The microfossils examined in acritarchs from the Neoproterozoic rocks in the southern margin of the Siberian craton have been ecobiologically interpreted. The studied sequences are of particular interest as they represent different sedimentation stages of an evolving marine basin. The conditions of sedimentation were reconstructed and the microfossil assemblages were recognized in three areas of the Sayany-Baikal fold system SBFS. The ecological and biological affiliation of a part of the organic-walled microfossil morphotypes was revealed owing to the reconstructions and actuopaleontological comparison. Members of green and brown algae, dinoflagellates, and bacteria assemblages from different depths of the paleobasin have been differentiated. Most of organic-walled forms from the SBFS have the property of retaining volume and characters in fossil remains. A modified variant of the acritarch classification is proposed considering this capacity and in an effort to develop in the future a natural classification scheme.
Neoproterozoic, Siberian craton, sedimentation conditions, microfossils, acritarchs, algae, bacteria, classification.
1. Akhmedov, Dokl. Akad. Nauk, v. 372, no. 5, 2000.
2. Andrejeva, Soil and Aerophilous Green Algae Chlorophyta: Tetrasporales, Chlorococcales, Chlorosarcinales, 1998.
3. Bozhko, Bull. Mosk. Obshch. Ispyt. Prirody, Otd. Geol., v. 74, no. 6, 1999.
4. Bruck, Sporopollenin Role in Palynology, The Report of Researches, British Petroleum Corporation, 1973.
5. Buldygerov, Geol. Geofiz., v. 29, no. 3, 1988.
6. Bulgatov, Tectonotype of Baikalids, 1983.
7. Burzin, Paleontol. Zhur., v. 2, 1997.
8. Butterfield, Fossils and Strata, v. 34, 1994.
9. Dobretsov, Geodynamic Map of Transbaikalia, 1991.
10. Dol'nik, Stromatolites and Microphytoliths in the Riphean and Vendian Stratigraphy of the Folded Framing of the Southern Siberian Platform, 2000.
11. Dol'nik, Reference Nodes of the Late Precambrian Unified Scheme of Central Siberia, 1980.
12. Domyshev, Riphean Basites of the Baikal--Sayany--Enisei Marginal Framing of the Siberian Platform, 1976.
13. Dott, J. Sediment. Petrol., v. 3, 1982.
14. Downie, Stanford Univer. Publ. in Geol. Sci., v. 7, 1963.
15. Dubin, Lower Cambrian and Upper Precambrian Stratigraphy of the Southern Siberian Platform, 1969.
16. Evitt, Proc. Natl. Acad. Sci. U.S.A., v. 49, no. 2, 1963.
17. Faizullin, Geol. Geofiz., v. 39, no. 3, 1998.
18. Fedorovskii, Lower Proterozoic of the Baikal Mountain Region, 1985.
19. Fombella, Rev. Espanola Micropaleontol., v. 9, 1977.
20. Golovenok, Dokl. Acad. Nauk SSSR, v. 272, no. 6, 1983.
21. Golovenok, Regional. Geol. i Metallogeniya, v. 4, 1995.
22. Golubic, J. Paleontol., v. 50, no. 6, 1976.
23. Gorlenko, Course of Lower Plants, 1981.
24. Gusev, Geotektonics, v. 25, no. 2, 1992.
25. Hofmann, Earth's Earliest Biosphere, 1983.
26. Horodyski, Precambrian Res., v. 61, 1993.
27. Hoult, Bacteria Guidebook by Berdji, vol. 2, 1997.
28. Jankauskas, Riphean Stratotype, Paleontology, Paleomagnetism, Transactions Geol. Inst. Russ. Acad. Sci., vol. 368, 1982.
29. Jankauskas, Precambrian Microfossils of the SSSR, 1989.
30. Kalina, Arch. Hydrobiol., Algological Studies 45, v. Suppl. Bd. 73, no. 4, 1987.
31. Kennett, Marine Geology, vol. 2, 1987.
32. Khabarov, Geol. Geofiz., v. 40, no. 8, 1999.
33. Khomentovsky, Geol. Geofiz., v. 39, no. 11, 1998.
34. Khomentovsky, Geol. Geofiz., v. 26, no. 7, 1985.
35. Khomentovsky, Upper Precambrian and Lower Cambrian Reference Sections in the Southern Margin of the Siberian Platform, 1972.
36. Kir'yanov, Silurian Acritarchs from the Volyno--Podolian Region, 1978.
37. Kir'yanov, Topical Issues of Modern Paleoalgology, 1986.
38. Knoll, J. Paleontol., v. 65, no. 4, 1991.
39. Konnikov, Geol. Geofiz., v. 35, no. 7--8, 1994.
40. Korobeinikov, Late Precambrian carbonaceous formations of the Western Baikal Region and Baikal--Patomskoe Upland, 1990.
41. Kovalenko, Geol. Geofiz., v. 36, no. 12, 1995.
42. Kuznetsov, Introduction to Geological Microbiology, 1962.
43. Levitskii, Dokl. Akad. Nauk SSSR, v. 288, no. 2, 1986.
44. Martin, Biol. Rev., v. 68, 1993.
45. Meien, Principles of Paleobotany, Reference Book, 1987.
46. Mikhailova, Izv. Akad. Nauk SSSR, Ser. Geol., v. 23, no. 9, 1987.
47. Mitrofanov, Late Precambrian and Early Paleozoic in the Central Part of the Baikal mountain region, 1978.
48. Moczydlowska, Palaeontology, v. 36, no. 3, 1993.
49. Moorman, J. Paleontol., v. 48, no. 3, 1974.
50. Nemerov, Dokl. Akad. Nauk SSSR, v. 298, no. 6, 1988.
51. Nemerov, Geol. Geofiz., v. 42, no. 3, 2001.
52. Pashkyavichene, Acritarchs from the Vendian--Cambrian Boundary Sediments of the Western East European Platform, 1980.
53. Perevalov, Precambrian Stratigraphy of Central Siberia, 1983.
54. Pyatiletov, Late Precambrian and Early Paleozoic Stratigraphy of Central Siberia, 1983.
55. Pyatiletov, Late Precambrian and Early Paleozoic of Siberia, Riphean and Vendian, 1988.
56. Reding, Depositional Environments and Facies, 2 vol., v. 1, 1990.
57. Ruchnov, Systematics, Evolution, Ecology of Algae and Their Significance for Practical Geological Research, 1981.
58. Rytsk, Tectonics, Geodynamics, and Magmatic and Metamorphic Processes, Proceedings of XXXII Tectonic Conference, vol. 1, 1999.
59. Rytsk, Isotope Dating of Geologic Processes: New Methods and Results, Proceedings of I Russian Conference on Isotopic Geochronology, 2000.
60. Rytsk, Stratigr. Geol. Korrelyatsiya, v. 9, no. 4, 2001.
61. Salop, Geology of Baikal Mountain Region, vol. 1, 1964.
62. Schlegel, General Microbiology, 1987.
63. Schopf, Earth's Earliest Biosphere, Its Origin and Evolution, 1983.
64. Semikhatov, General Issues of Precambrian Subdivision in the USSR, Proceedings of II All-Union Conference, 1990.
65. Semikhatov, Stratigr. Geol. Korrelyatsiya, v. 7, no. 5, 1999.
66. Sergejev, Precambrian and Cambrian Silicified Microfossils of the Urals and Central Asia, 1992.
67. Sergejev, Precambrian silicified microfossils: Nature, classification, facies confinement, and biostratigraphic significance, 2003.
68. Shenfil', Late Precambrian of the Siberian Platform, 1991.
69. Sklyarov, Precambrian Res., v. 119, 2003.
70. South, Basics of Algology, 1990.
71. Stanevich, Late Precambrian and Early Paleozoic of Siberia, Stratigraphy and Paleontology, 1986.
72. Stanevich, Riphean of Northern Eurasia, Geology, General Problems of Stratigraphy, 1997.
73. Stanevich, Proceedings of SPIE, vol. 4939, Instruments, Methods and Missions for Astrobiology VI, 2003.
74. Stanevich, Microfossils in Late Precambrian Stratigraphy of the Baikal--Patomskaya Mountain Region, 1992.
75. Stanevich, Geol. Geofiz., v. 38, no. 10, 1997.
76. Stanevich, Topical Problems of Palynology at the Third Millennium Boundary, 1999.
77. Stanevich, Late Precambrian and Early Paleozoic of Siberia, Issues of Regional Stratigraphy, 1990.
78. Stepanov, General Stratigraphy Principles and Methods of Stratigraphic Research, 1979.
79. Tappan, The Paleobiology of Plant Protists, 1980.
80. Tappan, Earth Sci. Rev., v. 9, 1973.
81. Tasch, Paleobiology of the Invertebrates, 1973.
82. Timofejev, Micropaleophytological Studies of Ancient Formations, 1966.
83. Timofejev, Precambrian and Early Cambrian Paleontology, 1979.
84. Tsarenko, Short Guidebook of Chlorococcal Algae of Ukrainian SSR, 1990.
85. Van den Hoek, Algae, An Introduction to Phycology, 1995.
86. Vasser, Algae, Reference Book, 1989.
87. Veis, Izv. Akad. Nauk SSSR, Ser. Geol., v. 5, 1988.
88. Vidal, Fossils and Strata, v. 9, 1976.
89. Vinkler, Genesis of Metamorphic Rocks, 1979.
90. Volkova, Paleontol. Zhur., v. 1, 1965.
91. Walker, Facies Models: Response to Sea Level Change, Geol. Association of Canada, edited by R. G. Walker, N. P. James, 1992.
