Hostname: page-component-78c5997874-mlc7c Total loading time: 0 Render date: 2024-11-20T00:01:20.614Z Has data issue: false hasContentIssue false

Contact metamorphism of the Tethyan Sedimentary Sequence, Upper Mustang region, west-central Nepal

Published online by Cambridge University Press:  24 April 2020

Iva Lihter*
Affiliation:
Earth, Environmental and Geographic Sciences, University of British Columbia Okanagan, Kelowna, BCV1V 1V7, Canada
Kyle P. Larson
Affiliation:
Earth, Environmental and Geographic Sciences, University of British Columbia Okanagan, Kelowna, BCV1V 1V7, Canada
Sudip Shrestha
Affiliation:
Earth, Environmental and Geographic Sciences, University of British Columbia Okanagan, Kelowna, BCV1V 1V7, Canada Present address: Fipke Laboratory for Trace Element Research, University of British Columbia Okanagan, Kelowna, BC V1V 1V7, Canada
John M. Cottle
Affiliation:
Department of Earth Science, University of California, Santa Barbara, CA93106–9630, USA
Alex D. Brubacher
Affiliation:
Earth, Environmental and Geographic Sciences, University of British Columbia Okanagan, Kelowna, BCV1V 1V7, Canada Present address: Newmont Corporation, Whitehorse, YT Y1A 0G1, Canada
*
Author for correspondence: Iva Lihter, Email: [email protected]

Abstract

The Upper Mustang region of west-central Nepal contains exposures of metamorphosed Tethyan Sedimentary Sequence rocks that have been interpreted to reflect either contact metamorphism related to the nearby Mugu pluton or regional metamorphism associated with the North Himalayan domes. New monazite geochronology results show that the Mugu leucogranite crystallized at c. 21.3 Ma, while the dominant monazite age peaks from the surrounding garnet ± staurolite ± sillimanite schists range between c. 21.7 and 19.4 Ma, generally decreasing in age away from the pluton. Metamorphic temperature estimates based on Ti-in-biotite and garnet–biotite thermometry are highest in the specimens closest to the pluton (648 ± 24°C and 615 ± 25°C, respectively) and lowest in those furthest away (578 ± 24°C and 563 ± 25°C, respectively), while pressure estimates are all within uncertainty of one another, averaging 5.0 ± 0.5 kbar. These results are interpreted to be consistent with contact metamorphism of the rocks in proximity to the Mugu pluton, which was emplaced at c. 18 ± 2 km depth after local movement across the South Tibetan detachment system had ceased. While this new dataset helps to characterize the metamorphic rocks of the Tethyan Sedimentary Sequence and provides new constraints on the thickness of the upper crust, it also emphasizes the importance of careful integration of metamorphic conditions and inferred processes that may affect interpretation of currently proposed Himalayan models.

Type
Original Article
Copyright
© Cambridge University Press 2020

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Aikman, AB, Harrison, TM and Lin, D (2008) Evidence for early (> 44 Ma) Himalayan crustal thickening, Tethyan Himalaya, Southeastern Tibet. Earth and Planetary Science Letters 274, 1423.CrossRefGoogle Scholar
Aleinikoff, JN, Schenck, WS, Plank, MO, Srogi, L, Fanning, CM, Kamo, SL and Bosbyshell, H (2006) Deciphering igneous and metamorphic events in high-grade rocks of the Wilmington Complex, Delaware: morphology, cathodoluminescence and backscattered electron zoning, and SHRIMP U-Pb geochronology of zircon and monazite. Geological Society of America Bulletin 118, 3964.Google Scholar
Andersen, TB (1984) Inclusion patterns in zoned garnets from Magerøy, North Norway. Mineralogical Magazine 48, 2126.CrossRefGoogle Scholar
Aoya, M, Wallis, SR, Terada, K, Lee, J, Kawakami, T, Wang, Y and Heizler, M (2005) North-south extension in the Tibetan crust triggered by granite emplacement. Geology 33, 853–56.CrossRefGoogle Scholar
Buick, IS, Hermann, J, Williams, IS, Gibson, RL and Rubatto, D (2006) A SHRIMP U–Pb and LA-ICP-MS trace element study of the petrogenesis of garnet–cordierite–orthoamphibole gneisses from the Central Zone of the Limpopo Belt, South Africa. Lithos 88, 150–72.CrossRefGoogle Scholar
Burchfiel, BC, Chen, Z, Hodges, KV, Liu, Y, Royden, LH, Deng, C and Xu, J (1992) The South Tibetan detachment system, Himalayan Orogen: extension contemporaneous with and parallel to shortening in a collisional mountain belt. Geological Society of America 269, 41.Google Scholar
Burton, KW (1986) Garnet-quartz intergrowths in graphitic pelites: the role of the fluid phase. Mineralogical Magazine 50, 611–20.CrossRefGoogle Scholar
Carosi, R, Montomoli, C, Rubatto, D and Visonà, D (2013) Leucogranite intruding the South Tibetan Detachment in western Nepal: implications for exhumation models in the Himalayas. Terra Nova 25, 478–89.CrossRefGoogle Scholar
Colchen, M (1999) The Thakkhola–Mustang graben in Nepal and the late Cenozoic extension in the Higher Himalayas. Journal of Asian Earth Sciences 17, 683702.CrossRefGoogle Scholar
Coleman, M and Hodges, K (1995) Evidence for Tibetan plateau uplift before 14 Myr ago from a new minimum age for east–west extension. Nature 374, 49.CrossRefGoogle Scholar
Corthouts, TL, Lageson, DR and Shaw, CA (2016) Polyphase deformation, dynamic metamorphism, and metasomatism of Mount Everest’s summit limestone, east central Himalaya, Nepal/Tibet. Lithosphere 8, 3857.CrossRefGoogle Scholar
Cottle, JM, Burrows, AJ, Kylander-Clark, A, Freedman, PA and Cohen, RS (2013) Enhanced sensitivity in laser ablation multi-collector inductively coupled plasma mass spectrometry. Journal of Analytical Atomic Spectrometry 28, 1700–6.CrossRefGoogle Scholar
Cottle, JM, Kylander-Clark, AR and Vrijmoed, JC (2012) U–Th/Pb geochronology of detrital zircon and monazite by single shot laser ablation inductively coupled plasma mass spectrometry (SS-LA-ICPMS). Chemical Geology 332–333, 136–47.Google Scholar
Cottle, JM, Larson, KP and Kellett, DA (2015) How does the mid-crust accommodate deformation in large, hot collisional orogens? A review of recent research in the Himalayan orogen. Journal of Structural Geology 78, 119–33.CrossRefGoogle Scholar
Cottle, JM, Larson, KP and Yakymchuk, C (2018) Contrasting accessory mineral behavior in minimum-temperature melts: empirical constraints from the Himalayan metamorphic core. Lithos 312, 5771.CrossRefGoogle Scholar
Cottle, J, Lederer, G and Larson, K (2019) The monazite record of pluton assembly: mapping manaslu using petrochronology. Chemical Geology 530, 119309.CrossRefGoogle Scholar
Fort, M, Freytet, P and Colchen, M (1982) Structural and sedimentological evolution of the Thakkhola Mustang graben (Nepal Himalayas). Zeitschrift für Geomorphologie 42, 7598.Google Scholar
Foster, CT (1991) The role of biotite as a catalyst in reaction mechanisms that form sillimanite. The Canadian Mineralogist 29, 943–63.Google Scholar
Godin, L, Parrish, RR, Brown, RL and 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, 729747.Google Scholar
Groppo, C, Rolfo, F and 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. Journal of Metamorphic Geology 31, 187204.CrossRefGoogle Scholar
Guillot, S, Cosca, M, Allemand, P and Le Fort, P (1999) Contrasting metamorphic and geochronologic evolution along the Himalayan belt. In Himalaya and Tibet: Mountain Roots to Mountain Tops (eds A Macfarlane, RB Sorkhabi and J Quade), pp. 117–28. Geological Society of America, Boulder, Special Paper no. 328.CrossRefGoogle Scholar
Guillot, S, Hodges, K, Fort, PL and Pêcher, A (1994) New constraints on the age of the Manaslu leucogranite: evidence for episodic tectonic denudation in the central Himalayas. Geology 22, 559–62.2.3.CO;2>CrossRefGoogle Scholar
Guillot, S, Le Fort, P, Pêcher, A, Barman, MR and Aprahamian, J (1995a) Contact metamorphism and depth of emplacement of the Manaslu granite (central Nepal). Implications for Himalayan orogenesis. Tectonophysics 241, 99119.CrossRefGoogle Scholar
Guillot, S, Pêcher, A and Le Fort, P (1995b) Contrôles tectoniques et thermiques de la mise en place des leucogranites himalayens. Comptes rendus de l’Académie des sciences. Série 2. Sciences de la terre et des planets 320, 5561.Google Scholar
Guo, L, Zhang, J and Zhang, B (2008) Structures, kinematics, thermochronology and tectonic evolution of the Ramba gneiss dome in the northern Himalaya. Progress in Natural Science 18, 851–60.CrossRefGoogle Scholar
Harrison, TM, Grove, M, Mckeegan, KD, Coath, CD, Lovera, OM and Fort, PL (1999) Origin and episodic emplacement of the Manaslu intrusive complex, central Himalaya. Journal of Petrology 40, 319.CrossRefGoogle Scholar
He, D, Webb, AAG, Larson, KP, Martin, AJ and Schmitt, AK (2015) Extrusion vs. duplexing models of Himalayan mountain building 3: duplexing dominates from the Oligocene to Present. International Geology Review 57, 127.CrossRefGoogle Scholar
Henry, DJ, Guidotti, CV and Thomson, JA (2005) The Ti-saturation surface for low-to-medium pressure metapelitic biotites: implications for geothermometry and Ti-substitution mechanisms. American Mineralogist 90, 316–28.CrossRefGoogle Scholar
Holdaway, MJ (2000) Application of new experimental and garnet Margules data to the garnet-biotite geothermometer. American Mineralogist 85, 881–92.Google Scholar
Hollister, LS (1966) Garnet zoning: an interpretation based on the Rayleigh fractionation model. Science 154, 1647–51.CrossRefGoogle Scholar
Horstwood, MS, Foster, GL, Parrish, RR, Noble, SR and Nowell, GM (2003) Common-Pb corrected in situ U–Pb accessory mineral geochronology by LA-MC-ICP-MS. Journal of Analytical Atomic Spectrometry 18, 837–46.CrossRefGoogle Scholar
Horstwood, MS, Košler, J, Gehrels, G, Jackson, SE, McLean, NM, Paton, C, Pearson, NJ, Sircombe, K, Sylvester, P, Vermeesch, P and Bowring, JF (2016) Community-derived standards for LA-ICP-MS U-(Th-) Pb geochronology – Uncertainty propagation, age interpretation and data reporting. Geostandards and Geoanalytical Research 40, 311–32.CrossRefGoogle Scholar
Hu, X, Garzanti, E, Wang, J, Huang, W, An, W and Webb, A (2016) The timing of India-Asia collision onset: Facts, theories, controversies. Earth-Science Reviews 160, 264–99.Google Scholar
Hubbard, MS (1996) Ductile shear as a cause of inverted metamorphism: example from the Nepal Himalaya. Journal of Geology 104, 493–99.CrossRefGoogle Scholar
Hurtado, JM, Hodges, KV and Whipple, KX (2001) Neotectonics of the Thakkhola graben and implications for recent activity on the South Tibetan fault system in the central Nepal Himalaya. Geological Society of America Bulletin 113, 222–40.2.0.CO;2>CrossRefGoogle Scholar
Jaeger, JC (1964) Thermal effects of intrusions. Reviews of Geophysics 2, 443–66.CrossRefGoogle Scholar
Jaeger, JC (1968) Cooling and solidification of igneous rocks. In Basalts, the Poldervaart Treatise on Rocks of Basaltic Composition (eds Hess, HH and Poldervaart, A), vol. 2, pp. 503–36. New York, London, Sidney: Wiley and Sons.Google Scholar
Jamieson, RA, Beaumont, C, Medvedev, S and Nguyen, MH (2004) Crustal channel flows: 2. Numerical models with implications for metamorphism in the Himalayan-Tibetan orogen. Journal of Geophysical Research 109, B06407.CrossRefGoogle Scholar
Jamieson, RA, Beaumont, C, Nguyen, MH and Grujic, D (2006) Provenance of the Greater Himalayan Sequence and associated rocks: predictions of channel flow models. In Channel Flow, Ductile Extrusion and Exhumation of Lower-mid Crust in Continental Collision Zones (eds RD Law, M Searle and L Godin), pp. 165–82. Geological Society of London, Special Publication no. 268.Google Scholar
Kawakami, T, Aoya, M, Wallis, SR, Lee, J, Terada, K, Wang, Y and Heizler, M (2007) Contact metamorphism in the Malashan dome, North Himalayan gneiss domes, southern Tibet: an example of shallow extensional tectonics in the Tethys Himalaya. Journal of Metamorphic Geology 25, 831–53.CrossRefGoogle Scholar
Kellett, DA, Cottle, JM and Larson, KP (2018) The South Tibetan Detachment System: history, advances, definition and future directions. In Himalayan Tectonics: A Modern Synthesis (eds PJ Treloar and MP Searle), pp. 1–24. Geological Society of London, Special Publication no. 483.Google Scholar
Kellett, DA and Godin, L (2009) Pre-Miocene deformation of the Himalayan superstructure, Hidden Valley, central Nepal. Journal of the Geological Society 166, 261–75.CrossRefGoogle Scholar
Klootwijk, CT, Gee, JS, Peirce, JW, Smith, GM and McFadden, PL (1992) An early India-Asia contact: paleomagnetic constraints from Ninetyeast ridge, ODP Leg 121. Geology 20, 395–98.2.3.CO;2>CrossRefGoogle Scholar
Kohn, MJ (2008) PTt data from central Nepal support critical taper and repudiate large-scale channel flow of the Greater Himalayan Sequence. Geological Society of America, Bulletin 120, 259–73.CrossRefGoogle Scholar
Kohn, MJ (2014) Himalayan metamorphism and its tectonic implications. Annual Review of Earth and Planetary Science 42, 381419.CrossRefGoogle Scholar
Kohn, MJ and Malloy, MA (2004) Formation of monazite via prograde metamorphic reactions among common silicates: implications for age determinations. Geochimica et Cosmochimica Acta 68, 101–13.CrossRefGoogle Scholar
Kohn, MJ and Spear, F (2000) Retrograde net transfer reaction insurance for pressure-temperature estimates. Geology 28, 1127–30.2.0.CO;2>CrossRefGoogle Scholar
Kylander-Clark, AR, Hacker, BR and Cottle, JM (2013) Laser-ablation split-stream ICP petrochronology. Chemical Geology 345, 99112.CrossRefGoogle Scholar
Larson, KP, Ambrose, TK, Webb, AAG, Cottle, JM and Shrestha, S (2015) Reconciling Himalayan midcrustal discontinuities: the Main Central thrust system. Earth and Planetary Science Letters 429, 139–46.CrossRefGoogle Scholar
Larson, KP, Godin, L, Davis, WJ and Davis, DW (2010a) Out-of-sequence deformation and expansion of the Himalayan orogenic wedge: insight from the Changgo culmination, south central Tibet. Tectonics 29, TC4013.CrossRefGoogle Scholar
Larson, KP, Godin, L and Price, RA (2010b) Relationships between displacement and distortion in orogens: linking the Himalayan foreland and hinterland in central Nepal. GSA Bulletin, 22, 1116–34.CrossRefGoogle Scholar
Larson, KP, Kellet, DA, Cottle, JM, Camacho, A and Brubacher, AD (2019) Mid-Miocene initiation of E-W extension and recoupling of the Himalayan Orogen. Terra Nova 12443, 18.Google Scholar
Law, RD, Searle, MP and Godin, L (eds) (2006) Channel Flow, Ductile Extrusion and Exhumation in Continental Collision Zones. Geological Society of London, Special Publication no. 268, 611 p.CrossRefGoogle Scholar
Lee, J, Hacker, B and Wang, Y (2004) Evolution of North Himalayan gneiss domes: structural and metamorphic studies in Mabja Dome, southern Tibet. Journal of Structural Geology 26, 2297–316.CrossRefGoogle Scholar
Lee, J, Hager, C, Wallis, SR, Stockli, DF, Whitehouse, MJ, Aoya, M and Wang, Y (2011) Middle to late Miocene extremely rapid exhumation and thermal reequilibration in the Kung Co rift, southern Tibet. Tectonics 30, TC2007.Google Scholar
Le Fort, P and France-Lanord, C (1995) Granites from Mustang and surrounding regions (central Nepal). Journal of Nepal Geological Society 11, 5357.Google Scholar
Liu, ZC, Wu, FY, Ji, WQ, Wang, JG and Liu, CZ (2014) Petrogenesis of the Ramba leucogranite in the Tethyan Himalaya and constraints on the channel flow model. Lithos 208, 118–36.CrossRefGoogle Scholar
Ludwig, KR (2012) Isoplot 3.75–4.15: A Geochronological Toolkit for Microsoft Excel. Berkeley Geochronology Center, Special Publication vol. 5, 75 p.Google Scholar
Mahéo, G, Leloup, PH, Valli, F, Lacassin, R, Arnaud, N, Paquette, J L, Fernandez, A, Haibing, L, Farley, KA and Tapponnier, P (2007) Post 4 Ma initiation of normal faulting in southern Tibet. Constraints from the Kung Co half graben. Earth and Planetary Science Letters 256, 233–43.CrossRefGoogle Scholar
Martin, AJ (2017) A review of Himalayan stratigraphy, magmatism, and structure. Gondwana Research 49, 4280.CrossRefGoogle Scholar
McDonough, WF and Sun, SS (1995) The composition of the Earth. Chemical Geology 120, 223–53.CrossRefGoogle Scholar
McKinney, ST, Cottle, JM and Lederer, GW (2015) Evaluating rare earth element (REE) mineralization mechanisms in Proterozoic gneiss, Music Valley, California. GSA Bulletin 127, 1135–52.Google Scholar
Nelson, KD, Zhao, W, Brown, LD, Kuo, J, Che, J, Liu, X, Klemperer, SL, Makovsky, Y, Meissner, RJJM, Mechie, J, Kind, R, Wenzel, F, Ni, J, Nábělek, JL, Leshou, C, Tan, H, Wei, W, Jones, AG, Brooker, UMJ, Kidd, WS, Hauck, ML, Alsdorf, AR, Cogan, M, Wu, C-M, Sandvol, E and Edwards, MA (1996) Partially molten middle crust beneath southern Tibet: synthesis of project INDEPTH results. Science 274, 1684–88.CrossRefGoogle ScholarPubMed
Otamendi, JE, de La Rosa, JD, Douce, AEP and Castro, A (2002) Rayleigh fractionation of heavy rare earths and yttrium during metamorphic garnet growth. Geology 30, 159–62.2.0.CO;2>CrossRefGoogle Scholar
Patton, C, Hellstrom, J, Paul, B, Woodhead, JH and Hergt, J (2011) Iolite: freeware for the visualization and processing of mass spectrometry data. Journal of Analytical Atomic Spectrometry 26, 2508–18.CrossRefGoogle Scholar
Pyle, JM and Spear, FS (1999) Yttrium zoning in garnet: coupling of major and accessory phases during metamorphic reactions. Geological Materials Research 1, 149.Google Scholar
Pyle, JM and Spear, FS (2003) Four generations of accessory-phase growth in low-pressure migmatites from SW New Hampshire. American Mineralogist 88, 338–51.CrossRefGoogle Scholar
Quigley, MC, Liangjun, Y, Gregory, C, Corvino, A, Sandiford, M, Wilson, CJL and Xiaohan, L (2008) U–Pb SHRIMP zircon geochronology and T–t–d history of the Kampa Dome, southern Tibet. Tectonophysics 446, 97113.Google Scholar
Rice, AHN (1987) Continuous out-of-sequence ductile thrusting in the Norwegian Caledonides. Geological Magazine 124, 249–60.CrossRefGoogle Scholar
Rice, AHN (1993) Textural and twin sector-zoning and displacement of graphite in chiastolite and pyralspite and grandite garnets in the Variscides of south-west England. In Proceedings of the Ussher Society 8, 124.Google Scholar
Rice, AHN and Mitchell, JI (1991) Porphyroblast textural sector-zoning and matrix displacement. Mineralogical Magazine 55, 379–96.CrossRefGoogle Scholar
Schärer, U (1984) The effect of initial 230Th disequilibrium on young U-Pb ages: the Makalu case, Himalaya. Earth and Planetary Science Letters 67, 191204.CrossRefGoogle Scholar
Searle, MP (2010) Low-angle normal faults in the compressional Himalayan orogen; Evidence from the Annapurna–Dhaulagiri Himalaya, Nepal. Geosphere 6, 296315.CrossRefGoogle Scholar
Searle, MP and Godin, L (2003) The South Tibetan detachment and the Manaslu leucogranite: a structural reinterpretation and restoration of the Annapurna-Manaslu Himalaya, Nepal. Journal of Geology 111, 505–23.CrossRefGoogle Scholar
Shrestha, S, Larson, KP, Duesterhoeft, E, Soret, M and Cottle, JM (2019) Thermodynamic modelling of phosphate minerals and its implications for the development of PTt histories: A case study in garnet-monazite bearing metapelites. Lithos 334, 141–60.CrossRefGoogle Scholar
Spear, FS and Pyle, JM (2002) Apatite, monazite, and xenotime in metamorphic rocks. Reviews in Mineralogy and Geochemistry 48, 293335.CrossRefGoogle Scholar
Spear, FS and Pyle, JM (2010) Theoretical modeling of monazite growth in a low-Ca metapelite. Chemical Geology 273, 111–19.CrossRefGoogle Scholar
Taylor, SR and McLennan, SM (1988) The significance of the rare earths in geochemistry and cosmochemistry. In Handbook on the Physics and Chemistry of Rare Earths (eds Gschneider, KA and Eyring, L), vol. 11, pp. 485578. Amsterdam: Elsevier Science Publication.Google Scholar
Tomascak, PB, Krogstad, EJ and Walker, RJ (1996) U-Pb monazite geochronology of granitic rocks from Maine: implications for late Paleozoic tectonics in the Northern Appalachians. Journal of Geology 104, 185–95.CrossRefGoogle Scholar
Tracy, RJ, Robinson, P and Thompson, AB (1976) Garnet composition and zoning in the determination of temperature and pressure of metamorphism, central Massachusetts. American Mineralogist 61, 762–75.Google Scholar
Treagus, SH and Treagus, JE (2002) Studies of strain and rheology of conglomerates. Journal of Structural Geology 24, 1541–67.CrossRefGoogle Scholar
Vermeesch, P (2018) IsoplotR: a free and open toolbox for geochronology. Geoscience Frontiers 9, 1479–93.CrossRefGoogle Scholar
Webb, AAG, Schmitt, AK, He, D and Weigand, EL (2011) Structural and geochronological evidence for the leading edge of the Greater Himalayan Crystalline complex in the central Nepal Himalaya. Earth and Planetary Science Letters 304, 483–95.CrossRefGoogle Scholar
Whitney, DL and Evans, BW (2010) Abbreviations for names of rock-forming minerals. American Mineralogist 95, 185–87.CrossRefGoogle Scholar
Wing, BA, Ferry, JM and Harrison, TM (2003) Prograde destruction and formation of monazite and allanite during contact and regional metamorphism of pelites: petrology and geochronology. Contributions to Mineralogy and Petrology 145, 228–50.CrossRefGoogle Scholar
Wu, CM (2015) Revised empirical garnet–biotite–muscovite–plagioclase geobarometer in metapelites. Journal of Metamorphic Geology 33, 167–76.CrossRefGoogle Scholar
Yardley, BWD (1989) An Introduction to Metamorphic Petrology. Longman Scientific & Technical, UK, 248 p.Google Scholar
Supplementary material: File

Lihter et al. supplementary material

Lihter et al. supplementary material 1

Download Lihter et al. supplementary material(File)
File 319.1 KB
Supplementary material: PDF

Lihter et al. supplementary material

Lihter et al. supplementary material 2

Download Lihter et al. supplementary material(PDF)
PDF 227.4 KB
Supplementary material: PDF

Lihter et al. supplementary material

Lihter et al. supplementary material 3

Download Lihter et al. supplementary material(PDF)
PDF 3.3 MB