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
- 2025
- 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
- Accepted/In press
Distinguishing microbially induced sedimentary structures from fluid-induced interfacial deformation structures (MISS versus FIDS)
Wignall, P. B., Peakall, J., Best, J. & Baas, J., 4 Mar 2025, (Accepted/In press) In: The Geological Society Special Publications.Research output: Contribution to journal › Article › peer-review
- 2024
- Published
Effect of Bed Clay on Surface Water-Wave Reconstruction from Ripples
Malarkey, J., Pollard, E., Fernández, R., Xuxu, W., Baas, J. & Parsons, D., 28 Dec 2024, In: Scientific Reports. 14, 1, p. 30688 30688.Research output: Contribution to journal › Article › peer-review
- E-pub ahead of print
Coming to light: How effective are sediment gravity flows in removing fine suspended carbonate from reefs?
Baas, J., Hewitt, W., Lokier, S. & Hendry, J., 27 Nov 2024, (E-pub ahead of print) In: The Depositional Record.Research output: Contribution to journal › Article › peer-review
- Published
Flow-induced Interfacial Deformation Structures (FIDS): Implications for the interpretation of palaeocurrents, flow dynamics and substrate rheology
Peakall, J., Best, J., Baas, J., Wignall, P. B., Hodgson, D. M. & Łapcik, P., Oct 2024, In: Sedimentology. 71, 6, p. 1709-1743Research output: Contribution to journal › Article › peer-review
- E-pub ahead of print
Integrating transitional-flow signatures into hybrid event beds: Implications for hybrid flow evolution on a submarine lobe fringe
Łapcik, P. & Baas, J., 4 Sept 2024, (E-pub ahead of print) In: Journal of Sedimentary Research.Research 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
- 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
Fine sediment in mixed sand-silt environments impact bedform geometry by altering sediment mobility
de Lange, S. L., Niesten, I., van de Veen, S. H. J., Baas, J., Lammers, J., Waldschlaeger, K., Boelee, D. & Hoitink, A. J. F., Jul 2024, In: Water Resources Research. 60, 7, e2024WR037065.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
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
Influence of cohesive clay on wave–current ripple dynamics captured in a 3D phase diagram
Xuxu, W., Malarkey, J., Fernández, R., Baas, J., Pollard, E. & Parsons, D., 30 Jan 2024, In: Earth Surface Dynamics. 12, p. 231-247Research output: Contribution to journal › Article › peer-review
- 2023
- 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
Does sand promote or hinder the mobility of cohesive sediment gravity flows?
Baker, M. L. & Baas, J., Feb 2023, In: Sedimentology. 70, 4, p. 1110-1130 21 p.Research output: Contribution to journal › Article › peer-review
- 2022
- Published
Effect of biological polymers on mobility and run-out distance of cohesive and non-cohesive sediment gravity flows
Sobocinska, A. & Baas, J., 1 Oct 2022, In: Marine Geology. 452, 106904.Research output: Contribution to journal › Article › peer-review
- Published
Discontinuity in Equilibrium Wave–Current Ripple Size and Shape and Deep cleaning associated with Cohesive Sand–Clay Beds
Wu, X., Fernández, R., Baas, J., Malarkey, J. & Parsons, D. R., Sept 2022, In: Journal of Geophysical Research: Earth Surface. 127, 9, p. e2022JF006771 e2022JF006771.Research output: Contribution to journal › Article › peer-review
- Published
Blood, lead and spheres: a hindered settling equation for sedimentologists based on metadata analysis
Baas, J. H., Baker, M. L., Buffon, P., Strachan, L. J., Bostock, H. C., Hodgson, D. M., Eggenhuisen, J. T. & Spychala, Y. T., Jun 2022, In: The Depositional Record. 8, 2, p. 603-615 13 p.Research output: Contribution to journal › Article › peer-review
- 2021
- Published
Current- and Wave-Generated Bedforms on Mixed Sand–Clay Intertidal Flats: A New Bedform Phase Diagram and Implications for Bed Roughness and Preservation Potential
Baas, J., Malarkey, J., Lichtman, I. D., Amoudry, L. O., Thorne, P., Hope, J. A., Peakall, J., Paterson, D. M., Bass, S., Cooke, R. D., Manning, A. J., Parsons, D. & Ye, L., 3 Nov 2021, In: Frontiers Earth Science. 9, 747567.Research 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
- 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
- 2020
- Published
Interactions between sediment microbial ecology and physical dynamics drive heterogeneity in contextually similar depositional systems
Hope, J. A., Malarkey, J., Baas, J. H., Peakall, J., Parsons, D., Manning, A. J., Bass, S., Lichtman, I., Thorne, P., Ye, L. & Paterson, D. M., Oct 2020, In: Limnology and Oceanography. 65, 10, p. 2403-2419Research output: Contribution to journal › Article › peer-review
- 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
An integrated process-based model of flutes and tool marks in deep-water environments: implications for palaeohydraulics, the Bouma sequence, and hybrid event beds
Peakall, J., Best, J., Baas, J. H., Hodgson, D. M., Clare, M. A., Talling, P. J., Dorrell, R. M. & Lee, D. R., Jun 2020, In: Sedimentology. 67, 4, p. 1601-1666 66 p.Research output: Contribution to journal › Article › peer-review
- Published
Biomediation of submarine sediment gravity flow dynamics
Craig, M., Baas, J. H., Amos, K. J., Strachan, L. J., Manning, A. J., Paterson, D. M., Hope, J. A., Nodder, S. D. & Baker, M. L., Jan 2020, In: Geology. 48, 1, p. 72-76Research output: Contribution to journal › Article › peer-review
- 2019
- Published
Integrating field and laboratory approaches for ripple development in mixed sand-clay-EPS
Baas, J. H., Baker, M., Malarkey, J., Bass, S. J., Manning, A. J., Hope, J. A., Peakall, J., Lichtman, I., Ye, L., Davies, A., Parsons, D. R., Paterson, D. M. & Thorne, P. D., Dec 2019, In: Sedimentology. 66, 7, p. 2749-2768 20 p.Research output: Contribution to journal › Article › peer-review
- Published
Dynamics and deposition of sediment-bearing multi-pulsed flows and geological implication
Ho, V. L., Dorrell, R. M., Keevil, G., Thomas, R. E., Burns, A. D., Baas, J. H. & McCaffrey, W. D., Nov 2019, In: Journal of Sedimentary Research. 89, 11, p. 1127-1139Research 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
- 2018
- 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
Bedform migration in a mixed sand and cohesive clay intertidal environment and implications for bed material transport predictions
Lichtman, I. D., Baas, J. H., Amoudry, L. O., Thorne, P. D., Malarkey, J., Hope, J. A., Peakall, J., Paterson, D. M., Bass, S. J., Cooke, R. D., Manning, A. J., Davies, A. G., Parsons, D. R. & Ye, L., 15 Aug 2018, In: Geomorphology. 315, p. 17-32 66 p.Research output: Contribution to journal › Article › peer-review
- 2017
- 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
- 2016
- 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
Comparing the transitional behaviour of kaolinite and bentonite suspension flows
Baas, J., Best, J. L. & Peakall, J., Oct 2016, In: Earth Surface Processes and Landforms. 41, 13, p. 1911-1921Research output: Contribution to journal › Article › peer-review
- Published
5th International Conference on Marine & River Dune Dynamics (MARID), April 4th-6th, Caernarfon, UK
Van Landeghem, K., Garlan, T., Baas, J. H. & Van Landeghem, K. J. (Editor), 4 Apr 2016, Unknown Publisher.Research output: Book/Report › Book
- 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
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
- 2015
- 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
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
- 2014
- 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
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
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
- 2013
- Published
Bedform development in mixed sand–mud: The contrasting role of cohesive forces in flow and bed
Baas, J. H., Davies, A. G. & Malarkey, J., 15 Jan 2013, In: Geomorphology. 182, p. 19-32Research output: Contribution to journal › Article › peer-review
- 2012
- 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
- 2011
- Published
Depositional processes, bedform development and hybrid bed formation in rapidly decelerated cohesive (mud–sand) sediment flows
Baas, J. H., Best, J. L. & Peakall, J., 1 Dec 2011, In: Sedimentology. 58, 7, p. 1953-1987Research output: Contribution to journal › Article › peer-review
- 2009
- Published
A phase diagram for turbulent, transitional and laminar clay suspension flows.
Baas, J. H., Best, J. L., Peakall, J. & Wang, M., 1 Mar 2009, In: Journal of Sedimentary Research. 79, 3-4, p. 162-183Research output: Contribution to journal › Article › peer-review
- 2008
- 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
Comparing flume and computer simulated turbidite flows – Implications for sediment deposition patterns and reservoir quality.
Bond, C. E., Baas, J. H., Vinnels, J., McCaffrey, W., Waltham, D. & McClean, S., 1 Jan 2008.Research output: Contribution to conference › Paper
- Published
Coupling flow and deposit properties of partly cohesive high-density turbidity currents: An experimental approach.
Manica, R., Baas, J. H., Peakall, J., Maestri, R. D. & Borges, A. O., 1 Jan 2008.Research output: Contribution to conference › Paper
- Published
Flow behaviour of ponded turbidity currents: an experimental study.
Patacci, M., McCaffrey, W. M., Haughton, P., Baas, J. H. & Keevil, G., 1 Jan 2008.Research output: Contribution to conference › Paper
- 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
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