Magnetic fabric constraints for syn-magmatic doming of the laccolithic Brocken granite pluton (Harz Mountains, northern Germany)
Abstract
Hyper-solidus fabrics of the early Permian Brocken granite pluton, exposed over an area of c. 160 km² and elongated in NNE–SSW direction, were determined by measuring the anisotropy of magnetic susceptibility (AMS). The Brocken granite pluton consists of five petrographically distinguishable and mappable granitic varieties characterized by a generally paramagnetic behavior with primary biotite, partly altered to chlorite, and secondary tourmaline as the major carrier of the susceptibility. Whereas biotite modal content isolines roughly follow petrographic trends, the tourmaline modal contents do not, hence implying secondary, post-emplacement processes that controlled tourmaline distribution. A few samples with primary and secondary magnetite show ferrimagnetic behavior and are co-axial with the paramagnetic fabrics. The generally low magnetic anisotropies in all granitic varieties are a distinct and challenging feature for determining magmatic flow directions. AMS data indicate the predominance of sub-horizontal fabrics outlining an NNE–SSW trending dome axis interpreted to have resulted from granite sheets stacked syn-magmatically in a high crustal level building up a laccolithic pluton. AMS fabrics together with age data and geophysical indications suggest that the emplacement and distribution of the Brocken granite pluton is structurally controlled by NNE–SSW striking deep fault structures, and only weakly influenced by WNW/NW-trending structures. Late Carboniferous-to-early Permian plutonism in the Harz Mountains evolved in an E–W directed extensional regime, and was accompanied by volcanic activity and development of NW- and NE-trending sedimentary basins.
Keywords
Brocken granite pluton Laccolith Syn-magmatic doming Anisotropy of magnetic susceptibility (AMS) Harz Mountains Early PermianNotes
Acknowledgements
Constructive reviews of H. de Wall and J. Žák as well as editorial handling of W. Dullo are gratefully acknowledged. We thank I. Klisch for an informative field-trip along the eastern part of the Brocken granite pluton and A. Kontny for fruitful discussions. We also acknowledge T. Güldner, T. Redtmann, and some other former students of the Martin-Luther University Halle-Wittenberg for their help during sampling.
Supplementary material
References
- Abraham K, Schreyer W (1973) Petrology of a ferruginous hornfels from Riekensglück, Harz Mountains, Germany. Contrib Miner Petrol 40:275–292CrossRefGoogle Scholar
- Aranguren A, Cuevas J, Tubia JM et al (2003) Granite laccolith emplacement in the Iberian arc: AMS and gravity study of the La Tojiza pluton (NW Spain). J Geol Soc Lond 160:435–445CrossRefGoogle Scholar
- Archanjo CJ, Launeau P, Bouchez JL (1995) Magnetic fabric vs. magnetite and biotite shape fabrics of the magnetite-bearing granite pluton of Gameleiras (Northeast Brazil). Phys Earth Planet Inter 89:63–75CrossRefGoogle Scholar
- Arthaud F, Matte P (1977) Late Paleozoic strike-slip faulting in southern Europe and northern Africa: Result of a right-lateral shear zone between the Appalachians and the Urals. Geol Soc Am Bull 88:1305–1320CrossRefGoogle Scholar
- Arzi AA (1978) Critical phenomena in the rheology of partially melted rocks. Tectonophysics 44(1–4):173–184CrossRefGoogle Scholar
- Awdankiewicz M (1999) Volcanism in a late Variscan intramontane trough: the petrology and geochemistry of the Carboniferous and Permian volcanic rocks of the Intra-Sudetic Basin, SW Poland. Geol Sudet 32:83–111Google Scholar
- Baumann A, Grauert B, Mecklenburg S, Vinx R (1991) Isotopic age determinations of crystalline rocks of the Upper Harz Mountains, Germany. Geol Rundschau 80:669–690CrossRefGoogle Scholar
- Benn K (1994) Overprinting of magnetic fabrics in granites by small strains: numerical modelling. Tectonophysics 233(3–4):153–162CrossRefGoogle Scholar
- Bouchez JL (1997) Granite is never isotropic: an introduction to AMS studies of granitic rocks. In: Bouchez JL, Hutton DHW, Stephens WE (eds) Granite: from segregation of melt to emplacement fabrics. Kluwer, Dordrecht, pp 95–112CrossRefGoogle Scholar
- Bouchez JL, Nguema TMM, Esteban L, Siqueira R, Scrivener R (2006) The tourmaline-bearing granite pluton of Bodmin (Cornwall, UK): magnetic fabric study and regional inference. J Geol Soc Lond 163:607–616CrossRefGoogle Scholar
- Brandl W (1939) Erdmagnetische untersuchungen im Brockenmassiv: Vergleich einer erdmagnetischen und einer feldgeologischen Spezialaufnahme. Abh Preuss Geol LA NF 188:5–8Google Scholar
- Breitkreuz C, Ehling BC, Sergeev S (2009) Chronological evolution of an intrusive/extrusive system: the Late Paleozoic Halle Volcanic Complex in the northeastern Saale Basin (Germany). Z dtsch Ges Geowiss 160(2):173–190Google Scholar
- Brink H (2011) The crustal structure around the Harz Mountains (Germany): review and analysis. Z dt Ges Geowiss 162/3:235–250Google Scholar
- Büthe F, Wachendorf H (1997) Die Rotliegend-Entwicklung des Ilfelder Beckens und des Kyffhäusers: Pull-Apart-Becken und Rhomb-Horst. Z geol Wiss 25(3/4):291–306Google Scholar
- Candela PA (1997) A review of shallow, ore-related granites: textures, volatiles, and ore metals. J Petrol 38:1619–1633CrossRefGoogle Scholar
- Chafii-Badavi A (1980) Die Geologie des westlichen Anteils des Brockenmassivs. Clausthaler Geowissenschaftliche Dissertationen 2:1–71Google Scholar
- Chrobok SM (1965) Untersuchungen zur Geologie des Brockenmassivs (Harz). Geol Beih 48:1–82Google Scholar
- Conrad W (1995) Regionale geophysikalische Messungen im Umfeld des Harzes. Nova Acta Leopoldina NF 71/291:191–215Google Scholar
- Corry CE (1988) Laccoliths: mechanics of emplacement and growth. Geol Soc Am 220:110 ppGoogle Scholar
- Cruden AR (1998) On the emplacement of tabular granites. J Geol Soc Lond 155(5):853–862CrossRefGoogle Scholar
- Cruden AR, McCaffrey KJW (2001) Growth of plutons by floor subsidence: implications for rates of emplacement, intrusion spacing and melt-extraction mechanisms. Phys Chem Earth Part A 26(4–5):303–315CrossRefGoogle Scholar
- Dietl C (2005) Die magnetische Suszeptibilität–eine wertvolle Materialeigenschaft zur Charakterisierung von Granitintrusionen. Z dt Geol Ges 155:299–309Google Scholar
- Doblas M, Oyarzun R, Lopez-Ruiz J, Cebria JM, Youbi N, Mahecha V, Cabanis B (1998) Permo-Carboniferous volcanism in Europe and northwest Africa: a superplume exhaust valve in the centre of Pangaea? J African Earth Sci 26:89–99CrossRefGoogle Scholar
- Dunlop DJ, Özdemir Ö (1997) Rock magnetism. Cambridge University Press, New YorkCrossRefGoogle Scholar
- Erdmannsdörffer OH (1908) Über Bau und Bildungsweise des Brockenmassivs. Jb Königlich Preuss Geol Landesanstalt Bergakademie Berlin 26(1905):379–405Google Scholar
- Fiebig B (1990) Beiträge zum strukturellen Bau des Harzes auf Grundlage der Interpretation geophysikalischer Daten. Dissertation, Martin-Luther-Universität Halle-WittenbergGoogle Scholar
- Fiedrich A, Kraus K, Appel P, Stipp M, Friedel C-H (2014) Age of metamorphism and structural development of the Eckergneiss, Harz Mountains. In: 15th Symposium on tectonics, structural geology and geology of crystalline rocks (TSK15), Potsdam, p 20Google Scholar
- Franke W, Dulce JC (2017) Back to sender: tectonic accretion and recycling of Baltica-derived Devonian clastic sediments in the Rheno-Hercynian Variscides. Int J Earth Sci 106(1):377–386CrossRefGoogle Scholar
- Franke W, Cocks LRM, Torsvik TH (2017) The Palaeozoic Variscan oceans revisited. Gondwana Res 48:257–284CrossRefGoogle Scholar
- Franz L, Schuster AK, Strauss KW (1997) Basement evolution in the Rhenohercynian Segment: discontinuous exhumation history of the Eckergneis complex (Harz Mountains, Germany). Chem der Erde Geochem 57:105–135Google Scholar
- Franzke H-J, Schwab M (2011) Harz, östlicher Teil mit Kyffhäuser Kristallin. Sammlung Geol Führer 104:327 ppGoogle Scholar
- Franzke HJ, Voigt T, von Eynatten H, Brix MR, Burmester G (2004) Geometrie und Kinematik der Harznordrandstörung, erläutert an Profilen aus dem Gebiet von Blankenburg. Geowiss Mitt Thüringen 11:39–62Google Scholar
- Friedel C-H, Hoth P, Franz G, Stedingk K (1995) Niedriggradige Regionalmetamorphose im Harz. Zbl Geol Paläontol 9:1213–1235Google Scholar
- Gabriel G, Jahr T, Jentzsch G, Melzer J (1997) Deep structure and evolution of the Harz Mountains: results of three-dimensional gravity and finite-element modeling. Tectonophysics 270(3–4):279–299CrossRefGoogle Scholar
- Gabriel G, Jahr T, Weber U (2001) The gravity field south of the Harz Mountains: predominated by granitic material? Zeitschrift für Geol Wissenschaften 29:249–266Google Scholar
- Geisler T, Vinx R, Martin-Gombojav N, Pidgeon RT (2005) Ion microprobe (SHRIMP) dating of detrital zircon grains from quartzites of the Eckergneiss Complex, Harz Mountains (Germany): implications for the provenance and the geological history. Int J Earth Sci 94:369–384CrossRefGoogle Scholar
- Goll M, Lippolt HJ, Obert C, Schwarz W (1998) Datierungen zum permokarbonen Magmatismus des Harzes-erste K-Ar-Ergebnisse. Terra Nostra 98(2):62–65Google Scholar
- Grégoire V, de Saint Blanquat M, Nédélec A, Bouchez J (1995) Shape anisotropy versus magnetic interactions of magnetite grains: experiments and application to AMS in granitic rocks. Geophys Res Lett 22:2765–2768CrossRefGoogle Scholar
- Greiling RO, de Wall H, Sadek MF, Dietl C (2014) Late Pan-African granite emplacement during regional deformation, evidence from magnetic fabric and structural studies in the Hammamat–Atalla area, Central Eastern Desert of Egypt. J Afr Earth Sci 99:109–121CrossRefGoogle Scholar
- Grimmer JC, Ritter JRR, Eisbacher GH, Fielitz W (2017) The Late Variscan control on the location and asymmetry of the Upper Rhine Graben. Int J Earth Sci 106:827–853CrossRefGoogle Scholar
- Hargraves RB, Johnson D, Chan CY (1991) Distribution anisotropy: the cause of AMS in igneous rocks? Geophys Res Lett 18(12):2193–2196CrossRefGoogle Scholar
- Hinze C, Jordan H, Knoth W, Kriebel U, Martiklos G (1998) Geologische Karte Harz. 1:100,000. Landesamt f. Geologie u. Bergwesen Sachsen-Anhalt, Halle/SGoogle Scholar
- Hoffmann U, Breitkreuz C, Breiter K, Sergeev S, Stanek K, Tichomirowa M (2013) Carboniferous–Permian volcanic evolution in Central Europe—U/Pb ages of volcanic rocks in Saxony (Germany) and northern Bohemia (Czech Republic). Int J Earth Sci 102:73–99CrossRefGoogle Scholar
- Hrouda F (1982) Magnetic anisotropy of rocks and its application in geology and geophysics. Surv Geophys 5:37–82CrossRefGoogle Scholar
- Hrouda F, Chlupacova M, Pokorny J (2006) Low-field variation of magnetic susceptibility measured by the KLY-4S Kappabridge and KLF-4A magnetic susceptibility meter; accuracy and interpretational programme. Studia Geophys Geod 50:283–298CrossRefGoogle Scholar
- Jelinek V (1981) Characterization of the magnetic fabric of rocks. Tectonophysics 79:63–67CrossRefGoogle Scholar
- Jelínek V (1978) Statistical processing of anisotropy of magnetic susceptibility measured on groups of samples. Studia Geophys Geod 22:55–62CrossRefGoogle Scholar
- Jentzsch G, Jahr T (1995) Der Tiefenbau des Harzes aus Untersuchungen des Schwerefeldes. Nova Acta Leopoldina NF 71 291:169–190Google Scholar
- Jezek J, Hrouda F (2004) Determination of the orientation of magnetic minerals from the anisotropy of magnetic susceptibility. In: Martin-Hernandez F, Lueneburg CM, Aubourg C, Jackson M (eds) Magnetic fabric: methods and applications. Geol Soc Lond Spec Publ, vol 238, pp 9–20Google Scholar
- Kley J, Voigt T (2008) Late Cretaceous intraplate thrusting in central Europe effect of Africa-Iberia-Europe convergence, not Alpine collision. Geology 36/11:839–842CrossRefGoogle Scholar
- Kontny A, de Wall H (2000) The use of low and high k(T)-curves for the characterization of magneto-minerological changes during metamorphism. Phys Chem Earth 25:421–429CrossRefGoogle Scholar
- Krohe A (1992) Structural evolution of intermediate-crustal rocks in a strike-slip and extensional setting (Variscan Odenwald, SW Germany): differential upward transport of metamorphic complexes and changing deformation mechanisms. Tectonophysics 205:357–386CrossRefGoogle Scholar
- Kroner U, Romer RL (2013) Two plates—many subduction zones: the Variscan orogeny reconsidered. Gondwana Res 24:298–329CrossRefGoogle Scholar
- Kruckenberg SC, Ferré EC, Teyssier C, Vanderhaeghe O, Whitney DL, Seaton NC, Skord JA (2010) Viscoplastic flow in migmatites deduced from fabric anisotropy: an example from the Naxos dome, Greece. J Geophys Res Solid Earth 115(B9):1978–2012CrossRefGoogle Scholar
- Lennox PG, de Wall H, Durney DW (2016) Correlation between magnetic fabrics, strain and biotite microstructure with increasing mylonitisation in the pretectonic Wyangala Granite, Australia. Tectonophysics 676:170–197CrossRefGoogle Scholar
- Lippolt H, Hess J (1996) Numerische Stratigraphie permokarbonischer Vulkanite Zentraleuropas. Teil II Westharz. Z dt Geol Ges 147:1–9Google Scholar
- Lotze F (1933) Das tektonische Bild des Brockenmassivs. Cent für Mineral Geol und Paläontologie, Abteilung B 633–647Google Scholar
- Mamtani MA, Greiling RO (2005) Granite emplacement and its relation with regional deformation in the Aravalli Mountain Belt (India)—inferences from magnetic fabric. J Struct Geol 27(11):2008–2029CrossRefGoogle Scholar
- McCann T, Pascal C, Timmerman MJ, Krzywiec P, López-Gómez J, Wetzel A et al (2006) Post-Variscan (end Carboniferous–Early Permian) basin evolution in Western and Central Europe. In: Gee DG, Stephenson RA (eds) European lithosphere dynamics, vol 32. Geological Society, London, Memoirs, pp 97–112Google Scholar
- Menand T (2008) The mechanics and dynamics of sills in layered elastic rocks and their implications for the growth of laccoliths and other igneous complexes. Earth Plan Sci Lett 267(1–2):93–99CrossRefGoogle Scholar
- Morgan S, Stanik A, Horsman E, Tikoff B, de Saint Blanquat M, Habert G (2008) Emplacement of multiple magma sheets and wall rock deformation: Trachyte Mesa intrusion, Henry Mountains, Utah. J Struct Geol 30(4):491–512CrossRefGoogle Scholar
- Morteani G, Möller P, Hoefs J (1986) Rare-earth element and oxygen isotope studies of altered Variscan granites: the Western Harz (Germany) and Southern Sardinia (Italy). Chem Geol 54:53–68CrossRefGoogle Scholar
- Nédélec A, Bouchez J-L (2015) Granites: petrology, structure, geological setting, and metallogeny. OUP, OxfordCrossRefGoogle Scholar
- Obst K, Katzung G, Haupt M (2001) Gangmagmatismus im Mittelharz als Indikator für spätvasiszlsche Dehnungstektonik. N Jb Geol Paläont Abh 219(3):393–432CrossRefGoogle Scholar
- Paul J (1982) Zur Rand-und Schwellen-Fazies des Kupferschiefers. Z dt geol Ges 133:571–605Google Scholar
- Paul J (1999) Evolution of a Permo-Carboniferous Basin: the Ilfeld Basin and its relationship to adjoining Permo-Carboniferous structures in Central Germany. N Jb Geol Paläont Abh 214:211–236CrossRefGoogle Scholar
- Petford N, Cruden AR, McCaffrey KJW, Vigneresse JL (2000) Granite magma formation, transport and emplacement in the Earth’s crust. Nature 408:669CrossRefGoogle Scholar
- Petronis MS, O’Driscoll B, Stevenson CTE, Reavy RJ (2012) Controls on emplacement of the Caledonian Ross of Mull Granite, NW Scotland: Anisotropy of magnetic susceptibility and magmatic and regional structures. Geol Soc Am Bull B 124:906–927CrossRefGoogle Scholar
- Piller H (1951) Über den Schwermineralgehalt von anstehendem und verwittertem Brockengranit nördlich St. Andreasberg. Heidelberger Beitrage 2:523Google Scholar
- Plaumann S (1978) Die Schwerekarte des Westharzes. Geol Jb E12:23–29Google Scholar
- Plesch A, Oncken O (1999) Orogenic wedge growth during collision—constraints on mechanics of a fossil wedge from its kinematic record (Rhenohercynian FTB, Central Europe). Tectonophysics 309:117–139CrossRefGoogle Scholar
- Pueyo EL, Román-Berdiel MT, Bouchez J-L, Casas AM, Larrasoaña JC (2004) Statistical significance of magnetic fabric data in studies of paramagnetic granites. Geol Soc Lond 238:395–420CrossRefGoogle Scholar
- Rocchi S, Westerman DS, Dini A, Innocenti F, Tonarini S (2002) Two-stage growth of laccoliths at Elba Island, Italy. Geology 30(11):983–986CrossRefGoogle Scholar
- Rochette P, Jackson M, Aubourg C (1992) Rock magnetism and the interpretation of anisotropy of magnetic susceptibility. Rev Geophys 30:209–226CrossRefGoogle Scholar
- Saint-Blanquat M de, Law RD, Bouchez JL, Morgan SS (2001) Internal structure and emplacement of the Papoose Flat pluton: An integrated structural, petrographic, and magnetic susceptibility study. Geol Soc Am Bull 113(8):976–995CrossRefGoogle Scholar
- Sant’Ovaia H, Bouchez JL, Noronha F, Leblanc D, Vigneresse JL (2000) Composite-laccolith emplacement of the post-tectonic Vila Pouca de Aguiar granite pluton (northern Portugal): a combined AMS and gravity study. Earth Environ Sci Trans R Soc Edinb 91(1–2):123–137CrossRefGoogle Scholar
- Scheck M, Bayer U, Otto V, Lamarche J, Banka D, Pharaoh T (2002) The Elbe Fault System in North Central Europe—a basement controlled zone of crustal weakness. Tectonophysics 360:281–299CrossRefGoogle Scholar
- Schoell M (1986) Radiometrische Altersbestimmungen am Brocken-Intrusions-komplex im Harz als Beispiel der Interpretation diskordanter Modellalter. In: Wendt I (ed) Radiometrische Methoden in der Geochronologie. Springer, New York, pp 132–157CrossRefGoogle Scholar
- Schust F (1995) The sequence of rock types of the Brocken pluton, Harz Mountains. Zbl Geol Paläont I 1993(9/10):1385–1399Google Scholar
- Schust F, Kaemmel T, Gotte W (1997) Zur geologischen Position und zum Intrusionsalter der postkinematischen Plutonite im NE–Rhenoherzynikum. Z Geol Wiss 25(3/4):413–431Google Scholar
- Schwab M, Lutzens H (1958) Zur Stratigraphie und Tektonik der Wernigeröder Schichten bei Wernigerode. Ber geol Ges DDR 3:235–237Google Scholar
- Stampfli GM, Hochard C, Vérard C, Wilhem C (2013) The formation of Pangea. Tectonophysics 593:1–19CrossRefGoogle Scholar
- Steiner W (1968) Die Harzer Granite (Brocken-Granite) und ihre Verwendung als Werk- und Dekorationssteine. Wissenschaftliche Zeitschrift Hochschule für Architektur und Bauwesen Weimar 5:551–576Google Scholar
- Stephan T, Kroner U, Hahn T, Hallas P, Heuse T (2016) Fold/cleavage relationships as indicator for late Variscan sinistral transpression at the Rheno-Hercynian–Saxo-Thuringian boundary zone. Central Eur Variscides Tectonophys 681:250–262Google Scholar
- Tanner DC, Krawczyk CM (2017) Restoration of the Cretaceous uplift of the Harz Mountains, North Germany: evidence for the geometry of a thick–skinned thrust. Int J Earth Sci (Geol Rundsch) 106:2963–2972CrossRefGoogle Scholar
- Tarling D, Hrouda F (1993) Magnetic anisotropy of rocks. Chapman & Hall, LondonGoogle Scholar
- Thieke HU (1969) Petrographische und tektonische Untersuchungen am Ilsesteingranit-Komplex (Harz). Geologie 18:400–428Google Scholar
- Timmerman MJ (2004) Timing, geodynamic setting and character of Permo-Carboniferous magmatism in the foreland oft he Variscan Orogen, NW Europe. Geol Soc Lond Spec Publ 223:41–74CrossRefGoogle Scholar
- Von Seckendorff V (2012) Der Magmatismus in und zwischen den spätvariszischen permokarbonen Sedimentbecken in Deutschland. Schriftr Deutsch Gesellschaft Geowiss 61:743–860Google Scholar
- von Seckendorff V, Arz C, Lorenz V (2004) Magmatism of the late Variscan intermontane Saar-Nahe Basin (Germany): a review. Geol Soc Lond 223(1):361–391CrossRefGoogle Scholar
- von Eynatten H, Voigt T, Meier A, Franzke H-J, Gaupp R (2008) Provenance of Cretaceous clastics in the Subhercynian Basin: constraints to exhumation of the Harz Mountains and timing of inversion tectonics in Central Europe. Int J Earth Sci 97:1315–1330CrossRefGoogle Scholar
- Wachendorf H (1986) Der Harz – variszischer Bau und geodynamische Entwicklung. Geol Jb A 91:3–67Google Scholar
- Wilson M, Neumann E-R, Davies GR, Timmerman MJ, Heeremans M, Larsen BT (2004) Permo-Carboniferous magmatism and rifting in Europe: introduction. Geol Soc Lond Spec Publ 223(1):1–10CrossRefGoogle Scholar
- Wilson PI, McCaffrey KJ, Wilson RW, Jarvis I, Holdsworth RE (2016) Deformation structures associated with the Trachyte Mesa intrusion, Henry Mountains, Utah: Implications for sill and laccolith emplacement mechanisms. J Struct Geol 87:30–46CrossRefGoogle Scholar
- Wrede V (2008) Nördliche Harzrandstörung: Diskussionsbeiträge zu Tiefenstruktur Zeitlichkeit und Kinematik. Z dt Ges Geowiss 159/2:293–316Google Scholar
- Zech J, Jeffries T, Faust D, Ullrich B, Linnemann U (2010) U/Pb-dating and geochemical characterization of the Brocken and the Ramberg Pluton, Harz Mountains, Germany. Geol Sax 56:9–24Google Scholar