Abstract
The Variscan Rand Granite as defined in this paper is a deformed I-type biotite granite that intruded along the southern-to-southeastern margin of the Central Schwarzwald Gneiss Complex. Former K-feldspar megacrysts (now porphyroclasts) of this K–Mg-rich alkali-calcic granite frequently show zonal crystallographic arrangement of mineral inclusions and are enclosed in a matrix of plagioclase, K-feldspar, quartz, biotite, apatite, zircon, and magnetite. Minor sphene and allanite are mostly altered. K-feldspar is orthoclase with perthitic exsolutions. Myrmekite is common and typically replaces marginal K-feldspar. Both feldspars show cataclastic and incipient ductile deformation that took place within the stability field of biotite (≥ 400 °C) as proven by grey varieties of Rand Granite with stable biotite. At most places, however, the Rand Granite shows a reddish colour, caused by late-stage chloritization of biotite and formation of hematite within K-feldspar. Furthermore, plagioclase became partially altered to sericite. This hydrothermal alteration took place at temperatures below the stability of biotite (< 400 °C). In situ ion probe U–Pb dating on zircon gave a concordant age of 330.9 ± 4.8 Ma (2σ), interpreted as the intrusion age of the Rand Granite. A large number of younger concordant to slightly discordant zircon ages between 309 and 90 Ma are interpreted to be due to episodic Pb loss during hydrothermal alteration. The Rand Granite apparently does not contain zircon domains older than the intrusion age and, furthermore, shows relatively high Zr contents (247–358 µg/g). These characteristics suggest high magma temperatures of at least 850–900 °C. The granitic magma most probably resulted from remelting of K-rich mafic to intermediate rocks in the middle crust at H2O-undersaturated conditions. Low Sr/Y ratios suggest a garnet-free residuum, which is only possible at pressures below ~ 0.9 GPa.
Similar content being viewed by others
References
Altherr R, Maass R (1977) Metamorphite am Südrand der Zentralschwarzwälder Gneisanatexitmasse zwischen Geschwend und Bernau. N Jb Geol Paläont Abh 154:129–154
Altherr R, Henjes-Kunst F, Langer C, Otto J (1999) Interaction between crustal-derived felsic and mantle-derived mafic magmas in the Oberkirch Pluton (European Variscides, Schwarzwald, Germany). Contrib Mineral Petrol 137:304–322
Altherr R, Holl A, Hegner E, Langer C, Kreuzer H (2000) High-potassium, calc-alkaline I-type plutonism in the European Variscides: northern Vosges (France) and northern Schwarzwald (Germany). Lithos 50:51–73
Annen C, Blundy JD, Sparks RSJ (2006) The genesis of intermediate and silicic magmas in deep crustal hot zones. J Petrol 47:505–539
Annen C, Blundy JD, Leuthold J, Stephen R, Sparks J (2015) Construction and evolution of igneous bodies: towards an integrated perspective of crustal magmatism. Lithos 230:206–221
Barth MG, Foley SF, Horn I (2002) Partial melting in Archean subduction zones: constraints from experimentally determined trace element partition coefficients between eclogitic minerals and tonalitic melts under upper mantle conditions. Precambrian Res 113:323–340
Beard JS, Lofgren GE (1989) Effect of water on the composition of partial melts of greenstone and amphibolite. Science 244:195–197
Bédard JH (2006) Trace element partitioning in plagioclase feldspar. Geochim Cosmochim Acta 70:3717–3742
Boehnke P, Watson EB, Trail D, Harrison TM, Schmitt AK (2013) Zircon saturation re-revisited. Chem Geol 351:324–334
Breiter K, Gardenová MV, Kanický V, Vaculovič T (2013) Gallium and germanium geochemistry during magmatic fractionation and post-magmatic alteration in different types of granitoids: a case study from the Bohemian Massif (Czech Republic). Geologica Carathica 64:171–180
Brockamp O, Schlegel A, Wemmer K (2015) Complex hydrothermal alteration and illite K–Ar ages in Upper Visean molasse sediments and magmatic rocks of the Variscan Badenweiler-Lenzkirch suture zone, Black Forest, Germany. Int J Earth Sci 104:683–702
Brown M (2013) Granite: from genesis to emplacement. Geol Soc Am Bull 125:1079–1113
Burgath K (1973) Kulmische Lahare im Südschwarzwald. Jb Mitt Oberrh Geol Ver NF 55:83–93
Burgath K, Maass R (1973) Die variszische Entwicklung im südlichen Schwarzwald. Compte Rendu Sept Congr Intern Stratigr Géol CarbonifèreKrefeld, 23–28 August 1971 II:195–209
Büsch W, Mehnert KR (1995) Ein Beispiel für Granitisation im Schwarzwald? (Umdeutung der ‘Feldspatisierungszone’ von Geschwend). Jh geol Landesamt Bad-Württ 35:7–24
Castillo PR (2012) Adakite petrogenesis. Lithos 134–135:304–316
Castro A (2014) The off-crust origin of granite batholiths. Geosci Front 5:63–75
Ceccato A, Menegon L, Pennacchioni G, Grafulha Morales LF (2018) Myrmekite and strain weakening in granitoid mylonites. Solid Earth 9:1399–1419
Chappell BW, White AJR (2001) Two contrasting granite types: 25 years later. Aust J Earth Sci 48:489–499
Chappell BW, Bryant CJ, Wyborn D (2012) Peraluminous I-type granites. Lithos 153:142–153
Chen F (2002) Garnet Sm–Nd and U–Pb systems: a case study of a granulite from the European Variscan belt. Chin Sci Bull 47:1284–1288
Chen F, Todt W, Hann HP (2003) Zircon and garnet geochronology of eclogites from the Moldanubian Zone of the Black Forest, Germany. J Geol 111:207–222
Chiaradia M (2015) Crustal thickness control on Sr/Y signatures of recent arc magmas: an Earth scale perspective. Sci Rep 5:8115
Clemens JD (1984) Water contents of silicic to intermediate magmas. Lithos 17:273–287
Clemens JD (2018) Granitic magmas with I-type affinities, from mainly metasedimentary sources: the Harcourt batholith of southeastern Australia. Contrib Mineral Petrol 173:93
Clemens JD, Vielzeuf D (1987) Constraints on melting and magma production in the crust. Earth Planet Sci Lett 86:287–306
Clemens JD, Stevens G, Farina F (2011) The enigmatic sources of I-type granites: the peritectic connexion. Lithos 126:174–181
Coleman DS, Gray W, Glazner AF (2004) Rethinking the emplacement and evolution of zoned plutons: geochronologic evidence for incremental assembly of the Tuolumne intrusive suite, California. Geology 32:433–436
Collins WJ, Huang H-Q, Jiang X (2016) Water-fluxed crustal melting produces Cordilleran batholiths. Geology 44:143–146
Cox RA, Dempster TJ, Bell BR, Rogers G (1996) Crystallization of the Shap Granite: evidence from zoned K-feldspar megacrysts. J Geol Soc Lond 153:625–635
Díaz-Alvarado J (2017) Experimental early crystallization of K-feldspar in granitic systems. Implications on the origin of magmatic fabrics in granitic rocks. Geologica Acta 15:261–281
Eisbacher GH, Lüschen E, Wickert F (1989) Crustal-scale thrusting and extension in the Hercynian Schwarzwald and Vosges, Central Europe. Tectonics 8:1–21
Foley S, Tiepolo M, Vannucci R (2002) Growth of early continental crust controlled by melting of amphibolite in subduction zones. Nature 417:837–840
Frost BR, Frost CD (2008) A geochemical classification for feldspathic igneous rocks. J Petrol 49:1955–1969
Frost BR, Barnes CG, Collins WJ, Arculus RJ, Ellis DJ, Frost CD (2001) A geochemical classification for granitic rocks. J Petrol 42:2033–2048
Gagnevin D, Daly JS, Poli G, Morgan D (2005) Microchemical and Sr isotopic investigation of zoned K-feldspar megacrysts: insights into the petrogenesis of a granite system and disequilibrium crystal growth. J Petrol 46:1689–1724
Gao P, Zheng Y-F, Zhao Z-F (2016) Experimental melts from crustal rocks: a lithochemical constraint on granite petrogenesis. Lithos 266–267:133–157
Geisler T, Schaltegger U, Tomaschek F (2007) Re-equilibration of zircon in aqueous fluids and melts. Elements 3:43–50
Girardi JD, Patchett PJ, Ducea MN, Gehrels GE, Cecil MR, Rusmore ME, Woodsworth GJ, Pearson DM, Mantei C, Wetmore P (2012) Elemental and isotopic evidence for granitoid genesis from deep-seated sources in the Coast Mountains Batholith, British Columbia. J Petrol 53:1505–1536
Glazner AF, Bartley JM, Coleman DS, Gray W, Taylor RZ (2004) Are plutons assembled over millions of years by amalgamation from small magma chambers? GSA Today 14:4–11
Güldenpfennig M (1998) Zur geotektonischen Stellung unterkarbonischer Grauwacken und Vulkanite der Zone von Badenweiler-Lenzkirch (Südschwarzwald). Z Dt Geol Ges 149:213–232
Guo X, Szenknect S, Mesbah A, Clavier N, Poinssot C, Wu D, Xu H, Dacheux N, Ewing RC, Navrotsky A (2016) Energetics of a uranothorite (Th1−xUxSiO4) solid solution. Chem Mater 28:7117–7124
Hanel M, Lippolt HJ, Kober B, Wimmenauer W (1993) Lower Carboniferous granulites in the Schwarzwald basement near Hohengeroldseck (SW-Germany). Naturwissenschaften 80:25–28
Hann HP, Sawatzki G (1998) Deckenbau und Sedimentationsalter im Grundgebirge des Südschwarzwaldes/SW-Deutschland. Z Dt Geol Ges 149:183–195
Hann HP, Zedler H (2011) Geologische Karte von Baden-Württemberg 1:25000, sheet 8113 Todtnau, mit Erläuterungen. Landesamt für Geologie, Rohstoffe und Bergbau, Freiburg i. Br.
Hann HP, Sawatzki G, Vaida M (1995) Chitinozoen und Arcritarchen des Ordoviziums aus metamorphen Grauwacken der Zone von Badenweiler-Lenzkirch, Schwarzwald, SW-Deutschland. N Jb Geol Paläont Mh 1995:375–383
Hann HP, Chen F, Zedler H, Frisch W, Loeschke J (2003a) The Rand Granite in the southern Schwarzwald and its geodynamic significance in the Variscan belt of SW Germany. Int J Earth Sci 92:821–842
Hann HP, Chen F, Zedler H, Sawatzki G (2003b) Zircon ages and geochemistry of metavolcanic layers from the northern Badenweiler-Lenzkirch Zone (southern Schwarzwald, Germany). N Jb Geol Paläont Abh 230:451–469
Hegner E, Chen F, Hann HP (2001) Chronology of basin closure and thrusting in the internal zone of the Variscan belt in the Schwarzwald, Germany: evidence from zircon ages, trace element geochemistry, and Nd isotopic data. Tectonophysics 332:169–184
Hegner E, Gruler M, Hann HP, Chen F, Güldenpfennig M (2005) Testing tectonic models with geochemical provenance parameters in greywacke. J Geol Soc Lond 162:87–96
Hoenes D (1941) Magmatische Tätigkeit, Metamorphose und Migmatitbildung im Grundgebirge des südwestlichen Schwarzwaldes. N Jb Miner Geol Paläont I Abh 76:153–256
Hoenes D (1948) Petrogenese im Grundgebirge des südlichen Schwarzwaldes. Contrib Mineral Petrol 1:121–202
Hoenes D (1956) Der prägranitische Bau des Grundgebirges im südlichen Schwarzwald und seine Ableitung aus dem Fremdgesteinsinhalt der hybriden Granite. Contrib Mineral Petrol 5:272–288
Hofmann AW (1988) Chemical differentiation of the Earth: the relationship between mantle, continental crust, and oceanic crust. Earth Planet Sci Lett 90:297–314
Holtz F, Johannes W (1994) Maximum and minimum water contents of granitic melts: implications for chemical and physical properties of ascending magmas. Lithos 32:149–159
Holtz F, Johannes W, Tamic N, Behrens H (2001) Maximum and minimum water contents of granitic melts generated in the crust: a reevaluation and implications. Lithos 56:1–14
Johnson BR, Glazner AF (2010) Formation of K-feldspar megacrysts in granodioritic plutons by thermal cycling and late-stage textural coarsening. Contrib Mineral Petrol 159:599–619
Kalt A, Grauert B, Baumann A (1994a) Rb–Sr and U–Pb isotope studies on migmatites from the Variscan Schwarzwald (Germany): constraints on isotopic resetting during Variscan high-temperature metamorphism. J Metam Geol 12:667–680
Kalt A, Hanel M, Schleicher H, Kramm U (1994b) Petrology and geochronology of eclogites from the Variscan Schwarzwald (F.R.G.). Contrib Mineral Petrol 115:287–302
Kalt A, Altherr R, Hanel M (2000a) The Variscan basement of the Schwarzwald. Beih 2 Eur J Mineral 12:1–43
Kalt A, Kober B, Pidgeon RT (2000b) Further time constraints on Variscan high-pressure metamorphism in the Schwarzwald (Germany). Beih 1 Eur J Mineral 12:91
Kneidl V, Krebs W, Maass R (1982) Über Condontenfunde im Oberdevon von Tunau (Südschwarzwald). N Jb Geol Paläont Mh 1982:25–35
Krecher M (1999) Ein Beitrag zur Kenntnis des Kulmkonglomerates in der westlichen Badenweiler-Lenzkirch Zone (Unterkarbon, Südschwarzwald). Ber Naturf Ges Freiburg i Br 88(89):277–296
Krohe A, Eisbacher GH (1988) Oblique crustal detachment in the Variscan Schwarzwald, southwestern Germany. Int J Earth Sci 77:25–43
Le Maitre RW (2002) Igneous rocks—a classification and glossary of terms Recommendations of the IUGS subcommission on the systematics of igneous rocks, 2nd edn. Cambridge University Press, Cambridge
Loeschke J, Güldenpfennig M, Hann HP, Sawatzki G (1998) Die Zone von Badenweiler-Lenzkirch (Schwarzwald): eine variskische Suturzone. Z Dt Geol Ges 149:187–212
Ludwig KR (2012) User’s manual for isoplot 3.75—a geochronological toolkit for microsoft excel. Berkeley Geochronol Center Spec Publ 5:1–75
Maass R, Prosch T, Schuler D (1990) The zone of Badenweiler-Lenzkirch—a Carboniferous accretionary wedge? N Jb Geol Paläont Mh 1990:717–734
Maniar PD, Piccoli PM (1989) Tectonic discrimination of granitoids. Bull Geol Soc Am 101:635–643
Marschall HR, Kalt A, Hanel M (2003) P–T evolution of a Variscan lower-crustal segment: a study of granulites from the Schwarzwald, Germany. J Petrol 44:227–253
McDonough WF, Sun S-S (1995) Composition of the Earth. Chem Geol 120:223–253
Mehnert KR, Büsch W (1981) The Ba content of K-feldspar megacrysts in granites: a criterion for their formation. N Jb Miner Abh 140:221–252
Mehnert KR, Büsch W (1985) The formation of K-feldpspar megacrysts in granites, migmatites and augengneisses. N Jb Miner Abh 151:229–259
Menegon L, Pennacchioni G, Stünitz H (2006) Nucleation and growth of myrmekite during ductile shear deformation in metagranites. J Metam Geol 24:553–568
Metz R, Rein G (1958) Erläuterungen zur geologisch-petrographischen Übersichtskarte des Südschwarzwaldes 1:50000. Lahr, Schauenburg, p 134
Miller CF, McDowell SM, Mapes RW (2003) Hot and cold granites? Implications of zircon saturation temperatures and preservation of inheritance. Geology 31:529–532
Montenari M, Maass R (1996) Die metamorphen Schiefer der Badenweiler–Lenzkirch-Zone/Südschwarzwald—Paläontologische Altersstellung (Acritarchen und Chitinozoen) und Tektonik. Ber Naturf Ges Freiburg i Br 84(85):33–79
Montenari M, Servais T (2000) Early Paleozoic (Late Cambrian-Early Ordovician) acritarchs from the metasedimentary Baden-Baden–Gaggenau zone (Schwarzwald, SW Germany). Rev Palaeobot Palynol 113:73–85
Montenari M, Servais T, Paris F (2000) Palynological dating (acritarchs and chitinozoans) of Lower Paleozoic phyllites from the Black Forest/southwestern Germany. C R Acad Sci Paris Sci Terre Planèt 330:493–499
Moore JG, Sisson TW (2008) Igneous phenocrystic origin of K-feldspar megacrysts in granitic rocks from the Sierra Nevada batholith. Geosphere 4:387–400
Moyen J-F (2009) High Sr/Y and La/Yb ratios: the meaning of the “adakitic signature”. Lithos 112:556–574
Padilla AJ, Gualda GAR (2016) Crystal-melt elemental partitioning in silicic magmatic systems: an example from the Peach Spring Tuff high-silica rhyolite, Southwest USA. Chem Geol 440:326–344
Pearce JA, Harris NB, Tindle AG (1984) Trace element discrimination for the tectonic interpretations of granitic rocks. J Petrol 25:956–983
Pearce NJG, Perkins WT, Westgate JA, Gorton MP, Jackson SE, Neal CR, Cheney SP (1997) A compilation of new and published major an trace element data for NIST SRM 610 and NIST SRM 612 glass reference materials. Geostand Newslett 21:115–144
Peccerillo A, Taylor SR (1976) Geochemistry of Eocene calc-alkaline volcanic rocks from the Kastamonou area, northern Turkey. Contrib Mineral Petrol 58:63–81
Pressley RA, Brown M (1999) The Phillips Pluton, Maine, USA: evidence of heterogeneous crustal sources, and implications for granite ascent and emplacement mechanism in convergent orogens. Lithos 46:335–366
Rudnick RL, Gao S (2014) Composition of the continental crust. In: Rudnick RL (ed) The crust, treatise on geochemistry, vol 3, 2nd edn. Elsevier Science, Oxford, pp 1–64
Sawatzki G, Hann HP (2003) Geologische Karte von Baden-Württemberg 1:50000, Badenweiler-Lenzkirch-Zone, mit Erläuterungen. Landesamt für Geologie, Rohstoffe und Bergbau Baden-Württemberg, Freiburg i. Br.
Schaltegger U (1997) Magma pulses in the Central Variscan Belt: episodic melt generation and emplacement during lithospheric thinning. Terra Nova 9:242–245
Schaltegger U (2000) U–Pb geochronology of the Southern Black Forest Batholith (Central Variscan Belt): timing of exhumation and granite emplacement. Int J Earth Sci 88:814–828
Schmitz MD, Bowring SA, Ireland TR (2003) Evaluation of Duluth Complex anorthositic series (AS3) zircon as a U–Pb geochronological standard: new high-precision isotope dilution thermal ionization mass spectrometry results. Geochim Cosmochim Acta 67:3665–3672
Schwarz WH, Trieloff M (2007) Intercalibration of 40Ar–39Ar age standards NL-25, HB3gr hornblende, GA1550, SB-3, HD-B1 biotite and BMus/2 muscovite. Chem Geol 242:218–231
Silver LT, Deutsch S (1963) Uranium-lead variations in Zircons: a case study. J Geol 71:721–758
Simpson C, Wintsch RP (1989) Evidence for deformation-induced K-feldspar replacement by myrmekite. J Metam Geol 7:261–275
Sisson TW, Bacon CR (1992) Garnet/high silica rhyolite trace element partition coefficients measured by ion microprobe. Geochim Cosmochim Acta 56:2133–2136
Sisson TW, Ratajeski K, Hankins WB, Glazner AF (2005) Voluminous granitic magmas from common basaltic sources. Contrib Mineral Petrol 148:635–661
Sittig E (1969) Zur geologischen Charakterisierung des Moldanubikums am Oberrhein (Südschwarzwald). Oberrhein Geol Abh 18:119–161
Sittig E (1981) Evidence for wrench faulting within the Paleozoic Badenweiler-Lenzkirch zone (Southern Schwarzwald Mountains, W-Germany). N Jb Geol Paläont Mh 1981:421–448
Stacey JS, Kramers JD (1975) Approximation of terrestrial lead isotope evolution by a two-stage model. Earth Planet Sci Lett 26:207–221
Steiger RH, Jäger E (1977) Subcommission on geochronology: convention on the use of decay constants in geo- and cosmochronology. Earth Planet Sci Lett 36:359–362
Stepanov A, Mavrogenes JA, Meffre S, Davidson P (2014) The key role of mica during igneous fractionation of tantalum. Contrib Mineral Petrol 167:1009
Stern CR, Wyllie PJ (1981) Phase relationships of I-type granite with H2O to 35 kilobars: the Dinkey Lakes biotite-granite from the Sierra Nevada batholith. J Geophys Res 86:10412–10422
Szenknect S, Costin DT, Clavier N, Mesbah A, Poinssot C, Vitorge P, Dacheux N (2013) From uranothorites to coffinite: a solid solution route to the thermodynamic properties of USiO4. Inorg Chem 52:6957–6968
Tiepolo M, Oberti R, Zanetti A, Vannucci R, Foley SF (2007) Trace-element partitioning between amphibole and silicate melt. Rev Mineral Geochem 67:417–452
Vaida M, Hann HP, Sawatzki G, Frisch W (2004) Ordovician and Silurian protolith ages of metamorphosed clastic sedimentary rocks from the southern Schwarzwald, SW Germany: a palynological study and its bearing on the Early Palaeozoic geotectonic evolution. Geol Mag 141:629–643
Vernon RH (1986) K-feldspar megacrysts in granites—phenocrysts, not porphyroblasts. Earth Sci Rev 23:1–63
Vernon RH (2010) Granites really are magmatic: using microstructural evidence to refute some obstinate hypotheses. J Virtual Explorer 35:1–36. https://doi.org/10.3809/jvirtex.2011.00264
Vernon RH, Paterson SR (2008a) How late are K-feldspar megacrysts in granites? Lithos 104:327–336
Vernon RH, Paterson SR (2008b) Mesoscopic structures resulting from cystal accumulation and melt movement in granites. Trans R Soc Edinb Earth Sci 97:369–381
Vielzeuf D, Holloway JR (1988) Experimental determination of the fluid-absent melting relations in the pelitic system. Contrib Mineral Petrol 98:257–276
Vielzeuf D, Schmidt MW (2001) Melting relations in hydrous systems revisited: application to metapelites, metagreywackes and metabasalts. Contrib Mineral Petrol 141:251–267
Watson EB, Harrison TM (1983) Zircon saturation revisited: temperature and composition effects in a variety of crustal magma types. Earth Planet Sci Lett 64:295–304
Weinberg RF, Hasalová P (2015) Water-fluxed melting of the continental crust: a review. Lithos 212–215:158–188
Whalen JB, Currie KL, Chappell BW (1987) A-type granites: geochemical characteristics, discrimination and petrogenesis. Contrib Mineral Petrol 95:407–419
Whitney JA (1988) The origin of granite: the role and source of water in the evolution of granitic magmas. Geol Soc Am Bull 100:1886–1897
Wickert E, Altherr R, Deutsch M (1990) Polyphase Variscan tectonics and metamorphism along a segment of the Saxothuringian-Moldanubian boundary: the Baden-Baden Zone, northern Schwarzwald (F.R.G.). Int J Earth Sci 79:627–647
Wiedenbeck MP, Allé P, Corfu F, Griffin W, Meier M, Oberli F, Von Quadt A, Roddick J, Spiegel W (1995) Three natural zircon standards for U–Th–Pb, Lu–Hf, trace element and REE analyses. Geostand Newslett 19:1–23
Wiedenbeck MP, Hanchar JM, Peck WH, Sylvester P, Valley J, Whitehouse M, Kronz A, Morishita Y, Nasdala L, Fiebig J, Franchi I, Girard J-P, Greenwood RC, Hinton R, Kita N, Mason PRD, Norman M, Ogasawara M, Piccoli PM, Rhede D, Satoh H, Schulz-Dobrick B, Skår O, Spicuzza MJ, Terada K, Tindle A, Togashi S, Vennemann T, Xie Q, Zheng Y-F (2004) Further characterisation of the 91500 zircon crystal. Geostand Geoanal Res 28:9–39
Wimmenauer W, Hanel M (1997) Die Fortsetzung der Randgranit-Assoziation nach Nordosten und Norden. Jh Geol Landesamt Baden Württemberg 37:7–24
Wimmenauer W, Schreiner A (1990) Geologische Karte 1:25000 von Baden-Württemberg, sheet 8114 Feldberg, mit Erläuterungen. Landesamt für Geologie Baden Württemberg, Stuttgart, p 140
Wu FY, Liu XC, Ji WQ, Wang JM, Yang L (2017) Highly fractionated granites: recognition and research. Sci China Earth Sci 60:1201–1219
Wyllie PJ (1976) Granitic magmas: possible and impossible sources, water contents, and crystallization sequences. Can J Earth Sci 13:1007–1019
Zhang C, Holtz F, Koepke J, Wolff PE, Ma C, Bédard JH (2013) Constraints from experimental melting of amphibolite on the depth of formation of garnet-rich restites, and implications for models of Early Archean crustal growth. Precambrian Res 231:206–217
Ziegler PA, Wimmenauer W (2001) Possible glaciomarine diamictites in Lower Paleozoic series of the Southern Black Forest (Germany): implications for the Gondwana/Laurussia puzzle. N Jb Geol Paläont Mh 2001:500–512
Acknowledgements
We would like to thank Christian Soder (Heidelberg) for discussions and Ilona Fin and Oliver Wienand (Heidelberg) for preparing excellent thin sections. Alexander Varychev helped with the SEM work and Martin Karl and Reinhard Fritsche (Terrachem Analytical Laboratory, Mannheim) carried out the bulk-rock analyses by WDXRF (major elements). Trace-element analyses by laser ablation were performed by Helene Brätz (University of Erlangen-Nürnberg). Many thanks to Thomas Ludwig (Heidelberg) for the assistance during the SIMS measurements. Helpful comments by A. von Quadt and an anonymous reviewer are gratefully acknowledged. The authors acknowledge financial support from the Klaus Tschira Stiftung gGmbh, Heidelberg.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Altherr, R., Hanel, M., Schwarz, W.H. et al. Petrology and U–Pb zircon age of the Variscan porphyroclastic Rand Granite at the southeastern margin of the Central Schwarzwald Gneiss Complex (Germany). Int J Earth Sci (Geol Rundsch) 108, 1879–1895 (2019). https://doi.org/10.1007/s00531-019-01738-2
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00531-019-01738-2