Biostratigraphy of plant macrofossils of Hojedk Formation in the Chah-Rekhneh area, south-west Tabas and its palaeoclimate analysis

Document Type : Original Article

Authors

1 Department of Stratigraphy and paleontology, College of Science, University of Ferdowsi, Mashhad, Iran

2 Department of Stratigraphy and paleontology, School of Geology, College of Science, University of Tehran, Tehran, Iran

3 Department of Geology, College of Science, University of Ferdowsi, Mashhad, Iran

Abstract

Introduction
Early and Middle Jurassic, continental sediments of considerable thickness are widespread in the
northern, central, and central-eastern Iran (Kilpper, 1964, 1968, 1971; Barnard and Miller, 1976;
Sadovnikov, 1976, 1984, 1991; Corsin and Stampfli, 1977; Fakhr, 1977; Schweitzer and Kirchner, 1995,
1996, 1998, 2003; Schweitzer et al, 1997, 2000, 2009; Vaez-Javadi and Pour-Latifi, 2004; Vaez-Javadi;
Mirzaei-Ataabadi, 2006; Vaez-Javadi, 2008, 2011, 2012, 2014, 2015a, b, 2018; Saadatnejad et al, 2010;
Vaez-Javadi and Abbasi, 2012, 2018; Vaez-Javadi and Allameh, 2015). For a more detailed study, plant
macrofossils from Chah-Rekhneh were considered here.
Materials and Methods
The plant fossils have been driven from a borehole in Chah-Rekhneh, 62km of SW Tabas city,
33˚17´56ʺ North latitude, 56˚24´01ʺ East longitude. A total of 84 specimens have been collected from
a 240 m stratigraphic-core section. Some specimens yielded more than one fossil. The flora from this
locality here is introduced for the first time. Material cited in this work (prefixed MJHCh; acronym for
Mehdizadeh, Javadi, Hojedk, and Chah-Rekhneh) is held in the collection of the Palaeobotany
Laboratory of the Department of Geology at the University of Ferdowsi, Mashhad.
Results and Discussion
Biostratigraphy of the Chah-Rekhneh
The Hojedk Formation consists of shale, siltstone, and fine-sandy silt alternating with thick mediumgrained
sandstone at the base of column. Several coal seams are present at the middle and upper part of
the core column. One assemblage biozone was established in this section with lower and upper
boundaries identified by FOO (First Observed Occurrence) and LOO (Last Observed Occurrence) of
Coniopteris hymenophylloides and Klukia exilis, respectively. Furthermore, three informal subzones
were recognized which are upward: I- Equisetites beanii- Ptilophyllum harrisianum Interval zone; IIPtilophyllum
harrisianum- Elatides thomasii Interval zone, III- Elatides thomasii - Nilssonia
macrophylla Interval zone.
Palaeoclimate Analysis
In order to recognize palaeoclimate of the Chah-Rekhneh area during the Middle Jurassic, plant
macrofossils relative abundance analysis and floral gradient method were used.
Ziegler et al. (1996) assigned all Jurassic leaf genera to ten coarser morphological categories (or
'morphocats'). Rees et al. (2000) explained "Floral gradient" analysis. They show how this analysis can
be used to interpret phytogeographic patterns based on the axis 1 scores of individual leaf genera and
corresponding plant localities, due to their relative degrees of association. Then the climatical
distribution in terms of the basic morphological characteristics of individual leaf genera and the
palaeogeographic distribution of plant localities can be understood. By calculating the average of the
scaled (0 to 100) axis 1 scores of the 32 genera common to all three intervals, a Jurassic 'floral gradient'
has been derived. Floral gradient score of this flora in Chah-Rekhneh is 41.81. It shows that the flora
assigned to the middle part of Floral Gradient table and suggests a humid and sub-tropical climate
during early Middle Jurassic.
Conclusion
The Hojedk Formation in the Chah-Rekhneh area, south west Tabas contains 33 plant macrofossil
species (21 genera) of various orders. On the basis of FOO and LOO of index species, one assemblage
zone- Coniopteris hymenophylloides-Klukia exilis Assemblage zone and three informal subzones were
recognized. These subzones are upward: I- Equisetites beanii- Ptilophyllum harrisianum Interval zone,
II- Ptilophyllum harrisianum- Elatides thomasii Interval zone, and III- Elatides thomasii - Nilssonia
macrophylla Interval zone. The occurrence of index fossils such as Klukia exilix and Elatides thomasii,
Aalenian-Bajocian are assigned for this assemblage. Statistical analysis studies reveal that Order
Filicales, Cycadales, Pinales and Equisetales with relative abundance of 46.31%, 23.50%, 12% and
9.26%, and Nilssonia, Klukia, Coniopteris and Equisetites were the most abundant genera with 22.81%,
13.38%, 8.40% and 8.40%, respectively in the Chah-Rekhneh area. Therefore, based on relative
abundance of Filicales and Cycadales, the occurrence of Equisetites beanii as index species of climatic
and ecologic, and average floral gradient score (41.81), a humid sub-tropical palaeoclimate was
dominant in this area during the Aalenian-Bajocian interval.

Keywords

References

  1. -آقا نباتی، س.ع.، 1377. چینه‌شناسی ژوراسیک ایران، جلد اول، انتشارات سازمان زمین‌شناسی ایران، تهران، 355 ص.
  2. -آقا نباتی، س.ع.، 1383. زمین‎شناسی ایران، سازمان زمین‎شناسی و اکتشافات معدنی کشور، تهران، 586 ص.
  3. -سعادت نژاد، ج.، قادری، ع. و نعیمی قصابیان، ن.، 1388. مطالعه و معرفی ماکروفسیل های گیاهی توآرسین- باژوسین منطقه گراخک-شاندیز، شمال خاور ایران، رخساره‌های رسوبی، شماره 2، ص 173- 203.
  4. -مهدیزاده، ا.، واعظ جوادی، ف.، عاشوری، ع. و قادری، ع.، 1395. مطالعه و معرفی ماکروفسیل‌ های گیاهی سازند هجدک در چاه شماره یک منطقه کالشور، جنوب‌غرب طبس، مجموعه مقالات یازدهمین همایش انجمن دیرینه شناسی ایران، دانشگاه پیام نور طبس، ص 120-126.
  5. -مهدیزاده، ا.، 1397. زیست چینه‌نگاری و تحلیل تطبیقی ماکروفسیل های گیاهی ژوراسیک میانی منطقه طبس و یزد و تهیه نقشه پراکنش پوشش گیاهی دیرینه، رساله دکتری در چینه‌شناسی و فسیل‌شناسی، دانشگاه فردوسی مشهد، 225 ص.
  6. -واعظ جوادی، ف.، 1387. ماکروفسیل های گیاهی ایران، انتشارات سازمان حفاظت محیط زیست، تهران، 236 ص.
  7. -واعظ جوادى، ف.، 1391الف. ماکروفسیل هاى گیاهى منطقه تیار جنوب آمل، تعیین سن و تطابق آن با سایر افق‌هاى گیاهى ایران، نشریه علوم زمین سازمان زمین‌شناسى کشور، شماره 83، ص 229-237.
  8. -واعظ جوادى، ف.، 1391ب. معرفی ماکروفسیل های گیاهی منطقه جعفرآباد، غرب طبس و تفسیر آب و هوای دیرینه آن، پژوهش‌هاى چینه‌نگارى و رسوب‌شناسى، شماره 51، ص 67-86.
  9. -واعظ جوادى، ف.، 1391ج. بیوستراتیگرافى سازند نایبند در منطقه معادن زغالسنگ پروده طبس بر مبناى ماکروفسیل هاى گیاهى، پژوهش‌هاى چینه-نگارى و رسوب‌شناسى، شماره 46، ص 113-143.
  10. -واعظ جوادى، ف.، 1394. معرفى ماکروفسیل هاى گیاهى و زیست چینه‌نگاری برش کالشانه، شمال غرب طبس و تحلیل آب و هوای دیرینه، پژوهش-هاى چینه‌نگارى و رسوب‌شناسى، شماره 61، ص 105-123.
  11. -واعظ جوادى، ف. و پورلطیفی، ع.، 1383. معرفى چند ماکروفسیل گیاهى از گلمکان، شمال خاورى ایران، نشریه علوم زمین سازمان زمین‌شناسى کشور، شماره 52، ص 98-107.
  12. -واعظ جوادى، ف. و عباسى، ن.، 1391. معرفى ماکروفسیل هاى گیاهى منطقه بلده (البرز مرکزى)، تعیین سن و بیوستراتیگرافى آنها، پژوهش‌هاى چینه‌نگارى و رسوب‌شناسى، شماره 48، ص 37-64.
  13. -واعظ جوادی، ف. و نامجو، ش.، 1394. زیست چینه‌نگارى سازند هجدک در کوچکعلى شمالى، باختر طبس و تحلیل آب و هوای دیرینه و تطابق با سایر فلوریزون هاى هم‌ارز ایران، دیرینه‌شناسی، شماره 3، ص 220-243.
  14.  
  15.  
  16. -Alavi, M. and Barale, G., 1970. Étude prèliminaire de la flore de le formation de Shemshak dans la region de Djam: Bulletin de la Societe Linnean de Lyon, v. 8, p. 241-252.
  17. -Assereto, R., 1966. The Jurassic Shemshak Formation in Central Elburz (Iran): Rivista Italiana di Paleontologia e Stratigrafia, v. 4, p. 1133-1182.
  18. -Barnard, P.D.W., 1965. Flora of the Schemshak Formation Part2. Liassic Plants from Dorud: Rivista Italiana di Paleontologia e Stratigrafia, v. 4, p. 1123-1168.
  19. -Beckett, P.H., 1956. Coal deposits near Kerman, South Persia: Economic Geology, v. 51, p. 197-198.
  20. -Brongniart, A., 1828-1837. Histoire des vegetaux fossils, ou recherches botaniques et geologiqes sur les vegetaux renfermes dans les diverses couches du globe: Paris, 72 p.
  21. -Corsin, P. and Stampfli, G., 1977. La formation de Shemshak dans l’Elburz oriental (Iran) flore –stratigraphie– paleogeographie: Geobios, v. 10, p. 509-571.
  22. -Fakhr, M.S., 1977. Contribution a l'etude de la flore Rheto- Liasique de la formation de Shemshak de l'Elbourz (Iran), Paris: Memoire de Section de Science, v. 5, 178 p.
  23. -Fürsich, F.T., Wilmsen, M. and Seyed-Emami, K., 2009. Lithostratigraphy of the Upper Triassic- Middle Jurassic Shemshak Group of northern Iran: Geological Society London, v. 312, p. 120-160.
  24. -Harris, T.M., 1961. The Yorkshire Jurassic flora, I. Thallophyta- pteridophyta: British Museum (Natural History), London, 212 p.
  25. -Jacob, K. and Shukla, B.N., 1955. Jurassic plants from the Saighan series of North Afghanistan and their palaeo-climatological and palaeo-geographical significance, India: Memoirs of the Geological Survey of India, Palaeontographica Indica, new series, v. 2, p. 1-64.
  26. -Kilpper, K., 1964. Über eine Rhät/Lias-Flora aus dem nordlichen Abfall des Alburs-Gebirges in Nordiran, I. Bryophyta und Pteridophyta, Stuttgart: Palaeontographica B, v. 114, p. 1-78.
  27. -Phillips, J., 1875. Illustrations of the geology of Yorkshire, or a description of the strata and organic remains, Part I. The Yorkshire Coast, 3rd. Edit. Edited by Etheridge, London, 354 p.
  28. -Sadovnikov, G., 1976. The Mesozoic flora of Alborz and central Iran and its stratigraphic importance: National Iran Steel Company of Iran, Tehran, 118 p.
  29. -Sadovnikov, G.N., 1991. On some gymnosperms from the late Triassic of North Iran: Paleontological Journal, v. 4, p. 95-106.
  30. -Scanu, G.G., Kustatscher, E. and Pittau, P., 2015. The Jurassic flora of Sardinia - A new piece in the palaeobiogeographic puzzle of the Middle Jurassic: Review of Palaeobotany and Palynology, v. 218, p. 80-105.
  31. -Schweitzer, H.J. and Kirchner, M., 1996. Die rhäto-jurassischen Floren des Iran und Afghanistans: Palaeontographica B, v. 238, p. 77-139.
  32. -Schweitzer, H.J., Van Konijnenburg-van Cittert, J.H.A. and van der Burgh, J., 1997. Die Rhaeto-Jurassic Flora of Iran and Afghanistan, 10. Bryophyta, Lycophyta, Sphenophyta, Pterophyta-Eusporangiatae and protoleptosporangiatae: Paleontographica B, v. 243, p. 103-192.
  33. -Schweitzer, H.J., Kirchner, M. and Van-Konijnenburg-Van Cittert, J.H.A., 2000. The Rhaeto-Jurassic flora of Iran and Afghanistan, 12. Cycadophyta II. Nilssoniales: Paleontographica B, v. 279, p. 1-108.
  34. -Schweitzer, H.J. and Kirchner, M., 2003. Die rhato-jurassischen Flora des Iran und Afghanistan 13. Cycadophyta. III.Bennettitales: Paleontographica B, v. 264, p. 1-166.
  35. -Schweitzer, H.J., Schweitzer, U., Kirchner, M., Van Konijnenburg-van Cittert, J.H.A. and Ashraf, R.A., 2009. The Rhaeto-Jurassic flora of Iran and Afghanistan, 14. Pterophyta, Leptosporangiatae: Palaeontographica B, v. 279, p. 1-108.
  36. -Takhtajan, A.L., 2013. Higher Taxa of Vascular Plants except Flowering: Takhtajania, Тахтаджяния, v. 2, p. 4-8.
  37. -Tipper, G.H., 1921. The geology and mineral resources of eastern Persia: Record of Geological Survey of India, v. 1, p. 51-80.
  38. -Vaez Javadi, F., 2004. Persicostrobus Vaez-Javadi n. gen. a new Equisetalean strobilus from the Triassic of Iran: Rivista Italina di Paleontologia e Stratigrafia, v. 3, p. 715- 718.
  39. -Vaez-Javadi, F., 2011. Middle Jurassic flora from the Dansirit Formation of the Shemshak Group, Alborz, north Iran: Alcheringa, v. 1, p. 77-102.
  40. -Vaez Javadi, F., 2014. Triassic and Jurassic Floras and Climate of Central-East Iran: Geological Survey of Iran: Rahi publication, Tehran, 290 p.
  41. -Vaez Javadi, F., 2018. Middle Jurassic Flora from the Hojedk Formation of Tabas, Central East Iran: Biostratigraphy and Palaeoclimate implications: Rivista Italiana di Paleontologia e Stratigrafia, v. 124(2), p. 299-316.
  42. -Vaez-Javadi, F. and Ghavidel-Syooki, M., 2002. Plant megafossil remains from Shemshak Formation of Jajarm area, NE Alborz, Iran: Paleobotanist, v. 51, p. 57-72.
  43. -Vaez Javadi, F. and Mirzaei-Ataabadi, M., 2006. Jurassic plant macrofossils from the Hojedk Formation, Kerman area, east-central Iran: Alcheringa, v. 30, p. 63-96.
  44. -Vaez Javadi, F. and Allameh, M., 2015. Biostratigraphy of the Bazehowz Formation at its Type section, South West Mashhad based on plant macrofossils: Geopersia, v. 1, p. 27-44.
  45. Vaez-Javadi, F. and Abbasi, N., 2018. Middle Jurassic biostratigraphy of plant macro and microfossils in Soltanieh Mountains, South of Zanjan, nw Iran. Geosciences, v.106, p. 91-102.
  46. -Vakhrameev, V.A., 1991. Jurassic and Cretaceous floras and climates of the Earth: Cambridge University Press: Great Britain, 318 p.
  47. -Vassiliev, Y., 1984. Mesozoic plant fossils from coal areas in Iran: Atlas of the Ministry of Mine and Metal, v. 2, 97 p.
  48. -Wilmsen, M., Fürsich, F.T. and Taheri, J., 2009. The Shemshak Group (Lower-Middle Jurassic) of the Binalud Mountains, NE Iran, Stratigraphy, depositional environments and geodynamic implications: Geological Society of London, v. 312, p. 175-188.
  49. -Ziegler, A.F., Parrish, J.M., Jiping, Y., Gyllenhaal, E.D., Rowley, D.B., Parrish, J.T., Shangyou, N., Bekker, A. and Hulver, M.I., 1993. Early Mesozoic phytogeography and climate, In: Allen, J.R.L., Hoskins, B.J., Sellwood, B.W., Spicer, R.A. and Valdes, P.J., 1297. Palaeo climates and their modelling: Philosophical Transactions of the Royal Society of London, v. 341, p. 297-305.
  50. -Ziegler, A.M., Rees, P.M., Rowley, D.B., Bekker, A., Quing, L. and Hulver, M.L., 1996. Messozoic assembly of Asia, Constraints from fossil floras, tectonics and paleomagnetism, 371-400. In Yin, A. and Harrison, M., (Eds.): The Tectonic Evolution of Asia: Cambridge, Cambridge University Press, p. 371-400.

Files

Share

How to cite

Statistics