Coal Correlation and its Depositional Account: a Palynological Outlook

Mahesh S¹ and Pauline Sabina. K²

¹Department of Studies in Geology, University of Mysore, Karnataka, India, ^*Current Address: Birbal Sahni Institute of Palaeobotany, Uttar Pradesh, India; ²Birbal Sahni Institute of Palaeobotany, Uttar Pradesh, India

docmax@rediff.com

Palynological studies have assisted geologists in correlating formations which are lithologically difficult to correlate. Coal formations of Gondwana period are effectively correlated using Palynology as a tool. In the present case study palynostratigraphical studies have been carried out on Lower Gondwana sediments from central India. Detailed quantitative and qualitative study of Permian palynomorphs and palynodebris from these deposits was carried out for different horizons and lithology. The obtained dataset was used to correlate the Gondwana coal formations with its counterparts in India as well as South America, Africa and Antarctic region. Two boreholes and Two opencast mine localities were sampled. Samples from boreholes MGE-09, and CMWY-96 and opencast mine samples from Hindustan Lalpeth colliery (HLC) and New Majri Opencast Mine from Maharashtra, India were analyzed. The assemblage derived from each of the above mentioned localities were assigned to their corresponding age based on abundance and paucity of significant palynomorph taxa recovered. The lithological dissimilarity and their constituent organic matter provide considerable data about the role of fluvial forces trending the sedimentary basin. The Palynofacies derived from the present study sites are characterized by different components of organic matter with variable preservation giving clues to the depositional history. The spores and pollen recovered from the samples were analyzed for their degree of preservation, abundance, Thermal alteration and diversity. This enabled us to create the Sporomorph eco-group using their botanical affinity which helps in reconstruction of palaeovegetation.

Lower Cambrian Small Shelly Fossils and biostratigraphy of the Northeastern Siberian Platform (Chekurovskaya anticline)

Novozhilova N. V. ¹, Ponomarenko A. V.²

1 A.A. Trofimuk Institute of Petroleum Geology and Geophysics sb ras, Novosibirsk, Russia

NovozhilovaNV@ipgg.nsc.ru

2 Novosivirsk State University, Novosibirsk, Russia

PonomarenkoAV@ipgg.nsc.ru

The section of the western limb of Chekurosvkaya anticline is one of the best Cambrian sections on the Siberian platform, which had previously been studied by many researchers [1, 2, 3, 5]. Lower Cambrian is represented by terrigenous-carbonate rocks of Tyuserskaya and Sektenskaya Formations. Despite the fact that, the section is complicated by local dislocations and folds, sequence of layers in the section is recognizable.

In the Lower Cambrian part of section in Tommotian and Atdabanian stages has previously been found 4 biostratigraphic units in the rank of beds with SSF (small shelly fossils) similar set in the Lower Cambrian stratotype on the Lena River [4]. As a result of further treatment of material in the upper of Tyuserskaya Formation were found SSF typical for beds with Microdictyon effusum-Lenargyrion knappologicum.

In the section of the Lower Cambrian western limb Chekurovskaya anticline is set this sequence of biostratigraphic units:

Beds with Lapworthella tortuosa and Lapworthella bella. It can be attributed to layers with Lapworthella tortuosa and almost all the lower member of Tyuserskaya Formation ranging from 2,5 m from the base, 23,5 m without intrusion. Tommotiids Lapworthella tortuosa and disarticulated chancelloriids Chancelloria sp. was found here. In 1 m from the base of the middle part of member of Tyuserskaya Formation, which would be assigned to the beds with L. bella were found L. tortuosa, L. bella, Camenella kozlowskii, C. admiranda, C. gabrovskae, Sachites proboscedeus, Hyolithellus tenuis, Torellella lentiformis, Marcuela prima; in 6 and 10 m from the base was found Hyolithellus sp., Chancelloria sp. Accordingly, the thickness of beds with L. bella is not less than 10 m.

Beds with Mobergella radiolata cover the upper regional zone of Tommotian stage Dokidocyathus lenaicus, and two lower regional zones Profallotaspis jakutensis, Repinaella, and lower part of Delgadella anabara – Nevadella. These beds are characterized by fossils Lapworthella tortuosa, L. bella, Lapworthella sp., Hyolithellus vladimirovae, Hyolithellus sp., Allonia sp., Torellella lentiformis, T. biconvexa, Archiasterella tetraspina, Chancelloria sp., Ch. fragilis, Allonia rossica, Rhombicorniculum sp., Halkieria sp., Archiasterella robusta, Arch. palmiformis, Arch. tetraspina, Arch. quadriradiata, Protohertzina sp., Rhombicorniculum sp., Chancelloria sp., Monospinites sp.

Assemblages of beds with Rhombicorniculum cancellatum are characterized by findings of next SSF and mollusks: Rhombicorniculum cancellatum, Lapworthella sp., Chancelloria sp., Ch. lenaica, Hyolithellus sp., Fomitchella explicata, Allonia? simplex, Rhombicorniculum sp., Fomitchella oblata, Monospinites sp., Pelagiella adunca, Hyolithellus vladimirovae, Torellella biconvexa, Archiasterella palmiformis, Arch. robusta., Allonia sp. The beds correspond to the upper part of the regional zone Delgadella anabara – Nevadella and bigger part of the regional zone Judomia – Uktaspis of Atdabanian Stage.

Beds with Microdictyon effusum-Lenargyrion knappologicum set at 14 m from the top of Tyuserskaia Formation and cover the upper part of the regional zone Judomia - Uktaspis (Prouktaspis) of Atdabanian Stage, Botomian and Toyonian Stages of the Lower Cambrian. SSF is represented by the findings Lenargyrion knappologicum, Hyolithellus vitricus, Archiasterella pentactina, Arch. robusta, Torellella sp., Allonia sp., Monospinites piriformis, Stellispinella sp., Siphogonuchites sp.

As a result of this work was extended faunistic description of studied section with new findings of SSF and identified five biostratigraphic units in rank of beds with SSF: Lapworthella tortuosa, Lapworthella bella, Mobergella radiolata, Rhombocorniculum cancellatum, Microdictyon effusum-Lenargyrion knappologicum which can be traced in sections of the Lower Cambrian of Anabar-Sinsk Facies Region of Siberian platform.

References:

1. Demokidov, K.K. Dividing Sinian and Cambrian deposits of the North Siberian Platform // Bull. Scientific and engineering. Inform. (Ministry of Geology and mineral resources of the USSR). M: Gosgeoltekhizdat, 1957, № 5/10, p.3-6.

2. The Cambrian of Siberia / Repina, L.N., Rozanov, A.Yu. (Eds.). Novosibirsk: Nauka, 1992. 135 p.

3. Missarzevsky, V.V. The oldest skeletal fossils and stratigraphy of the Precambrian-Cambrian boundary strata. Moscow: Nauka. In 1989. 238 p. (Trans. Geol. Inst. AN USSR, vol. 443).

4. Novozhilova, N.V. Problematic skeletal remains from the Lower Cambrian of the Northeastern Siberian Platform // Trans. of the All-Russian Youth Scientific Conference with the participation of foreign researchers "Trofimuk’s Readings - 2011", Novosibirsk, 2011, p. 203-204.

5. Repina, L.N. Lazarenko, N.P., Meshkova, N.P., Korshunov, V.I. et al. Biostratigraphy and fauna of the Lower Cambrian of Charaulach (ridge Tuora-Sis). M: Nauka, 1974, 299 p.