1995-96 - Birbal Sahni Institute of Palaeobotany

BSIP
Objective To record distribution of Precambrian microfossils in
Proterozoic succession of Cuddapah, Kaladgi and
Bhima basins
Morphotaxonomical work on the organic remains has been completed. Data pertaining
to size, shape and nature of the remains have been generated. The circular, discoidal
forms range from 1.00 to 10.00 mm. The filamentous forms show maximum length of
40 mm and width ranges from 0.5 to 5.00 mm. A terminal disc like structure, incipient
segmentation and akinites like inflated cells have been noticed in several filamentous
forms. Scanning electron microscopic work on the skeletelised remains from the Sahabad
Limestone Formation have been undertaken. Trace fossils and organic remains are assessed
for their biostratigraphical significance. Work on the problematic forms is under progress.
The major achievement of the work is the maiden record of shelly fauna from
Sahabad Limestone Formation. Besides, a trace fossil zone has been identified in Halkal
Shale Formation of Bhima basin during field work. Similarly organic remains akin to
Chuaria have been collected from Owk Shales Formation, Kumool Group. The study
indicates that the sediments are deposited betwcen Vendian and beginning of the Cambrian.
On the basis of present set of data on the Bhima Basin it can be concluded that the
sediments belong to latest part of the Terminal Proterozoic.
Manoj Shukla & Mukund Sharma
Programme 1.3
Objective
Calcareous skeletal algae from Indian Phanerozoic
sediments
To study the morphology of skeletal algae and
their significance in biostratigraphy
Thin sections of coralline and nodular limestones were studied from the Turonian of
Bagh beds (Dhar District, Madhya Pradesh) and it was observed that in relation to the
study of calcareous algae, only the samples of coralline limestone were productive,
whereas the nodular limestones were barren. Coralline limestones collected from the limestone
quarry of Ghursal Village, Zirabad, Sitapun, Baria, Sukar Nala and Dhanora localities
of Man River Section (Dhar District) yielded skeletal algae, chiefly belonging to
Dasycladaceae alongwith the association offaunal remains like echinoid spines, bryozoans
and foraminifers. The algal taxa identified are Neomeris, Linoporella, Halimeda, Bouenia,
Acicularia, Neomizza and Cymopolia.
While examining the thin sections of coralline limestones for the study of algal
assemblages from the Bagb beds, in a number of cases it has been noticed that
misidentification gt other skeletal remains like echinoids, bryozoans, ostracodes and foramInifers
as skeletal algae was done previously. An improved technique using petrographic
study (by polarising microscope) and specific carbonate staining have been employed to
solve the problem of misidentification. According to the present observation restoration of
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