceeding › Chapter › peer-review
- Published
Turbulence-modulated clay-laden flow over flat beds, ripple and dunes.
Baas, J. H. & Best, J. L., 1 Jan 2005.Research output: Contribution to conference › Paper
- Published
Turbulence modulation in high-concentration clay-rich flows and the possible origin of “massive” sand beds.
Baas, J. H. & Best, J. L., 1 Jan 2000, p. 6-7.Research output: Contribution to conference › Paper
- Published
Turbulence modulation in clay-rich sediment-laden flows and some implications for sediment deposition.
Baas, J. H. & Best, J. L., 1 Jan 2002, In: Journal of Sedimentary Research. 72, 3, p. 336-340Research output: Contribution to journal › Article › peer-review
- Published
Turbulence modulation in clay-rich flows: Implications for depositional process and bed form geometry.
Baas, J. H. & Best, J. L., 1 Jan 2005.Research output: Contribution to conference › Paper
- Published
Turbulence modulation in clay-laden flows over ripples and dunes.
Baas, J. H. & Best, J. L., 1 Jan 2005.Research output: Contribution to conference › Paper
- Published
Turbulence modulation behind ripples and dunes in clay-laden currents.
Baas, J. H. & Best, J. L., 1 Jan 2004.Research output: Contribution to conference › Paper
- Published
Thresholds of intrabed flow and other interactions of turbidity currents with soft muddy substrates
Baas, J., Manica, R., Puhl, E. & Borges, A. L. D. O., 1 Dec 2016, In: Sedimentology. 63, 7, p. 2002-2036Research output: Contribution to journal › Article › peer-review
- Published
The role of biophysical cohesion on subaqueous bed form size
Parsons, D. R., Schindler, R. J., Hope, J. A., Malarkey, J., Baas, J. H., Peakall, J., Manning, A. L., Ye, L., Simmons, S., Paterson, D. M., Aspden, R. J., Bass, S. J., Davies, A. G., Lichtman, I. D. & Thorne, P. D., 28 Jan 2016, In: Geophysical Research Letters. 43, p. 1566-1573Research output: Contribution to journal › Article › peer-review
- Published
The river-estuarine transition zone (RETZ) of the Afon Dyfi (West Wales) as test bed for sediment transfer between river catchments and coastal environments.
Baas, J. H., Jago, C. F., Macklin, M. & CCCR Team, 1 Jan 2008.Research output: Contribution to conference › Paper
- Published
The pervasive role of biological cohesion in bedform development
Malarkey, J., Baas, J. H., Hope, J. A., Aspenden, R. J., Parsons, D. R., Peakall, J., Peterson, D. M., Schindler, R. J., Ye, L., Lichtman, I. D., Bass, S. J., Davies, A. G., Manning, A. J. & Thorne, P. D., 6 Feb 2015, In: Nature Communications. 6, 6257Research output: Contribution to journal › Article › peer-review
- Published
The hiding-exposure effect revisited: A method to calculate the mobility of bimodal sediment mixtures
McCarron, C. J., Van Landeghem, K. J. J., Baas, J. H., Amoudry, L. O. & Malarkey, J., Apr 2019, In: Marine Geology. 410, p. 22-31Research output: Contribution to journal › Article › peer-review
- Published
The dynamics of turbulent, transitional and laminar clay-laden flow over a fixed current ripple.
Baas, J. H. & Best, J. L., 1 Jun 2008, In: Sedimentology. 55, 3, p. 635-66Research output: Contribution to journal › Article › peer-review
- Published
The Effect of Clay Type on the Properties of Cohesive Sediment Gravity Flows and their Deposits
Baker, M. L., Baas, J. H., Malarkey, J., Silva Jacinto, R., Craig, M. J., Kane, I. A. & Barker, S., 2017, In: Journal of Sedimentary Research. 87, 11, p. 1176-1195 59 p.Research output: Contribution to journal › Article › peer-review
- Published
The Deep-Water Architecture Knowledge Base: Towards objective comparison of deep-marine sedimentary systems.
Baas, J. H., McCaffrey, W. D. & Knipe, R. J., 1 Nov 2005, In: Petroleum Geoscience. 11, 4, p. 309-320Research output: Contribution to journal › Article › peer-review
- Published
The Deep-Water Architecture Knowledge Base: Towards objective comparison of deep-marine sedimentary systems.
Baas, J. H. & McCaffrey, W. D., 1 Jan 2006.Research output: Contribution to conference › Paper
- Published
Textural characteristics of deep-marine massive sandstones: distinguishing between deposits of turbiditic and debris flow origin.
Baas, J. H., Nemec, W. & Ravnas, R., 1 Jan 2000.Research output: Contribution to conference › Paper
- Published
Temporal flow structure of an experimental particulate density current linked to textural variation of the resultant flume deposit.
Barker, S., McCaffrey, B., Haughton, P., Baas, J. H. & Choux, C., 1 Jan 2004.Research output: Contribution to conference › Paper
- Published
TDURE : A mathematical model for the duration of deposition from decelerating high-density turbidity currents.
Baas, J. H., Van Dam, R. L. & Storms, J. E., 1 Jan 2000, p. 74-75.Research output: Contribution to conference › Paper
- Published
Suspended and bedload dynamics in a tidally influenced river: the river Dyfi, Wales, UK.
Brewer, P., Vericat, D., Baas, J. H., Jago, C. F., Brasington, J., Wheaton, J. M. & Causer, F., 1 Jan 2007.Research output: Contribution to conference › Paper
- Published
Submarine Mass Movements and their Consequences, by J. Locat, & J. Mienert
Baas, J. H. & Strachan, L., 1 May 2005, Unknown.Research output: Other contribution
- Published
Streamwise turbulence modulation in non-uniform open-channel clay suspension flows
de Vet, M. G. W., Fernandez, R., Baas, J. H., McCaffrey, W. D. & Dorrell, R. M., Aug 2023, In: Journal of Geophysical Research: Earth Surface. 128, 8, e2022JF006781.Research output: Contribution to journal › Article › peer-review
- Published
Sticky stuff: Redefining bedform prediction in modern and ancient environments
Schindler, R. J., Parsons, D. R., Ye, L., Hope, J. A., Baas, J. H., Peakall, J., Manning, A. J., Aspden, R. J., Malarkey, J., Simmons, S., Paterson, D. M., Lichtman, I. D., Davies, A. G., Thorne, P. D. & Bass, S. J., 27 Mar 2015, In: Geology.Research output: Contribution to journal › Article › peer-review
- Published
Spatio-temporal evolution of velocity structure, concentration and grainsize stratification within experimental particulate gravity currents.
McCaffrey, W. D., Choux, C. M., Baas, J. H. & Haughton, P. D., 1 Jun 2003, In: Marine and Petroleum Geology. 20, 6-8, p. 851-860Research output: Contribution to journal › Article › peer-review
- Published
Sole marks reveal deep-marine depositional process and environment: implications for flow transformation and hybrid event bed models
Baas, J., Tracey, N. D. & Peakall, J., 4 Oct 2021, In: Journal of Sedimentary Research. 91, 9, p. 986–1009Research output: Contribution to journal › Article › peer-review
- Accepted/In press
Softgrounds: Substrates controlled by sediment gravity flows and the evolution of deep-water trace fossils
Wang, Y., Wignall, P. B., Peakall, J., Baas, J. & Poulton, S. W., 10 Mar 2025, (Accepted/In press) In: The Geological Society Special Publications.Research output: Contribution to journal › Article › peer-review
- Published
Sediment gravity flows: Recent advances in process and field analysis – Introduction
Baas, J. H., 1 Aug 2005, In: Sedimentary Geology. 179, 1-2, p. 1-3Research output: Contribution to journal › Article › peer-review
- Published
Sediment Composition Influences Spatial Variation in the Abundance of Human Pathogen Indicator Bacteria within an Estuarine Environment
Perkins, T. L., Clements, K., Baas, J. H., Jago, C. F., Jones, D. L., Malham, S. K. & McDonald, J. E., 14 Nov 2014, In: PLoS ONE. 9, 11Research output: Contribution to journal › Article › peer-review
- Published
Sand Deposition from High-Density Turbidity Currents: Implications for the Emplacement Mode, Internal Structure, Texture and Geometry of Deep-Water Massive Sandstone Beds.
Baas, J. H., 1 Jan 2001, 2001 ed. Unknown.Research output: Book/Report › Commissioned report
- Published
Ripple, Ripple Mark, Ripple Structure.
Baas, J. H. & Middleton, G. V. (Editor), 1 Jan 2003, Encyclopedia of Sediments and Sedimentary Rocks. 2003 ed. Kluwer Academic Publishers, p. 565-567Research output: Chapter in Book/Report/Conference proceeding › Chapter
- Published
Ripple formation induced by biogenic mounds – Comment
Baas, J. H. & Best, J. L., 15 Aug 2000, In: Marine Geology. 168, 1-4, p. 145-151Research output: Contribution to journal › Article › peer-review
- Published
Reversed sediment wave migration in the Irish Sea, NW Europe: A reappraisal of the validity of geometry-based predictive modelling and assumptions
Van Landeghem, K. J., Baas, J. H., Mitchell, N., Wilcockson, D. & Wheeler, A. J., 15 Feb 2012, In: Marine Geology. 295-298, p. 95-112Research output: Contribution to journal › Article › peer-review
- Published
Rapid gravity flow transformation revealed in a single climbing ripple
Baas, J. H., Best, J. & Peakall, J., 1 May 2021, In: Geology. 49, 5, p. 493-497Research output: Contribution to journal › Article › peer-review
- Published
Processes and products of turbidity currents entering soft muddy substrates
Baas, J. H., Manica, R., Puhl, E., Verhagen, I. & de O.Borges, A. L., May 2014, In: Geology. 42, 5, p. 371-374Research output: Contribution to journal › Article › peer-review
- Published
Preservation of groove mark striae formed by armoured mud clasts: the role of armour sediment size and bed yield stress
Lock, C., Reid, M., Baas, J. & Peakall, J., Sept 2024, In: The Depositional Record. 10, 4, p. 426-440Research output: Contribution to journal › Article › peer-review
- Published
Predicting bedforms and primary current stratification in cohesive mixtures of mud and sand
Baas, J. H., Best, J. L. & Peakall, J., Jan 2016, In: Journal of the Geological Society. 173, 1, p. 12-45Research output: Contribution to journal › Article › peer-review
- Published
Physical Processes in Earth and Environmental Sciences, by M. Leeder & M. Pérez-Arlucea
Baas, J. H., 1 Sept 2006, Unknown.Research output: Other contribution
- Published
Passive sediment filling of U-shaped animal burrows.
Kellman, P., Baas, J. H., Best, J. L. & Uchman, A., 1 Jan 2004.Research output: Contribution to conference › Paper
- Published
On the origin of chevron marks and striated grooves, and their use in predicting mud bed rheology
McGowan, D., Salian, A., Baas, J., Peakall, J. & Best, J., Feb 2024, Sedimentology, 71, 2, p. 687-708 22 p.Research output: Contribution to specialist publication › Article
- Published
On the flow of natural clay suspensions over smooth and rough beds.
Baas, J. H. & Best, J. L., 1 Jan 2008.Research output: Contribution to conference › Paper
- Published
Non-cohesive, mixed and cohesive high-density turbidity currents: Flow and deposit properties inferred from laboratory experiments.
Manica, R., Baas, J. H., De Oliveira Borges, A. L., Maestri, R. D., Peakall, J. & McCaffrey, W. D., 1 Jan 2006.Research output: Contribution to conference › Paper
- Published
Muddy Coasts of the World: Processes, Deposits and Function, by T. Healy, Y. Wang & J.-A. Healy
Baas, J. H., 1 Jan 2003, Unknown.Research output: Other contribution
- Published
Modelling rheological and turbulence regimes in kaolinite-rich sediment flows.
Silva Jacinto, R. & Baas, J. H., 1 Jan 2007.Research output: Contribution to conference › Paper
- Published
Mixed Sand—Mud Bedforms Produced by Transient Turbulent Flows in the Fringe of Submarine Fans: Indicators of Flow Transformation
Baker, M. L. & Baas, J. H., Aug 2020, In: Sedimentology. 67, 5, p. 2645-2671 27 p.Research output: Contribution to journal › Article › peer-review
- Published
Marine redox dynamics and biotic response to the mid-Silurian Ireviken Extinction Event in a mid-shelf setting
Wang, Y., Wignall, P. B., Xiong, Y., Loydell, D. K., Peakall, J., Baas, J. H., Mills, B. J. W. & Poulton, S. W., 10 May 2024, In: Journal of the Geological Society. 181, 4, jgs2023-155.Research output: Contribution to journal › Article › peer-review
- Published
Looking inside turbidity currents: the effects of spatial and temporal changes in velocity, concentration and grain size on depositional properties.
Baas, J. H., McCaffrey, W. D., Choux, C. & Haughton, P. D., 1 Jan 2003.Research output: Contribution to conference › Paper