Deepwater Geoscience: 1st Bouma Special Publication

Based on the review of Letsch (2019), the earliest written suggestions on the origin of alternating deep-water sandstone–mudstone beds described from the Alpine flysch successions date from the 18th century (Gruner 1773). He explained the sand–mud alternations as caused by periodic sediment mobilization due to bottom currents on a muddy floor of a standing water body. Since the muds contained well-preserved traces of ancient marine and terrestrial life, he also concluded that the standing body of water must have lasted for long periods of time: Distinct episodes of sediment settling would have given rise to normally graded layers (!). Towards the end of the 19th century, catastrophic landslides into Swiss lakes roused interest among Swiss geologists, who carried out bathymetric soundings shortly after the catastrophe. Also, they appreciated the geological importance of such landslide processes and used this to explain the “mysterious” flysch successions (Heim et al. 1888). Twenty years later, Albert Heim’s son, also a geologist, classified the flysch beds as

“A not yet consolidated mass of loose sand or mud able to flow without being wrinkled into slump folds. While sliding, this mass dissolves into a mash or even a suspension (general turbidity of water) and its re-deposition results in a fine-grained layer of wide lateral extent and without any folds as if it were only the sequel of the earlier deposition. The difference to normal sedimentation is simply the fact, that the new deposit consists of reworked older sediment of a more nearshore facies character.”

(Heim 1908)

Decades later Reginald Daly came up with the theory that canyons in the continental slope had been excavated by submarine currents of silt-laden water, pouring down the continental shelf (Daly 1934, 1936, 1942). The work of Daly was cited in the benchmark publication on graded sandstone beds by Kuenen and Migliorini (1950). Yet, the works above passed each other and Kuenen unnoticed, as so often happens with research that is not timely. And so, it happened more than once up to the end of the 20th century that scientists, scattered around the globe, worked on the same problems with no mutual awareness.

Today, deepwater geoscience is unthinkable without joint, international, and intercontinental scientific efforts and communication, for example, through video conferences, rapid data sharing via the World Wide Web, and shared laboratory facilities. Simple proof are seminal papers co-authored by large groups of globally scattered but connected scientists. It is hard to imagine that ocean depth around the West Indies was measured by Kuenen in 1929 by means of a simple echo sounder that produced a sharp two-second interval whistle that kept entire crews awake (Kuenen 1941). The enormous progress and technical advancement in deepwater research is highlighted by recent developments enabling real-time monitoring of changing seafloor topography and measurement of both flow-velocity profiles and density of turbidity currents (Paull et al. 2018; Talling et al. 2022). And yet, present understanding of ocean environments and deepwater sedimentation would have been delayed without the contributions of Reginald Daly, Francis Shepard, Philip Kuenen, Arnold Bouma, and Emiliano Mutti. These individuals, standing on the shoulders of their teachers and predecessors, initiated and stimulated turbidite research for us and, no doubt, for generations to come. They laid the foundation for our present oceanographic research now aiming to investigate and monitor ocean currents, climate change, sediment transport, and carbon fluxes.

Current research in deepwater sedimentation is exemplified by studies contained in this Special Publication of JSR named to honor one of the pioneers of turbidite fan studies: Arnold H. Bouma. These studies were presented at the first in-person Bouma Deepwater Geoscience Conference hosted by Utrecht University, Netherlands, 17–21 April 2023. Funding to help students and early career researchers attend and present at this meeting came from the Arnold and Lieneke Bouma Fund from the SEPM Foundation.

At Utrecht University the conference attendants went back to the roots of Arnold Bouma’s career. Before Bouma registered as a Master’s student in Utrecht, he assisted Kuenen as an undergraduate student with experiments on the rounding of grains and later with Kuenen’s flume experiments of turbidity currents at the University of Groningen. How Arnold Bouma came to work on deepwater turbidite fans in 1955 is a remarkable story best told by himself. The following text is written by Bouma and copied from Bouma and Ravenne (2004):

“The experiments of Kuenen aroused his [thus Bouma’s] first interest, especially when he shared an office with Ernst Ten Haaf, who had started a Ph.D. study on Italian turbidites. Bouma was also able to assist Ten Haaf in the field. During that trip he learned that even professors are not always the gods they pretend to be. Kuenen had mentioned several times that most turbidites were the result of the failure of an entire delta. Such a failure then translated into a large turbidity current that would cover the entire basin with one layer. It would take 100,000 years before the delta had built itself up again and was ready for the next failure.” Although the idea of failure made a lot of sense, the calamity of a major one did not agree with the young undergraduate. Kuenen’s idea was that the fill of a basin would mimic a stack of large pancakes. At the same time, the massive turbidity currents would swipe away all bottom fauna, and, therefore, no trace fossils would be found. The purpose of the first stop on the trip with Ten Haaf to the Apennines was for Bouma to see real turbidites. It did not take long for him to also discover several types of trace fossils. Ten Haaf readily agreed with the interpretation that the features were trace fossils, and a cable was sent to Kuenen explaining the find. A few days later came an answer: “impossible, look better.”

After having obtained his Bachelor of Science degree, Bouma moved to the University of Utrecht in the center of The Netherlands. His new mentor, Professor Derk J. Doeglas, was persuaded by Kuenen (55 years of age at that time) to send the young graduate student to the French Maritime Alps to measure sections and paleo-current directions in the various scattered Grès d’Annot occurrences. The purpose was to demonstrate that all these locations were erosional remnants of a large basin fill, fed from the south. Submarine gravity measurements indicated that parts of the north-central Mediterranean were subsiding (F.A. Vening Meinesz, personal communication 1958), supporting the concept that the sediment source area was located to the south. We were still some years away from a clear idea of what would be called “seafloor spreading.”

In 1957, Bouma cleaned his old 96 cc motor bike, overloaded it, and went to southeastern France. That little bike had barely enough oomph to move over flat roads, requiring frequent repairs by the rider. As a result, the trip went via Marseille and the coastal road. From Nice going north the bike broke down again in Lucéram. Logically, that became the base of operations, and the Peïra–Cava area the main study area. Profiles along two roads, Col de l’Orme–La Cabanette and Col St. Roche–La Cabanette, form a triangle with a base of about 2 km with the top at La Cabanette, a few hundred meters away from the base. Correlation seemed impossible (Bouma 1959a).

It was Bouma’s initial idea to compare the Grès d’Annot characteristics with those of Tertiary fluvial deposits in Switzerland. Doeglas advised him to present a paper on the Grès d’Annot at the International Association of Sedimentologists Congress in Switzerland to make it easier to get in contact with Swiss professors. The presentation of that paper, published the next year (Bouma 1959b), changed everything.

After his presentation, a question came from the rear of the darkened room. The French was too fast for Bouma to understand. The repeated request was a similar machine-gun volley. Fortunately, the speaker was able to find Professor Doeglas, and met with the person who fired off the question. This happened to be Madame Yvonne Gubler, Director of Geology and Geochemistry of the Institut Français du Pétrole. Her first comment was “You are not permitted to conduct fieldwork in that area.” This caused considerable consternation, but after a lengthy discussion, permission was granted to carry out sedimentological studies only, and not to study structural nor stratigraphic details because it was the study area of M. Lanteaume who worked on a Thèse de l’Université. In addition, the young student was not permitted to cross the River Var to study the Annot and other turbidite locations. No explanation was given.

The trip to Switzerland was less exciting than expected, and with the field findings differing from Kuenen’s ideas, it became a strong attraction to continue in the Maritime Alps. More sections and paleocurrents were measured. Later on, Shell Oil provided funding to visit areas in Italy, Switzerland, Belgium, and Germany to identify if those areas could be interpreted as turbidites. Although vertical repetition of sedimentary structures was noticed in the field, it took laying out the measured sections on the floor, back in the hall of the Geological Institute in Utrecht, to recognize a turbidite sequence. Overwhelming incompleteness of the total sequence had prevented the recognition of a sequence while measuring sections in the field. Actually, it was more exciting to observe major differences in the ideas promoted by Kuenen than to find a turbidite sequence. Unfortunately, many of these ideas could not be put in the dissertation. At that time turbidites were considered to be the only deepwater sands, rather than part of the more exciting submarine fans.

Daniel Stanley, doing a Ph.D. study in the French Maritime Alps under Madame Gubler’s guidance (IFP), received the message not to cross the River Var to the east. Bouma’s publication from the IAS meeting provided Stanley with an answer as to why he was not permitted to cross that river. Only one set of letters was exchanged; no meeting was established. Both Stanley and Bouma defended their dissertation in the same month of 1961. It took the 1963 AAPG/SEPM meeting in Houston, Texas, for the two young doctors to meet for the first time, resulting in a joint publication emphasizing the different approaches, as well as the similarities of some of the geological characteristics (Stanley and Bouma 1964).

In The Netherlands, dissertations have to be published, a financial burden to the student. Elsevier was planning a new series of publications and asked Bouma if they could use his dissertation as the first. It was published in 1962 with the, by now, well-known title: Sedimentology of Some Flysch Deposits. A couple of years later someone coined the term “Bouma Sequence.” Although the name was an honor, it often embarrassed the young geologist because too many persons asked if he was the son of “the Bouma turbidite person.”

Following his 1962–1963 Fulbright post-doctoral fellowship under F.P. Shepard at the Scripps Institution of Oceanography at La Jolla, California, Bouma started as a professor of oceanography at Texas A&M University and the Bouma family emigrated to the U.S. The further development of deepwater geoscience from the sixties to the beginning of the 21st century is told by many writers of textbooks and not repeated here (see also Shanmugam 2016). The world’s need for hydrocarbons boosted development of new techniques to facilitate shallow and deep seismic data acquisition to map the modern seafloor and deeper ancient stratigraphic and architectural patterns. At the same time, the Stratigraphic Geology Division of Esso Production Research Company worked on stratigraphic mapping of ancient submarine fans in Italy and Spain with Emiliano Mutti (Mutti 1971, 1974; Mutti and Ricci Lucchi 1972). Cycles in turbidite sequences were described in a classic paper on facies associations in turbidite sequences from studies in the Apennines (Mutti and Ricci Lucchi 1975; see also Tinterri, this volume, for an extensive review). Many problems arose when comparing the findings in the modern environment with those in outcrop, which initiated a committee meeting on fans (COMFAN) in 1982.

Problems included the diversity of observations that made comparisons between fans difficult or suspect: studies of modern fans lack both sedimentologic and stratigraphic information below the upper tens of meters and ancient turbidite sequences seldom provide basin-wide information for time-equivalent intervals. Dorrik Stow (1985) summarized the deepwater science up to the point of COMFAN in a single diagram (Fig. 3), and the proceedings of the COMFAN meetings were published in Frontiers in Sedimentary Geology (Bouma et al. 1985), bringing together a range of papers describing the first contours of submarine fans on active and passive margins. It did not bring the desired order to the nomenclature noise, but proved an important start (Shanmugam 2016).

Over the last 20 years, there have been major advances in techniques for mapping the seafloor in shallow as well as in deepwater over set periods of time, and for daily monitoring of turbidity currents and sediment transport. Clare et al. (2019) reviewed the state-of-the-art of equipment now used to monitor turbidity currents, their shortcomings, and some recommended design improvements such as simplifying mooring configurations and minimizing surface area of measuring equipment to avoid interaction with the flow. At Monterey Bay Aquarium Research Institute (MBARI) new sensors were developed that are embedded in moving near-bed layers to recording their acceleration and sense of rotation, and new techniques helped in recovering data from such sensors through gliders. These innovations enabled new research goals, aimed specifically at measuring energetic turbidity currents as they flow down canyons and across the sea floor (Talling et al. 2015, 2022).

On site monitoring in the major canyons of the world is now embedded in a Coordinated Canyon Experiment (CCE) project, co-funded by the Natural Environmental Research Council (UK), the Monterey Bay Aquarium Research Institute (US), and the Ocean University of China. Repeated sea-floor mapping in fjords (Squamish delta and Bute Inlet, Canada, BC) and continental-slope canyons provide an overwhelming amount of data demonstrating how these become filled with river-flood-generated sediments. Monitoring fjord-head deltas proved upslope migration of large 50–100-m-size cyclic-step bedforms (e.g., Hughes Clark 2016; Clare et al. 2016; Chen et al. 2021), and upslope migration of several-km-long erosion and deposition zones (Lobato et al., this volume). Maier et al. (this volume) provides a detailed study of an offshore New Zealand co-seismic turbidite event traced from canyon to fan over a distance of 1300 km.

Repeated high-resolution bathymetry maps show trains of upslope-migrating bedforms in steeper proximal settings and have recently been mapped in many locations worldwide. Experiments and monitoring make clear that these bedforms are produced by supercritical turbidity currents. Tinterri (this volume) gives an overview of facies types formed by these bedforms and shows how these various facies types can be used to reconstruct basin evolution, with examples from the Apennines and Western Alps (Annot and Peïra Cava areas). Handford mapped giant sediment waves in Mississippian carbonates (this volume) and interprets these as being caused by supercritical flow. Future work should aim to understand the role of dense, near-bed layers in turbidity currents in the formation of supercritical bedforms, whether they are the result or the cause of cyclic hydraulic jumps, and the various ways supercritical bedforms can be preserved.

Turbidity currents are commonly significantly affected by the dynamic conditions of the water bodies they flow into. The resulting strata often display architectures that do not fit with depositional models defined solely from a gravity-flow perspective, but necessitate integrated interpretations combining the effects of gravity flow with ocean circulation phenomena such as internal tides, breaking internal waves (Miramontes et al. 2020b), and deepwater oceanic currents, including contour currents. The study of moat architecture on seismic datasets has proved helpful in unraveling ocean current history (Unland et al., this volume; Kreps et al., this volume).

Considerable advances have been made in understanding flow dynamics in dilute physical experiments or models, and temperature- and/or salinity-driven density currents in the field. Large flume tanks (like Eurotank at Utrecht University) suitable for three-dimensional flume-tank experiments are used now to study the synchronous interaction between contour currents and turbidity currents to understand the effect of these combined currents on channel–levee architecture (Miramontes et al. 2020a).

Physical modeling studies of sand transport reveal how clay and silt dramatically impact the depositional processes of sediment gravity flows (Baas and Best 2002). A few percent of mud in sandy sediment mixtures can control erosion of sediment in entirely different ways by altering the nature of the turbulence affecting the flow structure leading to coagulation and support of more sand (Haughton et al. 2003; Talling et al. 2004). Once deposited, it may be homogenized to various degrees by biogenic activity (Ortiz et al., this volume). It is important to understand the extent of turbulence damping within turbidity currents, especially as flows decelerate, and whether it produces late-stage flow transformations. More precisely, quantitative constraints on what controls the sediment-carrying-capacity and competence of flows is essential. In this volume, Łapcik and Baas integrate transitional flow characteristics into hybrid event beds. The modeling approaches contained in this volume range from laboratory experiments to tackle deposition on the grain scale (Reimer et al.) up to basin-scale numerical models that investigate the stacking and heterogeneity of deepwater fans (Macky et al.; Tahiru et al.).

A well-known statement of Arnold Bouma’s is: “There are still discoveries to be made, but it won’t be the computer that tells us what it all means; for that, we always have to go back to the rock.” It underlines the ongoing importance of outcrop studies. Process stratigraphy refers to the practice of using flow processes and the hydraulics of sediment-laden flows to analyze the nature and distribution of deepwater deposits in the rock record. Combining conceptual, analog and numerical process-based models with deposit characteristics allows one to make predictions away from data control. When successful, this approach leads to a narrower band of possibilities than purely empirical studies and reduces uncertainty. For such studies excellent outcrops are a pre-requisite. Outcrop study methodologies are nowadays enhanced significantly by laser techniques and drones. Excellent outcrop examples contained in this book are from the Tachrift system (NE Marocco, Marini et al., Invernizzi et al., Pantopoulos et al.), from the Fort Payne Formation (Lower Mississippian, Kentucky–Tennessee, U.S.A, Handford), from Cretaceous Tres Pasos Formation (southern Chile, Jobe et al.), from the Permian Wolfcamp XY Formation (Delaware Basin, Texas, Putri et al.), and from the Apennines (Italy, Tinterri).

In final summary, this evolving context of present-day deepwater geoscience has inspired us, the editors, to organize these papers into four groups representing the sessions in the original three day conference: Modern Environments, Mud Matters, Modeling, and Process Stratigraphy.

Of course, there can be no special issue without the help of many independent and highly qualified reviewers. A big thanks to Lawrence Amy (2×), Abdulwahab Bello, Hanna Brooks, Bryan Cronin, Thomas Dodd, Juan Fedele, Paul Hamilton, Robertson Handford, Peter Haughton, Zane Jobe, David Keighley, Kick Kleverlaan (2×), Ben Kneller, Rafael Manica, Mattia Marini, Adam McArthur, Salvatore Milli, Alex Normandeau, George Pantopoulos, Marco Patacci, Brad Prather, Buddy Price, Michele Robesco, Sara Rodrigues, Octavio Sequieros, Arnaud Slootman, David Stanbrook, Alfred Uchmann, and Flor Vermassen.

The editors appreciate the help of the SEPM office in bringing the first Bouma conference to life, with warm thanks to Harold Harper, Theresa Scott, Cassie Turley, and Michele Tomlinson. The 1st Bouma Special Issue was made possible thanks to Kathleen Marsaglia and Peter Burgess (former editors of JSR) and Dustin Sweet (present editor). Last, but not least, a big thanks to the SEPM journal managing editor Melissa Lester, who kept a sharp eye on the streamlining of the manuscripts, and to John Southard, who made sure that manuscripts were edited in the style of the Journal.

Editor

• George Postma

Associate Editors

• Gilian Apps

• David Hoyal

• Elda Miramontes

• Peter Burgess

• Joris Eggenhuisen

Dynamic near-seafloor sediment transport in Kaikōura Canyon following a large canyon-flushing event

Katherine L. Maier, Scott D. Nodder, Stacy Deppeler, Peter Gerring, Grace Frontin-Rollet, Rachel Hale, Oliver Twigge, and Sarah J. Bury DOI: 10.2110/jsr.2023.117

Testing turbidite conceptual models with the Kaikōura Earthquake co-seismic event bed, Aotearoa New Zealand

Katherine L. Maier, Lorna J. Strachan, Stephanie Tickle, Alan R. Orpin, Scott D. Nodder, and Jamie Howarth DOI: 10.2110/jsr.2023.115

The role of bottom meso-scale dynamics in contourite formation in the Argentine Basin

Gastón Kreps, Tilmann Schwenk, Silvia Romero, Agustín Quesada, Jens Gruetzner, Volkhard Spiess, Hanno Keil, Ruben Kantner, Lester Lembke-Jene, Ramiro Ferrari, Frank Lamy, and Elda Miramontes DOI: 10.2110/jsr.2024.012

Evolution of a buried moat-drift system in the Ewing Terrace uncovering highly dynamic bottom currents at the Argentine margin from the early Oligocene to middle Miocene

Ellen Unland, Elda Miramontes, Volkhard Spiess, Graziella Bozzano, Sabine Kasten, and Tilmann Schwenk DOI: 10.2110/jsr.2024.030

Decadal architecture and morphodynamics of modern, river-fed turbidite systems: Bute Inlet and Congo Fan

Gustavo Lobato, George Postma, D. Gwyn Lintern, Ricardo S. Jacinto, and Matthieu J.B. Cartigny DOI: 10.2110/jsr.2024.094

Integrating transitional-flow signatures into hybrid event beds: implications for hybrid-flow evolution on a submarine lobe fringe

Piotr Łapcik and Jaco H. Baas DOI: 10.2110/jsr.2024.023

Paleoenvironmental conditions and evolution of a muddy turbidite system: an integrated sedimentological and ichnological analysis

José F. Cabrera-Ortiz, Javier Dorador, Francisco J. Rodríguez-Tovar, and José N. Pérez-Asensio DOI: 10.2110/jsr.2024.101

Deep-water fan hierarchy: assumptions, evidence, and numerical modeling analysis

Ibrahim Tinni Tahiru, Peter M. Burgess, and Christopher Stevenson DOI: 10.2110/jsr.2023.130

Simple model, complex strata: 2-D numerical forward model analysis of heterogeneity and controls in submarine fan systems

Alfie W. Mackie, Christopher J. Stevenson, and Peter M. Burgess DOI: 10.2110/jsr.2023.017

Experiments on the settling of carbonate sand–mud suspensions

John J.G. Reijmer, Max De Kruijf, Arnoud Slootman, L. Jonathan Kranenburg, and Rosa A. De BoerDOI: 10.2110/jsr.2024.116

Giant sediment-wave field and supercritical flows in a distally steepened ramp, Fort Payne Formation (Lower Mississippian), Kentucky–Tennessee, U.S.A.

C. Robertson Handford DOI: 10.2110/jsr.2024.032

How many turbidity currents pass through a submarine channel during its lifespan?

Zane Jobe, Stephen Hubbard, and Brian W. Romans DOI: 10.2110/jsr.2024.050

A new turbidite facies tract scheme including supercritical and transitional sand–mud flows: an outcrop perspective from Mediterranean-type foreland basins

Roberto Tinterri DOI: 10.2110/jsr.2024.033

Depositional-process controls on chemofacies in mixed-lithology submarine lobe deposits: a high-resolution core study from the Permian Wolfcamp XY Formation, Delaware Basin, Texas, U.S.A.

Shaskia Herida Putri, Zane Jobe, Jesse Melick, Lesli Wood, and Marsha FrenchDOI: 10.2110/jsr.2024.015

Temporal and spatial changes in style of accretion at the bend of a sinuous turbidite slope channel (channel–levee Complex 5, Tachrift System of NE Morocco)

Mattia Marini, George Pantopoulos, Daniele Invernizzi, Fabrizio Felletti, Imad El Kati, and Adam D. McArthur DOI: 10.2110/jsr.2024.052

Reconstruction of the sedimentary heterogeneity in outcropping deep-water channel–levee deposits (Taza–Guercif Basin, late Tortonian, NE Morocco)

Daniele Invernizzi, Moreno Pizzutto, Fabrizio Felletti, George Pantopoulos, Mattia Marini, and Adam D. McArthur DOI: 10.2110/jsr.2024.040

Quantification of the internal heterogeneity across a submarine channel bend: a unique example from the late Tortonian Tachrift channel complex 5 (Taza–Guercif Basin, NE Morocco)

Georgios Pantopoulos, Mattia Marini, Daniele Invernizzi, Imad El Kati, Adam D. McArthur, and Fabrizio Felletti DOI: 10.2110/jsr.2024.068