What is the size of these forms

Bandana:

Looks like organic walled microfossil (? Pollen or Spore) of Late Maastrichtian age. As suggested by Dr. Dogra, put a magnification scale and details / frequency of associated palynofossils.

Best

Syed

Do they look like foraminifers?? Can you throw some light on the rock formations in which they occur and their depositional environments. Hope the intertrappeans are fresh water sediments.  

The morphs seem to be organic walled  microfossils  most  likely microforaminiferal tests. Scale bar, lithology of sediments and depositional environment(if already calibrated using other proxies) may help ascertaining the identity of these morphs.

Mohammed et al.:

Intertrappean sediments are here of Latest Maastrichtian age and environment is essentially Lacustrine with higher Salinity. We have requested for magnification and details of frequency and associated palynomorphs for identification of these forms. Tests of Foraminifera are ruled out as the sample must have been subjected to acid treatment.

Best

Syed

These fossils are from intertrappean chert of central India. They are of 50-60 micron in size. No palynomorphs or micro organism were found associated with these fossils. Some gastropods are present in chert. Depositional environment is lacustrine.

Alright! But very often foraminiferal linings are seen in palynological preparations after usual acid, alkali treatments. I request Dr. Samant to take some more photographs, preferably under phase contrast microscope  for better understanding of the morphs. In both the figures wall character is conspicuously different from atectate/tectate sporoderm of spore/pollen . Although, these morphs have some superficial resemblance with the polyads of Fabaceae(Acacia spp.). 

Cordially

Subir Bera

Bandana:

How did you isolate the specimens from the Chert? Subir may be right that some resemblance is suggested with polyads of Acacia etc. or Hippocrateceae (Hippocratea volubilis) See link:

http://sofia.usgs.gov/publications/papers/pollen_atlas/plate21-23.html

Best

Syed 

Bandana,

It looks like Pollen or Spore.

Best,

Hakima

the opening at the right of the second picture  suggests some kind of acritarch or dinoflagelate.

The fossils are polyad pollen grains belonging to the Genus: Polyadopollenites,( of Eocene and younger age) found in deposits of that age in Nigeria including the Niger Delta. Also found and formally named  by Salard-Cheboldaeff, M., 1981-Palynologie Maestrichtienne et Tertiaire du Cameroun: Resultats botaniques. Review of Palaeobotany and Palynology, vol. 32 pp. 401-439. from the sedimentary basin of Cameroun.

All the best.

Obianuju P. Umeji

Thanks a lot for comments and suggestions.

Bandana

Bandana:

You need to take a stand on this form recovered from Intertrappean Chert. Do you agree with the identification of Obianuju and whether you could expect this form to occur in Late Maastrichtian?

Best

Syed

Polyadopollenites grains I did recover from infratrappeans too long back.I have not given much weightage to these findings, for it was in association with Maestrichtian assemblage . I considered Maestrichtian assemblage  indigenous to infratrappeans..Also a huge difference in the state of preservation was clearly visible in Maestrichtian palynobiota and Polyadopollenites, the former being thermally mutured and the later with no indication of thermal maturation hence, ignored. Thermal maturation in the grains recovered by Bandana from intertrappeans does not appear to the level as I have seen in the intra-and intertrappean palynobiota so for.

NND:

Did you also recover them from Chert? What age did you assign to the INFRATRAPPEAN sediments? Irrespective of Thermal maturation, would you kindly document a few specimens from Infratrappeans (?Formation). The specimens of Bandana are of Latest Maastrichtian age and recovered from Cherts. This appears to be an important find requiring further research.

Best

Syed

organic walled fossils are microfossils (especially palynofossils) whose outermost covering, that is, exine or cyst wall is made up of organic matter- called sporopollenin (a most resistant material in the organic world) such as, fossil spores, pollen grains, dinoflagellates, acritarchs, chitinozoans etc. These remains are resistant chemically and durable physically that's why they constitute the oldest record of life on the earth,