Abstract
The stable isotope composition of veins, pressure shadows, mylonites and fault breccias in allochthonous Mesozoic carbonate cover units of the Helvetic zone show evidence for concurrent closed and open system of fluid advection at different scales in the tectonic development of the Swiss Alps. Marine carbonates are isotopically uniform, independent of metamorphic grade, where δ 13C=1.5±1.5 (1 σ) and δ 18O=25.4±2.2 (1 σ). Total variations of up to 2‰ in δ 13C and 1.5‰ in δ 18O occur over a cm scale. Calcite in pre- (Type I) and syntectonic (Type II) vein arrays and pressure shadows are mostly in close isotopic compliance with the matrix calcite, to within ±0.5‰, signifying isotopic buffering of pore fluids by host rocks during deformation, and closed system redistribution of carbonate over a cm to m scale. This is consistent with microstructural evidence for pressure solution — precipitation deformation.
Type III post-tectonic veins occur throughout 5 km of structural section, extend several km to the basement, and accommodate up to 15% extension. Whereas the main population of Type III veins is isotopically undistinguishable from matrix carbonates, calcite in the largest of these veins is depleted in 18O by up to 23‰ but acquired comparable δ 13C values. This generation of veins involved geopressurized hydrothermal fluids at 200 to 350° C where δ 18O H2O=−8 to +20‰, representing variable mixtures of 18O enriched pore and metamorphic fluids, with 18O depleted meteoric water. Calc-mylonites (δ 18O=25 to 11‰) at the base of the Helvetic units, and syntectonic veins from the frontal Pennine thrust are characterized by a trend of 18O depletion relative to carbonate protoliths, due to exchange with an isotopically variable reservoir (δ 18O H2O=20 to 4‰). The upper limiting value corresponds to carbonate-buffered pore fluid, whereas the lower value is interpreted as 18O-depleted formation brines tectonically expelled at lithostatic pressure from the crystalline basement. Carbonate breccias in one of the large scale late normal faults exchanged with infiltrating 18O-depleted meteoric surface waters (δ 18O=−8 to −10‰).
During the main ductile Alpine deformation, individual lithological units and associated tectonic vein arrays behaved as closed systems, whereas mylonites along thrust faults acted as conduits for tectonically expelled lithostatically pressured reservoirs driven over tens of km. At the latest stages, marked by 5 to 15 km uplift and brittle deformation, low 18O meteoric surface waters penetrated to depths of several km under hydrostatic gradients.
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References
Baertschi P (1957) Messung und Deutung relativer Häufigkeitsvariationen von 18O und 13C in Karbonatgesteinen und Mineralien. Schweiz Mineral Petrogr Mitt 37:73–152
Burkhard M (1986) La déformation des calcaires de l'Helvétique de la Suisse occidentale (Phénomènes, mécanismes et interprétations tectoniques). Revue Géol dyn Géogr phys 27/5:281–301
Burkhard M (1988) L'Helvétique de la bordure occidentale du massif de l'Aar (Evolution tectonique et métamorphique). Eclogae Geol Helv 81/1:63–114
Cathles LM (1983) An analysis of the hydrothermal system responsible for massive sulfide deposition in the Hokuroku Basin of Japan. Econ Geol Mono 5:439–487
Clayton RN, Mayeda TK (1963) The use of bromine pentafluoride in the extraction of oxygen from oxides and silicates for isotopic analysis. Geochim Cosmochin Acta 27:43–52
Clayton RN, Friedman I, Graf DL, Mayeda TK, Meents WF, Shimp NF (1966) The origin of saline formation waters: I isotopic composition. J Geophys Res 71:3869–3882
Clayton RN, O'Neil JR, Mayeda TK (1972) Oxygen isotope exchange between quartz and water. J Geophys Res 77:3057–3067
Dietrich D, Mc Kenzie JA, Song H (1983) Origin of calcite in syntectonic veins as determined from carbon isotope ratios. Geology 11/9:547–551
Durney DW (1972) Deformation history of the Western Helvetic nappes. Ph.D.thesis, Imperial College, London, p 327
Durney DW, Ramsay JG (1974) Incremental strains measured by syntectonic crystal growths. In: DeJong KA, Scholten R (eds) Gravity and tectonics. Wiley, New York pp 67–91
Etheridge MA (1983) Differential stress magnitudes during regional deformation and metamorphism: upper bound imposed by tensile fracturing. Geology 11:231–234
Etheridge MA, Wall VJ, Vernon RH (1984) The role of the fluid phase during regional metamorphism and deformation. J Metamorphic Geol 1:205–226
Etheridge MA, Wall VJ, Cox SF, Vernon RH (1983) High fluid pressures during regional metamorphism and deformation — implications for mass transport and deformation mechanisms. J geophys Res 89/B6:4344–4358
Franck P, Wagner JJ, Escher A, Pavoni N (1984) Evolution des contraintes tectoniques et sismicité dans la région du Col Sanetsch, Alpes valaisannes helvétiques. Eclogae Geol Helv 77/2:383–393
Frey M (1986) Very low grade metamorphism of the Alps an introduction. Schweiz Mineral Petrog Mitt 66:13–27
Frey M, Hunziker JC, O'Neil JR, Schwander HW (1976) Equilibrium-disequilibrium relations in the Monte Rosa Granite, W Alps: petrological, Rb-Sr and stable isotope data. Contrib Mineral Petrol 55:147–179
Frey M, Teichmüller M, Teichmüller R, Mullis J, Künzi B, Breitschmid A, Gruner U, Schwitzer B (1980) Very low grade metamorphism in external parts of the Central Alps: Illite crystallinity, coal rank and fluid inclusion data. Eclogae Geol Helv 73/1:173–203
Furrer H, Hügi T (1952) Telemagmatischer Gang im Nummulitenkalk bei Trublen westlich Leukerbad (Kanton Wallis). Eclogae Geol Helv 45/1:42–51
Fyfe WS, Price NJ, Thompson AB (1978) Fluids in the earth's crust. Elsevier, Amsterdam pp 320
Fyfe WS, Kerrich R (1985) Fluids and thrusting. Chem Geol 49:353–362
Gregory RT, Criss RE (1986) Isotopic exchange in open and closed systems. In: Valley JW, Taylor HP, O'Neil JR (eds) Stable isotopes in high temperature geologic processes. Reviews in Mineralogy. Min Soc Amer vol 16:91–127
Hoefs J (1973, 1987) Stable isotope geochemistry. Springer, Berlin pp 135, 241
Hoefs J, Frey M (1976) The isotopic composition of carbonaceous matter in a metamorphic profile from the Swiss Alps. Geochimica et Cosmochimica Acta 40:945–951
Hoefs J, Stalder HA (1977) The carbon isotope composition of CO2-bearing fluid inclusions in fissure quartz from the Central Alps. Schweiz Mineral Petrogr Mitt 57:329–347
Hoernes S, Friedrichsen H (1978) Oxygen and hydrogen isotope study of the polymetamorphic area of the Northern Oetztal-Stubai Alps. Contrib Mineral Petrol 67:305–315
Hoernes S, Friedrichsen H (1980) Oxygen and hydrogen isotopic composition of Alpine and Pre-Alpine minerals in the Swiss Central Alps. Contrib Mineral Petrol 72:19–32
Holland HD, Malinn SD (1979) The solubility and occurence of Non-ore minerals. In: Barnes HL (ed) Geochemistry of hydrothermal ore deposits. Wiley, New York, pp 567
Hubbert MK, Rubey WW (1959) Role of fluid pressure in mechanics of overthrust faulting. Geol Soc America Bull 70:155–166
Hudson JD (1977) Stable isotopes and limestone lithification. J Geol Soc London 133:637–660
Hunziker JC, Frey M, Clauer N, Dallmeyer RD, Friedrichsen H, Flehmig W, Hochstrasser K, Roggwiler P, Schwander H (1986) The evolution of illite to muscovite: mineralogical and isotopic data from the Glarus Alps Switzerland. Contrib Mineral Petrol 92:157–180
Kerrich R (1978) An historical review and synthesis of research on pressure solution. Zbl Geol Paläont Teil I, H 5/6:512–550
Kerrich R (1986) Fluid transport in lineaments. Phil Trans R Soc London A 317:219–251
Kerrich R, Beckinsdale RD, Durham JJ (1977) The transition between deformation regimes dominated by intercrystalline diffusion and intracrystalline creep evaluated by oxygen isotope thermometry. Tectonophysics 38:241–257
Kerrich R, Beckinsale RD, Shackelton NJ (1978) The physical and hydrothermal regime of tectonic vein systems: evidence from stable isotope and inclusion studies. Neues Jahrbuch Mineral Abh 131:225–239
Kerrich R, Rehrig W (1987) Large scale fluid motion associated with Tertiary mylonitization and detachment faulting: 18O/16O evidence from Pichacho metamorphic core complex Arizona. Geology 15:58–62
Kübler B, Pittion JL, Heroux Y, Charollais J, Weidmann M (1979) Sur le pouvoir réflecteur de la vitrinite dans quelques roches du Jura, de la Molasse, et des Nappes préalpines, helvétiques et penniques. Eclogae Geol Helv 72/2:347–375
Kyser TK (1987) Short course in stable isotope geochemistry of low temperature fluids. Mineral Assoc Canada vol 13: pp. 452
Laubscher HP (1983) Detachment, shear and compression on the Central Alps. In: Contr to the Tectonics and Geophysics of Mountain Chains. Geol Soc Amer Mem 158:191–211
Longstaffe FJ (1987) Stable isotope studies of diagenetic processes. In: Kyser (ed) Short course in stable isotope geochemistry of low temperature fluids. Mineral Assoc Canada vol 13:187–257
Magaritz M (1974) Lithification of chalky limestone: a case study in Senonian rocks from Israel. J Sed Petrol 44:947–954
McCrea JM (1950) The isotopic chemistry of carbonates and a paleotemperature scale. J Chem Phys 18:849–857
Milnes AG, Pfiffner OA (1980) Tectonic evolution of the Central Alps in the cross section St. Gallen — Como. Eclogae Geol Helv 73:619–633
Mugnier JL, Ménard G (1986) Le dévelopement du bassin molassique suisse et l'évolution des Alpes externes un modèle cinématique. Bull Centre Rech Explor Prod Elf Aquitaine 10/1:191–203
Mullis J (1979) The system methan-water as a geologic thermometre and barometre from the external part of the central Alps. Bull Mineral 102:526–536
Mullis J (1987) Fluid inclusion studies during very low grade metamorphism. In Frey M (ed) Low temperature metamorphism. Blackie Glasgow: 162–199
Oliver J (1986) Fluids expelled tectonically from orogenic belts their role in hydrocarbon migration and other geologic phenomena. Geology 14:99–102
O'Neil JR (1987) Preservation of H, C, and O isotope ratios in the low temperature environment. In: Kyser (ed) Short course in stable isotope geochemistry of low temperature fluids. Mineral Assoc Canada vol 13:85–128
O'Neil JR, Clayton RN, Mayeda TK (1969) Oxygen isotope fractionation in divalent metal carbonates. J Chem Phys 51:5547–5558
Pfiffner OA (1982) Deformation mechanisms and flow regimes in limestones from the Helvetic zone of Swiss Alps. J Struct Geol 4:429–442
Poty P, Stalder A, Weisbrod A (1974) Fluid inclusions studies in quartz from fissures of Western and Central Alps. Schweiz Mineral Petrogr Mitt 54/2+3:717–752
Powell R, Condliffe DM, Condliffe E (1984) Calcite-dolomite geothermometry in the system CaCO3-MgCO3-FeCO3: an experimental study. J Metamorphic Geol 2:33–41
Ramsay JG, Huber MI (1983) The techniques of modern structural geology, vol 1, strain analysis. Academic Press, London p 307
Schmid SM (1982) Laboratory experiments on rheology and deformation mechanisms in calcite rocks and their application to studies in the field. Mitt Geol Inst ETH Univ Zürich 241:1–62
Schmid SM, Casey M, Starkey J (1981) The microfabric of calcite tectonites from the Helvetic nappes (Swiss Alps). In: McClay K, Price NJ (eds) Thrust and nappe tectonics. Spec Publ geol Soc London 9:151–158
Secor DT (1965) Role of fluid pressure in jointing. American J Sci 263:633–646
Taylor BE, Bucher-Nurminen K (1986) Oxygen and carbon isotope and cation geochemistry of metasomatic carbonates and fluids — Bergell aureole Northern Italy. Geochim Cosmochim Acta 50:1267–1279
Tucker ME (1983) Diagenesis and origin of Precambrian dolomite: the Beckspring dolomite of eastern California. J Sediment Petrol 53:1097–1119
Trümpy R (1980) Geology of Switzerland. Part I, Wepf Basel, pp 104
Valley JW, Taylor HP, O'Neil JR (1986) Stable isotopes in high temperature geological processes. Reviews in Mineralogy vol 16, Mineral Soc Amer, pp 570
Veizer J, Hoefs J (1976) The nature of 018/016 and C13/C12 secular trends in carbonate rocks. Geochim Cosmochim Acta 40:1387–1395
Weissert H, Bernoulli D (1984) Oxygen isotope composition of calcite in Alpine ophicarbonates: a hydrothermal or Alpine metamorphic signal. Eclogae Geol Helv 77:29–43
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Burkhard, M., Kerrich, R. Fluid regimes in the deformation of the Helvetic nappes, Switzerland, as inferred from stable isotope data. Contr. Mineral. and Petrol. 99, 416–429 (1988). https://doi.org/10.1007/BF00371934
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DOI: https://doi.org/10.1007/BF00371934