Geologische Rundschau

, Volume 62, Issue 1, pp 187–197 | Cite as

Regional metamorphism in the Sini-Sonapet quadrangle Singhbhum, East India

  • S. Ray
  • S. Bhattacherya
Aufsätze

Abstract

A study of Barrovian metamorphic zones in a belt of essentially pelitic schists in Singhbhum, E. India, broadly completes the metamorphic map of the main Singhbhum anticlinorium. Isograds run parallel with the sub-horizontal fold-axes and close where the latter shows considerable plunge. The index mineral of the highest zone crystallised succeeding crystallisation of lower grade ones in their true order in that zone. A particular index mineral presumably crystallised in successive lower zones progressively in time. Intensity of metamorphism and deformation was broadly simultaneous.

Keywords

India Lower Grade Lower Zone True Order Regional Metamorphism 

Zusammenfassung

Eine Untersuchung der barrowischen metamorphen Zonen in einem Gebiet von im wesentlichen pelitischen Schiefern in Singhbhum (östliches Indien) vervollständigt die Karte vom Metamorphikum des Singhbhum-Hauptantiklinoriums. Die Isograden erstrecken sich parallel zu den subhorizontalen Faltenachsen und schließen sich, wo die Faltenachsen beträchtlich untertauchen. Leitmineralien der höchsten Zone kristallisierten zeitlich nach denen der niedrigeren Zonen. Ein bestimmtes Leitmineral kristallisierte mutmaßlich in nacheinanderfolgenden Zonen in zeitlicher Abfolge. Die Stärke der Metamorphose und der Deformation entsprachen sich weitgehend.

Résumé

Des études sur les zones métamorphiques de type barrowien, entreprises dans des schistes essentiellement pélitiques à Singhbhum, Inde orientale, complètent la carte métamorphique de l'anticlinorium principal de Singhbhum. Les isogrades sont dirigées parallèllement aux axes de plis et se ferment là où ceux-ci montrent un plongement considérable. Dans cette zone, les minéraux-index de la zone la plus élevée ont succédé à la cristallisation des minéraux de degré inférieur dans leur ordre véritable. Un minéral index particulier a probablement cristallisé, au cours du temps, dans les zones inférieures successives. L'intensité du métamorphisme et de la déformation était dans les grands traits simultanée.

Краткое содержание

Исследование породы метаморфных зон обла сти преимущественно пел итового сланца у Singhbhum, восточная И ндия, дополняет карту метаморфизма в основ ном антиклинории Singhbhum. Изоли нии проходят паралле льно к субгоризонтальным осям складок и замыка ются там, где эти оси си льно погружены. Ведущие ми нералы самой высокой зоны вы кристаллизовались п осле таковых более низких зон. Некий ведущий мин ерал выкристаллизов ался в последующих зонах в д альнейшем течении вермени. Степ ень метаморфизма и де формации совпадают.

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References

  1. Bhattacherya, D. S.: Structure of the rocks of the Sonapet velley, Singhbhum district, Bihar, India. - Bull. Geol. Mining Met. Soc. India, No. 36, 1–21, 1966.Google Scholar
  2. Chakravarti, K. R. &Sen, S. K.: Regional metamorphism of pelitic rocks around Kandra, Singhbhum, Bihar.- Contr. Mineral. Petrol.,16, 210–212, 1967.Google Scholar
  3. Clifford, T. N.: Radiometric dating in Pre-Silurian geology of Africa. - In:Hamilton, E. I. &Farquhar, R. M., Radiometric dating for geologists. - Inter Science Publishers, New York 1968, p. 305.Google Scholar
  4. Dunn, J. A.: Geology of north Singhbhum and parts of Ranchi and Manbhum. - Memoir Geol. Surv. India, 54, 1–166, 1929.Google Scholar
  5. Dunn, J. A. &Dey, A. K.: Mineral deposits of eastern Singhbhum. - Memoir Geol. Surv. India,69, pt. 1, 151, 1937.Google Scholar
  6. Griggs, D. T.,Turner, F. J. &Heard, H. C.: Deformation of rocks at 500° to 800° C. - In:Griggs, D. T. &Handin, J., Rock deformation. - Geol. Soc. America, Memoir,79, 39, 1960.Google Scholar
  7. Mitra, R.: Pelitic metamorphites around Kandra. - Quart. Jour. Geol. Mining Met. Soc. India,26, 149–168, 1954.Google Scholar
  8. Naha, K.: Time and place of progressive regional metamorphism; a study from the Precambrian of Eastern India. - Geol. Rdsch.,52, 810–818, 1962.Google Scholar
  9. —: Metamorphism in relation to stratigraphy, structure and movements in part of east Singhbhum, eastern India.- Quart. Jour. Geol. Mining Met. Soc. India,37, 41–88, 1965.Google Scholar
  10. Naha, K. &Ghosh, S. K.: Archaean palaeogeography of eastern and northern Singhbhum, eastern India. - Geol. Mag.,97, 436–439, 1960.Google Scholar
  11. Naha, K. &Roy, A. B.: Metamorphic and deformational episodes in the Precambrian of eastern and central Singhbhum, Bihar. - Publication 6, Centre of Advanced Study in Geology, Punjab University, Chandigarh, 8–15, 1969.Google Scholar
  12. Roy, A. B.: Interrelation of Metamorphism and Deformation in C. Singhbhum, E. India. - Geol. En Mijnbow,45, 365–374, 1966.Google Scholar
  13. Sarkar, S. N. &Saha, A. K.: Revision of pre-Cambrian stratigraphy and tectonics of Singhbhum and adjacent regions. - Quart. Jour. Geol. Mining Met. Soc. India,34, 105, 1962.Google Scholar
  14. -: Geochronology of the Pre-Cambrian rocks of Singhbhum and adjacent regions of eastern India. - Geol. Mag.,106, 15–45.Google Scholar
  15. Spry, Alan: Metamorphic textures. - Pergamon Press, London 1969, p. 350.Google Scholar

Copyright information

© Ferdinand Enke Verlag Stuttgart 1973

Authors and Affiliations

  • S. Ray
    • 1
  • S. Bhattacherya
    • 1
  1. 1.Geology LaboratoryPresidency CollegeCalcutta 12India

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