Archean Block in the Core of the Paleoproterozoic Lapland-Kola Orogen: New Data on Composition and Age of Rocks from Poriya Guba Islands

Capa

Citar

Texto integral

Acesso aberto Acesso aberto
Acesso é fechado Acesso está concedido
Acesso é fechado Acesso é pago ou somente para assinantes

Resumo

Petrological and geochronological (zircon, U-Th-Pb (LA-ICP-MS)) studies of rocks from the Poriya Guba tectonic mélange exposed on Ozerchanka and Palenyi islands were carried out to decipher composition and tectonic history of the Paleoproterozoic Lapland-Kola orogen (LKO). Tonalite-trondhjemite-granodiorite (TTG) (Grt)-Cpx-Opx gneisses dominate on the Ozerchanka island. They contain numerous bodies of mafic granulites and are intruded by syn- and post-tectonic granitoids. The TTG gneisses are Archean in age (>2.6 Ga, ТNd(DM) = 2.9–3.0 Ga). These are strong depleted in heavy REEs, which indicates that their parental melts of their igneous protoliths were formed in equilibrium with a garnet-bearing restite. Mafic granulite bodies vary widely in geochemical characteristics and likely represent fragments of several Paleoproterozoic mafic intrusions and dikes. Mineral assemblages in the gneisses recorded early granulite-facies (Т = 780–820°С and Р = 8.6–9.4 kbar) and later amphibolite-facies (Т = 640–650°С and Р = 6.7–7.3 kbar) metamorphic events that occurred at 1.9 Ga according to zircon ages. On the Palenyi island, Grt-Cpx-Opx gneisses are predominant and vary in composition from andesibasalts to rhyolites. The volcanic protoliths of these rocks have island-arc geochemical signatures, a Paleoproterozoic age of 1958 ± 6 Ma, and juvenile origin (εNd(1960) = +1.7 ÷ +3.1; ТNd(DM) = 2.2–2.3 Ga). These rocks were metamorphosed under granulite facies conditions at about 1.9 Ga. Two models can explain the presence of the Archaean Ozerchanka block which occurs in the Poriya Guba tectonic mélange composed of the Paleoproterozoic juvenile island arc complexes in the core of the LKO. First, this Archean block could represent a single fragment of Archean lithosphere that was separated during Paleoproterozoic continental rifting and the opening of the Lapland-Kola ocean and subsequently was tectonically juxtaposed with Paleoproterozoic subduction complexes during the Lapland-Kola collisional orogeny. Second, the Archean Ozerchanka block may represent the edge of an adjacent Archean continent exposed in an erosional window within the Paleoproterozoic Poriya Guba tectonic mélange.

Texto integral

Acesso é fechado

Sobre autores

A. Samsonov

Institute of Ore Geology, Petrography, Mineralogy and Geochemistry, Russian Academy of Sciences; Institute of Geology, Karelian Research Centre RAS

Autor responsável pela correspondência
Email: samsonovigem@mail.ru
Rússia, Moscow; Petrozavodsk

K. Erofeeva

Institute of Ore Geology, Petrography, Mineralogy and Geochemistry, Russian Academy of Sciences; Institute of Geology, Karelian Research Centre RAS

Email: samsonovigem@mail.ru
Rússia, Moscow; Petrozavodsk

O. Maksimov

Institute of Geology, Karelian Research Centre RAS

Email: samsonovigem@mail.ru
Rússia, Petrozavodsk

A. Stepanova

Institute of Geology, Karelian Research Centre RAS

Email: samsonovigem@mail.ru
Rússia, Petrozavodsk

Yu. Larionova

Institute of Ore Geology, Petrography, Mineralogy and Geochemistry, Russian Academy of Sciences; Institute of Geology, Karelian Research Centre RAS

Email: samsonovigem@mail.ru
Rússia, Moscow; Petrozavodsk

Bibliografia

  1. Азимов П.Я., Бушмин С.А. P–T история высокотемпературного/высокобарного (HT/HP) гранулитового метаморфизма, сопряженного с надвигообразованием в зоне сочленения Порьегубского и Умбинского блоков Лапландского гранулитового пояса (северо-восток Балтийского щита) // Докл. АН. 2009. Т. 425. № 3. С. 367–371.
  2. Балаганский В.В. Главные этапы тектонического развития северо-востока Балтийского щита в палеопротерозое. Автореф. дисс. … докт. геол.-мин. наук. СПб.: ИГГД РАН, 2002. 32 с.
  3. Балаганский В.В., Глебовицкий В.А. Лапландский гранулитовый пояс и комплементарные структуры / Ранний докембрий Балтийского щита. Л.: Наука, 2005. С. 124–175.
  4. Балаганский В.В., Тиммерман М.Я., Кислицын Р.В. и др. Изотопный возраст пород Колвицкого пояса и Умбинского блока (юго-восточная ветвь Лапландского гранулитового пояса), Кольский полуостров // Вестник МГТУ. 1998. Т. 1. № 3. С. 19–32.
  5. Богданова М.Н., Ефимов М.М., Каулина Т.В. Геохронология заключительных этапов раннепротерозойского магматизма в коллизионном шве Беломоро-Лапландского пояса Балтийского щита (Колвицкая зона) // Докл. АН. 1996. Т. 350. № 5. С. 665–668.
  6. Бушмин С.А., Доливо-Добровольский Д.В., Лебедева Ю.М. Инфильтрационный метасоматоз в условиях гранулитовой фации высоких давлений (на примере ортопироксен-силлиманитовых пород сдвиговых зон Лапландского гранулитового пояса) // Докл. АН. 2007. Т. 412. № 3. С. 383–387.
  7. Бушмин С.А., Глебовицкий В.А., Савва Е.В. и др. Возраст высокобарического метасоматоза в зонах сдвиговых деформаций при коллизионном метаморфизме в Лапландском гранулитовом поясе: U-Pb-SHRIMP-II-датирование цирконов из силлиманит-гиперстеновых пород Порьегубского покрова // Докл. АН. 2009. Т. 428. № 6. С. 792–796.
  8. Бушмин С.А., Вапник Е.А., Иванов М.В. и др. Флюиды гранулитов высоких давлений // Петрология. 2020. Т. 28. № 1. С. 23–54. https://doi.org/10.31857/S0869590320010021
  9. Глебовицкий В.А., Алексеев Н.Л., Доливо-Добровольский Д.В. Реакционные структур и P–T режимы охлаждения глубинных образований Кандалакшско-Колвицкой структурно-формационной зоны, Кольский полуостров // Записки РМО. 1997. № 2. С. 1–22.
  10. Глебовицкий В.А., Дук В.Л., Шарков Е.В. Эндогенный процессы / Земная кора восточной части Балтийского щита. Л.: Наука, 1978. С. 112–171.
  11. Глебовицкий В.В., Балтыбаев Ш.К., Левченков О.А., Кузьмина Е.В. PT-t режим метаморфизма пород из верхней и нижней частей Умбинского покрова (Балтийский щит) // Докл. АН. 2006. Т. 409. № 1. С. 100–103.
  12. Глебовицкий В.А., Балтыбаев Ш.К., Левченков О.А., Кузьмина Е.В. Термодинамический режим Свекофеннского (1.9 млрд лет) метаморфизма умбинского покрова Лапландского коллизионного орогена // Петрология. 2009. Т. 17. № 4. С. 355–377.
  13. Доливо-Добровольский Д.В. Компьютерная программа TWQ_Comb. Версия 1.2.0.4. 2006a. URL: http://www.dimadd.ru/ru/Programs/twqcomb
  14. Доливо-Добровольский Д.В. Компьютерная программа TWQ_View. Версия 1.2.0.22. 2006б. URL: http://www.dimadd.ru/ru/Programs/twqview
  15. Каулина Т.В. Заключительные стадии метаморфической эволюции Колвицкого пояса и Умбинского блока (юго-восточная ветвь Лапландского гранулитового пояса): U-Pb датирование циркона, титанита, рутила // Вестник МГТУ. 2009. Т. 12. № 3. С. 386–393.
  16. Каулина Т.В., Богданова М.Н. Основные этапы развития северо-западного Беломорья (по U-Pb изотопным данным) // Литосфера. 2000. № 12. С. 85–97.
  17. Кислицын Р.В. Возраст и кинематика тектонических движений в ядре раннепротерозойского Лапландско-Кольского орогена: Автореф. дисс. ... канд. геол.-мин. наук. Апатиты: ИГ КНЦ РАН, 2001. 22 с.
  18. Кориковский С.П., Котов А.Б., Сальникова Е.Б. и др. Возраст протолита метаморфических пород юго-восточной части Лапландского гранулитового пояса (юг Кольского полуострова): корреляции с Беломорским подвижным поясом в связи с проблемой архейских эклогитов // Петрология. 2014. Т. 22. № 2. С. 107–125. https://doi.org/10.7868/s0869590314020046
  19. Ларионова Ю.О., Самсонов А.В., Шатагин К.Н. Источники архейских санукитоидов Карельского кратона: Nd и Sr изотопно-геохимические данные // Петрология. 2007. Т. 15. № 6. С. 590–612.
  20. Лебедева Ю.М. Метасоматические процессы при высоких температурах и давлениях в Лапландском гранулитовом поясе (на примере Порьегубского покрова): Автореф. дисс. … канд. геол.-мин. наук. СПб.: ИГГД РАН, 2015. 19 с.
  21. Лебедева Ю.М., Глебовицкий В.А., Бушмин С.А. и др. Возраст высокобарического метасоматоза в зонах сдвиговых деформаций при коллизионном метаморфизме в Лапландском гранулитовом поясе: Sm-Nd метод датирования парагенезисов из силлиманит-ортопироксеновых пород Порьегубского покрова // Докл. АН. 2010. Т. 432. № 1. С. 99–102.
  22. Лебедева Ю.М., Бушмин С.А., Глебовицкий В.А. Термодинамические условия метасоматоза в высокотемпературных и высокобарических зонах сдвиговых деформаций (Кандалакшско-Умбинская зона, Кольский полуостров) // Докл. АН. 2012. Т. 445. № 2. С. 191–195.
  23. Митрофанов Ф.П., Балаганский В.В., Балашов Ю.А. и др. U-Pb возраст габбро-анортозитов Кольского полуострова // Докл. АН. 1993. Т. 331. № 1. С. 95–98.
  24. Светов С.А., Степанова А.В., Бурдюх С.В. и др. Прецизионный ICP-MS анализ докембрийских горных пород: методика и оценка точности результатов // Труды КарНЦ РАН. 2023. № 2. С. 73–86. https://doi.org/10.17076/geo1755
  25. Скублов С.Г., Балашов Ю.А., Марин Ю.Б. и др. U-Pb-возраст и геохимия цирконов из салминских эклогитов (месторождение Куру-Ваара, Беломорский пояс) // Докл. АН. 2010. Т. 432. № 5. С. 668–675.
  26. Степанов В.С. Основной магматизм докембрия Западного Беломорья. Л.: Наука, 1981. 216 с.
  27. Тугаринов А.И., Бибикова Е.В. Геохронология Балтийского щита по данным цирконометрии. М.: Наука, 1980. 132 с.
  28. Ashwal L.D., Tucker R.D., Zinner E.K. Slow cooling of deep crustal granulites and the Pb-loss in zircon // Geochim. Cosmochim. Acta. 1999. V. 63. P. 2839–2851.
  29. Balagansky V., Shchipansky A., Slabunov A. et al. Archean Kuru-Vaara eclogites in the northern Belomorian Province, Fennoscandian Shield: Crustal architecture, timing and tectonic implications // Int. Geol. Rev. 2015. V. 57. P. 1543–1565.
  30. Balagansky V.V., Maksimov O.A., Gorbunov I.A. et al. Early Precambrian eclogites in the Belomorian Province, eastern Fennoscandian Shield // Precam. Res. 2024. V. 413. 107579. https://doi.org/10.1016/j.precamres.2024.107579
  31. Berman R.G. Internally-consistent thermodynamic data for minerals in the system Na2O-K2O-CaO-MgO-FeO-Fe2O3-Al2O3-SiO2-TiO2-H2O-CO2 // J. Petrol. 1988. V. 29. P. 445–522.
  32. Berman R.G. Thermobarometry using multi-equilibrium calculations: А new technique, with petrological applications // Canad. Mineral. 1991. V. 29. № 4. P. 833–855.
  33. Bogdanova M.N., Yefimov M.M. Origin of parental anorthosite magmas: Tectonic and metamorphic processes in the evolution of anorthosites (Kolvitsa anorthosite association). Apatity: KSC RAS, 1993. 62 p.
  34. Bogdanova S.V., Gorbatschev R., Garetsky R.G. EUROPE | East European Craton. Reference Module in Earth Systems and Environmental Sciences, Elsevier. 2016.
  35. Bridgwater D., Scott D.J., Balagansky V.V. et al. Age and provenance of Early Precambrian metasedimentary rocks in the Lapland-Kola Belt, Russia: Evidence from Pb and Nd isotopic data // Terra Nova. 2001. V. 13. P. 32–37. https://doi.org/10.1046/j.1365-3121.2001.00307.x
  36. Bridgwater D., Marker M., Mengel F. The eastern extension of the Early Proterozoic Torngat orogenic zone across the Atlantic // Eds. R.J. Wardle, J. Hall. Lithoprobe, Eastern Canadian Shield Onshore-Offshore Transect (ECSOOT), Memorial University of Newfoundland, 1992. № 27. P. 76–91.
  37. Cawood P.A., Kröner A., Collins W.J. et al. Accretionary orogens through Earth history // Geol. Soc. Spec. Publ. 2009. V. 318. P. 11–36. https://doi.org/10.1144/SP318.
  38. Cawood P.A., Hawkesworth C.J., Pisarevsky S.A. et al. Geological archive of the onset of plate tectonics // Phil. Trans. R. Soc. 2018. A 376: 20170405. http://dx.doi.org/10.1098/rsta.2017.0405
  39. Daly J.S., Balagansky V.V., Timmerman M.J. et al. The Lapland–Kola orogen: Palaeoproterozoic collision and accretion of the northern Fennoscandian lithosphere // Eds. D.C. Gee, R.A. Stephenson. European Lithosphere Dynamics. Geol. Soc. London. Memoirs. 2006. V. 32. P. 579–598.
  40. Erofeeva K.G., Samsonov A.V., Larionov A.N. et al. Buried Paleoproterozoic orogen of the East European Craton: Age and origin of the Vyatka terrane // Gondw. Res. 2024. V. 129. P. 53–74. https://doi.org/10.1016/j.gr.2023.12.009
  41. Fonarev V.I., Konilov A.N. Pulsating evolution of metamorphism in granulite terrains: Kolvitsa meta-anorthosite massif, Kolvitsa Belt, Northeast Baltic Shield // Inter. Geol. Rev. 2005. V. 47. P. 815–850. https://doi.org/10.2747/0020-6814.47.8.815
  42. François C., Pubellier M., Robert C. et al. Temporal and spatial evolution of orogens: A guide for geological mapping // Episodes. 2022. V. 45. № 3. P. 265–283. https://doi.org/10.18814/epiiugs/2021/021025
  43. Frisch T., Jackson G.D., Glebovitsky V.A. et al. U-Pb ages of zircon from the Kolvitsa gabbro-anorthosite complex, southern Kola peninsula, Russia // Petrology. 1995. V. 3. P. 219–225.
  44. Glebovitsky V., Marker M., Alexejev N. et al. Age, evolution and regional setting of the Palaeoproterozoic Umba igneous suite in the Kolvitsa-Umba zone, Kola Peninsula: Constraints from new geological, geochemical and U-Pb zircon data // Precam. Res. 2001. V. 105. P. 247–267. https://doi.org/10.1016/S0301-9268(00)00114-5
  45. Goldstein S.J., Jacobsen S.B. Nd and Sr isotopic systematics of river water suspended material: implications for crustal evolution // Earth Planet. Sci. Lett. 1988. V. 87. P. 249–265.
  46. Jacobsen S.B., Wasserburg G.J. Sm-Nd isotopic evolution of chondrites and achondrites, II // Earth Planet. Sci. Lett. 1984. V. 67. № 2. P. 137–150.
  47. Jensen L.S. A new cation plot for classifying subalkalic volcanic rocks. Ontario Department of Mines, Miscellaneous Paper. 1976. V. 66. 22 p.
  48. Konopelko D., Savatenkov V., Glebovitsky V. et al. Nd isotope variation across the Archaean–Proterozoic boundary in the North Ladoga Area, Russian Karelia // GFF. 2005. V. 127. № 2. P. 115–122. https://doi.org/10.1080/11035890501272115
  49. Kusky T., Windley B., Safonova I. et al. Recognition of Ocean Plate Stratigraphy in accretionary orogens through Earth history: A record of 3.8 billion years of sea floor spreading, subduction, and accretion // Gondw. Res. 2013. V. 24. P. 501–547. https://doi.org/10.1016/j.gr.2013.01.004
  50. Lahtinen R., Huhma H. A revised geodynamic model for the Lapland-Kola Orogen // Precam. Res. 2019. V. 330. P. 1–19. https://doi.org/10.1016/j.precamres.2019.04.022
  51. Le Bas M.J., Le Maitre R.W., Streckeisen A., Zanettin B. A chemical classification of volcanic rocks based on the total alkali-silica diagram // J. Petrol. 1986. V. 27. № 3. P. 745–750.
  52. Murphy J.B. Arc magmatism II: Geochemical and isotopic characteristics // J. Geol. Assoc. Can. 2007. V. 34. P. 7–35.
  53. Pearce J.A., Ernst R.E., Peate D.W., Rogers C. LIP printing: Use of immobile element proxies to characterize Large Igneous Provinces in the geologic record // Lithos. 2021. V. 392–393. P. 106068
  54. Safonova I., Santosh M. Accretionary complexes in the Asia-Pacific region: Tracing archives of ocean plate stratigraphy and tracking mantle plumes // Gondw. Res. 2014. V. 25. P. 126–158. https://doi.org/10.1016/j.gr.2012.10.008
  55. Stepanova A., Stepanov V., Larionov A. et al. Relics of Palaeoproterozoic LIPs in the Belomorian Province, Eastern Fennoscandian Shield: Barcode reconstruction for a deeply eroded collisional orogeny // Eds. R.K. Srivastava, R.E. Ernst, K.L. Buchan, and M. De Kock. Large Igneous Provinces and their Plumbing Systems. Geol. Soc. London, Spec. Publ. 2022. V. 518. https://doi.org/10.1144/SP518-2021-30
  56. Thirlwall M.F. Long-term reproducibility of multicollector Sr and Nd isotope ratio analysis // Chem. Geol. 1991. V. 94. № 2. P. 85–104. https://doi.org/10.1016/0168-9622(91)90002-E
  57. Vermeesch P. IsoplotR: a free and open toolbox for geochronology // Geosci. Front. 2018. V. 9. P. 1479–1493. https://doi.org/10.1016/j.gsf.2018.04.001.
  58. Villa I.M., De Bièvre P., Holden N.E., Renne P.R. IUPAC-IUGS recommendation on the half life of 87Rb // Geochim. Cosmochim. Acta. 2015. V. 164. P. 382–385.
  59. Warr L.N. IMA-CNMNC approved mineral symbols // Mineral. Mag. 2021. V. 85. P. 291–320. https://doi.org/10.1180/mgm.2021.43
  60. Wedepohl K.H., Hartmann G. The composition of the primitive upper Earth’s mantle, kimberlites, related rocks and mantle xenoliths // Eds. H.O.A. Meyer, O.H. Leonardos. Companhia de Pesquisa de Recursos Minerais. 1994. V. 1. P. 486–495.
  61. Wilcox R.R. Applying Contemporary Statistical Techniques / Rank-based and nonparametric methods San Diego; London; Burlington: Academic Press, 2003. P. 557–608.

Arquivos suplementares

Arquivos suplementares
Ação
1. JATS XML
Baixar
2. Fig. 1. Geological position of the study objects. (a) Tectonic zoning of the Fennoscandian Shield (Bogdanova et al., 2016). LCO – Lapland-Kola Orogen. (b) Scheme of the geological structure of the Kandalaksha-Kolvitsa-Umba segment of the LCO (Balagansky, 2002). Umba block: 1 – enderbites and charnockites of the Umba granitoid complex, 1.91–1.94 Ga; 2 – aluminous gneisses with sillimanite and felsic granulites, 1.94–2.1 Ga; Kolvitsa block: 3 – gabbro-anorthosites, 2.45–2.46 Ga; 4 – amphibolites of the Kandalaksha formation, 2.47 Ga; 5 – basic and intermediate granulites; 6 – granite gneisses, 2.7 Ga; 7 – granulite mélange of Porya Bay; 8 – faults; 9 – thrusts. (c) Schematic geological map of the Porya Bay area (Balagansky, 2002). 1 – metasedimentary rocks of the Umba block, 1.94–2.10 Ga; 2–7 – Kolvitsky volcano-plutonic complex: 2 – basic granulites with calciphyre interlayers; 3 – basic granulites; 4 – garnet-amphibole orthogneisses of intermediate composition of the Kandalaksha formation, 2.47 Ga; 5 – garnet amphibolites of the Kandalaksha formation, 2.47 Ga; 6 – basic granulites; 7 – gabbro-anorthosites of the Kolvitsky massif, 2.45–2.46 Ga; 8–13 – granulites of the mélange zone: 8 – banded leucocratic and mesocratic basic granulites, 9 – melanocratic basic granulites, 10 – garnet-bearing granulites, 11 – alternation of basic and intermediate (Kolwitz) granulites after charnockites and enderbites of the Umbina complex, 12 – alternation of aluminous gneisses, acid granulites and melanocratic basic granulites, 13 – leucocratic intermediate granulites (presumably strongly foliated charnockites and enderbites of the Umbina complex) with interlayers of basic (Kolwitz) granulites; 14 – Neoarchean migmatized granite gneisses (basic and intermediate granulites), basite dikes (basic granulites); 15 – main thrust faults established (a) and inferred (b); 16 – thrusts established (a) and assumed (b).

Baixar (89KB)
Metadados
3. Fig. 2. (a) Scheme of the geological structure of Ozerchanka Island. (b–d) Photographs of outcrops on Ozerchanka Island: (b) banded (Grt)-Cpx-Opx gneisses with thin interlayers of mafic granulites; (c) boudins and lenses of mafic granulites in (Grt)-Cpx-Opx gneisses; (d) sheeted body of early gneissic granites cutting the gneissicity of (Grt)-Cpx-Opx gneisses and tectonized bodies of mafic granulites. (e–g) Micrographs of rocks on Ozerchanka Island: (e) fine-grained gray (Grt)-Cpx-Opx gneisses (sample UM1-1); (e) medium-grained two-pyroxene mafic granulites (amphibolites) (sample UM1-14); (g) Grt-Cpx-Opx granulites (sample UM1-22) from a thick interlayer in (Grt)-Cpx-Opx gneisses. Mineral abbreviations are given after (Warr, 2021).

Baixar (155KB)
Metadados
4. Fig. 3. (a) Scheme of the geological structure of Paleny Island (Bushmin et al., 2009, 2020). 1 – Opx and Grt-Cpx-Opx mafic granulites and gneisses; 2 – Grt-bearing mafic granulites and Cpx-Opx gneisses; 3 – Qz-rich rocks and Qz blastomylonites with different contents of Sil, Opx, Grt, Crd, Bt, Spl, Spr; 4 – Opx-Grt rocks with variable contents of Sil, Qz, Crd, Bt; 5 – diopside rocks with scapolite; 6 – rocks for which U-Pb dating of zircon was previously carried out (Bushmin et al., 2009); 7 – rock bedding elements. (b–d) Photographs of outcrops on Paleny Island: (b) banded Grt-Cpx-Opx gneisses with ochre and rusty color zones; (c) vein of post-tectonic granite pegmatites cutting granulites; (d) banded texture of Grt-Cpx-Opx gneisses. (e–g) Micrographs of rock varieties on Paleny Island: (e) Grt-Cpx-Opx gneisses (sample UM2-7); (e) Grt Grt-Cpx-Opx gneisses (sample UM2-1); (g) Bt-Amp gneisses with high pyrite and ilmenite contents (sample UM2-4).

Baixar (150KB)
Metadados
5. Fig. 4. Features of distribution of major and rare elements in rocks of Porya Guba islands. (a) TAS classification diagram after (Le Bas et al., 1986); (b) classification diagram after (Jensen, 1976), ISH – calc-alkaline series; (c) variations in contents of petrogenic elements relative to SiO2; (d, e) distribution spectra of lithophile elements in rocks of Ozerchanka Island (d) and Paleny Island (d), normalized to the primitive mantle (PM) after (Wedepohl, Hartmann, 1994).

Baixar (105KB)
Metadados
6. Fig. 5. (a, b) Cathodoluminescence images and scheme of the internal structure of zircon grains and (c, d) distribution spectra of U-Th-Pb age of zircon from samples of (Grt)-Cpx-Opx gneisses of Ozerchanka Island.

Baixar (67KB)
Metadados
7. Fig. 6. (a, d, f) Cathodoluminescence images of grains, (b, d, h) U-Th-Pb age distribution spectra and (c, f, i) concordia diagrams for zircon from the Grt-Cpx-Opx gneisses of Paleny Island: (a–c) sample UM2-1, (d–f) sample UM2-9, (g–i) sample UM2-11.

Baixar (98KB)
Metadados
8. Fig. 7. εNd–T diagram for rocks of the southeastern part of LKO. Data for rocks of the Kolvitsky and Umbinsky blocks are according to (Balagansky et al., 1998). The field shows the region of Nd isotopic compositions of the Archean crust of the Kolvitsky block. The evolution line of the isotopic composition of the depleted mantle is calculated according to (Goldstein, Jacobsen, 1988).

Baixar (27KB)
Metadados
9. Fig. 8. Comparison of metamorphic parameters and P–T trends for gneisses, Ozerchanka Island with literature data for the Lapland–Kola Orogen. (a) P–T trends of metamorphism: 1 – for Grt-Cpx-Opx gneisses, Ozerchanka Island, where I – peak of granulite metamorphism (see Fig. 8b), II – retrograde stage (see Fig. 8c); 2 – Grt-Opx gneisses, Shombach Cape (Azimov, Bushmin, 2009); 3 – paragneisses, Umbina block (Glebovitsky et al., 2009); 4 – gabbro-anorthosites, Kolvitsky block (Glebovitsky et al., 2009); 5 – P–T trend of metamorphic and metasomatic transformations of two-pyroxene crystalline schists of Ozerchanka Island. Paleny, Poryegubsky cover (Lebedeva et al., 2012). (b, c) – TWQ (Grt + Opx + Bt + Pl + Qz) diagrams for the peak of granulite metamorphism (I) and the retrograde stage (II) of gneisses of Ozerchanka Island.

Baixar (57KB)
Metadados
10. Representative analyses (SEM) of mineral compositions from the studied rocks of Ozerchanka Island
Baixar (29KB)
Metadados
11. Chemical composition of granulites of Ozerchanka and Paleny islands
Baixar (24KB)
Metadados
12. Cathodoluminescence images of zircon grains from granulites of Ozerchanka and Paleny islands
Baixar (41MB)
Metadados
13. Results of U-Th-Pb dating of zircon (LA-ICP-MS) from granulites of Ozerchanka and Paleny islands
Baixar (82KB)
Metadados

Declaração de direitos autorais © Russian academy of sciences, 2025