Geographical Cycle” at the Turn of the 1960S
Total Page:16
File Type:pdf, Size:1020Kb
TWO RE-EVALUATIONS OF DAVIS’S “GEOGRAPHICAL CYCLE” AT THE TURN OF THE 1960S DUAS REAVALIAÇÕES DO “CICLO GEOGRÁFICO” DE DAVIS NA VIRADA DA DÉCADA DE 1960 DEUX RÉÉVALUATIONS DU «CYCLE GÉOGRAPHIQUE» DE DAVIS AU TOURNANT DES ANNÉES 1960 CHRISTIAN GIUSTI1 1 Faculté des Lettres, Sorbonne Université, Paris. Laboratoire de Géographie Physique, UMR 8591 CNRS, Meudon. E-mail: [email protected] ORCID: https://ORCID.0000-0002-6531-3572 Received 15/11/2020 Sent for correction: 30/11/2020 Accepted: 15/12/2020 To Marie-Hélène Auclair, Librarian in Sorbonne (1975-1985), a most helpful friend during my early years of research. ABSTRACT Many geomorphologists today refer to Davis and his ideas without really knowing what that implies. In the second half of the 20th century, two re-evaluations of the Davisian system were carried out, which the renewed popularity of the “peneplain” concept has led us to bring back to light and discuss. Key words: Davis, geographical cycle, peneplain, Chorley, Klein. RESUMO Muitos geomorfólogos hoje se referem a Davis e suas ideias sem realmente saber o que isso implica. Na segunda metade do século XX, foram realizadas duas reavaliações do sistema Davisiano, cuja renovada popularidade do conceito de “peneplanície” nos levou a trazer de volta à luz e discutir. Palavras-chave: Davis, ciclo geográfico, peneplanície, Chorley, Klein. RÉSUMÉ De nombreux géomorphologues font aujourd'hui référence à Davis et à ses idées sans vraiment savoir ce que cela implique. Dans la seconde moitié du XXe siècle, deux réévaluations du système davisien ont été effectuées, que la popularité renouvelée du concept de «pénéplaine» nous a amenées à remettre en lumière et à discuter. Mots clés: Davis, cycle géographique, pénéplaine, Chorley, Klein. « Le sentiment joue son rôle même dans la science ». E. de Martonne (1929, 419). The publication of the seminal hydrophysical paper by Robert E. Horton [1875-1945] in March 1945 is regarded as the starting point of the quantitative fluvial revolution in the aftermath of World War II (KENNEDY, 1978; 1992; STRAHLER, 1992; CHORLEY, 1995; KENNEDY, 2006, p. 98-111). Richard J. Chorley [1927-2002], commenting on Horton (1945) fifty years later, stated that “Horton’s article ushered in a period of engineering geomorphology that still lasts” (CHORLEY, 1995, p. 533). In France, the active promoters of a quantitative approach in geomorphology were mainly a geologist, André Cailleux [1907- 1986], and a geographer, Jean Tricart [1920-2003], both involved in the construction of a breakthrough structural and climatic geomorphology, fully opposed to the physiographic timebound approach developed by William M. Davis [1850-1934] and his followers, among whom Henri Baulig [1877-1962] may by far be considered as the most influential (BECKINSALE; CHORLEY, 1991, p. 256-283). GIUSTI, C. TWO RE-EVALUATIONS OF DAVIS’S “GEOGRAPHICAL CYCLE” AT THE TURN OF THE 1960S Arthur N. Strahler [1918-2002] gave a detailed account of the period 1945-1960 in Columbia, years during which quantitative dynamic geomorphology developed, before being widely distributed (STRAHLER, 1992; KENNEDY, 2006; CHORLEY, 2008, p. 925-960). A totally whiggish view of history would consist in contrasting the old qualitative geomorphology, embodied by Davis’s obsolescent ideas, with the young quantitative geomorphology embodied by Strahler and his tutee followers, the bearer of all promises and the future of geomorphology1. No one envisages of contesting that a change of scales and methods accompanying a paradigm shift occurred in the middle of the last century. But both Strahler and his American pupils – notably Stanley. A. Schumm [1927-2011] and Mark A. 22 Melton [1930-2019] – never stopped working on all sort of rivers, the main feature of the cyclic mode of evolution. One can cite the fundamental article on time, space and causality (SCHUMM; LICHTY, 1965), as well as the synthesis on the fluvial system (SCHUMM, 1977). In this now classic book, the first chapter illustrates that the scientific project was to put “the idealized fluvial system” to the test against the reality (SCHUMM, 1977, p. 3)2, i.e., observation and experience facts (the same manner Davis had constructed an “idealized cycle” and multiplied block diagrams). Based on a cross-analysis of Hutton, Lyell, Darwin, Dana, Gilbert and Horton, Barbara A. Kennedy [1943-2014] insisted on “the impossibility of making simple divorce between the dynamic (or physical) approach and the historical”, adding that “if we simply consider a sequence of events of all, physically-possible shapes and sizes, then both equilibria and cataclysms may be accommodated as potential occurrences” (KENNEDY, 1992)3. To which it will be added that the Davisian geomorphology is also a dynamic geomorphology in its own way, centred on the dynamism of landforms, not on that of processes (KLEIN, 1993). As M. Morisawa (1985) clearly stated, “the real legacies of the hydrophysical approach were the rapid demise of the Davisian system and also the tendency of much geomorphology in the second half of the century to concentrate on the smaller scales of space and time and on the effects of measurable processes” (in CHORLEY, 1995, p. 552). The issue of the quantitative revolution in geomorphology, well documented (e.g., KEYLOCK, 2003; KENNEDY, 1996. BURT et al., 2008), therefore does not seem to ask for further development. Actually, this essay is rather an attempt to compare two re-evaluations of the Davisian system. The first one occurred at the end of the 1950s, namely the acyclic theory of Claude Klein [1924-2005], which went largely unnoticed outside the French-speaking sphere (KLEIN, 1959a,b; 1960). The second one was initiated by Richard J. Chorley in the early 1960s, first as a lecture given at Madingley Hall4 in 1963, which proved strongly influential (CHORLEY, 1965), later extended through an authoritative biography of Davis (CHORLEY; 1 A variation would be to assert that Gilbert had built a sound foundation for the study of landforms and processes, but because of Davis, it was not until 1945 that the true scientific method would have been again put to work. 2 On the other hand, the ‘physical’ approach is favored in Fluvial Processes in Geomorphology, although peneplains and pediments appear in the end (LEOPOLD et al., 1964), and also in River variability and complexity (SCHUMM, 2005). 3 See the long-time misunderstood work of J H. Bretz on the Channeled Scablands (1923; 1928; BRETZ; SMITH; NEFF, 1956), as well as the synthesis by D. M. Burr, P. A. Carling and V. M. Baker (2009). 4 “Madingley Hall” is the conference center for the University of Cambridge. See: https://en.wikipedia.org/wiki/Madingley (accessed January 2021, 4th). William Morris Davis - Revista de Geomorfologia, v. 1, n. 2, 30 de dezembro de 2020, p. 21-59. DOI: https://doi.org/10.48025/ISSN2675-6900.v1n2.p/21-59.2020 GIUSTI, C. TWO RE-EVALUATIONS OF DAVIS’S “GEOGRAPHICAL CYCLE” AT THE TURN OF THE 1960S BECKINSALE; DUNN, 1973). After having call up both re-readings of the “geographical cycle5”, the Davisian system will be put in perspective. 1. KLEIN’S ACYCLIC THEORY AND THE LIMITS OF THE CYCLIC THEORY (1959-60)6 The noteworthy English translation of “Die morphologische Analyse” (PENCK, 1924) a few years after the end of World War II by Hella Czech and Katherine C. Boswell (PENCK, 1953)7 has enabled many non-German-speaking readers to discover the thought of Walther Penck freed from the Davisian prism of interpretation (TUAN, 1958; SIMONS, 1962; 23 GIUSTI, 2012b). In France, opinions are divided. On one side, Henri Baulig defends until his last breath Davisian geomorphology (BAULIG, 1950; 1951; 1952 a,b,1956a), while carefully echoing the American quantitative studies (BAULIG, 1950, p. 64-68 on KESSELI; MACKIN; 1959 on STRAHLER; SCHUMM; MELTON)8. On the opposite side, Jean Tricart develops a fierce opposition to Davis and lead most French geomorphologists towards climatic morphology (MARTONNE, 1913; 1940; 1946; CHOLLEY, 1950; TRICART, 1965), which he enlarges and deepens after his pioneering thesis on the Eastern Paris Basin (TRICART, 1949-1952, TRICART; CAILLEUX, 1962-1974). The position of Pierre Birot [1909-1984] is much more elaborated, defending a middle line between Davis and Penck (BIROT, 1958). As a student at the ‘École normale supérieure de Saint-Cloud’, Claude Klein had the opportunity to hear Birot’s lessons in the late 1940s. And a few years later, when Klein exposes his views on acyclism at the end of the 1950s, his conceptual geomorphological toolbox includes Cholley’s polygenism9, Baulig’s eustatic polycyclism, Erhart’s biorhexistasis theory10, Quaternary evolution of the Eastern Paris Basin (TRICART, 1952), plus Davis read with Baulig’s perceptive commentaries, and Walther Penck read through the antithetic prism of Baulig (negative) and Birot (positive). For twenty years or so (1953-1973), Claude Klein studied the geology and geomorphology of a large area at the contact with the Armorican Massif and the Paris Basin (GUILCHER, 1974). A hefty thesis was soon published under the form of two impressive volumes (KLEIN, 1975), though the principles of the acyclic theory were fully defined from 1959-1960: “Surfaces polygéniques et surfaces polycycliques” (KLEIN, 1959a), “Surfaces de regradation et surfaces d’aggradation” (KLEIN, 1959b), and “La notion de rythme en 5 This expression is hardly ever used, most often replaced by “cycle of erosion” or more rarely (Baulig, after Lawson) by “geomorphic cycle”. An essential part of Davis’s scientific message is thus obscured: the spatial expression of landforms in the landscape. Because Carl O. Sauer [1889-1975] was clearly aware of this attribute, he reacted vigorously by reminding American geographers that a landscape cannot be reduced to its only (geo)morphological features, to the exclusion of its other attributes: natural and cultural (Sauer, 1925).