Abstract
Leucogranite bodies are ubiquitous in the upper structural levels of the Himalayan metamorphic slab. Their formation has ramifications for myriad processes including the generation of crustal melts and orogenic heat budgets. One particularly enigmatic variety of the Himalayan leucogranites, abundant in the Langtang region of Nepal, are the banded tourmaline leucogranites; typified by centimetre-scale compositional banding between tourmaline-rich and quartzo-feldspathic domains. Here, we use in-situ Rb–Sr isotopic chemistry and microstructural analysis to show these banded tourmaline leucogranites do not represent a direct product of melt crystallization but instead were formed by metasomatism of psammitic country-rock. This metasomatism was likely driven by the release of boron-rich volatiles during the crystallization of neighboring muscovite–biotite leucogranite bodies. Rb–Sr isochrons based on biotite–plagioclase ± white mica and K-feldspar data define overlapping dates of ca. 17.5 Ma from both the banded tourmaline leucogranite and its paired muscovite–biotite leucogranite. The characteristic banding appearance of these rocks is a product of heteroepitaxial nucleation of tourmaline on biotite folia and the replacement of pre-existing biotite and plagioclase with tourmaline and K-feldspar. The heteroepitaxy relationship of tourmaline on biotite is characterized by the {10–10} face of tourmaline parallel to biotite (001), with the tourmaline c-axis parallel to either the biotite [110] or [010] direction. One of the broader implications of our findings is that field estimates based on the volume of coarse-grained leucocratic outcrop overestimates the amount of melt generated at the top of the Himalayan slab.
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All Rb–Sr and EMPA data used in this article are available in the online supplementary material file and stored in the Open Science Framework online repository at: https://osf.io/d4yrj/?view_only=e3579968f86748a9a4c27077095e365b
References
Ague JJ (1998) Simple models of coupled fluid infiltration and redox reactions in the crust. Contrib Mineral Petrol 132:180–197
Ayres M, Harris N (1997) REE fractionation and Nd-isotope disequilibrium during crustal anatexis: constraints from Himalayan leucogranites. Chem Geol 139:249–269
Barbey P, Brouand M, Le Fort P, Pecher A (1996) Granite-migmatite genetic link: the example of the Manaslu granite and Tibetan Slab migmatites in central Nepal. Lithos 38:63–79
Brown M (1994) The generation, segregation, ascent and emplacement of granite magma: the migmatite-to-crustally-derived granite connection in thickened orogens. Earth-Sci Rev 36:83–130
Brown M, Solar GS (1998) Granite ascent and emplacement during contractional deformation in convergent orogens. J Struct Geol 20:1365–1393
Camacho A, Lee JK, Gerald JF et al (2012) Planar defects as Ar traps in trioctahedral micas: a mechanism for increased Ar retentivity in phlogopite. Earth Planet Sci Lett 341:255–267
Camacho A, Lee JKW, Zhao J et al (2020) A test of the interlayer ionic porosity model as a measure of argon diffusivity in trioctahedral micas. Geochim Cosmochim Acta 288:341–368
Cao H-W, Pei Q-M, Santosh M, et al (2022) Himalayan leucogranites: A review of geochemical and isotopic characteristics, timing of formation, genesis, and rare metal mineralization. Earth-Science Reviews 104229
Carlson WD, Gordon CL (2004) Effects of matrix grain size on the kinetics of intergranular diffusion. J Metamorphic Geol 22:733–742
Carmichael DM (1969) On the mechanism of prograde metamorphic reactions in quartz-bearing pelitic rocks. Contrib Mineral Petrol 20:244–267
Catlos EJ, Harrison TM, Kohn MJ et al (2001) Geochronologic and thermobarometric constraints on the evolution of the main central thrust, central Nepal Himalaya. J Geophy Res: Solid Earth 106:16177–16204
Cottle J, Lederer G, Larson K (2019) The monazite record of pluton assembly: Mapping manaslu using petrochronology. Chem Geol 530:119309
Cottle JM, Larson KP, Yakymchuk C (2018) Contrasting accessory mineral behavior in minimum-temperature melts: empirical constraints from the Himalayan metamorphic core. Lithos 312:57–71
Cottle JM, Searle MP, Horstwood MS, Waters DJ (2009) Timing of midcrustal metamorphism, melting, and deformation in the Mount Everest region of southern Tibet revealed by U (-Th)-Pb geochronology. J Geol 117:643–664
Deniel C, Vidal P, Fernandez A et al (1987) Isotopic study of the Manaslu granite (Himalaya, Nepal): inferences on the age and source of Himalayan leucogranites. Contrib Mineralogy Petrol 96:78–92
Dyck B, St-Onge M, Searle MP et al (2018) Protolith lithostratigraphy of the greater Himalayan Series in Langtang, Nepal: implications for the architecture of the northern Indian margin. Geo Soc, London, Special Pub 483(SP483):9. https://doi.org/10.1144/SP483.9
Dyck B, Waters DJ, St-Onge MR, Searle MP (2020) Muscovite dehydration melting: reaction mechanisms, microstructures, and implications for anatexis. J Metamorphic Geo 38:29–52
Errandonea-Martin J, Garate-Olave I, Roda-Robles E, et al (2022) Metasomatic effect of Li-bearing aplite-pegmatites on psammitic and pelitic metasediments: Geochemical constraints on critical raw material exploration at the Fregeneda–Almendra Pegmatite Field (Spain and Portugal). Ore Geology Reviews 105155
Fuchsloch WC, Nex PA, Kinnaird JA (2019) The geochemical evolution of Nb–Ta–Sn oxides from pegmatites of the Cape Cross-Uis pegmatite belt, Namibia. Mineral Magaz 83:161–179
Godin L, Parrish RR, Brown RL, Hodges KV (2001) Crustal thickening leading to exhumation of the Himalayan metamorphic core of central Nepal: Insight from U-Pb geochronology and 40Ar/39Ar thermochronology. Tectonics 20:729–747
Groppo C, Rolfo F, Mosca P (2013) The cordierite-bearing anatectic rocks of the higher Himalayan crystallines (eastern Nepal): low-pressure anatexis, melt productivity, melt loss and the preservation of cordierite. J Metamorphic Geo 31:187–204
Guillot S, Le Fort P (1995) Geochemical constraints on the bimodal origin of high Himalayan leucogranites. Lithos 35:221–234
Guo Z, Wilson M (2012) The Himalayan leucogranites: constraints on the nature of their crustal source region and geodynamic setting. Gondwana Res 22:360–376
Harris N, Ayres M, Massey J (1995) Geochemistry of granitic melts produced during the incongruent melting of muscovite: implications for the extraction of Himalayan leucogranite magmas. J Geophy Res: Solid Earth 1978–2012(100):15767–15777
Harrison MT, Grove M, Mckeegan KD et al (1999) Origin and episodic emplacement of the Manaslu intrusive complex, central Himalaya. J Petro 40:3–19
Herwegh M, Berger A, Ebert A (2005) Grain coarsening maps: a new tool to predict microfabric evolution of polymineralic rocks. Geol 33:801–804
Higgins MD (2011) Textural coarsening in igneous rocks. Inter Geol Rev 53:354–376
Hodges KV (2006) A synthesis of the channel flow-extrusion hypothesis as developed for the Himalayan-Tibetan orogenic system. Geo Soc, London, Special Pub 268:71–90
Hogmalm KJ, Zack T, Karlsson AK-O et al (2017) In situ Rb–Sr and K-Ca dating by LA-ICP-MS/MS: an evaluation of N 2 O and SF 6 as reaction gases. J Analytical Atomic Spectrom 32:305–313
Holness MB (1997) Deformation-enhanced fluid transport in the earth’s crust and mantle. Springer Science & Business Media
Hu Z, Gao S, Liu Y et al (2008) Signal enhancement in laser ablation ICP-MS by addition of nitrogen in the central channel gas. J Analy Atomic Spectrom 23:1093–1101
Inger S, Harris N (1993) Geochemical constraints on leucogranite magmatism in the Langtang Valley, Nepal Himalaya. J Petrol 34:345–368
Jochum KP, Weis U, Stoll B et al (2011) Determination of reference values for NIST SRM 610–617 glasses following ISO guidelines. Geostandards Geoanalytical Res 35:397–429
Kelemen PB, Hirth G, Shimizu N et al (1997) A review of melt migration processes in the adiabatically upwelling mantle beneath oceanic spreading ridges. Philos Trans Royal Soc London 355:283–318
Kelemen PB, Whitehead JA, Aharonov E, Jordahl KA (1995) Experiments on flow focusing in soluble porous media, with applications to melt extraction from the mantle. J Geophy Res: Solid Earth 100:475–496
Kellett DA, Grujic D, Erdmann S (2009) Miocene structural reorganization of the South Tibetan detachment, eastern Himalaya: Implications for continental collision. Lithosphere 1:259–281
Kohn MJ (2008) PTt data from central Nepal support critical taper and repudiate large-scale channel flow of the Greater Himalayan Sequence. Geo Soc Am Bulletin 120:259–273
Kohn MJ, Corrie SL (2011) Preserved Zr-temperatures and U-Pb ages in high-grade metamorphic titanite: evidence for a static hot channel in the Himalayan orogen. Earth Planet Sci Lett 311:136–143
Larson KP (2020) ChrontouR:, doi: https://doi.org/10.17605/OSF. IO/P46MB
Larson KP, Cottle JM, Camacho A et al (2022) Miocene anatexis, cooling and exhumation in the Khumbu Himal. Nepal Inter Geo Rev 64:2008–2033
Le Fort P, Cuney M, Deniel C et al (1987) Crustal generation of the Himalayan leucogranites. Tectonophysics 134:39–57
Leloup PH, Liu X, Mahéo G et al (2015) New constraints on the timing of partial melting and deformation along the Nyalam section (central Himalaya): implications for extrusion models. Geo Soc, London, Special Pub 412:131–175
Lentz DR, Gregoire C (1995) Petrology and mass-balance constraints on major-, trace-, and rare-earth-element mobility in porphyry-greisen alteration associated with the epizonal True Hill granite, southwestern New Brunswick, Canada. J Geochem Exploration 52:303–331
Liu L, Zhu D-C, Wang Q, et al (2022) Leucogranite records multiple collisional orogenies. Geophys Res Lett 49:e2021GL096817
London D (1999) Stability of tourmaline in pei aluminous granite systems: the boron cycle from anatexis to hydrothermal aureoles. Eur J Mineral 253–262
London D, Manning DA (1995) Chemical variation and significance of tourmaline from Southwest England. Eco Geo 90:495–519
Macfarlane AM (1993) Chronology of tectonic events in the crystalline core of the Himalaya, Langtang National Park, central Nepal. Tectonics 12:1004–1025
Macfarlane AM (1995) An evaluation of the inverted metamorphic gradient at Langtang national park, central Nepal Himalaya. J Metamorphic Geo 13:595–612
Macfarlane AM (1999) The metamorphic history of the crystalline rocks in the high Himalaya, Nepal: insights from thermobarometric data. J Asian Earth Sci 17:741–753
Macfarlane AM (1992) The tectonic evolution of the core of the Himalaya, Langtang National Park, central Nepal. Massachusetts Institute of Technology
Parrish RR, Hodges V (1996) Isotopic constraints on the age and provenance of the lesser and greater Himalayan sequences, Nepalese Himalaya. Geo Soc Am Bulletin 108:904–911
Paton C, Hellstrom J, Paul B et al (2011) Iolite: Freeware for the visualisation and processing of mass spectrometric data. J Analyt Atomic Spectrom 26:2508–2518
Powell R, Green EC, Marillo Sialer E, Woodhead J (2020) Robust Isochron Calculation Geochronol 2:325–342
Rampone E, Romairone A, Hofmann AW (2004) Contrasting bulk and mineral chemistry in depleted mantle peridotites: evidence for reactive porous flow. Earth Planet Sci Lett 218:491–506
Redaa A, Farkaš J, Gilbert S et al (2021) Assessment of elemental fractionation and matrix effects during in situ Rb–Sr dating of phlogopite by LA-ICP-MS/MS: implications for the accuracy and precision of mineral ages. J Analytical Atomic Spectrom 36:322–344
Reddy SM, Searle MP, Massey JA (1993) Structural evolution of the High Himalayan gneiss sequence, Langtang valley. Nepal Geo Soc, London, Special Pub 74:375–389
Roduit N (2008) JMicroVision: Image analysis toolbox for measuring and quantifying components of high-definition images. Version 1.2. 7. Software available for free download at http://www.jmicrovision.com
Rösel D, Zack T (2022) LA-ICP-MS/MS Single-Spot Rb-Sr Dating. Geostandards and Geoanalytical Research
Ruggles TJ, Rampton TM, Khosravani A, Fullwood DT (2016) The effect of length scale on the determination of geometrically necessary dislocations via EBSD continuum dislocation microscopy. Ultramicroscopy 164:1–10
Scaillet B, France-Lanord C, Le Fort P (1990) Badrinath-Gangotri plutons (Garhwal, India): petrological and geochemical evidence for fractionation processes in a high Himalayan leucogranite. J Volcanol Geotherm Res 44:163–188
Scaillet B, Pichavant M, Roux J (1995) Experimental crystallization of leucogranite magmas. J Petrol 36:663–705
Scaillet B, Searle MP (2006) Mechanisms and timescales of felsic magma segregation, ascent and emplacement in the Himalaya. Geol Soc, London, Special Pub 268:293–308
Searle MP (1999) Emplacement of Himalayan leucogranites by magma injection along giant sill complexes: examples from the Cho Oyu, Gyachung Kang and Everest leucogranites (Nepal Himalaya). J Asian Earth Sci 17:773–783
Searle MP, Cottle JM, Streule MJ, Waters DJ (2010) Crustal melt granites and migmatites along the Himalaya: melt source, segregation, transport and granite emplacement mechanisms. Geo Soc Am Special Papers 472:219–233
Searle MP, Law RD, Jessup MJ (2006) Crustal structure, restoration and evolution of the Greater Himalaya in Nepal-South Tibet: implications for channel flow and ductile extrusion of the middle crust. Geo Soc, London, Special Pub 268:355
Searle MP, Parrish RR, Hodges KV et al (1997) Shisha Pangma leucogranite, south Tibetan Himalaya: field relations, geochemistry, age, origin, and emplacement. J Geol 105:295–318
Searle MP, Windley BF, Coward MP et al (1987) The closing of tethys and the tectonics of the Himalaya. Geo Soc Am Bulletin 98:678–701. https://doi.org/10.1130/0016-7606
Sheather SJ, Jones MC (1991) A reliable data-based bandwidth selection method for kernel density estimation. J Royal Statist Soc 53:683–690
Spiegelman M, Kelemen PB, Aharonov E (2001) Causes and consequences of flow organization during melt transport: the reaction infiltration instability in compactible media. J Geophys Res 106:2061–2077
Streule MJ, Searle MP, Waters DJ, et al (2010) Metamorphism, melting and channel flow in the Greater Himalaya Sequence and Makalu leucogranite: constraints from thermobarometry, metamorphic modelling and U–Pb geochronology. Tectonics 29, TC5011
Suhr G (1999) Melt migration under oceanic ridges: inferences from reactive transport modelling of upper mantle hosted dunites. J Petro 40:575–599
Suhr G, Seck HS, Shimizu N et al (1998) Circulation of refractory melts in the lowermost oceanic crust: evidence from a trace element study of dunite-hosted clinopyroxenes in the Bay of Islands Ophiolite. Contrib Mineral Petrol 122:387–405
Vernon RH (1979) Formation of late sillimanite by hydrogen metasomatism (base-leaching) in some high-grade gneisses. Lithos 12:143–152
Vidal P, Cocherie A, Le Fort P (1982) Geochemical investigations of the origin of the Manaslu leucogranite (Himalaya, Nepal). Geochim Cosmochim Acta 46:2279–2292
Visonà D, Lombardo B (2002) Two-mica and tourmaline leucogranites from the Everest-Makalu region (Nepal–Tibet). Himalayan leucogranite genesis by isobaric heating? Lithos 62:125–150
Walther JV, Orville PM (1982) Volatile production and transport in regional metamorphism. Contrib Mineral Petrol 79:252–257
Webb AG, Yin A, Harrison TM et al (2007) The leading edge of the greater Himalayan Crystalline complex revealed in the NW Indian Himalaya: implications for the evolution of the Himalayan orogen. Geology 35:955–958
Weinberg RF (2016) Himalayan leucogranites and migmatites: nature, timing and duration of anatexis. J Metamorphic Geo 34:821–843
Weinberg RF, Searle MP (1999) Volatile-assisted intrusion and autometasomatism of leucogranites in the Khumbu Himalaya Nepal. J Geo 107:27–48
Wolf MB, London D (1997) Boron in granitic magmas: stability of tourmaline in equilibrium with biotite and cordierite. Contrib Mineral Petrol 130:12–30
Xu Y-G, Menzies MA, Thirlwall MF et al (2003) “Reactive” harzburgites from Huinan, NE China: products of the lithosphere-asthenosphere interaction during lithospheric thinning? Geochim Cosmochim Acta 67:487–505
Yang L, Liu X-C, Wang J-M, Wu F-Y (2019) Is Himalayan leucogranite a product by in situ partial melting of the Greater Himalayan Crystalline? A comparative study of leucosome and leucogranite from Nyalam, southern Tibet. Lithos 342:542–556
Zack T, Hogmalm KJ (2016) Laser ablation Rb/Sr dating by online chemical separation of Rb and Sr in an oxygen-filled reaction cell. Chem Geo 437:120–133
Zhang H, Harris N, Parrish R et al (2004) Causes and consequences of protracted melting of the mid-crust exposed in the North Himalayan antiform. Earth Planet Sci Lett 228:195–212
Acknowledgements
Marc St-Onge is thanked for the helpful in-field discussions and assistance. We thank Sudip Shrestha and Mark Button for analytical support. We thank Dante Canil for editorial handling and Roberto Weinberg and two anonymous reviewers whose comments helped to improve this manuscript.
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Dyck, B., Larson, K.P. Metasomatic origin of the Himalayan banded tourmaline leucogranite. Contrib Mineral Petrol 178, 37 (2023). https://doi.org/10.1007/s00410-023-02020-0
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DOI: https://doi.org/10.1007/s00410-023-02020-0