The Impact of Bombs of World War I on Limestone Slopes of Monte Grappa
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Proceedings of the International Conference on Environmental Changes in Karst Areas -I.G.U.- U.I.S.-ltaly 15- 27 Sept. 1991 ; Quaderni del Dipartimento di Geografia n. 13. 1991 -Università di Padova. pp. 279-287 THE IMPACT OF BOMBS OF WORLD WAR I ON LIMESTONE SLOPES OF MONTE GRAPPA Monica CELI Via G. Giardino, 89 Romano d'Ezzelino 36060 VICENZA, ITALIA ABSTRACT W: Karst pollution, war impact, bombs, artificial dolinas Geogr.K.W: Italy, Venetian Prealps, Monte Grappa This paper will evalue the impact of the war events in the karstic territory of Monte Grappa. The consequence of the World War I on this karstic territory, that notice here are main1y two: a modification of the natural morphology of the karstic territory and the possible pollution given from the war residuals. The 50% of the closed depressions of various size, that are the results of the bombs and mortars explosion, are now evolving to dolinas. The war residuals are a source of heavy metals, that the meteoric water can carry in the karstic system and polluting the natural underground water. INTRODUCTION The war event has represented a very strong impact on the karstic territory. Particularly during the two World Wars the large use of anns as bombs and mortars has left manifest traces in the straked territories. The Massif of Monte Grappa, sited in the Venetian Prealps, reports clear witness of the hard battles, that have saw him as leading character of the World Wars. The leitmotive of the morphology of Massif, particularly near the summit of Monte Grappa, are the innumerable closed depressions of various size, that afe the results of the bombs and mortars explosions. Trenches and galleries afe also presento GEOMORPHOLOGY OF MASSIF OF GRAPPA MOUNT The Massif of Grappa Mount falls within the generaI stratigraphy of the Veneto Prealps. In short we can notice main rock units: 1. dolomite (Trias); 2. grey limestones and Ammonitic limestones (Jurassic);3. white and red marly limestones (Cretaceous); 4 marls, sandstones, conglomerates (Eocene, Oligocene, Miocene). The covers of Quatemary age afe represented tram alluvial and slope debris and tills. As the others Prealpine groups (Monti Lessini, Asiago Plateau, Cansiglio) also the Grappa Massif presents typical karstic characteristics, which afe stressed by the natural morphology of the territory and by the presence of springs. In the upper part we can recognize dolinas, 279 G.K. shafts and Karren. Generally don't exist horizontal caves. We can find often caves With vertical spits (Carraro et al., 1990). SAMPLING During the spring 1991 we have surveyed 100 basins sited in the side of Coston Maunt in the Grappa Massif, which were originated by the explosion of bombs and mortars during the First World War. The 100 basins selected among the 300 and more of this zone, with a casual sampling, divided in three groups on the grounds of theirlocation: on valley bottom, on slope, on the summit of Monte Costano PREVIOUS WORK The impulse far this research was supplied from a previous work (Paoletti et Al., in press), that was realized far to value the impact of the chemical pollution in the karstic systems of Asiago Pl.ateau and Massif of Grappa Mount. The influence of the external usage of karstic territory outside the cave environment and its possible consequences on the geochemistry of substrata and invertebrate troglobitic organisrns afe analyzed in this previous work. We tested far the presences of some heavy metals (Cd, Cf, Cu, Pb, Zn) in mud, water, bat guano and troglobitic invertebrates. For such objective was considered, together others caves, a horizontal cave, Buso della Torta, sited in the side of Massif of Grappa Mount, that turns in the Brenta valley. In this cave was carryed out the chernical analyse of bat guano, abandoned in large deposits from a colony, nowadays extinguished. The results of the analyses haven showed high leve1.s of same metals: Cu, Zn, Cd (Table 1). The comparison with the results obtained from the analyses of bat guano in others cave, sited in different zone of Venetian region (Grotta della Guerra in Berici Mounts, Grotta Grande di Ponte di Veia in Lessini Mounts) have showed that these levels afe anomalous. The heap of contarninants seems a1.soto co.ntinue nowadays. One among the possible causes of this pollution is maybe the enorrnous quantity of war residuals, abandoned in the cave during the retreat and the chips of bombs and mortars, which covered the territory of karstic alimentation. The water in 70 years about, can have dissolved and carryed the metals in this cave. Here a organic substratum, as bat guano, has accumulated the metals and allowed to give prominence to this processo It is a1.soresulted very important to quantify the effects of the war event on the the karstic system and the possible input on the karstic spring. OBJECTIVES First stage of this research is the recording of the princjpal measures for identification of the bombs basins: 1. a) the maximum diameter; b) the relative maximum depth; c) the difference in level between its extremities; 2. a) the maximum depth (between highest and lowest point); b) the relative diameter; 280 I distoD.m. I D.p.m. I disl.p.m.I pr.max. pr.min. pr.D. evol,dol.1 312 104 32512 104 111 7 111 m -.2!.- 98 114 16 114 ~ m 40 257 100 109 9 69 ~ 281 81 225 104 109 5 281 ~ 290 O 220 90 94 4 38 no 400 40- 400 112 124 12 82 no 540 ffi 510 189 203 14 188 no~~ 920 240 920 240 350 110 2350 -soo- 204 500 204 225 21 225 340 O 326 127 136 9 60 no m ffi 715 I 235 340 105 340 ~ ill 221 _585 I 221 265 44 265 ~~ 482illlli 181 430 191 201 lO 201 124 323 168 168 O 124 no O 3'ii5" 19 60 41 48 ~ 446 12 295 18 62 44 56 no 280 42 253 55 73 18 53 no 420 40 405 90 90 O 77 no 458 T5 443 73 94 21 67 no 442 60 392 42 114 72 98 no 635 80 ill 80 122 42 122 no 24ii 30 240 I~70~130 53 23 53 noE.2..-~ ffO 19 19 55 36 55 505 O 440 93 163 70 92 213 17 213 17 33 16 33 ~ m 51 m 57 175 118 175 ~ m 36" m 36 82 46 82 ~~ 730 110 730 110 150 40 150 290~ 29 290 29 67 38 67 no 49 36iiNm49 77 28 77 no ffi O" 52 67 15 45 no 630lli IO 68 172 104 130 no I~- 315 19 42 23 42 no 430 430 40 35 40 ~E- m- lO:1 340 lO 50 40 49 280 20 280 20 44 24 44 no m O 290 56 56 41 ~ m ""i8" ~~'l I ,,~ IE_~~I96 68 96 no m~o n- 173 151 173 ~ O 23 84- -~ 71 ves LEGEND GB = Gauss-Boaga coordinates Lat. grid = grid latitude Long. grido = grid longitude D.max. = Maximum diameterdisl. D.m. = Denivelation along the maximum diameter D.p.m. = diameter trought the maximum depthdisl.p.m. = Denivelation along the diameter trought the maximum depth pr.max. = maximum depth pr.min.= minimum depth pr.D. = maximum depth along the maximum diameterevol.dol. = evolution as dolinas 282 ~]~.=-&~~. valley bottom, slope and ridge sumrnit but we can see that the valley basins more easily afe evolving as dolinas particularly respect to the slope basins. The vallèy gather in fact a greater quantity of water accelerating the karst processes. The doline evolution seem linked to the depth. For lower depth (about less than 1.5 m) we have a probability of about 50% to evolve as dolinas, far depths of more than the 1.5 m nearly all the basins afe evolving as dolinas. For the maximum depths we can see that about 75% of the holes have a dejpth betv~een0.5 and 2 meters. Generally this is valid far all topographic The linear regression between the m lxir sho,NSthere is a direct proportionality. The metal-detector don't allowed th ex thatis present in the soil. The presence of much chips gave a continuous background recording, that disturbed it. 283 ~ Frequency distribution of maximum diameter m 200-300 cm [J 300-400 cm 8400-fXXJcm 8 5(X)-laX) cm [J 600-700 cm 8700-SOOcm D800-<xXJcm 8 900-1 (XX) cm 81(XX).1100cm 81100-1200cm Frequency dmlributk>nof rTnxlmum dklmetern valleybottom XI: D. mal. T =:=j~~=j' Can: r ~:() I~ axJ ::IX) 18 4X) 133 133~ '-Mode 200 300 400 500 tOO 700 800 900 lCXX>1100 Frequency dlslributlon of maximum diame'.r In slop. Frequency distribullon 01 Ihe maximum dlameler in rldge 200 300 ~ 500 600 700 800 9(XJ l (XX) 1100 284 Frequency dlslrlbullon 01 maxlmum deplh m o-socm C 50-1 00 cm 8 1 CX>-1SOcm 8 150-200cm C 2CX>-2SOcm 8250-300cm O 300-350cm 8 35().400 cm Frequency dlatribution 01 maxlmum depth in valley bottom XI: PI. rnax rom:() To:«) -~ I lro I ~ I -Mode 50 100 150 200 250 300 350 400 Frequenc;y dis1ribution of Frequ.ncy distributlon of maximum maximum depth In ridge d.pth in liop. 285 ~'elcert: Llnear regression: maximum diameter/maxlmum depth pro max Simpie Regresslon XI: pro max VI: D. max. Count: R: RMS Residual: 100 .79 118.011 Analysis of Varlance Table Source DF: Sum SQuares: Mean SQuare: F-test: REGRESSION 1 2269183.095 2269183.095 162.938 RESIDUAL 98 1364813.655 13926.67 I p = .0001 TOTAL 99 3633996.75 286 advanced to give an explanation to the high levels of CuI Zn and Cd found in the but guano of the Buso della Torta cave.