Quantitative geography: Revolution or counter-revolution?Quantitative geographie: Revolution oder konterrevolution?La géographie quantitative: Révolution ou contre-révolution?

There has been a crisis of the so-called “quantitative geography” for a few years. It is partly due to a poor use of mathematics, often presented for its own sake. There are also deeper reasons: refusal of rational formalization; and more emphasis on social and political studies.This paper tries to snow that a formal language (i.e., vocabulary and syntax) is necessary. Linguistics show how a language can be perverted by ideology into a myth. This has happened with traditional geography and is still present in some recent radical studies.     

De L'opportunité d'utiliser les coefficients de corrélation en météorologie forestière

Résumé En complément d'une étude précédente, les auteurs ont examiné si les coefficients de corrélation pouvaient s'utiliser avec profit pour résoudre les problèmes écologiques et plus spécialement de météorologie forestière. Pour cela ils ont calculé les coefficients résultant de la comparaison de l'accroissement forestier avec 12 grandeurs météorologiques. Afin d'obtenir des coefficients plus élévés ils ont considéré ensuite la courbe d'accroissement sur la base de sa droite de régression au lieu de sa moyenne. Ils ont enfin calculé diverses corrélations partielles en tenant compte d'une seconde grandeur météorologique. Il ressort de l'important matérial ainsi rassemblé, qu'il n'existe pas de corrélation entre les éléments météorologiques et l'accroissement forestier, du moins pas au sens mathématique du terme. Comme cette conclusion est en contradiction avec l'expérience pratique, on en déduit que cette méthode est inutilisable dans le cas particulier. Cette déduction est en outre étayée par des considérations d'ordre physiologique.

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Summary The present paper is a complement to an earlier work. It's purpose is to investigate the utility of correlation calculus with regard to ecological problema especially of the forest-meteorological kind. The authors computed, first of all, the direct correlation between treegrowth and each of 12 meteorological quantities. They tried then to improve the results by referring the annual treegrowth to it's regression line instead of the mean. Finally, they examined partial correlation taking into account two meteorological influences at the same time. The results seem to indicate, that there is no statistical evidence for any significant correlation between treegrowth and meteorological data. This is of course contrary to practical experience, whence the authors infer, that correlation calculus is an inadequate tool for handling their problem and similar ecological researches. This conclusion is supported by physiological considerations.

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Zusammenfassung In Ergänzung zu einer früheren Arbeit untersuchen die Autoren, ob Korrelationskoeffizienten in oekologischen, speziell forstmeteorologischen Aufgaben sinnvoll angewendet werden können. Zuerst werden die direkten Korrelationen zwischen dem jährlichen Holzzuwachs und je einer von 12 meteorologischen Grössen berechnet; dann wird zur Erzielung höherer Koeffizienten die Kurve des Holzzuwachses auf ihre zeitliche Regressionsgerade statt auf den Mittelwert bezogen, und schiesslich werden verschiedene partielle Korrelationen unter Berücksichtigung von je einer zweiten meteorologischen Grösse angegeben. Aus dem ziemlich unfangreichen Zahlenmaterial scheint hervorzugehen, dass zwischen Holzzuwachs und Witterung kaum ein statistischer Zusammenhang im mathematischen Sinne besteht. Da dieses Ergebnis der praktischen Erfahrung widerspricht, muss geschlossen werden, dass die Korrelationsrechnung der vorliegenden Aufgabe nicht angemessen ist, eine Folgerung, die durch Ueberlegungen physiologischer Natur gestützt und eingehend begründet ist.

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Riassunto A complemento di un precedente lavoro, gli autori studiano se abbia un senso l'impiego di coefficienti di correlazione in problemi ecologici e in particolare in quelli meteorologici-forestali. Dapprima vengono calcolate le correlazioni dirette tra la crescita annua del legno e ciascuna di 12 grandezze meteorologiche; in seguito, allo scopo di raggiungere coefficienti più elevati la curva della crescita del legno vien riferita alla sua retta di regressione del tempo invece che al valore medio; in ultimo vengono rese note diverse correlazioni parziali ottenute considerando anche una seconda grandezza meteorologica. Dal materiale assai abbondante utilizzato, sembra potersi dedurre che tra crescita del legno e condizioni meteorologiche non esiste una relazione statistica in senso matematico. Siccome questo risultato è in contrasto con l'esperienza pratica, bisogna dedurre che il calcolo del coefficiente di correlazione non è adatto per il problema in questione. E' questa una conseguenza che può appoggiarsi su ragionamenti di natura fisiologica ed essere minuziosamente motivata.

     

A Compilation of Silicon and Thirty One Trace Elements Measured in the Natural River Water Reference Material SLRS-4 (NRC-CNRC)

The natural river water certified reference material SLRS-4 (NRC-CNRC, National Research Council-Conseil National de Recherches Canada) has been routinely analysed for major and trace elements by six French laboratories. Most measurements were made using inductively coupled plasma-mass spectrometry. For silicon and thirty one trace elements (rare earth elements, Ag, B, Br, Cs, Ga, Ge, Li, P, Pd, Rb, Se, Th, Ti, Tl, W, Y and Zr), no certified values are assigned by NRC-CNRC. We propose some compilation values and related uncertainties according to the results obtained by the different laboratories.     

The 1987–88 Alaskan Bight tsunamis: Deep ocean data and model comparisons

Excellent deep ocean records have been obtained of two tsunamis recently generated in the Alaskan Bight on 30 November 1987 and 6 March 1988, providing the best available data set to date for comparison with tsunami generation/propagation models. Simulations have been performed with SWAN, a nonlinear shallow water numerical model, using source terms estimated by a seafloor deformation model based on the rectangular fault plane formalism. The tsunami waveform obtained from the model is quite sensitive to the specific source assumed. Significant differences were found between the computations and observations of the 30 November 1987 tsunami, suggesting inadequate knowledge of the source characteristics. Fair agreement was found between the data and the model for the first few waves of the 6 March 1988 tsunami. Model estimates of the seismic moment and total slip along the fault plane are also in fair agreement with those derived from the published Harvard centroid solution for the 6 March 1988 event, implying that the computed seafloor deformation does bear some similarity to the actual source.     

Changement de faunes de bryozoaires dans le Valanginien supérieur des Alpes-de-Haute-Provence. Parallélisme avec la crise observée dans le Jura à la même époque

Dans le Valanginien supérieur (Marnes à Toxaster et Grande Lumachelle) des Alpes-de-Haute-Provence, la succession de deux faunes de bryozoaires est observée. Parmi les causes du changement de faune, le remplacement d'un fond vaseux en eau calme (Marnes à Toxaster) par un fond sableux coquillier en eau assez agitée (Grande Lumachelle) est certainement important. Cependant, ces modifications résultent elles-mêmes d'événements plus généraux.Le changement de faune peut être comparé à celui qui intervient dans le Jura au début de la zone à Trinodosum. La faune des Marnes à Toxaster (zone à Verrucosum) montre certaines des espèces caractéristiques de la “faune 1” du Jura et, de plus, les deux mêmes espèces dominantes. Le milieu de vasière des Marnes à Toxaster, opposé à celui de plate-forme carbonatée du Jura, entraîne seulement un appauvrissement spécifique. Quant à la faune de la grande Lumachelle, elle est absolument semblable à la “faune 2” récoltée dans les Marnes à bryozoaires et le Calcaire à Alectryonia du Jura.Ce parallélisme des deux faunes avec celles du Jura, malgré les différences de faciès sédimentaire, montre que le changement de faune, maintenant reconnu sur près de 400 km, résulte d'une même cause principale. Ainsi, l'hypothèse d'un refroidissement que j'ai proposée pour le Jura semble pouvoir être étendue à la Provence.The change of bryozoan fauna in the upper Valanginian of the Alpes-de-Haute-Provence. Parallelism with the crisis observed in the Jura at the same time.In the upper Valanginian (Marnes à Toxaster and Grande Lumachelle) of the Alpes-de-Haute-Provence, the succession of two bryozoan faunas is observed. Among the reasons for the change of fauna, the replacement of a muddy bottom in calm water (Marnes à Toxaster) by a sandy-shelly bottom in rather agitated water (Grande Lumachelle) is certainly important, but these modifications are the result of more general events. The change of fauna could be compared with the one that took place at the beginning of the Trinodosum Zone in the Jura. The fauna of the Marnes à Toxaster (Verrucosum Zone) shows some characteristic species of the “faune 1” of the Jura and, moreover, the same two dominating species. The muddy basin environment of the Marnes à Toxaster, unlike the carbonate platform environment in the Jura, involves only a specific impoverishment. As for the fauna of the Grande Lumachelle, it is totally identical to the “faune 2” found in the Marnes à bryozoaires and the Calcaire à Alectryonia of the Jura.This parallelism of the two faunas with those of the Jura, in spite of the differences of sedimentary facies, shows the change of the fauna now observed over about 400 km, has the same principal cause. Thus it seems possible to extend the cooling hypothesis I have proposed for the Jura, to Provence.     

Continuous monitoring of distal gas emanations at Vulcano,southern Italy

The increasing activity of Vulcano Island (Italy) since 1985 led to the initiation of continuous geochemical monitoring of the lateral soil gas emissions. On the basis both of their relative geochemical characteristics and of local considerations, three gaseous components were selected for monitoring, namely CO₂, He and ²²²Rn. Monitoring has been performed by means of specific analysers. Gases extracted from a water well located at the foot of the active cone were selected for monitoring, on the basis of their geochemical and isotopic characters that indicate their genetic link with central high temperature fumarolic gases emitted at the crater. Very strong variations of gas composition can be observed within one day (from 1 to about 94% for CO₂). Some variations display a daily character and can be correlated with that of atmospheric pressure. The three monitored gases are highly correlated, suggesting very high kinetics of gas transfer in the system. Because of these considerable variations of chemical composition, bulk concentrations obviously are not suitable for monitoring at Vulcano. However, the evolution with time of ratios such as ²²²Rn/CO₂ and He/CO₂ (the latter being corrected for atmospheric contamination) supplies numerical parameters that the expected to characterize the intensity of the degassing process. A new input of magmatic gases, that would lead to an increase in the ²²²Rn/CO₂ and He/CO₂ ratios, should therefore be detected by such a monitoring station.     

Coarse cliff-top aeolian sedimentation in northern Gaspésie,Québec (Canada)

This paper deals with the effects of wind on rockwall dynamics. On 5 and 6 January, 1988 very strong northwest winds (blizzard) were blowing onto the rockwall of Mount Saint-Pierre (alt.: 424 m), Gaspésie, Québec (Canada). The most violent recorded squall reached 99·4 km h^?1. During this event, the summit plateau received a large amount of aeolian sediments originating from the shale rockwall that forms the mountain's northwest side. In the 15 to 20 m wide by 75 m long belt located along the top of the rockwall, over a 1200 m² area, a continuous layer of debris completely covered the snow. This layer of debris had a mean thickness of 11·4 mm, which represents an accumulated volume in the order of 13 m³. Largely dominated by sand and granules (2–4 mm), the 28 samples collected for grain-size analysis also contained numerous thin shale flakes, many of which were longer than 10 mm. The largest flake measured had a width of 134 mm and a weight of 164·3 g. Six available ¹⁴C dates provide information concerning mean cliff-top aeolian sedimentation rate for the last thousand years (c. 1·8 mmyr^?1).     

Composite magnetic anisotropy fabrics: experiments, numerical models and implications for the quantification of rock fabrics

Magnetic fabrics from rocks with multiple mineral-preferred orientations may have anisotropy ellipsoids whose shape and orientation arise from the addition of two or more component fabrics. Our numerical models and experiments demonstrate that such composite magnetic fabrics do not directly reflect the shapes and/or orientations of the individual mineral fabrics and we provide criteria for the recognition and interpretation of composite fabrics in natural rocks. These criteria include:

1. (1) the orientation of the maximum susceptibility axis is located at the intersection of two planar fabrics, and

2. (2) the shape of the susceptibility ellipsoid changes from oblate to prolate and the degree of anisotropy decreases, as the relative intensity of two planar component fabrics becomes equal and as the angle between the planar fabrics increases.

Composite magnetic fabrics are observed in the shales and slates of the Martinsburg Formation, Lehigh Gap, Pennsylvania. Modeling of the AMS (anisotropy of magnetic susceptibility) and ARMA (anhysteretic remanent magnetization anisotropy) behavior constrains the relative degree of anisotropy of the bedding-parallel and cleavage-parallel fabrics. In particular, ARMA model results allow a good estimate of magnetite fabric strength.

We conclude that, in the presence of composite magnetic fabrics, quantitative measures of finite strain in deformed rocks are limited by the ability to accurately determine the degree of anisotropy and relative susceptibility of each component fabric. Such determinations require knowledge of the mineral(s) that are responsible for the measured magnetic fabric and their behavior during deformation.