Dr Jaco Baas
Uwch Ddarlithydd

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
- Cyhoeddwyd
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 Ion 2005.Allbwn ymchwil: Cyfraniad at gynhadledd › Papur
- Cyhoeddwyd
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 Gorff 2014.Allbwn ymchwil: Cyfraniad at gynhadledd › Papur
- Cyhoeddwyd
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., Tach 2018, Yn: Journal of Geophysical Research: Earth Surface. 123, 11, t. 2784-2801 35 t.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Visualizing the flow fields of sediment-laden density currents.
Peakall, J., Best, J. L., Baas, J. H. & Al-Musallami, Z., 1 Ion 2000.Allbwn ymchwil: Cyfraniad at gynhadledd › Papur
- Wedi ei Dderbyn / Yn y wasg
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 Gorff 2024, (Wedi ei Dderbyn / Yn y wasg) Particulate Gravity Currents in the Environment. American Geophysical UnionAllbwn ymchwil: Pennod mewn Llyfr/Adroddiad/Trafodion Cynhadledd › Pennod › adolygiad gan gymheiriaid
- Cyhoeddwyd
Turbulence-modulated clay-laden flow over flat beds, ripple and dunes.
Baas, J. H. & Best, J. L., 1 Ion 2005.Allbwn ymchwil: Cyfraniad at gynhadledd › Papur
- Cyhoeddwyd
Turbulence modulation in high-concentration clay-rich flows and the possible origin of “massive” sand beds.
Baas, J. H. & Best, J. L., 1 Ion 2000, t. 6-7.Allbwn ymchwil: Cyfraniad at gynhadledd › Papur
- Cyhoeddwyd
Turbulence modulation in clay-rich sediment-laden flows and some implications for sediment deposition.
Baas, J. H. & Best, J. L., 1 Ion 2002, Yn: Journal of Sedimentary Research. 72, 3, t. 336-340Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Turbulence modulation in clay-rich flows: Implications for depositional process and bed form geometry.
Baas, J. H. & Best, J. L., 1 Ion 2005.Allbwn ymchwil: Cyfraniad at gynhadledd › Papur
- Cyhoeddwyd
Turbulence modulation in clay-laden flows over ripples and dunes.
Baas, J. H. & Best, J. L., 1 Ion 2005.Allbwn ymchwil: Cyfraniad at gynhadledd › Papur
- Cyhoeddwyd
Turbulence modulation behind ripples and dunes in clay-laden currents.
Baas, J. H. & Best, J. L., 1 Ion 2004.Allbwn ymchwil: Cyfraniad at gynhadledd › Papur
- Cyhoeddwyd
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 Rhag 2016, Yn: Sedimentology. 63, 7, t. 2002-2036Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
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 Ion 2016, Yn: Geophysical Research Letters. 43, t. 1566-1573Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
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 Ion 2008.Allbwn ymchwil: Cyfraniad at gynhadledd › Papur
- Cyhoeddwyd
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 Chwef 2015, Yn: Nature Communications. 6, 6257Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
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., Ebr 2019, Yn: Marine Geology. 410, t. 22-31Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
The dynamics of turbulent, transitional and laminar clay-laden flow over a fixed current ripple.
Baas, J. H. & Best, J. L., 1 Meh 2008, Yn: Sedimentology. 55, 3, t. 635-66Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
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, Yn: Journal of Sedimentary Research. 87, 11, t. 1176-1195 59 t.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
The Deep-Water Architecture Knowledge Base: Towards objective comparison of deep-marine sedimentary systems.
Baas, J. H., McCaffrey, W. D. & Knipe, R. J., 1 Tach 2005, Yn: Petroleum Geoscience. 11, 4, t. 309-320Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
The Deep-Water Architecture Knowledge Base: Towards objective comparison of deep-marine sedimentary systems.
Baas, J. H. & McCaffrey, W. D., 1 Ion 2006.Allbwn ymchwil: Cyfraniad at gynhadledd › Papur
- Cyhoeddwyd
Textural characteristics of deep-marine massive sandstones: distinguishing between deposits of turbiditic and debris flow origin.
Baas, J. H., Nemec, W. & Ravnas, R., 1 Ion 2000.Allbwn ymchwil: Cyfraniad at gynhadledd › Papur
- Cyhoeddwyd
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 Ion 2004.Allbwn ymchwil: Cyfraniad at gynhadledd › Papur
- Cyhoeddwyd
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 Ion 2000, t. 74-75.Allbwn ymchwil: Cyfraniad at gynhadledd › Papur
- Cyhoeddwyd
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 Ion 2007.Allbwn ymchwil: Cyfraniad at gynhadledd › Papur
- Cyhoeddwyd
Submarine Mass Movements and their Consequences, by J. Locat, & J. Mienert
Baas, J. H. & Strachan, L., 1 Mai 2005, Unknown.Allbwn ymchwil: Cyfraniad arall › Cyfraniad Arall
- Cyhoeddwyd
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., Awst 2023, Yn: Journal of Geophysical Research: Earth Surface. 128, 8, e2022JF006781.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
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 Maw 2015, Yn: Geology.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
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 Meh 2003, Yn: Marine and Petroleum Geology. 20, 6-8, t. 851-860Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
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 Hyd 2021, Yn: Journal of Sedimentary Research. 91, 9, t. 986–1009Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Wedi ei Dderbyn / Yn y wasg
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 Maw 2025, (Wedi ei Dderbyn / Yn y wasg) Yn: The Geological Society Special Publications.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Sediment gravity flows: Recent advances in process and field analysis – Introduction
Baas, J. H., 1 Awst 2005, Yn: Sedimentary Geology. 179, 1-2, t. 1-3Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
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 Tach 2014, Yn: PLoS ONE. 9, 11Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
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 Ion 2001, 2001 gol. Unknown.Allbwn ymchwil: Llyfr/Adroddiad › Adroddiad Comisiwn
- Cyhoeddwyd
Ripple, Ripple Mark, Ripple Structure.
Baas, J. H. & Middleton, G. V. (Golygydd), 1 Ion 2003, Encyclopedia of Sediments and Sedimentary Rocks. 2003 gol. Kluwer Academic Publishers, t. 565-567Allbwn ymchwil: Pennod mewn Llyfr/Adroddiad/Trafodion Cynhadledd › Pennod
- Cyhoeddwyd
Ripple formation induced by biogenic mounds – Comment
Baas, J. H. & Best, J. L., 15 Awst 2000, Yn: Marine Geology. 168, 1-4, t. 145-151Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
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 Chwef 2012, Yn: Marine Geology. 295-298, t. 95-112Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Rapid gravity flow transformation revealed in a single climbing ripple
Baas, J. H., Best, J. & Peakall, J., 1 Mai 2021, Yn: Geology. 49, 5, t. 493-497Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Processes and products of turbidity currents entering soft muddy substrates
Baas, J. H., Manica, R., Puhl, E., Verhagen, I. & de O.Borges, A. L., Mai 2014, Yn: Geology. 42, 5, t. 371-374Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
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., Medi 2024, Yn: The Depositional Record. 10, 4, t. 426-440Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Predicting bedforms and primary current stratification in cohesive mixtures of mud and sand
Baas, J. H., Best, J. L. & Peakall, J., Ion 2016, Yn: Journal of the Geological Society. 173, 1, t. 12-45Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Physical Processes in Earth and Environmental Sciences, by M. Leeder & M. Pérez-Arlucea
Baas, J. H., 1 Medi 2006, Unknown.Allbwn ymchwil: Cyfraniad arall › Cyfraniad Arall
- Cyhoeddwyd
Passive sediment filling of U-shaped animal burrows.
Kellman, P., Baas, J. H., Best, J. L. & Uchman, A., 1 Ion 2004.Allbwn ymchwil: Cyfraniad at gynhadledd › Papur
- Cyhoeddwyd
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., Chwef 2024, Sedimentology, 71, 2, t. 687-708 22 t.Allbwn ymchwil: Cyfraniad at gyhoeddiad arbenigol › Erthygl
- Cyhoeddwyd
On the flow of natural clay suspensions over smooth and rough beds.
Baas, J. H. & Best, J. L., 1 Ion 2008.Allbwn ymchwil: Cyfraniad at gynhadledd › Papur
- Cyhoeddwyd
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 Ion 2006.Allbwn ymchwil: Cyfraniad at gynhadledd › Papur
- Cyhoeddwyd
Muddy Coasts of the World: Processes, Deposits and Function, by T. Healy, Y. Wang & J.-A. Healy
Baas, J. H., 1 Ion 2003, Unknown.Allbwn ymchwil: Cyfraniad arall › Cyfraniad Arall
- Cyhoeddwyd
Modelling rheological and turbulence regimes in kaolinite-rich sediment flows.
Silva Jacinto, R. & Baas, J. H., 1 Ion 2007.Allbwn ymchwil: Cyfraniad at gynhadledd › Papur
- Cyhoeddwyd
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., Awst 2020, Yn: Sedimentology. 67, 5, t. 2645-2671 27 t.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
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 Mai 2024, Yn: Journal of the Geological Society. 181, 4, jgs2023-155.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
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 Ion 2003.Allbwn ymchwil: Cyfraniad at gynhadledd › Papur