Palaeoenvironmental and taphonomic biases in palynological assemblages preserved in amber versus sediments from the Umarsar Lignite, Kutch Basin, Gujarat, India

ABSTRACT

Indian Eocene amber, like other dammar-type fossil resins, has a unique feature where inclusions are easily extracted with organic solvents. This allows for a comparison of palynological assemblages embedded in the amber with those in associated sediments. Pollen assemblages extracted from the amber are rich with diverse angiosperm flora dominated by Liliacidites sp., Palmidites elongatus, Palmidites naviculus, Monocolpopollenites sp., Proxapertites cursus, Proxapertites sp., Albertipollenites crassireticulatus, Polybrevicolporites cephalus and Dipterocarpuspollenites retipilatus. Besides, pteridophyte spores, bryophytes, algal and a variety of fungal. In the associated sediments, mainly represented by clays carbonaceous shales and lignite, pollens are less diverse and poorly represented (nearly 23%). Palynological assemblages were recorded in both amber and in the sediment samples, but the palynological assemblage extracted from the amber is more diverse and better preserved. Resin, on the amber-producing trees, was able to intercept pollen from the full forest column from the canopy to the upper canopy to the soil to a taphonomic bias in comparison to sediment-derived palynological assemblages. The exceptionally well-preserved and diverse amber flora exhibits a tropical humid moist environment and shows the existence of Palm and Dipterocarpaceae-dominated deciduous forest (including herbs and shrubs) along with other mixed angiospermic, pteridophytic and bryophytic vegetation, growing near the seashore.

KEYWORDS:

• Amber biota
• Naredi formation
• early Eocene
• bio-diversity
• Western India

Highlights

• Amber flora and fauna in early Eocene Kutch basin, Gujarat are reported for the first time.

• Documented (amber embedded/extracted) biota are richly diversified.

• Thirty-one Palynofloral taxa and some insect remains are extremely significant.

• The composition of the recorded organisms is closely similar to Cambay amber, India.

• Recorded amber biota indicates marginal marine dense evergreen low land rain forest.

Acknowledgments

Author is thankful to the Director, Birbal Sahni Institute of Palaeosciences, Lucknow for granting permission to publish the data (BSIP/RDCC/80/2018-19). I am grateful to Dr. R.K. Saxena (Former head, Tertiary Palynology Division, BSIP) for his constructive suggestions. Sincere appreciation is expressed to Mr. H.O. Selvanayagam (Manager, GMDC, Ahmadabad), Mr. B. K. Mahto (Senior General Manager), Mr. A. K. Dani (General Manager), Mr. Rakesh (Safety officer) and Mr. P.S. Shaktawat (Senior Geologist), GMDC Umarsar lignite mine (Kutch) for their kind support during field visit. This work has been benefited from the financial support by Science and Engineering Research Board (SERB) New Delhi (Project No. EEQ/2016/000112) is acknowledged. Grateful thanks are also due to Mr. Sumit Singh Project Assistant for processing the samples and Dr. Subodh Kumar for SEM photography.

I thank the Editor-in-Chief and anonymous reviewers for critically reviewing the manuscript and giving constructive comments and suggestions which significantly improved the quality of this article.

I wish to dedicate present work to my beloved elder brother late Shri Ram Singh Rana in his memories who was kind supportive for the development of science.

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:

The authors declare that them have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Additional information

Funding

This work was supported by the Science and Engineering Research Board, Department of Science and Technology, New Delhi, India [Project No. EEQ/2016/000112].