1. Short biography

John attended St Philip’s Grammar School in Birmingham. His academic career was unusual and remarkable in the context of scientific history. After attaining a first-class degree in geology at the University of Sheffield, UK, in 1955, he began a PhD at the same university, supported by a maintenance award from the Department of Scientific and Industrial Research. His PhD work was on the Old Red Sandstone of the Clee Hills (note: sandy rocks deposited in a fluvial regime called the Old Red Sandstone). However, he was never actually awarded a PhD degree. In John’s own words, ‘but never presented a thesis (partly my own fault)’. One can imagine how hard this must have been for him.

Thanks be to Heaven. Fortunately for John and for sedimentology, his talent was recognized by Professor Perce Allen FRS (1917–2008) ^{Footnote 2} , of the Department of Geology at the University of Reading, UK. To avoid confusion between the two Allens, many referred to John as JRL. With the help of Perce Allen, John received the GM Lees ^{Footnote 3} Research Fellowship in 1958 and a successful academic career began. He became a Lecturer in Geology in 1961, a Reader in Geology in 1967 and was promoted to a Personal Professorship of Geology in 1972. The University of Sheffield awarded John an honorary LLD (Doctor of Law) degree in 1969 for an extended history of wide-ranging research. John also held a Visiting Scientist position at the Department of Geology, Brown University, USA, in 1964 (Allen, Reference Evans1965 a, p. 91, bottom footnote) and in the Department of Physical Geography, University of Uppsala, Sweden, in 1971 (Allen 1971, p. 157, the first affiliation). John was the Ernst Cloos Memorial Scholar at the Department of Earth and Planetary Sciences, Johns Hopkins University, USA, from 1976 to 1977. He was appointed Director of the Postgraduate Research Institute for Sedimentology (PRIS) at the University of Reading in 1988. From 2001, as an Emeritus Professor, John was a Visiting Research Fellow in the Department of Archaeology at the University of Reading. In 2010 John was awarded an honorary DSc degree of the University of Reading for a wide-ranging body of international lauded research.

2. John’s major research interests, contributions and impacts

What motivated John to be interested in physical sedimentology? The lines above are from John’s reply after the President’s citation for John’s presentation with the Lyell Medal in 1980 (Society meetings January–June 1980, Journal of the Geological Society, 138, 1 July 1981, p. 503, para. 1). Clearly, in his own words, John’s primary interest in physical sedimentology was motivated by ‘playing with sand’ during his early life with his maternal grandmother on the Lancashire coast.

John made many contributions to quantitative sedimentology, particularly in the field of experimental sedimentation. He also made notable contributions to the study of fluvial and deltaic sedimentation. His outstanding work was notable for the way in which it was brought to bear on problems concerning the origin, transport and deposition of clastic sediment and the tectonic significance of the Old Red Sandstone. He made a distinguished contribution to fluvial sedimentology and palaeogeomorphology, the latter of which skilfully blended field studies of modern and ancient fluvial environments with laboratory experiments. His influence can be felt throughout modern sedimentary geology.

John published his first paper in 1957, which was on the Pre-Cambrian geology of Caldecote and Hartshill, Warwickshire and which arose from his undergraduate thesis (mapping) possibly under the supervision of Professor Leslie Rowsell Moore (1912–2003) (Allen, Reference Allen1957). John’s first paper in the Geological Magazine also appeared in 1960 (Allen, Reference Allen1960 a). The Mam Tor paper (1960b) was important because it was concerned with a classic area. The Cornstone paper (1965a) was the first of his PhD thesis papers. John must take a lot of credit for his work on the nature and significance of palaeosols, particularly the caliches (Cornstones) of the Old Red Sandstone. Allen’s (Reference Allen1962) paper entitled ‘Petrology, origin and deposition of the highest Lower Old Red Sandstone of Shropshire, England’, which was published in Journal of Sedimentary Petrology 32, 657–97, John’s third paper, won the Best Journal Paper Award ^{Footnote 4} .

John was a prolific writer, and some suggested, semi-seriously, that his many published papers were written by three different authors: John Allen, Robert Allen and Lawrence Allen. John seemed to write faster than one could read. He enjoyed writing lengthy papers (e.g. Allen, Reference Allen1965 a, 2000a). His 101-page landmark review of ‘Recent alluvial sediments’ was published in 1965 (Allen, Reference Allen1965 a). His productivity was the envy of the vast majority of geologists at the height of their academic careers. Many of John’s publications are single-authored. John published at least 226 books and papers (University of Reading research website) spanning the years from 1957 to 2019 (see Appendix) before his passing. John also published a number of classic books, e.g. the 433-page book on Current Ripples (Allen 1968) and a 272-page book on Principles of Physical Sedimentology (Allen, Reference Allen1985 a). There were two contrasting reviews of Allen’s (Reference Allen1968) Current Ripples, one by Collinson (Reference Collinson1970), the other by Kennedy (Reference Kennedy1970). Allen (Reference Allen1985 a) and its predecessor Physical Processes of Sedimentation (Allen, Reference Allen1970) were the standard undergraduate sedimentology textbooks in most British geology departments for a quarter of a century. One may say that John’s magnum opus Sedimentary Structures (Allen, Reference Allen1982 a,b) is much more important than his Current Ripples (Allen 1968). One cannot see how any account of John’s output and impact could leave out his truly seminal book Sedimentary Structures (Allen, Reference Allen1982 a,b) that perhaps is his greatest assembly of information – cited now over 3000 times.

One would see a number of John’s contributions as seminal works – it’s personal as to which: his work on the Old Red Sandstone of course as mentioned above, but also that on sandwaves, bedform theory, grain dynamics, flow separation, etc. Indeed, there are so many to choose from that one may feel it would actually be better to highlight some of their impacts.

How have they influenced our thought and knowledge on these areas? Why was John pioneering in these areas? How did they advance the field? On looking back at his published papers and books, it is seen that John was fully aware of the great importance of fluid mechanics to sedimentary geology. His readings of the classic books on fluid mechanics were extensive, including Prandtl (Reference Prandtl1952), Lin (Reference Lin1955), Schlichting (Reference Schlichting1960), Chandrasekhar (Reference Chandrasekhar1961) and Yih (Reference Yih1965). At a young age (Fig. 2), John already thought that teaching fluid mechanics to young geologists was important. As an example, he wrote a paper for young geologists entitled ‘Simple experiments to demonstrate wave-motion, flow-separation, helicoidal flow and stationary vortices’ (Allen, Reference Allen1965 b).

Fig. 2. This portrait of the young John at about the age of 33 appeared on the front page of his paper (Allen, Reference Allen1965b) in the Journal of Geological Education. Reproduced with permission of the Journal of Geological Education.

In his short ‘Note on the use of Plaster of Paris in flow visualization, and some geological applications’, which was published in the Journal of Fluid Mechanics, Allen (Reference Allen1966, p. 331, lines 1–3) wrote that ‘The methods of fluid mechanics are helpful to geologists interested in the origin and environmental significance of current-formed structures present in sedimentary rocks and in modern sediments.’ He applied one of the conventional methods of fluid mechanics, i.e. flow visualization, to promote understanding of bed ripples and sand waves, and other sedimentary features.

Allen (Reference Allen1984, p. 227, introduction, para. 1, lines 1–5) wrote that ‘A major development in the field of fluid mechanics of relevance to sedimentology is the realization that turbulent flows are both deterministic and stochastic in character, and that they are composed of coherent flow configurations whose properties depend uniquely on such flow characteristics as thickness, mean velocity and shear stress (see reviews by Laufer, Reference Laufer1975, …).’ Allen (Reference Allen1984, p. 227, introduction, para. 2, lines 1–4) further wrote that ‘Coherent structures occur on two main spatial scales in turbulent boundary layers, represented naturally by river, tidal, and turbidity currents and by the wind blowing past a surface, provided that the flows are hydraulically smooth or transitional.’ ‘Coherent structures’, which is the advanced concept in turbulent boundary layers, was applied to an improved understanding of parallel lamination developed from upper-stage plane beds (Allen, Reference Allen1984).

In his review of ‘Loose-boundary hydraulics and fluid mechanics’, Allen (Reference Allen, Brenchley and Williams1985 b, p. 7, left column, bottom line, right column, lines 1–4) wrote that ‘Sorby (Reference Sorby1859, Reference Sorby1908) a century previously had demonstrated the power of a quantitative and experimental approach to sediments, but we did feel that now its time had come.’ John, as a geologist, also read applied mathematicians’ books on turbulent shear flow written by Townsend (Reference Townsend1956, Reference Townsend1975). John also read the advanced papers of British fluid dynamicists, e.g. Simpson (Reference Simpson1972), Sleath (Reference Sleath1974), Britter & Linden (Reference Britter and Linden1980) and Longuet-Higgins (Reference Longuet-Higgins1981). Allen (Reference Allen, Brenchley and Williams1985 b, p. 7, Summary, lines 1–4) believed that ‘A major and acknowledged role in the advance of sedimentological knowledge is played by the methods of physics as expressed through fluid mechanics and loose-boundary hydraulics. Turbulence is increasingly being seen as involving orderly flow structures, and these are significant for the origin of several sedimentary structures and for suspension transport.’

Clearly, John was pioneering in these areas by applying the following methods and theories to sedimentary geology: (1) the methods of fluid mechanics; (2) the theories of fluid mechanics, e.g. the turbulent boundary layer; (3) the methods of loose-boundary hydraulics; (4) the theories of loose-boundary hydraulics, e.g. erosion, deposition, bedload, suspension, etc.

In the author’s view, these studies by John advanced the field by: (1) providing physical insights into sedimentary processes; (2) relating sedimentary geology with fluid mechanics and hydrodynamics, e.g. tidal bedding vs tidal cycles; (3) semi-quantifying the mechanics of sedimentary processes; (4) enabling some simple mathematical modelling and prediction.

After his ‘retirement’ John also worked on estuarine processes (Severn Estuary) (e.g. Allen Reference Allen1985c , Reference Allen1986, Reference Allen1989, Reference Allen1990 a, b, Reference Allen1991, Reference Allen1994, Reference Allen2000 a, b) and geoarchaeology (e.g. Allen & Fulford Reference Allen and Fulford1986, Reference Allen and Fulford1987, Reference Allen and Fulford1990). It is astonishing how he turned his mind to new fields of fascination. In his own words, John ‘wanted a new scientific challenge’. John used mathematics in several different areas of his work from an early date (e.g. one-dimensional mathematical modelling of salt-marsh growth) with the assistance of others (e.g. H. Begg, who was acknowledged in Allen (Reference Allen1990 a, p. 745, right column, line 1)).

The 29th Annual Meeting of the British Sedimentological Research Group (BSRG), chaired by Andrew Parker, was held at the University of Reading on 16–19 December 1990. It was at this meeting that the author first met John. The meeting included a one-day field excursion to the salt marshes of the Severn Estuary, England, on Wednesday 19 December 1990. John led this field excursion (Fig. 3).

Fig. 3. John, wearing a worn, light blue hat, leading the BSRG-meeting one-day field excursion to the salt marshes of the Severn Estuary, England, on Wednesday 19 December 1990. The thick yellow arrows point to John. Photo credit: John Z. Shi.

Together with Kenneth Pye, John organized the Workshop on the Morphodynamics, Conservation and Engineering Significance of Saltmarshes, at the Postgraduate Research Institute for Sedimentology, University of Reading, on 24 April 1991. The outcome of this workshop was a book (Allen & Pye, Reference Allen and Pye1992). The author attended this workshop and got to know John better.

One day in June 1992, the present author presented his first scientific talk, entitled ‘Recent sedimentation in the Dyfi Estuary, west Wales’, at the PRIS. John listened to the talk very carefully. As was the tradition, there was a celebration in the pub after the talk. John, together with Andrew Parker (1941–2017) ^{Footnote 5} , was kindly present and chatted with the present author there.

John was a great contributor to his field and one whose research impact has had, and will continue to have, a direct impact in many areas. All physical sedimentologists across the globe have read and used his work extensively – from early to later studies. As such, John’s impact on his field has been enormous.

Some personal experiences are used to show how John’s interest in salt marshes has influenced the present author’s work. John’s influence on the author has been very strong. As a Visiting Scientist, using John’s Armstrong flume (Fig. 4), the author did a laboratory flume study of vegetated flow structures. John had kindly provided the author with his flume. This work resulted in two papers (Shi & Hughes, Reference Shi and Hughes2002; Shi et al. Reference Shi, Li, Hughes and Zhao2013).

Fig. 4. A portion of John’s Armstrong flume in the Sedimentology Research Laboratory at the PRIS, University of Reading. The present author used the flume for a study of vegetated flow structures. The photo was taken by Erika Mellor in 1993.

On looking back at John’s flume (Fig. 4), not surprisingly, one may think it is not just a sedimentology laboratory but also a fluid mechanics laboratory or hydraulics laboratory. It is hardly different from the one at the GK Batchelor Laboratory, at the Department of Applied Mathematics and Theoretical Physics (DAMTP), University of Cambridge, UK. This is why John was a pioneer in physical sedimentology.

After the author returned to China from his visit to Reading, John maintained contact and was interested in the present author’s work on salt marshes, requesting reprints of e.g. Shi et al. (Reference Shi, Lamb and Collin1995) and Shi et al. (Reference Shi, Hamilton and Wolanski2000). In the author’s Chinese-language book Physical Processes of Estuarine and Coastal Fine Sediment (Shi, Reference Shi2013), which was inspired by John’s style of citing references, a total of 2655 references are made. The book was dedicated to John. When the author emailed John about it during the author’s visit to the GK Batchelor Laboratory, John replied, ‘Dear John, I do hope your stay at Cambridge will be enjoyable and profitable. I’m flattered that you should dedicate a book to me – I hope it does well and brings you great acclaim’ (email to the author, 10 October 2012). In the author’s recent review paper (Shi, Reference Shi2021), a total of 397 references are cited. John’s influence on the author’s research is still continuing.

3. John’s role in the former Postgraduate Research Institute for Sedimentology

In the late 1950s, sedimentology was just emerging as a discipline. A small group of UK researchers, including Harold Garnar Reading (1924–2019), John, and Peter Furneaux Friend, set it on the route to becoming a very significant part of modern geology (based on the citation for the Prestwich Medal of the Society for 2010 awarded to Peter Friend ^{Footnote 6} ). Perce Allen’s most important geological achievement at Reading was probably the foundation of the Sedimentology Research Laboratory in 1962. Undoubtedly, however, John, together with Andrew Parker, played a pivotal role in establishing the former Postgraduate Research Institute for Sedimentology. It is a pity that this Institute does not exist anymore. One may argue that John never established a ‘research school’ in the way that other contemporaries did. As shown in Figure 5, however, John, as the first Director, was leading the PRIS. Mark Brian Roberts, an archaeologist at University College London, is best known for his discovery and subsequent excavations at the Lower Palaeolithic site of Boxgrove Quarry in southern England. John, as the first Director, had taken part in the PRIS’s field trip to Eartham Pit near Boxgrove, West Sussex, England, in the summer of 1992 which was organized by Peter Worsley (Fig. 6). Roberts was invited to be a guide. In this author’s view, inviting cooperation in this way can be considered one of the functions of a ‘research school’.

Fig. 5. Group photo of the PRIS in June 1992. The white arrow points to John. The photo was taken by JL Watkins.

Fig. 6. John, wearing a worn, light blue hat, as Director of the PRIS, taking part in the Institute’s field trip to Eartham Pit near Boxgrove, West Sussex, England, in the summer of 1992. The thick yellow arrow points to John. Photo Credit: John Z. Shi.

4. John’s philosophy of physical sedimentology

In this tribute, the author does not attempt to give a detailed account of John’s scientific mind and character. However, like other geologists, John was very much influenced by the uniformitarian principles developed by James Hutton (1726–1797), John Playfair (1748–1819), William Whewell (1794–1866) and Charles Lyell (1797–1875) in the early 18th and 19th centuries.

John appears to have been most strongly influenced by Hugh Miller (1802–1856), Henry Clifton Sorby (1826–Reference Sorby1908) and Ralph Alger Bagnold (1896–1990). The following lines are from the citation by the President of the Geological Society of London for John’s presentation with the Lyell Medal in 1980 (Society meetings January–June 1980, Journal of the Geological Society, 138, 1 July 1981, p. 502, right column, para. 4):

On looking back at the Contents of Sorby (Reference Sorby1908, p. 171) (Fig. 7), one can see what the President’s citation really meant in saying ‘…sedimentological seeds … made them grow…’ since they also clearly outlined what John had done following Sorby, and how he had done it.

Fig. 7. The front page of Sorby (Reference Sorby1908), showing the main contents and Sorby’s object. Reproduced with permission of www.biodiversitylibrary.org.

As shown in Figure 8, this was quoted just below the title of Section ‘1. INTRODUCTION’ in John’s 42-page review ‘Some recent advances in the physics of sedimentation’ (Allen, Reference Allen1969, p. 2). Clearly, in a way, John regarded Sorby as his scientific research model and made the philosophy of his own research clear via Sorby’s objective (or philosophy).

Fig. 8. A portion of Allen (Reference Allen1969, p. 2) showing his quotation of Sorby’s (1908, p. 171, Introduction, para. 2) raison d’être.

In his Volume 150 Celebration Paper for the Journal of the Geological Society, London entitled ‘Sedimentary structures: Sorby and the last decade’, Allen (Reference Allen1993, p. 417, abstract) wrote that ‘Henry Clifton Sorby pioneered in the last century the description and especially the hydrodynamic interpretation of sedimentary structures, together with their use as palaeocurrent indicators.’ He further wrote that ‘Henry Clifton Sorby (1826–Reference Sorby1908) of Sheffield may with every justification be called the “Father of Sedimentology”’ (Allen, Reference Allen1993, p. 417, lines 1–2). In the author’s view, since John was also from Sheffield, he might be thought of as the reincarnation of Sorby. The author sees John as the natural successor to Sorby.

John had a really unique career, first playing with sand, then playing with mud and finally playing with pottery. Through the whole of his career the publication of research was a prime motive in his life. As stated in the citation by the President of the Geological Society of London for John’s presentation with the Lyell Medal in 1980, ‘John, you have kept faith with Michael Faraday’s statement of a scientist’s responsibilities: Work, Finish, Publish!’ (Society meetings January–June 1980, Journal of the Geological Society, 138, 1 July 1981, p. 502, right column, last para., lines 1–2). John’s output in papers and books was prodigious. Given the fact that modern universities impose funding, teaching and publications pressures on scientists, it would be difficult to carry out research in John’s style nowadays.

5. Awards and recognition

There are many geologists with extraordinary achievements to their names, and many who have won major prizes. But even in this illustrious company, John stands out. He was elected a Fellow of the Royal Society in 1979 (for his election certificate, see the above) and a Fellow of the Society of Antiquaries of London in 1991. He was the recipient of many awards: the Lyell Medal of the Geological Society of London (1980) ^{Footnote 8} ; the David Linton Award of the British Geomorphological Research Group (1983) (for the citation, see Whalley, Reference Whalley1985; the Twenhofel Medal of the Society of Economic Paleontologists and Mineralogists (1987) ^{Footnote 9} ; the GK Warren Prize of the US National Academy of Sciences (1990) ^{Footnote 10} ; the Sorby Medal of the International Association of Sedimentologists (1994) ^{Footnote 11} ; and the Penrose Medal (and an Honorary Fellowship) of the Geological Society of America (1996) ^{Footnote 12} .

6. Personality

John’s personality was pleasant and friendly; he liked people to call him simply ‘John’. In the author’s view, John seems a revered, if sometimes controversial, personality. He enjoyed working independently, with minimum help from others. Of course, John did have a productive relationship with Brian Williams on the Old Red Sandstone in South Wales. In addition, he had other very productive and successful working relationships, particularly with Joy Rae, Kenneth Pye, Michael Fulford, Simon Haslett, Petra Dark and Martin G. Bell.

In the author’s view, nevertheless, as a dedication to John (Shi, Reference Shi2013, p. 2), his early scientific life is best described by the poetic line, ‘… a mind forever Voyaging through strange seas of Thought, alone’ (words used by William Wordsworth (1770–1850) to imagine Newton, in The Prelude, book III, ‘Residence at Cambridge’, 1805; Wordsworth, Reference Wordsworth1894).

7. Postscript

The author has profound respect for John’s achievements and has tried to give a short account of John Robert Lawrence Allen as he knew him and to indicate some of the ways in which the author’s own scientific ideas were inspired by John. The geographical separation of home countries in particular makes it impossible for the author to claim to be one of John’s intimate friends, but the author hopes he has conveyed some impression of how much he liked and admired John. The author believes that many geoscientists worldwide will appreciate this initiative.

After John’s passing, there were a number of heartfelt obituary notices available online, e.g. https://www.sedimentologists.org/repository/newsletters/4477dea4701011e9a9231301: page 4

https://www.geolsoc.org.uk/About/History/Obituaries-2001-onwards/Obituaries-2020/John-Allen

https://www.livinglevels.org.uk/news/2021/5/27/professor-john-rl-allen.